Roger A. Sedjo
Resources for the Future, Washington, DC 20036, USA
High yield industrial forest plantations have existed in many regions of the globe for about four decades. This presentation will examine some of our experiences with forest plantations over that time. Additionally, the past and potential impacts of plantation forestry on the U.S. and global timber supply will be examined. Prospects domestically and abroad will be addressed. Finally, likely future innovations in plantation forestry, including biotechnology, will be examined.
Fazil Selek
41001-Izmit, Turkey
As a fast growing and easily processible raw material, poplar is an important tree species that offers the possibility of meeting the growing demand for wood raw material in Turkey. The main purpose of poplar cultivation is to obtain a great amount of wood material with high technical properties in a short time. The aim of this study is to examine the types and life cycles of the harmful Lepidoptera species of poplar plantations around Izmit and Adapazari provinces. First, all available literature was reviewed to obtain knowledge about the species that exist in this environment. Secondly, planned periodical surveys of the biology and damage of these insects were carried out. The adults collected from fields and obtained in the laboratory were identified by the help of experts. Their morphologies, biological stages, and their damages on poplars were also examined. As a result of this study, 21 harmful Lepidoptera species, which belong to 9 families, living on poplar around Izmit and Adapazari provinces were determined and are listed below: Family Phylocnistidae, Phylocnistis suffusella Zeller; Family Tortricidae, Archips rosana (Linnaeus) and Gypsonoma dealbana (Frölich); Family Aegeriidae, Aegeria apiformis Clerck and Paranthrene tabaniformis (Rott.); Family Noctuidae, Apatele psi (Linnaeus), Catocala elocata (Esper), Nycteola asiatica (Krulikovskii), and Scoliopteryx libatrix (Linnaeus); Family Lymantriidae, Leucoma salicis (Linnaeus), Lymantria dispar (Linnaeus), and Orgya antiqua (Linnaeus); Family Arctiidae, Hyphantria cunea (Drury), and Phragmatobia fuliginosa (Linnaeus); Family Notodontidae, Cerura vinula (Linnaeus), Pheosia tremula Clerck, Pygaera anastomosis (Linnaeus), Pygaera curtula (Linnaeus); Family Lasiocampidae, Malacosoma neustria (Linnaeus); Family Sphingidae, Smerinthus populi (Linnaeus).
Shengzuo Fang, Xizeng Xu, Xiang Yu, and Zhengcai Li
Faculty of Forest Resources and Environmental Science, Nanjing Forestry University, Nanjing 210037, China
Poplars are the major tree component of the traditional agroforestry system throughout the south temperate central area of China, which includes all or portions of Jiangsu, Anhui, Zhejiang, Hubei, Henan, Shandong, and Shanxi provinces, an area of roughly 600,000 km2. However, lack of experimental data or basic information on interplanting is a serious gap in our knowledge, and consequently, a stable, optimal poplar-crop interplantation pattern is hard to achieve. To develop such a pattern that is economically viable, environmentally sound, technically workable, and socially compatible, some new poplar-crop interplanting patterns were designed and established using the principle of edge effects in 1992. Six spacing were designed in the experiment with narrow-wide spacing pattern, i.e., I: (3x3) x 20 m, II: (3x3) x 30 m, III: (3x3) x 40 m, IV: (4x4) x 20 m, V: (4x4) x 30 m, and VI: (4x4) x 40 m, and the block arrangement was made at random. Based on a 7-year investigation, this paper mainly tests the difference of these new patterns on temporal and spatial variations in microclimate in various phenological phases of winter wheat, variations in wheat yield and wheat quality, biomass productivity, and light-use efficiency. An economic assessment and the potential viability of these new patterns are also discussed in the paper. These preliminary results can provide some basic principles for developing optimal poplar-crop interplantation patterns in the plain areas of China.
D.S. Sidhu
Department of Forestry and Natural Resources, Punjab Agricultural University, Ludhiana-141 004, Punjab, India
The Forest Research Institute of Dehra Dun (India) began introducing Populus species/clones as early as 1950. These species/clones were distributed in many agroclimatic regions to test their adaptability and growth performance. Clones G-3 and G-48 (Australian origin) of P. deltoides have been widely adopted by farmers of the north-western parts of India under agroforestry systems. In Punjab, systematic introduction of P. deltoides clones began in 1987. Since then, about 300 different clones originating in Australia, the United States, the United Kingdom, Italy, West Germany, and India have been introduced for evaluation and further selection. All of these clones are being maintained in germplasm at Punjab Agricultural University, Ludhiana. These clones were introduced in 11 groups, and each group was/is being tested consecutively for 3 years in the nursery. Some clones showed remarkable growth, significantly better than the control (G-3). Such clones were put under five field testing trials in different agroclimatic regions of Punjab. Periodical observations on tree height, diameter, and susceptibility to insect pests were recorded. On the basis of growth performance and resistance to insect pests, the Research Evaluation Committee (REC) of Punjab Agricultural University recommended the commercial cultivation of seven clones (PL-1 to OL-7; four for the central plain region, two for the semi-arid region, and one for both regions) in Punjab. Some other clones even outperformed these in other testing trials. These are expected to be recommended for commercial cultivation by the REC of the University. There were clone x site interactions. Some clones outperformed on specific sites, and others showed genetic stability and their performance was very good on all sites. The results of the study have been discussed in the light of genetic superiority, genetic stability, and genotype x site interactions.
Ziya Simsek
Faculty of Forestry, University of Ankara, 182000, Cankiri /Turkey
This study was done to determine the order Lepidoptera species in Cankiri Forest Nursery between May and September 1999. This area is 97 ha and its altitude is 760 m. Populus x euramericana, Robinia pseudoacacia L., Acer negundo L., Fraxinus excelsior L., Elaeagnus angustifolia L., Pinus nigra Arn., Cedrus libani A. Rich., Ailanthus altissima (Mill.) Swingle, and Morus alba L. have been growing in this nursery. Populus euramericana, Salix sp., Thuja orientalis L., and Quercus sp. have been growing as natural flora in the same area. Pennsylvania type light trap was used for catching the pests and determining their flight period. Adult insects were obtained from the larvae on the infested plants. The relationship between host plants and the Lepidoptera species was established.
In this study 582 moths were identified representing 58 species and 14 families. Moths in the families Arctiidae (9), Geometridae (8), Noctuidae (11), Notodontidae (6), and Sphingidae (9) were captured most frequently. The 58 species were determined in the forest nursery where 25 of them were found to be important or potentially important pests in the forest area. The most important 25 pest species are Arctia caja L., Eilema sp. (Arctiidae), Cossus cossus L., (Cossidae), Elicrinia cardiaria Hbn. (Geometridae), Malacosoma neustrium L., Phyllodesma tremulifolia Hübner (Lasiocampidae), Euproctis chrysorrhoea L., Leucoma salicis L., (Lymantriidae), Agronicta megacedphala F., Dysgonia algira L., Earias chlorana L. (Noctuidae ), Cerura bifida L., C. vinula L., Pterosoma palpinum L., Notodonta ziczac L., Pygaera curtula L. (Notodontidae), Saturnia pyri Schiff. (Saturnidae), Paranthrene tabaniformis (Rott.) (Sesiidae), Hyloicus pinastri L., Laothoe populi L., Smerinthus kindermanni Lederer, S. ocellatus L. (Sphingidae), Thaumetopoa pityocampa (Schiff.) (Thaumetopoeidae),Gypsonoma dealbana (Fröl.), and Tortrix viridana L. (Tortricidae).
The other 33 species were found to be harmful on orchards, herbs, and annual plants. They were Diaphora mendica L., Epatalmis casearea Goeze., Epicallia villica L., Lithosia quadra L., Phragmatobia fuliginosa L., Phrogmatobia placida Frivaldsky, Tyria jacobaeae L. (Arctiidae), Ethemia bipunctella F. (Ethemiidae), Acidaria decorata [D-S], Aplocera plagiata L ., Calothyanis amata L., Opisthograptis luteolata L., Rhodostrophia tabidoria Zeller, Semiothisa clathrata L., Timandra amata L. (Geometridae), Malacosoma castrensis L. (Lasiocampidae), Dysgonia torrida (Guenee), Emmeria trabealis Scop, Hyles euphorbia L., H. nicaea Prunner, Noctua orbona Hufn., N. pronuba L., Polyphaenis subsericata H-S, Triphaena fimbria L. (Noctuidae), Phoesia tremula L. (Notodontidae), Crambus craterellus Scop, C. pinellus L. (Pyralidae), Agrius convolvuli L., Deilophila suellus Stgr., Hyles hippophoes Esp., Macroglossum stellatarum L., Rethera komarovi Christeph. (Sphingidae), and Hedya nubiferana Hw. (Tortricidae) dir.
