Assessing relationship of forest biophysical factors with NDVI for carbon management in key coniferous strata of temperate Himalayas

Abstract

Assessing biophysical variables are essential for evaluation of carbon dynamics due to anthropogenic activities. Biomass carbon is an important biophysical parameter of forest ecosystems that indicates carbon mitigation and human–forest interactions. Spectral modeling approach was used to assess the relation of Normalized Difference Vegetation Index (NDVI) with biomass carbon, crown density, tree density, slope, altitude, aspect, species, and forest division in temperate conifer region of Himalaya. Field inventory was recorded from 188 biomass plots of 0.1 ha each across the study area. NDVI was observed to have a positive relation with aboveground biomass carbon, crown density, tree density, and altitude. The NDVI and ABC values ranged from (0.11 to 0.43) and (1.54 to 276.82 t ha−1), respectively. Among the aspects, highest and lowest average NDVI was observed for south east (0.289) and north (0.258), respectively. Similarly highest and lowest average aboveground biomass carbon was observed for north east (72.63 t ha−1) and east (44.30 t ha−1), respectively. NDVI expressed a fairly good relation with biophysical parameters including altitude, aspect, crown density, tree density, species, and location (forest division). NDVI using principal tree species composition (forest type) revealed a relation with aboveground biomass carbon for Cedrus deodara (R2 = 0.63), Mixed I (R2 = 0.61), Pinus wallichiana (R2 = 0.57), and Mixed-II (R2 = 0.48). NDVI demonstrates potential to understand biomass carbon variability through establishment of relations with forest biophysical parameters using spectral modeling approach. Varying NDVI can be ascribed to vegetation canopy density, number of stems, species, and altitude. The database and established relations would help indicate biomass carbon dynamics and enable to adopt site-specific management. The study further helps draw inferences on mitigation and adaptation perspectives in view of varying biophysical conditions that occur in a forest.