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DocumentModelling pine and spruce wood mechanical properties in different initial stand density plantations in Lithuania
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Two main parameters of wood quality in constructions are wood modulus of elasticity (MOE) and bending strength (MOR). To understand what kind of quality wood we are growing in our forests and how environment and forest management could affect wood quality parameters, we need to model these parameters by stand, tree, and sample results. This would help to predict MOE and MOR for the future stands.
To determine the influence of stand density and thinning intensity on wood mechanical and physical properties of Scots pine and Norway spruce, the data was obtained from experimental trials plots, which were established in 1990 by Institute of Forestry. The experimental object was divided to a smaller trial plots with different initial stand density: 2 plots with 3000-4400 trees per hectare, 2 plots with 2000-2400 trees per hectare, 2 plots with 1000-1200 trees per hectare. In these trial plots different thinning programs were used 3; 2; 1 time. From each trial plot 6 model trees were chosen (38 Spruce and 76 Pine trees).
Models were created by SAS statistical package. General linear regression models were chosen to create 4 models for prediction of: dynamic modulus of elasticity for log (MOElog); dynamic modulus of elasticity for samples (MOEdyn); global static modulus of elasticity (MOE) and bending strength (MOR) All parameters for creating models were chosen as random effects. Stand parameter was stand density (SD). Tree parameters were diameter at breast high (DBH), competition index (CI), average ring width (RD), average ring density (RD) and log high (LH). Sample parameters were knot at fracture point (K) and sample wood density (WD).
Best result for MOE models was in pine stand R2=0,82 spruce stand R2=0,85. R2=0,57 was in pine stand for MOR and R2=0,65 in spruce stand. Keywords: Sustainable forest management, Research ID: 3484790 -
ArticleEffects of land use and land use change on soil properties in northeast rainforest landscapes of Madagascar
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Soil is a major natural resource acting as a key interface between climate and biogeochemical systems. Tavy system or slash-and-burn agriculture influences soil quality and is responsible for releases of carbon stored in the soil. This study aims to evaluate soil properties in each land use and to determine the impact of land use change on these soil properties. The study area was located in an area in the rainforest of northeastern of Madagascar. Soil samples were collected on 135 study sites composed of nine land use types including natural forest, three cropland stages, tree fallow, mixed fallow, grassland and two cash crop plantations (vanilla and coffee). Mid-Infrared Spectroscopy (MIRS) was used to estimate organic carbon (C org), total nitrogen (N tot), cation exchange capacity (CEC), soil texture and pH KCl, while available phosphorus (P Olsen), soil bulk density (BD) and soil carbon stock (SOC) for 0-30 cm and 0-100 cm were estimated with conventional methods. At plot scale and at 0-30 cm, soil in the study area relevant highly variability. Statistical analysis shows that land use change in tavy system contributes significantly to this variability with a p-value <0.001 for P Olsen, C org and N tot, p-value < 0.01 for pH KCl and p-value < 0.05 for CEC and BD. Soil nutrients (P Olsen, C org and N tot) decrease during cultivation period and increase during fallow periods. The CEC and pH KCl were stable but decline rapidly at the grassland stage. SOC for both depths declines over two periods: after the first cropland and the third cycle of cropland after deforestation. The presence of tree vegetation in cash crops (vanilla and coffee) maintains a mean value of soil properties. The results presented in this study will be useful for forest landscape management and will allow the integration of the soil pool in the accounting of the SOC flow in the implementation of REDD+. Keywords: Agriculture, Biodiversity conservation, Climate change, Deforestation and forest degradation, Landscape management ID: 3483094 -
DocumentProduction and fuel properties of wood chips from logging residues by timber harvesting methods
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.This study calculated the productivity and cost of extraction and processing of logging residues by cut-to-length (CTL) and whole-tree (WT) harvesting methods. In addition, the comparative analysis of the characteristics of wood chip fuel to examine whether it was suitable for the fuel conditions of the energy facility. In the harvesting and processing system to produce the wood chips of logging residues the system productivity and cost of the CTL harvesting system were 1.6 Gwt/SMH and 89,865 won/Gwt, respectively. The productivity and cost of the WT harvesting system were 2.9 Gwt/SMH and 72,974 won/Gwt, respectively. The WT harvesting productivity increased 1.3times while harvesting cost decreased by 18.7% compared to the CTL harvesting system. The logging residues of wood chips were not suitable for CTL wood chips based on International Organization for Standardization (ISO 17225-4:2021) and South Korea standard (NIFoS, 2020), but the quality (A2, Second class) was improved through screening operation. The WT-unscreened wood chips conformed to NIFoS standard (second class) and did not conform to ISO but were improved through screening operation (Second class). In addition to the energy facility in plant A, all wood chips except CTL-unscreened wood chips were available through drying processing. The WT-unscreened wood chips were the lowest at 99,408 won/Gwt. Plants B, C, and D had higher moisture content than plant A, so WT-unscreened wood chips without drying processing were the lowest at 57,204 won/Gwt. Therefore, the production of logging residues should improve with operation methods that improve the quality of wood chips required for applying the variable biomass and energy facility. Keywords: Research, Sustainable forest management ID: 3622432
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