This study found that Phyllodesma tremulifolia, Leucoma salicis, Cerura bifida, Cerura vinula, Pterosoma palpinum, Paranthrene tabaniformis, Leucoma populi, Smerinthus ocellatus, and Gypsonoma dealbana are the important species in the poplar nursery, but Arctia caja, Cossus cossus, Malacosoma neustrium, Euproctis chrysorrhoea, Hyloicus pinastri, Tortrix viridana, and Thaumetopoa pityocampa are the most harmful species in our forest ecosystem.
H. Sixto1, J.M. Grau1, A. Ferrer2, and F. Gonzalez-Antoñanzas1
1Silviculture Dep. CIFOR-INIA
2Sustainable Use Dep. SGIT-INIA Crta. De la Coruña Km.7, Madrid 28045, Spain
Salinization of soils is a phenomenon that has increased significantly in many parts of the world, proving to be a limiting factor for agricultural and forestry productions in many arid and semi-arid regions. Many areas in Spain, both large and small, are affected in an important way, like the Ebro and Guadalquivir basin. Rusticity and plasticity of white poplar determine a wide geographic distribution in Spain and justify its potential use in ecologically difficult areas where aridity, height, temperatures, or salinity are problems. This work covers, under greenhouse conditions, the response to salt (7 and 14 dS/m) of different clones of P. alba, which belong to a CIFOR collection of this genus with different origins within the territory. Also included are two hybrids from the crossing P. deltoides x P. alba in which the male parent is from south-east Spain; P. euphratica and four clones of P. euramericana (I-214, IMC, Triplo, and Flevo). We considered different parameters (agronomic and physiological) to facilitate the detection of genetic variability in tolerance to salt in poplar, such as percent of survival, height increase, and rate of net photosynthesis.
When the evaluation of tolerance was carried out following the criterion of survival, three P. alba clones (of the same family) showed survival levels of 100% without symptoms, compared to others of the same species that showed sensitivity. P. euphratica and the clones from P. x euramericana showed tolerant and sensitive behaviour, respectively, using this evaluation criterion. When the parameter observed was increased in height, we noticed a significant height reduction in relation to the controls, with the exception of P. euphratica at the lower dose, although the height loss was, in percentage terms, less in those considered tolerant to the survival parameter. The rate of photosynthesis was not seen to be negatively affected for any clone/dose combination 24 hours after the start of the experiment. However, in the middle of the experiment, when poplars had been exposed to salt for a month, it was possible to detect differences in the rate of photosynthesis in clones considered tolerant were clones similar to the controls and clones considered sensitive were significantly different from the controls. At the end of the experiment (2 months of salt) in every case, including P. eupratica, the rate of photosynthesis was reduced significantly, regardless of survival percentage and height increases. The majority of the clones used in this work showed behaviour that is typical of non-halophytic plants in comparison with P. eupratica, which is considered tolerant to difficult conditions, including salinity. However, the variation observed in relations to survival among autochthonous clones of P. alba and hybrids of P. deltoides x P. alba demonstrated variability within the species that can be used in both the selection of adaptive characters, such as tolerance to salt, and in the possible reforestation of areas affected by this problems.
Jeffrey S. Skinner, Caiping Ma, Richard Meilan, and Steven H. Strauss
Department of Forest Science, Oregon State University, Corvallis, OR 97331-5752, USA
Genetic engineering of sterility provides a means to greatly reduce transgene spread into the environment. One means of engineering sterility involves the use of a floral-specific gene's regulatory region (promoter) to direct the expression of a cytotoxin to developing floral organ primoridia, preventing the development of flowers. Based on several years of field trials with several dozen lines of transgenic poplars, we found that heterologous floral promoters caused reduced growth when fused to the barnase or DTA cytotoxins. We have therefore searched for floral genes from poplar whose promoters direct strongly floral-specific expression. We isolated a number of floral homeotic genes homologous to the well-known Arabidopsis genes LEAFY, AGAMOUS, APETALA1, and APETALA3 from Populus trichocarpa (black cottonwood). One of these genes, PTD, which is highly homologous to the Arabidopsis gene APETALA3 and the Antirrhinum gene DEFICIENS, had expression specifically confined to floral tissues based on gel-blot and in situ expression analysis, suggesting that its promoter would be useful for engineering of cytotoxin-based sterility. To test this hypothesis, the PTD promoter was used to direct expression of a reporter gene and cytotoxin in transgenic Arabidopsis, tobacco, and early-flowering poplar (poplar co-expressing 35S::LFY). The reporter was specifically expressed in a subset of floral tissues in each plant type, suggesting that the PTD promoter would be useful in diverse species. In Arabidopsis, 63 of 69 PTD::DTA lines failed to flower or display arrested petal and stamen development and were self-sterile. Petals, stamens, and carpels were ablated in all 18 PTD::DTA lines of tobacco that flowered. In 35S::LFY transformed poplar, the frequency of flowering decreased from 90% (18 of 20 lines) in plants containing 35S::LFY alone to 10% (1 of 10 lines) when PTD::DTA was also present. Results will be presented on the phenotypes observed, and the remaining challenges for using this gene in constructs intended to provide stable, long-term sterility in poplar.
J. Smesrud, J. Dickey, S. Asare, A. Cox, A. Lanier, J. Jordahl, and M. Madison
CH2M Hill Inc., Portland, OR 97232-2146, USA
The use of hybrid poplar is increasing for application in plant-based wastewater reuse systems. In the system described, a hybrid poplar plantation received primary treated landfill leachate as applied by microspray irrigation. The site is located in McMinnville, Oregon, USA and has been operated with leachate application for seven growing seasons, beginning in 1993. In every year of operation, monitoring of nutrient and metals concentrations in leachate, groundwater, soil pore water, bulk soil, and leaf tissue has been conducted to aid in irrigation management. The primary environmental objective of site management has been to avoid any degradation of groundwater quality as a result of leachate constituents percolating out of the root zone and towards underlying groundwater. Because the leachate contains high concentrations of ammonia, nitrogen transport in the soil, plant, and groundwater system is of particular concern. Monitoring results indicate that there has been no degradation of groundwater during operation of the leachate reuse system. Nitrogen (N) concentrations in soil have increased over time in the upper root zone but have been attenuated before being leached out of the influence of tree roots. Although soil pH has remained fairly constant over time (6.4 +/- 0.72), soil cation exchange capacity (CEC) has decreased from 31.4 meq/kg in 1993 to 14.9 meq/ kg in 1999. This trend may indicate a gradual saturation of exchange sites over time. In 1997, an additional leachate pretreatment process, breakpoint chlorination, was implemented to reduce N concentrations so that a greater volume of leachate could be applied to the fixed capacity poplar tree reuse system. This process introduced a significant quantity of sodium (Na) and chloride (Cl) into the plant-soil system. Although no impact to groundwater was detected, Na, Cl, and total dissolved solids (TDS) concentrations in soil pore water did increase substantially in 1997, 1998, and 1999 as compared to previous irrigation seasons. In general, the poplar tree system was effective in the sequestration of leachate constituents, and the objective of beneficially reusing the wastewater while preventing any negative groundwater quality impact was achieved. However, long-term operation of this site should address the issues of decreasing CEC and increasing Cl, Na, and TDS.
Song Baoming, Wang Mingzhi, Gaozhihua, Li Yujun, Reng Xiangcheng, Zhang Weidong, Wang Yuxia, Zhou Ruixiang, Feng Zhengfu, Yu Guosheng, Chen Shao, and Pierre Sigaud
Research Team of the Project GCP/CPR/009/BEL on Nursery and Afforestation Techniques, Tongliao, Inner Mongolia, China
Comparing the survival rate and growth increment between the Medium-Depth Planting (MDP) and traditional planting methods, it is noted that significant differences in survival and increments exist between the two methods. Research shows that the Medium-Depth Planting technique is suitable for Korqin Sandy Lands. Comparison trials on different planting times, different stock types, and different treatments have been established. The results show that 2-year-old stock is better than 1-year-old stock; if planting in spring, stock must be buried underground during the previous winter.
Konstantinos Spanos, Paulos Koukos, and Georgios Giakzidis
N.AG.REF. - Forest Research Institute, 57006 - Vassilika, Thessaloniki, Greece
This paper presents the first results on growth, measured as diameter at breast high (dbh), of ten 1-year-old poplar clones, established in an experimental planting at spacing 1.0 x 1.0 m in the forest nursery of Strymonas. The clones were planted as cuttings. The 10 tested clones were the following: a) Italian clones: I-74/76, I-77/74, I-81/74, I-102/74, Belloto, Tiepolo, CIMA, I-214, I-45/51, and b) Greek clone: He-X/3. The aim of this work is to study the biomass production (fresh/dry matter, tonnes/ha) at age 3-4 years (rotation period).
