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ArticlePromoting Terminalia brownii as a commercial indigenous tree species in drylands, East Africa
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Kenya’s forest cover is estimated at 7.4% of the land mass cover. Forests are important in ensuring biodiversity conservation and providing ecosystem goods and services, improving community livelihoods and national GDP. There is need to enhance afforestation and reforestation programmes to achieve the envisioned 10% tree cover target. However, this effort is constrained by climate change issues arising from unsustainable exploitation of wood for charcoal and firewood leading to the depletion of important tree species such as T. brownii. The domestication of T. brownii under agroforestry systems and other tree planting programmes are constrained by lack of adequate supply of superior and high quality seeds and seedlings, poor silvi-cultural management techniques, low rates of integration into smallholder agroforestry programs, limited knowledge on crop-tree interactions and lack of allometric models to estimate biomass yield and carbon stock. A multidisciplinary research project funded by the National Research Fund (NRF) is ongoing and is geared towards promoting the propagation and regeneration of T. brownii under agroforestry systems in the drylands of Kenya to mitigate climate change. A number of preliminary findings have been reported, such are; (1) Terminalia brownii fruits have mechanical dormancy imposed by the hard samara fruit and that extracted T. brownii seeds record a high percentage of above 80% under warm conditions; (2) germination of T. brownii fruits and seeds are significantly affected by fungal pathogens and insect pests; (3) five variables significantly influence the decision to domesticate T. brownii these are; education level of household head, importance of farm to the household income, access to credit, dependency ratio and intercropping; (4) studies on the spatial distribution and occurrence and development of allometric equation for estimating above and below-ground biomass of T. brownii in the drylands of Kenya are ongoing. Further assessment on growth performance have shown that T. brownii is generally fast growing; can attain an increase in height of (~1.0 m) and DGL (3.0 cm) annually, with significance difference in growth within and between provenances and that the it can withstand many other growth challenges despite the harsh weather conditions. These findings suggest that T. brownii is a promising tree species in agroforestry systems and afforestation in drylands and that there exist genetic variability among the available provenances thus the need to involve more stakeholders in seedling production and to embark on...... Key words: T. brownii, Commercial tree, growth performance, drylands of Kenya ID: 3623166 -
ArticleAllometric models for estimating above ground biomass of Bambusa tulda Roxb. and Melocanna baccifera (Roxb.) Kurz
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Allometric equations are used to estimate the biomass and carbon stock of forests. There is a dearth of species- specific allometric equations for bamboos growing in Bangladesh. Bambusa tulda and Melocanna baccifera are the two most common bamboo species of commercial importance in Bangladesh. This study reports allometric equations for estimating biomass of bamboo compartments (leaf, branches, and stem) and total above-ground biomass. Data was collected from natural bamboo forests of different locations of Khagrachhari district. A total of 50 bamboos (25 B. tulda and 25 M. baccifera) were sampled following the destructive method. Bamboo leaf, branch, and stem were measured for fresh weight in the field. Sub-samples were collected in sufficient amounts and processed in the laboratory for density and oven-dry weight to derive fresh to oven-dry weight ratio. Commonly used 10 candidate equations were tested using Diameter at Breast Height (DBH), diameter at base (D5), and height (H) as explanatory variables to find the best fitted allometric equation. In total, the study developed 60 models with 10 for each component of the two species. Applying the goodness-of-fit statistics, 4 best-fitted models were selected for estimating stem and total above-ground biomass (TAGB) of the two bamboo species. The best fit allometric biomass models for M. baccifera were, Ys = 0.398*DBH1.542 and Yt = 0.627*DBH1.382, where, Ys = stem biomass and Yt = total above-ground biomass. On the other hand, best fit allometric biomass models for B. tulda were, Ys = 0.041*DBH1.0658*H1.2311, and Yt = 0.235*D5 1.867, where, D5 is diameter at the base (5 cm above the ground). The relationship between the biomass and dendrometric variables in the form of best-fitted models was statistically significant at p < 0.05 levels. The allometric models developed by this study will be useful for better estimation of biomass and sequestered carbon in the plain land homestead forests of Bangladesh. Keywords: Khagrachhari, Bamboo, Carbon sequestration, Bambusa tulda and Melocanna baccifera ID: 3623846 -
ArticleAllometric equation for estimating tree above ground biomass modified by ecological environmental factors in tropical dipterocarp forests
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Tropical Dipterocarp Forest (DF) plays an important role in mitigating climate change thanks to its carbon sequestration capacity. In order to estimate the CO2 absorption capacity of DF as a basis for the development of forest ecological services, a system of biomass equations is needed; while very few models for estimating biomass in DF have been published and have not yet reflected the impact of ecological environmental factors. The purpose of the study was to validate and select the best model for estimating tree above ground biomass (AGB, kg) in DF under the influence of ecological environmental factors, thereby improving the reliability. Twenty-eight 0.25 ha plots in the Central Highlands and one 1 ha plot in the Southeast ecoregion in Viet Nam were measured. A total of 329 trees were destructively sampled to obtain a dataset of AGB; Methods for developing equations were weighted nonlinear fixed/mixed models with/without random effects fit by Maximum Likelihood; Using K-fold cross validation with K = 10, we compared and selected the best model with and without ecological environmental factors. As a result, separate ecological environmental factors did not affect AGB, while the combination of the factors influences the AGB model through the form: AGB = AVERAGE × MODIFIER, AGB = a × Db ×WDd × exp (e2 × (P - 1502) + e3 × (BA - 12.62)) that was significantly more reliable than a model without these factors involved; where D (cm), WD (g / cm3), P (mm year-1) and BA (m2 ha-1) are the diameter at breast height, wood density, averaged annual rainfall and total basal area of forest stand, respectively. Keywords: above ground biomass, dipterocarp forest, ecological factor ID: 3473259
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