This research aimed to assess vegetation composition and the indicator species around water source areas of pine forest plantation. Data were collected through interview and vegetation survey. Vegetation communities were first compared using multi-response permutation procedure (MRPP) analysis. Indicator species analysis was then employed to determine the indicator species for each condition by considering historical data from the interview. Canonical correspondence analysis (CCA) and simple correlation analysis were also included. The result showed significant differences in species composition between water source areas in Watujali (lower low flow) and Silengkong (higher low flow) catchments, indicated by T = −5.104, p = 0.000. Pinus merkusii was dominant in Watujali (important value = 78%, D′ = 0.62) compared to Silengkong (important value = 41%, D′ = 0.21), and in becoming an indicator species (value = 52.1, p = 0.042) for Watujali. Meanwhile, Laportea sinuata, as the specific tree of water source areas, was an indicator for Silengkong (value = 29.4, p = 0.004). At a smaller level, indicator species differentiated the two catchments, even though they shared similar in D′ and H′. Among specific plants of water source areas, only Ficus septica was an indicator for Watujali (value = 29.4, p = 0.004), given its adaptability. Specific plants of water source areas, including Laportea sinuata, Coctus spicatus, and Calocassia gigantea, were significant indicators for Silengkong catchments, illustrated by 34.6, 35.9, and 33.0 of indicator values, respectively. These results also reflected the relationship among tree vegetation change, environmental features, and the growth of smaller species, as implied by both CCA and simple correlation. This finding could be used as basic information for early assessment of environmental change and environmental restoration efforts around water source areas on pine forest plantations. Repetition of this study is suggested to be carried out in other pine forest areas, as each region sometimes has its own specific native and natural species.

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.

We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and abiotic factors. The survey, which included the measurement of trees and seedlings, was carried out from March to October in 2016 and 2018. Monitoring sites in the coniferous forests of Seorak Mountain were divided into 27 quadrats. We analyzed relationships using simple and multiple linear regression. The majority of Abies nephrolepis individuals had a diameter at breast height less than l0 cm, and the number of seedlings increased over the study period. This reflects survival and growth due to successive annual mast seeding events. Aspect direction (R² = 0.201, p < 0.05), rock exposure (R² = 0.364, p < 0.001), canopy openness (R² = 0.322, p < 0.05), herbaceous cover (R² = 0.268, p < 0.01), and basal area (R² = 0.199, p < 0.05) show significant linear relationships with seedling density. Seedling density was positively related to rock exposure, canopy openness, and species richness, and there was a negative relationship between herbaceous cover and basal area (p < 0.0001). The relative importance of predictor variables was as follows: Rock exposure (40.3%), canopy openness (30.2%), basal area (13.9%), herbaceous cover (11.5%), and species richness (4.1%). Seedling density was most strongly influenced by the presence of large rocks, which provide shelter from harsh winds and a substrate for moss. We conclude that appropriate canopy openness creates a synergistic relationship. We found a positive association between the Abies nephrolepis seedling density in subalpine forests and certain physical environmental factors. Therefore, environmental gradients about the roles of rocks and canopies apply, even in this habitat.