The results of the first growth period (1997) showed that diameter growth (dbh) differed significantly between clones. Data analysis proved that clone I-45/51 had the highest diameter growth (2.4 ± 0.40 cm i.e. mean ± standard error) and clone I-214 had the lowest growth (1.8 ± 0.35 cm). The growth of the other poplar clones ranged between these two values (CIMA: 2.3 ± 0.28 cm, I-74/76: 2.2 ± 0.34 cm, He-X/3: 2.2 ± 0.34 cm, Tiepolo: 2.2 ± 0.37 cm, I-81/74: 2.2 ± 0.31 cm, Belloto: 2.1 ± 0.31 cm, I-77/74: 2.1 ± 0.32 cm, I-102/ 74: 1.9 ± 0.30 cm). Results also demonstrated clone I-214 which is widely used in poplar plantations is less productive in narrow spacing (1.0 x 1.0 m) compared to other clones. Furthermore, since diameter growth is correlated well with biomass production, it is implied that the growth of dbh can predict the production of biomass of the tested poplar clones.
Marijke Steenackers, Tine Maes, and Pierre Van Peteghem
Institute for Forestry and Game Management, Gaverstraat 4, 9500 Geraardsbergen, Belgium
The watermark disease caused by the bacterium Brenneria salicis (formerly Erwinia salicis) is of significant concern wherever arborescent willows are grown or occur naturally. A research program was set up in order to discover a suitable identification and detection method for B. salicis. We derived primers from the nucleotide sequence of the 16S rRNA gene of B. salicis for the development of a PCR to detect this pathogen. One set of primers, Es1a-Es4b, directed the amplification of a 553-bp fragment from B. salicis genomic DNA as well as B. salicis cells. The minimum number of cells that could be detected from the vascular fluid of willows was 20 CFU/ml. The PCR assays proved to be very sensitive and reliable in detecting B. salicis in willow plant material. In the willow selection and breeding program at the Institute for Forestry and Game Management (IFG), emphasis is placed on the establishment of a gene bank and on the selection of clones resistant to diseases, especially to watermark disease, and with a high growth potential. Through the years, a collection was built, containing about 800 indigenous tree-forming willow clones, 80% of them belonging to the white willow species (Salix alba), crack willow species (Salix fragilis), and their interspecific hybrids. During recent years, the basic collection was screened using the PCR-based detection method for B. salicis. Up to 78% of the nursery trees were contaminated with the bacteria, without showing external disease symptoms. First results will be presented.
M. Steenackers, B. Michiels, and J. Van Slycken
Institute for Forestry and Game Management, Gaverstraat 4, 9500 Geraardsbergen, Belgium
Poplar breeding in Belgium was initiated in 1948 by Swedish Match to develop fast-growing clones for match production. Since then, several vigorous hybrids have been selected by crossing P. deltoides Marsh. with the endogenous P. nigra L.[P. x euramericana (Dode) Guinier] or with P. trichocarpa Torrey & Gray[P. x interamericana]. The basis for this breeding program is a collection of several hundred clones of P. nigra, P. deltoides, and P. trichocarpa.
Since 1980, the resistance of most of the commercialised clones to Melampsora larici-populina has broken down. This has led to the identification of five main pathotypes of the rust species. However, several poplar clones, belonging to different species and hybrids, have remained tolerant to the different pathotypes. This paper presents an actual situation of poplar resistance to M. larici-populina and discusses future strategies for poplar resistance breeding.
Charles T. Stiff1 and James A. Eaton1
1Stiff Applied Technology Inc., Olympia, WA, USA
2Potlatch Corporation Hybrid Poplar Program, Boardman, OR, USA
Potlatch Corporation's hybrid poplar program at Boardman, Oregon, USA is testing various clones for potential fibre supply and the production of solid wood products. Clones are being tested using a randomised design with four replicated plots per clone in the clonal test, and three replicated plots per clone in the spacing test. Each replicate is physically arranged as seven plots deep and six plots wide. Each plot has 49 trees of the clone assigned to that plot, planted at 7 x 7 trees. All plots were hand-planted in 1993 and have received the same cultural treatments. Cuttings in the clonal tests were planted at 10 x 8 foot spacing, and cuttings in the spacing tests were planting at 10 x 8, 10 x 10, and 10 x 12 foot spacing. Water and nutrients were supplied during the past 7 growing seasons using a drip irrigation system. This study will report growth and yield differences for a 7-year-old DxN clone grown at three planting densities (363, 436 and 544 trees/acre).
In January 2000, 7-year-old trees were destructively sampled on the clonal and spacing test sites using stem analysis techniques. Data analyses will be completed by mid-April 2000. We will report our growth and yield results on the three spacings at the IPC 2000 conference in September 2000.
Steven H. Strauss, Richard Meilan, and Stephen P. DiFazio
Department of Forest Science, Richardson Hall, Oregon State University, Corvallis, OR 97331-5752, USA
From a biological viewpoint, poplars are the ideal species with which to introduce genetically modified (GM) trees into forest plantations. Based on transformability and the availability of genes that confer traits valued by growers, GM trees could now be in commercial use. A number of laboratories have demonstrated normal growth and morphology of transgenic poplars in field trials of commercial clones, and the genes used-herbicide resistance, insect resistance, and modified wood chemistry-could each be of substantial economic value. However, questions remain about potential impacts of genetically engineered poplars; and economic, political, and social factors have converged to push the timeline for deployment in most countries back several years. Most significant is the strong political reaction in much of the developed world against GM food crops. They are effectively banned in many parts of Europe, and public outcry is growing in the USA and other countries. In all places, the dissent has been led by environmental and consumer activist organisations that believe that food and environmental safety issues have not been adequately addressed. Some groups, however, are against GM in any form for ethical or political reasons.
Distortion of scientific information has been a key tool of activists against GM crops. On a number of occasions preliminary results have been blown far out of proportion to their scientific meaning. A key element of concern derives from the control of GM crops by a few large, multinational companies that clearly are using them in a very aggressive manner in their businesses. The combination of a novel technology that produces food and environmental safety concerns, and that stands to restructure economic power in global agriculture, has created a great deal of unease over the adequacy of government controls. The GM controversy has engaged forestry, mainly prompted by a report issued by the Worldwide Fund for Nature in 1999 (http://www.panda.org/ resources/publications/forest/gm-overview.html). The report reiterates a number of scientific challenges for use of GM crops, well known to practitioners for many years. But it also suggests, without evidence, that dangerous releases are happening, and that a moratorium on field trials is therefore needed. The main consequence of the report has been to further polarise discussions of GM trees, bringing the kind of disorder that has plagued Europe to bear on the public discussion about GM trees within the global forestry community.
To go forward with transgenic poplars in the developed world, we believe that companies doing research and considering deployment will need to be more transparent and co-operative than they have been in the past. If the public is to consider these new kinds of trees entering the environment on a large scale, they will need to be informed fully and given a chance to comment, and will likely need to be convinced that there will be broad economic benefits that go beyond those that accrue to a select few multinational companies. Second, more research on potential environmental effects and means to mitigate them, and eventual monitoring of plantations, will be needed. Most critical will be avenues to reduce the spread of genes via sexual reproduction because "biopollution" is likely to be the most important, and most recalcitrant, environmental and public concern. Finally, more field research is needed to assess the long-term stability of transgenic traits in the face of environmental variation, particularly for biosafety-related traits like sterility, and to estimate the frequency with which somaclonal variation might have latent effects on clonal yield and adaptability.
Su Xiaohua1, Zhang Xianghua1, Li Jinhua1, Zhang Qiwen1 and Zheng Xianwu2
1The Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091
2Institute of Genetics, Academia Sinica, Beijing 100101
In the present study a three-generation Populus deltoides(R)xP. cathayana(S) hybrid poplar pedigree, comprising F and F progenies, was used to investigate the genetic control of resistance to Alternaria alternata (Ala). The susceptibility of parents, F and F to Ala was tested in both the greenhouse and the field. The results suggested that the resistance may be determined by a single recessive gene for P. deltoides. To identify the markers linked to Ala resistance, using RAPD markers, in combination with bulked segregant analysis, we analysed approximately 4200 selectively amplified DNA fragments using 400 primers and identified two markers linked to this resistance gene. The results are the basis for molecular marker assisted selection and early identification of disease resistance varieties.
Francisco Tapia F., Gabriel Bascur B., and Carlos Covarrubias Z.
