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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 -
ArticleTree diversity, stand structure and community composition of tropical forests in Dalma Wildlife Sanctuary of Jharkhand, India
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Species diversity and density of trees were assessed in forests of Dalma Wildlife Sanctuary of Jharkhand comprising mostly of tropical deciduous forests. We compared tree community characteristics like stem density, basal area, diversity index, Beta(β diversity), Girth class, Canopy height class and species composition of tree species in all three zones ( Altitude between 199 -603m) in the study area. A total of 41 tree species of 25 families, 71 genera, and 95 species were recorded. Gramineae (10) family is most represented followed by Euphorbiaceae(6). It was noticed that the tree density varied from 30.64 to 62.51. The maximum basal area contributed by Terminalia belerica(1.323 m2ha-1) followed by Albezzia stipulate(1.145 m2ha-1). Shannon Weiner index (H’) ranged from 3.073 to 3.997 and species richness index ranged from 1.05 to 1.20. Beta diversity of tree species varied from 2.32 to 3.80. The highest number of tree species was occurred in girth class of 61 – 80 cm in all three zones. At present the biodiversity of these forests are under threat due to the anthropogenic and illegal interference of outside people for cutting of furniture tree species. The present study will help us to understand the patterns of tree species composition and diversity in the Dalma Wildlife Sanctuary, of India. Keywords; Species diversity, Beta diversity, Basal area, Girth class, Canopy height and Species composition. ID: 3469677 -
DocumentBiomass estimation in mangrove forests: a comparison of allometric models incorporating species and structural information
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Improved estimates of aboveground biomass are required to improve our understanding of the productivity of mangrove forests to support the long-term conservation of these fragile ecosystems which are under threat from many natural and anthropogenic pressures. To understand how individual species affects biomass estimates in mangrove forests, five species-specific and four genus-specific allometric models were developed. Independent tree inventory data were collected from 140 sample plots to compare the aboveground biomass (AGB) among the species-specific models and seven existing frequently used pan-tropical and Sundarbans-specific generic models. The effect of individual tree species was also evaluated using model parameters for wood densities (from individual trees to the whole Sundarbans) and tree heights (individual, plot average and plot top height). All nine species-specific models explained a high percentage of the variance in tree AGB (R2 = 0.97 to 0.99) with the diameter at breast height (DBH) and total height (H). At the individual tree level, the generic allometric models overestimated AGB from 22% to 167% compared to the species-specific models. At the plot level, mean AGB varied from 111.36 Mg ha-1 to 299.48 Mg ha-1, where AGB significantly differed in all generic models compared to the species-specific models (p < 0.05). Using measured species wood density (WD) in the allometric model showed 4.5% to 9.7% less biomass than WD from a published database and other sources. When using plot top height and plot average height rather than measured individual tree height, the AGB was overestimated by 19.5 % and underestimated by 8.3% (p < 0.05). The study demonstrates that species-specific allometric models and individual tree measurements benefit biomass estimation in mangrove forests. Tree level measurement from the inventory plots, if available, should be included in allometric models to improve the accuracy of forest biomass estimates, particularly when upscaling individual trees up to the ecosystem level. Keywords: Climate change, Monitoring and data collection, Sustainable forest management ID: 3621710
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