Tree Species Richness,Carbon Stock and Regeneration Status of Maltol Community Forest and Dhanushdham Protected Forest in Dhanusha, Nepal

Abstract

Tree species are the dominant component of forest ecosystems which influence most structural and functional attributes of these ecosystems. This study aims to assess and compare tree diversity and carbon stocks in two different management regimes namely Maltol Community forest (MCF) and Dhanushadham Protected forest (DPF). The studied MCF and DPF lied in tropical region at an altitude 80 to 230 masl in Dhanusha District of Nepal. Altogether 120 plot of 25 × 25 m2 each was established by following the stratified random sampling technique for assessing tree diversity and carbon stock in both forests. Species enrooted and encountered inside the plot were recorded. All tree species (≥6cm DBH) were tagged and their both DBH and height were measured. The allometric equation biomass-diameter regression (Model II) developed by Chave et al., (2005) was used for estimation of carbon stock of tree species and tree species diversity by Simpsons and Shannon-Wiener indices. Descriptive statistics with Pearson correlation and one way ANOVA from SPSS- Software and Microsoft Excel were used to perform the statistical analysis. The carbon stock value was found to be 1.2305t/ha in MCF and 5.592t/ha in DPF. Community forest found to have lower value of tree carbon stock than the carbon stock of protected forest. But in case of tree diversity it was recorded high in MCF (34) than in DPF (29). Shorea robusta was found to be the single dominant species in both DPF and MCF with higher basal area (26.802m²/ha and 6.65m²/ha) and contributed 87.93% and 61.99% of the carbon stock respectively. The contribution of carbon stock of two co-dominant tree species in MCF are 8.98% of Terminalia chebula and 5.18% Lannea coromandelica. Lower value of basal area in both forest types in the present study suggests that both the forests are in an immature developmental phase. The size class distribution diagram of all trees showed reverse J shaped pattern indicating a good regenerating capability of the forest. But the regeneration of Shorea robusta of both forests in the present study followed the trend as trees density/ha > saplings density/ha > seedlins density/ha indicated the poor regeneration of Shorea robusta. There was significant (P<0.05) difference between the carbon stock in both forest types.