Agricultural Engineers, M.Sc. CRI La Platina, INIA Santiago, Chile
To maximise the use of soil in a forest of poplars to develop agro-forestry poplar-crops, the effect of the crop's planting space to the trees was evaluated through the productivity of the crops and growth of the poplars. In the clone I-488 in the first and second year of the plantation, established at a density of 278 trees/ ha (6 x 6 m), crops planted three distances from the poplars (0.5, 0.75, and 1.0 m) were studied. The crops included annual species like onion, tomato, sweet corn, corn, green beans, dry beans, potato, and wheat were studied. The productivity of the crops was evaluated by yield and leaf area; in poplars, diameter at breast height (dbh) and at the base of the first branch, and total height and height to first branch were measured. For the agro-forestry system, the incidence of photosynthetic active radiation (PAR), effect on soil fertility, variation of the environmental and soil temperature (30 cm depth), and fluctuations of the water table were evaluated.
The results indicated that the crop yield was not affected when varying the distance to the tree. However inside the agro-forestry system, the smallest planting space produced a significantly greater yield of each species. Regarding tree growth in the first year a significant and positive effect on dbh was observed in crops of onion, potato, and green beans in some distances; however, in the second year, significant differences were not obtained. In relation to PAR, during the first year, the trees did not interfere with incident light on the crops; in the second year, the effect was observed only from spring season when the incident PAR decreased by between 10 and 50%. The antecedents indicate that at least during the first 2 years of plantation, it is possible to establish poplars with associated crops to 0.50 m, maximising the use of soil without affecting the growth of the trees.
P.J. Tharakan, L.P. Abrahamson, D.J. Robison, J.G. Isebrands, C.A. Nowak, T.A. Volk, and E.H. White
State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA
Coppice short-rotation intensive culture systems (SRIC) are being established over large areas in different parts of the world to produce pulpwood, fuel, bioproducts, or firewood. Once the root system is established, the aboveground portion of the trees are cut back to produce vigorous growth through a flush of multiple stems. Coppice systems are known to exhibit superior biomass production potential. This is primarily attributed to efficient photosynthate transport between root and shoot, rapid occupation of land through high leaf area deployment, early bud break and late leaf senescence, resulting in a more efficient use of the growing season. Willows (Salix spp.) and hybrid poplars (Populus spp.) have excellent coppicing ability. Differences between them may be expected in coppicing potential and in post-coppice growth patterns, including biomass production. Although several studies have analysed the phenomenon of coppicing and the associated biomass production potential in willow and hybrid poplars, little has been reported on their differential response to coppicing. In addition, it is of practical interest to study the changes in stem morphology through which post-coppice growth vigour is expressed. A coppice rotation system selection trial of 38 poplar and willow clones was established in central New York State (NY) in 1997. In December 1997, at the end of the first growing season, the trees were cutback at 2-5 cm off the ground to promote coppice regrowth. A suite of tree dimension variables (diameter, height, and number of stems), and stool biomass was monitored in 1997 and 1998. This paper presents an analysis of the effect of coppicing on individual stem dimensions, number of stems, and stool biomass production for willow and hybrid poplar clones and identifies the specific attributes that best explain the variation in post-coppice biomass production rates.
Tingzhen Zhang and Zhan TanTai
Northwest Science-Tech University of Agricultural and Forestry, Yangling, Shanxi, China
Poplar is one of the rapidly growing tree species that are being adopted widely in the world. To culture and select the species that can adapt well in the arid and semi-arid areas in northwestern China, by using conventional breeding methods, Populus alba, P. tomentosa, and Populus bolleana were crossed and produced 150,000 hybrid seedlings. After primary selection, seven better hybrids were expanded to seven clones thereafter.
To depict the growing patterns of the seven clones, the properties of annual growth for every clone were simulated by the logistic equation (Y= k/(1+eA+Bt)) to determine the maximum points of growth rate per day and the fast-growing period. Also, genetic parameters such as the hereditary and genetic variation coefficient of height, diameter and timber volume were estimated, and the results showed that the genetic correlation coefficient among the three parameters was highly significant. To study drought-resistant features, 13 properties related to drought resistance such as stem water potential productivity of transpiration, dry weight per unit area of leaves, the anatomical structure of leaves, PV parameters, leaf water holding ability, and so on, were used to comprehensively evaluate their anti-drought ability by means of standardisation of data range. According to the results, the order of drought resistance was arranged. At the same time, an investigation was made on cold-resistant and anti-pest features of the seven clones to ensure that the very clones we hope to select will also have better adaptability to the environment. In addition, the rooting characters of the seven clones were studied, and the results indicated that there are highly significant differences in the earliest date of rooting, number of main roots, sum of the lengths of main roots, and number of lateral roots in the seven clones.
Taking into consideration all the indexes above (including growth, rooting character, and resistance to adversity), three clones of 96-06, 96-03, 96-07 among the seven clones show better adaptability to an arid environment on the basis of calculation by the AHP (Analytical Hierarchy) method. They are worthy of being popularised and can give some help to develop western China.
Tingzhen Zhang, Chengshe Wang, and Xiaoli Hu
Northwest Sci-Tech University of Agriculture & Forestry, Yangling, Shaanxi, China
The triploids of Chinese white poplar are new poplar varieties that have been widely utilised in north-west China in recent years due to all their good qualities, such as fast-growth, stem pattern, good adaptability, superior timber, resistance to disease and pests, etc. The wood volume of the triploids of Chinese white poplar is as much as two or three times that of common Chinese white poplar (Populus tomentosa) in only 8 years. Effective in vitro multiplication methods were developed for Chinese white poplar due to the recalcitrant response of its cuttings in rooting and to facilitate commercial production. In vitro terminal and auxiliary buds were stimulated on modified MS medium, which seemed to be most adequate for mass production of healthy shoots including 0.3-1.0 mg/litre BA, 0.05-0.1 mg/litre NAA and 0-0.5 mg/litre GA3. Each terminal and auxiliary bud produced more than 10-20 shoots with a length of 3.0 to 8.0 cm within 4 weeks. Calli were induced from leaf and stem explants under dark on modified MS medium with 0.5-1.2 mg/litre 2,4-D and 0.3- 0.5 mg/litre BA or KT 2 weeks later. Shoot differentiation was significant after calli cultures were transferred to modified MS medium containing 0.5 to 1.5 mg/litre BA and 0.05~0.1mg/litre NAA after one month. An average of 10 shoots were derived from each calli within 5 weeks. Multiplied shoots were subcultured on modified MS medium with lower concentration plant growth regulators every 20 days. In vitro shoots were successfully rooted on 1/2 modified MS medium with 0-0.1 mg/litre NAA. Those plantlets with a system of strong roots were successfully transplanted to soil and grew vigorously.
Tongming Yin1, Minren Huang1, Tu Zhongming2, Xinye Zhang1, Mingxiu Wang1, and Rongling Wu3
1Key Laboratory of Tree Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
2Biological Division, National Natural Science Foundation of China, Beijing, China
3Program in Statistical Genetics, Department of Statistics, North Carolina State University, Raleigh, NC 27695-8203, USA
A composite linkage map for Populus was constructed using random amplified polymorphic DNA, amplified fragment length polymorphism and microsatellite markers from a pseudo-backcross progeny population of P. deltoides and P. nigra. A traditional strategy for genetic mapping in outcrossing species, such as forest trees, is based on two-way pseudo-testcross configurations of the markers (testcross markers) heterozygous in one parent and null in the other. By using the markers segregated in both parents (intercross markers) as bridges, the two parent-specific genetic maps can be aligned. In this study, we detected a number of non-parental hetero-duplex markers resulting from the PCR amplification of two DNA segments that have a high degree of homology to one another but differ in their nucleotide sequences. These hetero-duplex markers detected served as bridges to generate an integrated map that includes 19 major linkage groups equal to the Populus haploid chromosome number and 24 minor groups. The 19 major linkage groups cover a total of 2,600 cm, with an average spacing between two markers of 10.5 cm. The map developed in this study provides a first step in producing a highly saturated linkage map of the Populus genome.
Ferit Toplu
Director, Southeast Anatolia Forest Research Institute, 23049 - Elazig - Turkey
This study evaluates the performance of 40 hybrid poplar clones in the first selection clone trial established in the Mediterranean region of Turkey. Evaluations were carried out according to growth (height, diameter), survival, and stem quality (bole straightness) values of the clones at the sixth year of the trial, in 1999. All clones tested in this trial were created as a result of artificial crossing work carried out at Casale Monferrato Poplar Research Institute in Italy during 1983-1984, and then introduced to Turkey. In the crossing work, individuals of Populus deltoides Marsh. (Oklahoma, Texas, Tennessee, Illinois, and Iowa) were used as female and polycross of Populus nigra L. as male partners. The objective of this study is to determine the fast-growing and resistant (to the biotic and abiotic agencies) clones for use in poplar plantations in the region to help meet rapidly increasing demands for wood for local and industrial uses. The experimental site is located in Ceyhan Nursery in the Cukurova plain of the Mediterranean region of Turkey. The experimental design was a randomised complete block with five replications. Forty clones were laid out in row plots represented by four saplings.
