Enhancement of carbon storage through the establishment of man-made forests has been considered as a mitigation option to reduce increasing atmospheric CO2 levels. Therefore the present study was carried out to estimate the biomass and carbon storages of the main stem of Eucalyptus grandis using allometric relationships using the plantations of Nuwara Eliya and Badulla districts in Sri Lanka. Tree diameter and total height were measured for the samples trees and stem volume was estimated using a previously built individual model for the same species. Stem biomass was estimated using core samples and carbon was determined using Walkley-Black method. Finally the biomass values were converted separately to the carbon values. Non-liner regression analysis was employed for the construction of models which had age as the explanatory variable. Linear regression was used in order to build the models to predict the above ground and stem biomass and carbon using volume as the explanatory variable. For both linear and non-linear types, the model quality was tested using R2 and fitted line plots. According to the results, stem biomass and carbon values at the 7th year were 110.8 kg and 68.7 kg respectively. Stem biomass and carbon values at the 40th year were 1,095.8 kg and 679.4 kg respectively. Carbon content at the age 20 was 62.0% from the stem biomass. Exponential models were proven to be better than the logistic models to predict the diameter, height, stem volume, biomass and carbon with age. R2 values and the fitted line plots indicated that the selected models are of high quality. Linear models built to predict the stem biomass and carbon using stem volume also showed the high accuracy of these models which had R2 values above 97.9%.
The tropical rainforest environment is nutritionally poor and tricky to navigate as compared to open habitats. This poses challenges for human subsistence. There has been little evidence to suggest that human populations relied on rainforest resources before the start of the Holocene, 10,000 years ago. Roberts et al. analyzed earlier fossil human and animal tooth enamel from Sri Lanka. The diet of these humans suggests rainforest rather than open-habitat foraging. Thus, humans were effectively exploiting rainforests in Sri Lanka since at least 20,000 years ago throughout periods of considerable climatic and environmental flux.Science, this issue p. 1246 Human occupation of tropical rainforest habitats is thought to be a mainly Holocene phenomenon. Although archaeological and paleoenvironmental data have hinted at pre-Holocene rainforest foraging, earlier human reliance on rainforest resources has not been shown directly. We applied stable carbon and oxygen isotope analysis to human and faunal tooth enamel from four late Pleistocene–to–Holocene archaeological sites in Sri Lanka. The results show that human foragers relied primarily on rainforest resources from at least 20,000 years ago, with a distinct preference for semi-open rainforest and rain forest edges. Homo sapiens’ relationship with the tropical rainforests of South Asia is therefore long-standing, a conclusion that indicates the time-depth of anthropogenic reliance and influence on these habitats.