Emergent Trees Identified as Major Source of Uncertainty in Estimating Above-ground Biomass in Mixed Dipterocarp Forest of Brunei Darussalam
Abstract
It is known that over half of the total Above-ground Biomass (AGB) in global vegetation is in tropical forests. However, there are many uncertainties in the estimation of tree biomass in tropical forests. Studies estimating AGB in tropical forests are especially biased toward South America forests, and quantification of AGB in Southeast Asian forests are still limited. This study aimed to determine AGB in Mixed Dipterocarp Forest (MDF) which is one of the major forest types, mainly dominated by Dipterocarpaceae family, in tropical forests in Southeast Asia. Two study sites (Bukit Teraja and Andulau), located 38km apart, were selected in Brunei Darussalam. Nine 20m×20m plots were established at each site, and diameter at breast height (DBH) of all live trees (DBH≥10cm) were measured within the plot. AGB (Mg ha-1) was estimated from the measured DBH using biomass estimation equation which was previously developed for tropical forests in Southeast Asia. The density of live trees in Bukit Teraja and Andulau were 783.33 trees ha-1 and 731.56 trees ha-1, respectively, and the mean DBH in Bukit Teraja and Andulau were 27.86±9.92cm and 22.51±4.28cm, respectively. AGB in Bukit Teraja (1167.88±1285.53 Mg ha-1) was higher by three-fold than AGB at Andulau (368.32±188.57 Mg ha-1) with large variation, and it might be due to the presence of emergent trees (DBH≥200cm) in Bukit Teraja. Although only four emergent trees were found in three plots at Bukit Teraja, their AGB was 64.76, 68.97, 76.30 and 87.07 Mg tree-1, respectively. These results highlights that the large uncertainties in the estimation of tree biomass in tropical forests could be due to the presence of the emergent trees. Environmental factors affecting the presence of these emergent trees should be studied for further understanding of variation in AGB of tropical forests.
*This study was carried out with the support of ´R&D Program for Forest Science Technology (Project No. 2018110C10-2020-BB01)' provided by Korea Forest Service (Korea Forestry Promotion Institute), and a Use Permit ([221]1JPH/UND/17 PT.1) from the Brunei Forestry Department. We thank Universiti Brunei Darussalam and the Brunei Forestry Department for logistics and fieldwork support.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMGC0090007J
- Keywords:
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- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE;
- 1655 Water cycles;
- GLOBAL CHANGE