According to the results of analysis of variance carried out in 1999, there were significant differences among the clone means in survival (F = 1.628*), diameter growth (F = 5.141***), height growth (F = 2.587***), and bole straightness (F = 3.549***). The top seven fastest growing clones, which have been selected for the second selection clone trial, have 16% higher diameter growth than the site mean. These seven clones have also shown 9% higher height growth, 22% better bole straightness, and 3% higher survival rate over the site mean. In the establishment of the second selection clone trial, P. x euramericana I-214, which is the most widely used clone at poplar plantations in Turkey, will be included as a control clone.
Anatoly P. Tsarev
Petrozavodsk State University, Petrozavodsk, Karelia, Russia
Poplar breeding in Russia has its history and achievements. Most widespread in Russia are Populus tremula L. (~19 M ha) and P. suaveolens Fisch. (~1 M ha). Other poplars that have economic significance (P. alba L., P. nigra L., P. laurifolia Ldb. a.o) grow in river valleys in natural conditions. The first poplar selected in natural forests in the middle of the 19th century was P. tremula L. It was selected for its early opening of buds (P. t. f. praecox) and late opening of buds (P. t. f. tardifolia). Some plants of euramericana hybrids of black poplars were introduced in the country. Many of hybrids were created by home breeders and multiplied in different regions of Russia in 1937-1970. After the organisation of the Central Institute of Forest Genetics and Breeding (1971), the principal investigations of poplar breeding were carried out in the central part of European Russia. The main directions of research were: productivity of stem wood and biomass; quality of stem and wood; resistance to frost, diseases, and pests; environment protection, plant verdure, and some others. There was research on the selection of the best forms and natural hybrids in natural stands, artificial hybridisation, and introduction of best clones from different parts of the Soviet Union and abroad. All these clones, forms, hybrids, and cultivars were collected ex situ, and many of them were tested on special plantations in different parts of Russia.
The most impressive results were found in testing plantations in the central forest-steppe zone (Semiluksky populetum near Voronezh), which was created by the author in 1974 with cuttings on an area of 4.5 ha. The type of growing conditions is D2 , soil-tchernozem; the original area per tree was 20 m2 . The 24 ramets of each clone were planted in four repetitions with randomised spacing. Eighty clones were tested from different sections of poplars:
1. White poplars and their hybrids with pyramidal crown;
2. White poplars and their hybrids with spreading crown;
3. Black poplars and their hybrids with pyramidal crown;
4. Black poplars and their hybrids with spreading crown;
5. Balsam poplars and their hybrids.
The best clones at age 21years in section 1 had 71 m3/ha; in section 2 - 237 m3/ha; in section 3 - 448 m3/ha; in section 4 - 769 m3/ha; and in section 5 - 378 m3/ha. The superiority of the best clones compared to the control was 70% - 250% in different sections. On that and another plantation disease and pest resistance and quality woods were investigated. This research provides an opportunity to determine the potential of the productivity increase of different poplars clones and to use them in poplar plantations of Russia.
Korhan Tunçtaner
Poplar and Fast Growing Forest Trees Research Institute, Izmit, Turkey
Turkey is a significant country in the world for its largely varying climatic and topographic conditions, resulting in wide diversity of forest tree species and ecosystems. But, genetic resources and natural habitats of forest tree species have been continuously impaired in the country. The loss of these resources and the degradation of the land have affected not only the national economy but also the welfare of the people. Therefore, active steps must be taken to conserve and utilise this valuable heritage. In recent years, extensive efforts have been given to conservation, management, and utilisation of existing forest genetic resources in Turkey by the Ministry of Forestry. Great emphasis has also been given to the genetic resources to be used in the establishment of industrial plantations with poplars and fast-growing forest tree species. Conservation and utilisation of genetic resources of poplars have been carried out by the Poplar and Fast Growing Forest Trees Research Institute in Izmit with the co-operation of related departments of the Ministry of Forestry. Planning has been made for in situ and ex situ conservation of autochthonous poplars (Populus nigra, P. alba, P. tremula, and P. euphratica), but the highest priority has been given to ex situ conservation of black poplars (Populus nigra L.), eastern cottonwood (Populus deltoides Bartr.), and their hybrids (P. x euramericana). A collection with 1,100 clones of these three species was established at Izmit nursery stoolbeds in 1996. Various clone banks and clone trials have also been established in different climatic regions with P. x euramericana, P. deltoides, and P. nigra clones. An ex situ conservation program for P. nigra has been in progress under the framework of the European Forest Genetic Resources Program (EUFORGEN).
Intensive culture of poplars is becoming increasingly important as a source of wood and fibre. Therefore, breeding strategies have been developed and implemented to measure, capture, recombine, and exploit the genetic variation of poplars in many countries. Commercial plantations of poplars have considerable economic importance in Turkey for industrial wood production. To release the much more productive hybrid clones for improving the quantity and quality of wood harvested from these plantations, classical breeding programs with P. deltoides and native species P. nigra are in progress. The results of a comparative study implemented in the Marmara Region with 26 P. deltoides clones representing different site conditions in the USA and P. x euramerican clone I-214, showed that some of the clones from the southern USA, produced higher amounts of wood than I-214 did, at the end of a 12-year period of rotation (mai/ha: the best clone of P. deltoides = 45.2 m3, I-214 = 28.8 m3). Similar results have been obtained from other trials with different clones in the Marmara Region. P. deltoides clones have shown considerably high volume increment in an 11-to 12-year rotation period (mai: 25-45m3/ha). In accordance with these results, breeding programs have been concentrated on interspecific and intraspecific crossings of P. deltoides and P. nigra. About 500 hybrid clones obtained from these crossings have been tested at the clone trials. Some of these clones are promising based on the research study of selection and biotechnological improvement of poplars for the paper industry.
Gerald A. Tuskan, Gregg Marland, and Marie Walsh
Oak Ridge National Laboratory, Oak Ridge, TN 37830-6422
The 1997 Kyoto Protocol put forth a set of prescriptions and policy implications designed to reduce current and future levels of atmospheric carbon to a level based on 1990 estimates of individual national carbon emissions. The signatory nations agreed to work toward these goals through reduced emissions of six greenhouse gases and a net positive terrestrial carbon exchange. The legally binding framework, the complexity of the accounting system and the lack of displacement credits, along with domestic politics, contributed to the U.S. decision not to become a signatory nation. However, in recognition of the potential problems associated with elevated CO2 in the atmosphere, the current administration with the support of Congress has funded the Bioenergy Initiative with the goal of increasing the use of bio-based products and bioenergy by 3-fold (over base year 2000) by the year 2010 and 10-fold by 2020. This increase translates to 7.86 Quads by 2010 and 26.2 Quads by 2020, or ca. 7.5% of the total national energy equivalents by 2010 and 22.2% by 2020. There are numerous petroleum-based commodity chemicals, e.g., polylactic acid, furfural, succinic acid, etc., that could be manufactured from biomass. Yet, the world-wide demand for most of these chemicals is individually low, and thus, the largest ultimate contributor to the Bioenergy Initiative goals will be energy. The quantity of bio-based products or energy production created by 2010 will depend upon the cost of the feedstock. At $50 per dry delivered ton, there are ca. 5.55 Quads of net energy equivalents available for use toward the Bioenergy Initiative goals. Most of this resource comes from agricultural, forestry and mill wastes and residuals. Energy crops represent only 1.1 Quads of this new production. To increase energy crop contributions to the 2010 goal and to be able to achieve the 2020 goal, energy crop productivity must increase and production costs must be reduced.
Basic biological research, logistic improvements and policy changes will be needed to substantially increase the economic supply potential from energy crops in 2010. Production economics, i.e., net present value, of short rotation woody silvicultural systems is impacted most extensively by improvements in yield. Silvicultural enhancements such as irrigation and fertilisation do increase yields but at an added economic and energy consumptive cost. Alternatively, more effective weed control and optimised spacing have lower costs and energy consumption associated with their implementation. Optimisation of rotation lengths, spacing and equipment choice will have positive effects on production economics. Likewise, traditional selection for improved growth rates, pest resistance and higher feedstock density result in net positive energy and yield benefits. Optimising the product, co-product and by-product mix through genetic manipulations of individual SRWC plantations could result in positive energy and economic budgets, but the specific improvements will need to be product and site dependent. Fundamentally changing the production system, i.e., changing tree form and silvicultural requirements of energy crops, has the greatest potential for reducing the costs associated with SRWC production. Finally, agricultural and energy policies will need to be changed to allow successful competitive establishment of energy crops as an element in an integrated carbon management strategy.
