Allometric equations considering the influence of hollow trees: A case study for tropical peat swamp forest in Sarawak

Abstract

Biomass estimations in tropical peat swamp forests are quite complex when hollow trees are frequently found due to the unavailability of data on hollow size and the limited data on accurate measures of biomass. Destructive samplings were done for both above-(AGB) and belowground biomass (BGB) and hollow sizes of remained trees at a logged-over peat swamp forest in Sarawak, Malaysia. Subsequently, allometric equations taking hollows into account for both the above-and belowground biomass of tropical peat swamp forests were also being developed. It was observed that these were hollows in Shorea albida and Combretocarpus rotundatus trees with diameters at breast height (DBH) exceeding 40 cm; S. albida is a dominant or co-dominant species, and C. rotundatus grows in peat swamp forests throughout Sarawak. The hollow volumes ranged from 0.23 to 1.08 m 3 , and occupied 42.3% of stem volume on average. The larger biomass produced by previous allometric models were partially due to the presence of hollows. Thus, new models for estimating both AGB and BGB were developed that included one (only DBH), two (DBH and height [H]

Characterizing forest structure variations across an intact tropical peat dome using field samplings and airborne LiDAR

“…Firstly, although hollow and brittle trunks are common in tropical trees, sampling for such stem characteristics is rare and difficult (Anderson , Monda et al. ). Our study accounted for hollow trunks and heart rot, both of which can significantly reduce wood density and hence AGB estimations compared to previous PSF studies.…”

“…Peat swamp forests are an extremely variable forest type where within the same co‐dominant species Shorea albida, tree physiology and wood density varied across different phasic communities (Monda et al. ; P. S. Ashton, personal communication ). Our remote sensing‐based results highlight the dramatic changes in the physiognomy of canopy individuals in an intact peat swamp forest, whereas our transect study exemplifies structure and biomass density from the most carbon‐dense vegetation community within this PSF.…”

“…Wood density of 0.619 g/cm 3 was used for S. albida (Monda et al. ) and 0.6 g/cm 3 was applied for all other species (Osunkoya et al. ).…”

“…To account for the very strong tendency of large S. albida individuals to be hollow, we multiplied their estimated dry mass from (2) by 0.577, using the average fraction of dense wood volume for S. albida in Sarawak, Malaysia observed in Monda et al. ().…”

Effects of selective management system on biomass structure and forest sustainability: a case study of a tropical rainforest in Peninsular Malaysia

“…Similarly, compared with smaller trees, most large individuals are more likely to contain hollows in their stems, thereby reducing the usable volume (Monda et al 2015). For this reason, hollow logs are sometimes abandoned in the forest.…”