Influence of Tree Vegetation and The Associated Environmental Factors on Soil Organic Carbon; Evidence from “Kulon Progo Community Forestry,” Yogyakarta, Indonesia

Abstract

This study aimed to assess the influence of tree vegetation and some environmental factor on soil organic carbon (SOC), which is part of soil organic matter (SOM). Vegetation survey and soil sampling were carried out in five stand types in the protected forest of Kulon Progo Community Forestry, including Pinus (PN), Aleurites-Swietenia (AS), Swietenia-Acacia (SA), Melaleuca-Acacia (MA) and Tectona-Dalbergia (TD). Tree vegetation composition and characteristics (diversity, basal area, density, canopy height and canopy cover), SOC and SOM were analyzed using some comparative analyses. The influence of tree vegetation characteristics and environmental factors related to topographic, edaphic and anthropogenic aspects on SOC was performed by employing principal component analysis (PCA) and redundancy analysis (RDA). Our result confirmed that species composition among stand types was significantly different. Characteristically, PN was relatively close to MA, having similarities in canopy cover, canopy height and basal area. While AS, SA and TD were relatively similar to each other in diversity, basal area, density and canopy cover. Moreover, PN and MA similarly hold less SOC and SOM compared to TD, while AS and SA showed not significantly different from TD. RDA confirmed the high influence of tree vegetation, where the most influencing factor for SOC and SOM was an interaction among canopy cover, canopy height and below-stand utilization, where canopy cover was directly proportional to canopy height and increased with decreasing below-stand utilization. We concluded that in relatively small variations of environmental factors, selecting dense-canopy trees and adaptive management of below-stand utilization promised SOC sequestration and storage. Our findings provide fundamental information for maximizing the potential of forest carbon to meet the global payments for ecosystem services and contribute to low-carbon development strategies and emission reduction.