Sedat Uludag
Poplar and Fast Growing Forest Tree Species, Research Institute, P.O. Box 93, 41001 Izmit, Turkey
The quality of poplar saplings has an important and inescapable place in poplar development programs and in the promotion of these programs. The poplar cultivation programs cover a set of activities such as nursery soil preparation, selection of good quality material, interrow cultivation, pruning, fertilisation, application of parasites, etc. Therefore, to obtain successful results in every stage of nursery activities, special attention should be paid to each of these aspects. Spacing creates an area for the plant to live, grow, and obtain water and minerals from soil. So the selection of the spacing has a special weight in nursery techniques. The machines that are run between rows are important factors affecting the width of the rows. Determination of planting spacing in poplar nurseries was taken from one of the research topics and an experiment was established. The objective of the experiment was to obtain information about the most suitable spacing in the poplar nursery. The experimental design was randomised complete blocks with three replications. The experiment was established in the Ankara Forest Nursery.
Treatments were:
1- Spacing between rows 1.50 m and 1.80 m
2- Spacing in rows 0.20 m, 0.30 m, 0.40 m, 0.50 m, and 0.60 m
At the end of first and second growth periods, diameter and height growth were measured and assessed with the analysis of variance.
The results of Populus nigra (Gazi) obtained are outlined. At the end of the vegetation period, it was seen that different spacing are significantly effective on diameter and height growth on both parcels of 1.50 m and 1.80 m. At the end of second vegetation period, the treatments were effective only on diameter growth in the parcels of 1.80 m. According to the results of analysis of variance and Duncan tests, it was seen that the most suitable spacing on diameter growth were 1.80 m x 0.80 m and 1.80 m x 0.70 m spacing given area of 0.90 m2 and 0.75 m2 per plant. Although no significant results were obtained in the plots of 1.50 m, the best diameter growth was determined in the treatments of 1.50 m x 0.60 m and 1.50 m x 0.50 m. In comparing plots of 1.80 m and 1.50 m, better diameter and height growth were obtained in the treatments of 1.80 m x 0.70 m and 1.80 m x 0.70 m.
Kazim Uluer, Meral Gurer, and Necdet Guler
Poplar and Fast Growing Forest Tree Species Research Institute, 41001-Izmit, Turkey
Cytospora chrysosperma (Pers.) Fr. is one of the most important fungi that causes losses among poplar plantations in our country. This fungus causes bark necrosis on poplars. Samples were collected from the diseased poplar areas, and the Cytospora fungus was isolated. The causal fungus was cultured on PDA (potato dextrose agar) at 22-24º C with a 12-hour photoperiod for 7 days. The isolate 7 (Çerke, near Ankara) was selected as the most virulent one and stored in a refrigerator to be tested as inoculum. Eight 1- and 2-year-old poplar clones were used to determine the susceptibility response to Cytospora according to the Split Plot Design with five replicates on November 19, 1996 and on April 24, 1997. The inoculations were made by puncturing the bark (1.3 m height from ground) with a cork-borer 10 mm in diameter, substituting a culture disc 6 mm in diameter in place of the removed disc, replacing the bark disc on the culture, and then covering it. The cellophane tape was removed 1 month later. Necrotic lesions were measured and dried saplings were counted. The results were evaluated according to analysis of variance. As a result, 77/10, Samsun, and 67/1 were found to be susceptible clones. I-214, Anadolu, and 64/13 were found to be the most resistant ones. Two-year-old saplings planted and inoculated in the spring were the least affected ones. Most of the spring inoculation wounds were overgrown by new callus, but cankers and dieback developed in the saplings inoculated in the fall.
Cytospora was more harmful in poplar plantations than in nurseries. To determine the effects of the factors on Cytospora canker experiments were conducted in Izmit, Torbali, Ipsala, Konya, Isparta, and Altintas, in 1993 for the project "Investigations on Yield Researches of Common black poplar (Gazi)". The observations on Cytospora canker were recorded during 5 years. The characteristics of soil type and climate were determined. As a result, most of the damages were observed in the first year of planting and decreased in the second and successive years. A positive correlation between Cytospora canker and the proportion of clay and lime was found. The fungus damage increased as the days of winter injuries increased and it decreased with rain effectiveness.
F. Ulzen-Appiah, R.D. Briggs, L.P. Abrahamson, and D.H Bickelhaupt
State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
During the past decade, the focus of research in short-rotation forestry (SRF) systems has shifted from feasibility and biomass production to environmental sustainability and productivity. Beneficial attributes associated with SRF (i.e., carbon sequestration in aboveground biomass and soil, conservation of fossil fuels) could reduce atmospheric CO2 enrichment and associated negative impacts on global climate change.
While research has amply demonstrated the capability of SRF for high aboveground carbon sequestration, the capability of SRF to sequester soil carbon needs to be demonstrated. Soil carbon is sequestered in SRF as soil organic matter (SOM), litter and tree roots. The SOM pool contributes significantly to soil fertility. Changes in the SOM pool under SRF management could affect soil fertility, productivity, and system sustainability. Research is needed to determine the long-term effects (either positive or negative) on SOM. Such an effort requires a sensitive and accurate index to monitor SOM changes over time.
There is ample evidence that SOM is composed of a variety of fractions or pools differing in decomposition rates. In a broad sense, two pools are recognised: a labile or actively cycling fraction and a stable or recalcitrant fraction. We hypothesised that changes in SOM in SRF will be reflected in the labile fraction because of the relatively high turnover rate. Soil microbial biomass (SMB) represents a labile SOM fraction, responds rapidly to conditions that alter SOM levels and is a sensitive and accurate indicator of changes in SOM levels. Soil microbial biomass carbon may indicate potential microbial activity and SOM dynamics. This paper presents our assessment of SOM changes using SMB carbon in willow (Salix) and hybrid poplar (Populus) short-rotation intensive culture plantations established in 1995 on three different sites in New York State and sampled in 1997 and 1999.
A. Vandenbroeck, K. Cox, J. Van Slycken, and D. Halfmaerten
Institute for Forestry and Game Management, Geraardsbergen, Belgium
The massive introduction of a small number of P. x euramericana clones and P. nigra varieties is often supposed to be one principal reason for the reduction of genetic diversity in the species Populus nigra, although very few scientific data are available on this topic. In this study, flower phenology, seed production, and contribution of parent trees in the offspring was observed in a mature ex situ stand of black poplar in the framework of the FAIR-project "Genetic diversity in river populations of European black poplar for evaluation of biodiversity, conservation strategies, nature development, and genetic improvement" (Fair5-PL97- 3386). One of the objectives of the project is to provide management tools for both conservation and restoration of wild river populations of black poplar. Flower phenology was observed twice a week during two successive springs (1999 and 2000) in a mature ex situ stand (planted in 1965) containing several male and female trees of Populus nigra. The stand was surrounded by poplars of the species Populus trichocarpa and Populus deltoides. This gave us the opportunity to study the contribution of foreign genes in the offspring of Populus nigra. We observed the start, duration, and end of flowering period of each male and female clone, and the beginning, duration, and end of seed release. Seeds were collected in bulk under the mature P. nigra trees and grown in the greenhouse. We also collected seeds on three females. Viability of seeds and seedlings were assessed and morphological characteristics of the young seedlings were noticed. Isozyme analysis was used to study the introgression of foreign genes in the offspring.
Considerable variation in time of flushing between black poplar clones was observed. P. nigra cv. Italica flushed before the other black poplars observed; this indicates that there might be no danger for introgression from this cultivar in indigenous black poplars in Belgium. Generally P. x euramericana flushed before P. nigra, although there was a lot of variation in flushing time in both species; introgression of foreign genes in P. nigra could not be excluded from this point of view. Although different efforts, like climbing into trees, were made, the quantity of seeds that could be harvested on the females was very low. The difficulties that we experienced in harvesting seeds on the females could be due to some compatibility problems in the mating system within the species P. nigra in this ex situ stand. Seeds harvested in bulk produced only 50% seedlings with morphological characteristics of (pure) P. nigra. Isozyme data (available in July 2000) will give us more information about the number of foreign genes in the offspring of the black poplar stand.
A.Vandenbroeck, J. Van Slycken, D. Halfmaerten, and D. Depraeter
Institute for Forestry and Game Management, Geraardsbergen, Belgium
The European black poplar, Populus nigra L., is a common pioneer tree in riparian forests, ranging from central and southern Europe to central Asia and north Africa. The genetic diversity of the species is thought to be threatened in a number of ways. Two of the most important reasons are: (i) the reduction of perturbed areas due to regularisation of river flows, which decreased the regeneration of trees all over Western Europe; and (ii) the massive introduction of a small number of P. x euramericana clones and P. nigra varieties likely to intercross with wild P. nigra trees, which may lead to a reduction in the genetic diversity of offspring. In this study, gene diversity and differentiation of gene banks of Populus are measured by means of allozyme variation in the framework of the FAIR-project "Genetic diversity in river populations of European black poplar for evaluation of biodiversity, conservation strategies, nature development, and genetic improvement" (Fair5-PL97-3386). One of the objectives of the project is to describe the genetic diversity within ex situ collections and within and between natural populations in order to evaluate the current state of conservation in Europe.
