Table 1. Criteria and indicators for evaluating the naturalness recovery in plantation forests of Gwangneung Forest. Indicators are categorized into structure, species diversity, and species composition. Threshold values for Good, Fair, and Poor were determined using the Jenks Natural Breaks method

Category Indicator Description Evaluation Score
Good (3) Fair (2) Poor (1)
Structure Importance Value of Planted Species The relative importance value of planted species was calculated by applying weighted dominance weighted value: Tree (3), Subtree (2), Shrub (1), and Herbaceous (0.5), normalized by the total weight (6.5) 1-39% 39-68% 68-95%
Canopy Cover of Tree Layer Total canopy cover of the tree layer 70-95% 40-70% 0-40%
Crown density Weighted dominance was assigned by vegetation layer (excluding herbaceous species) 55-73% 35-55% 22-35%
Vertical Stratification Vegetation was considered established when the canopy cover reached or exceeded 15% 4 layers 3 layers 2 layers or less
Species Diversity Species Richness Species richness within the quadrat 37-58 species 21-37 species 5-21 species
Species Evenness H/In(S) 0.48-0.72 0.3-0.48 0.09-0.3
Shannon Diversity Index i = 1 s p i ln p i 1.69-2.75 1.04-1.69 0.23-1.04
Simpson Diversity Index 1 i = 1 s p i 2 0.62-0.89 0.35-0.62 0.09-0.35
Species Composition Proportion of Indicator Families Importance value of Asteraceae, Poaceae, and Fabaceae 0-3.3 3.3-17 17-37.1
Number of Annual Herbaceous Species Number of annual herbaceous species observed 0-1 species 1-5 species 5-11 species
Number of Naturalized Species Number of naturalized plant species observed Not observed 1-2 species 2-5 species