Forty individuals of the P. nigra gene bank of the Hungarian Forest Research Institute Erdeszeti Tidomanyos Intelet (Sarvar, Hungary), 163 of the Belgian Populus nigra gene bank (Institute for Forestry and Game Management, Geraardsbergen), and 25 clones of the EUFORGEN Core collection were sampled. The EUFORGEN Core collection is a P. nigra collection of 42 clones representing the whole P. nigra distribution area in Europe. Seven enzyme stainings were considered revealing 10 loci (IDH-A, PGM, PGI-B, LAP, MDH-A/B, MDH-C, MDH-D, SKDH-A, and MNR) of which 6 were polymorphic (IDH-A, MDH-A/B, MDH-D, SKDH-A, PGM, PGI-B). PGM, PGI-B, LAP, and SKDH-A were useful for identifying species-specific alleles and genotypes of Populus x euramericana.
The highest genetic diversity was observed in the Hungarian Gene Bank (H=0.11) although the relative sample size was small (N=44). Compared with the estimated genetic diversity for the species P. nigra (H=0.18), and considering the sample size, the Hungarian ex situ collection represents a great genetic diversity. The relative high value for H for the Hungarian Gene Bank can be explained by the absence of many rare alleles in the gene bank and an even distribution of the other alleles. The measure of genetic diversity H is described as a measure of evenness, which means that a sample with one frequently occurring allele and three occasionally observed (rare) alleles (a total of four) is less diverse than a sample with four alleles that occur with about the same frequency. The genetic diversity for the Core Collection (H=0.094) is rather small, taking into account the great differences in geographical origin of the genotypes. For the Belgium gene bank (H= 0.038), low genetic diversity was observed, probably due to the long and existing absence of natural populations and the vegetative propagation and multiplication by man of the relict individuals. A first screening of morphological characteristics clearly indicates a great diversity within the Belgian gene bank. This diversity could not be assessed with this isozyme study, the use of other molecular markers will probably give more information on genetic diversity.
R. Van de Velde, J. Van Acker, and M. Stevens
Laboratory of Wood Technology, University of Ghent, Coupure Links, 653, 9000 Ghent, Belgium
To overcome the massive infections of rust diseases and pests, the trend toward polyclonal poplar management is rightly receiving growing interest. The advantages from an ecological point of view have been undoubtedly established, but little has been known about the impact on the industrial processing of clone-mixed poplar packs. In this respect, different clones from Populus deltoides x Populus nigra (Serotina), P. trichocarpa x P. deltoides (Beaupré, Hoogvorst, Hazendans, 69038/1, and 70045/1) and P. deltoides x (P. trichocarpa x P. maximowiczii) were considered together to evaluate the processed end products. The study aimed at investigating the technical and esthetic value of the rotary-peeled veneers of the different clones, the reaction of the veneer to a uniform drying regime, the technical properties of plywood industrially manufactured with the veneers and liquid phenol-formaldehyde resin, and their mutual variation in quality. All stems could be peeled until a core of 10-cm diameter. The clone Serotina from P. deltoides x P. nigra can be considered as the one with the highest yield, significantly higher than the other two hybrids. P. trichocarpa x P. deltoides, for its part, had significantly higher yield than the hybrid P. deltoides x (P. trichocarpa x P. maximowiczii), but shows a lot of internal significant differences among the clones.
Drying is a very delicate step in the production of veneer for plywood. An inadequate drying regime can make the veneer brittle. The overall conclusion can be made that Beaupré produces the largest amount of veneer, with sufficient technical quality and with a high proportion of aesthetically valued white veneer. Also, Hoogvorst scores well on technical criteria, but gives only a minority of white quality A (face veneer). So do Hazendans and 70045/1, evaluated as a clone with average veneer technical quality. It was found that these veneers are brittle, probably due to a non-adapted drying regime, in spite of the positive descriptive comments during the peeling process itself. The clone 69038/1 shows more than 50% of white A quality veneer, which is somewhat brittle. Also, the clones from Populus deltoides x (trichocarpa x maximowiczii) produce 50% faultless white veneer, out of only a moderate production of A/B quality (cross-band veneer). The reference clone Serotina, appreciated for its good technical quality A/B veneer, cannot deliver the desirable white colour. Three-point bending tests on plywood of the different clones will be performed in the near future and results will be presented.
Riet Van de Velde, Joris Van Acker, and Marc Stevens
Laboratory of Wood Technology, Ghent University, Belgium
The aim of this investigation, incorporated into the European project PAMUCEAF, is to identify existing markets for poplar products within the EU states, to study the size of these markets, and to identify novel or underexploited poplar products that might be economically produced on surplus agricultural land. The size of the poplar market as raw material, in terms of current production types, market supply, and prices paid to growers, the industry's quality requirements, and views of the future on profitability, problems, and market trends, were analysed by means of a questionnaire. This was addressed to 50 poplar producers in Belgium. An extension of the results to other European countries is expected in the near future. Additionally, a similar questionnaire was set up for the poplar processing industries, to study the size of the markets with poplar based end products and to estimate actual and potential demand for poplars to produce these end products. The questionnaire handled topics such as company specifications, supply of raw material, and requirements for wood processing, size of the market of the end products, and future views. Seventeen poplar processing companies in Belgium answered the questionnaires; more answers are expected from other European countries.
From the data gathered by the two questionnaires, a wood stream of poplar can be designed for different EU countries, and mutual links can be deduced. An exploratory poplar wood survey for Belgium is illustrated in the poster. It gives an overview from poplar stands, through the poplar processing industry to poplar end product supply, considering the national market as well as the import and export market. From the results, it can be noted that the processed poplar wood mainly comes from the country itself (65%), while 35% of the poplar wood is imported from Germany, the Netherlands, and France. The division into the different poplar-processing sectors will vary from country to country. In Belgium, emphasis is on the processing of sawn timber for packaging material as pallets and cases (70%), and the production of veneer for plywood and packaging (23%) also plays an important role. Besides, the end products mainly remain on the national market. Only 29% are exported to the Netherlands, France, UK, and Germany.
We will use these and other data to demonstrate what the existing supply of poplar means for a country, and what the coupled industry entails. Taking into account existing and potential poplar area and productivity, together with distance limitations, the potential for new industries in countries with a low portion of poplar areas can be regarded. At the same time, potential demand for poplars to produce defined products and their likely value can be estimated. Additionally, modelling this wood stream can let us vary parameters e.g., an increasing (e.g., Ireland, UK, Sweden) or decreasing wood supply, or increasing wood demand worldwide.
R. van den Driessche
Department of Forest Biology University of Victoria, P.O. Box 3020, Victoria, BC, V8W 3N5, Canada and New Dendrology Inc., 2361 Queenswood Drive, Victoria, BC, V8N 1X4, Canada
Four clones of Populus trichocarpa x P. deltoides were fertilised at planting, either by banding along the row or by placing fertiliser beside the cuttings. The fertiliser (18:40:0 + 0.5% Cu, 0.5% Zn) was applied at 0, 100, and 200 kg N and P/ha in the banded treatment and 0, 22.5 g, and 45 g N and P per cutting (equivalent to 0, 25, and 50 kg/ha) in the placement treatment. The six treatments were split to accommodate four clones and randomised in eight blocks. All clones responded strongly to N fertiliser under the cultural conditions that included a weed- free site. Placement treatment increased stem volume 2.7-fold more than banding treatments after 2 years, and was 11-fold more effective in terms of fertiliser cost. N and P uptakes were increased by fertilization in the first two growing seasons, although only leaf N concentration was increased in the first year.
Mike Van Ham1, Lisa M. Zabek2, and Cees van Oosten3
1Sylvis Environmental, Vancouver, BC, Canada
2University of British Columbia, Vancouver, BC, Canada
3SilviConsult Inc., Naniamo, BC, Canada
Culture of cottonwoods and their hybrids in the Pacific Northwest and British Columbia has grown and undergone important changes in recent years - from management on longer rotations to current practices of intensive management on reduced rotations and short rotations for wood and fibre markets, respectively. Through clone selection and stand management practices, including fertilisation, managers have been able to significantly increase plantation productivity. Research conducted in British Columbia has explored fertiliser formulations, placement, and timing of both inorganic and organic fertilisers.
Organic residuals, in particular bio-solids from municipal wastewater treatment plants and primary and secondary sludge from pulp mills and combinations thereof, have been applied to poplar plantations to increase productivity. Research conducted on the use of these residuals as plantation fertiliser has focused on nutrient dynamics, nitrogen supply, and the effect on the trees and the environment. The beneficial use of organic residuals as fertilisers provides a recycling opportunity for municipalities and associated industries, while providing nutrients and organic matter to increase tree growth. The values associated with these plantations include the production of fibre or wood products plus the environmental benefits inherent in providing an alternative to traditional methods of residuals disposal (landfill, incineration). They can also provide values associated with site rehabilitation, habitat enhancement, and non-point source pollution abatement. Concurrent with research leading to operational poplar fertilisation programs has been the development of successful and cost-effective technologies for the application of fertilisers. This presentation will provide an overview of inorganic and organic fertilisation of hybrid poplar in British Columbia. The opportunity for increasing plantations and plantation productivity will be discussed with emphasis on socio-economic and land management issues and practices in British Columbia.
J. Van Slycken1, L. Meiresonne1, Terry Thomas2, and R. Whitaker3
1Institute for Forestry and Game Management, Gaverstraat 4, B-9500 Geraardsbergen, Belgium
2School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, UK
3Cae Ffos, Treborth Road, Bangor, Gwynnedd, LL57 2RJ Wales, UK
The productivity of poplar clones can vary strongly according to site conditions. A detailed study of the interaction between site and productivity of two Belgian clones Ghoy and Beaupré has been carried out. For the clone Ghoy the study was done on a country scale; the clone Beaupré was studied on a European scale. Sixteen experimental plantations of the clone Ghoy, aged between 15 and 20 years and distributed over the main poplar regions in Belgium, were characterised for growth (annual girth and height growth). Out of these parameters, a site index, height at indefinite age, was calculated. For each plot, the soil profile and root distribution was described and each horizon was characterised for chemical status (pH, EC, N, P, K, Ca, Mg, Fe) and physical soil properties (structure, O.M., CaCO3, texture, saturated hydraulic conductivity, bulk density, soil moisture retention curve).
Twenty-five experimental plots of the clone Beaupré distributed over the north-western part of Europe have been studied in a similar way in the context of the E.U.-AAIR-project `Poplar for farmers.' A site-index based on height at age 7 was used as a measure of growth performance, due to the limited age of the available plots. Besides the parameters used in the Ghoy study, climatic factors were included in the analysis. Multivariate analysis (multiple regression analysis and principal component analysis) was used to relate the site index and the climatic data (only Beaupré) and the soil chemical and physical properties. To fulfil the requirements of biometric analysis, the soil horizons were grouped into a top layer (with 80% of the total root biomass) and a sub-horizon (from the lower boundary of the rooted layer down to the reduction horizon). Only those parameters that showed no mutual correlation (r < 0.70) were taken into account.
The analysis of the data for the clone Ghoy revealed that for the top layer the electric conductivity and N-content could explain 76% of the total variation in site-index. For the sub-horizon the chemical characteristics were not significant. A combination of physical factors (thickness of the horizon, O.M., structure, bulk density, sum of clay and silt fraction, useful pore space, or saturated hydraulic conductivity) explains 80% of the total variation. The analysis of the data of the clone Beaupré shows comparable results. The climatic data contribute to the explanation of the variation in site index, as the investigated plots cover a wider range of climatic conditions. The results are discussed and related to the water supply. Some examples of validation of the developed models are given. Finally, the possibility of using the models as a decision tool is discussed.
Theo Verwijst
Swedish University of Agricultural Sciences, Department of Short Rotation Forestry, P.O. Box 7016, SE-750 07 Uppsala, Sweden
From a global perspective and compared to poplar cultivation, willow cultivation has been the stepchild of the use of the Salicaceae. The cultivation of willows for a large number of different purposes traditionally has been carried out at a small scale, mainly in the Northern Hemisphere.
However, the number of species in the genus Salix exceeds the number of Populus species by one order of magnitude, and the geographical distribution and physiognomic range of willow species is larger than that of poplars. Only recently an effort has been made to exploit the large biological variation within the genus Salix by means of breeding and selection programs and by means of new planting and management schemes.
During only one century, the major constraint to the availability of forest products has shifted from physical limitations via economic hindrances to ecological constraints. Therefore, the huge potential of environmental assets of willow cultivation is expected to boost willow cultivation during the next century, and a rapid development of all aspects of willow cultivation is envisaged.
Many of the lessons learned during the large-scale cultivation of poplars, can be transferred directly to the field of willow growing. These include the design of production systems in relation to the targeted products and services, purpose-directed management, logistics, and breeding and selection methods and goals.
Further exploitation of willow in its potential position in between forestry and agriculture, as recipient of organic nutrient surplus from urbanised and intensively used agricultural areas and as a buffer between productive land and water courses, will lead to a sustainable short rotation forestry that meets our needs during this century.
M. Villar1, C. Bastien1, P. Faivre Rampant2, and J. Pinon3
1INRA Orléans, France
2Université Nancy, France
3INRA, Nancy, France
Most active tree breeding programs over the world take into account resistance to pests and diseases. Breeders do not search anymore for total immunity or complete absence of any damage, but select for reasonable tolerance - natural attacks leading to non-significant reduction of growth. The response of a tree to pests and diseases is determined by three major parameters:
Tree geneticists have largely studied these interactions from the host point of view, stating that most interactions are complex mechanisms, controlled by many loci with probably epistatic effects. You can refer to Bastien (1999) to see how breeding has evolved from variation among populations to the use of screening techniques and recently of biochemical/molecular markers. Construction of durable resistance (pyramiding major and minor resistance genes) will very likely use these new tools. The next step for breeders will be to find a balance between improved genetic basis of their artificial plantations and enough variability of these genotypes to face present and potentially new aggressors (strains, races, introduced parasites, insect populations...).
Geneticists cannot construct such long lasting resistance without taking into account the genetic variability of the aggressor. In that sense, interactions between geneticists/breeders and pathologists/entomologists must be of top priority! The story of poplars and rusts (overcoming of complete resistance) in Europe is a good example: links between these disciplines are even stronger as emergence of new races of Melampsora larici populina has been favoured (and revealed!) by the selection and large-scale plantations of resistant hybrids!
Finally, the role of factors in the environment--where the plantations are finally established--have to be studied and characterised (humidity, temperature, wind, presence of alternate host...). Furthermore, we must understand the biology of both organisms (tree: phenology and leaf duration, leaf area density, leaf orientation and inclination angle, internal leaf structure for hardwoods... parasite: biological cycles, range and dissemination patterns, variability in pathogenicity and populations). And because several major pathogens can affect the same tree genus, it is sometimes necessary to find complex solutions like interspecific hybrids including indigenous and exotic parentage. In conclusion, even though we can assume that resistance to pests and diseases in forest trees is genetically inherited, we have to take into account the whole interaction combining the biology of the host and the aggressor and their genetic characteristics within the complex natural environment of the forest tree stand. The key for the future will be to manage in time and space the host genotypes to maintain reasonable variability.
M. Villar1, H. Van de Sype1, A. Berthelot2, V. Breton3, C. Ginisty3, P. Monchaux2, and J. Pinon1
1INRA Orléans and Nancy, France
2AFOCEL Charrey/Saône and Paris, France
3Cemagref Nogent/Vernisson
France has structured research forces on poplar by combining expertise of three research institutes: AFOCEL, Cemagref, and INRA. This scientific consortium `GIS Peuplier' will be in charge of a program of poplar clonal selection, within the technical structure of the Experimental Nursery of Guéméné Penfao (conducted by the Forestry Department of the Ministry of Agriculture and Fisheries). Its first task will be to test the new clones or cultivars originating from foreign poplar institutes (mainly from Belgium, Italy, and the Netherlands) under French climatic and soil conditions. Its second task will be to create and select new interspecific hybrids.
We present in this paper the different selection steps of this second task. First step: from the 1,500 progenies produced every year by controlled pollination (50 families x 30 progenies), an initial nursery test (six randomised complete blocks, single tree plots) will be established for 2 years to screen rapidly and accurately for general resistance to rusts (the host Larix spp. will be mixed with poplar in order to have an equal frequency of the different rust races). Second step: the 500 remaining clones will be tested in a nursery trial of 4 years of growth (10 blocks) to obtain a good estimation of potential of growth and to provide wood disks in which wood quality traits can be measured (colour, basic density, tension wood, etc.) These 500 clones will also be tested for their tolerance to rust, in an experimental trial of 2 years of growth where half of the trial (8 blocks) will be chemically treated against rust. Third step: the 50 remaining clones will then be field-tested (high density trial - 1,000 trees/ha and two-large scale trials - 200 trees/ha), to finally select 5 clones for establishing certification tests (17 years after the initial controlled pollination). In parallel, these 50 remaining clones will be studied in further nursery trials for other threatening diseases (Xanthomonas populi, Marssonina brunnea). Plant material will be based on a collection of genotypes of Populus deltoides and P. trichocarpa originating from provenance and clonal tests from INRA and from the French collection of Populus nigra. F1 or F2 /BC types of crosses will be discussed.
