Abstract:

Forest ecosystems play an irreplaceable role in terrestrial ecosystems. The cross-border forests among China, North Korea, and Russia have abundant forest resources, providing wide habitats for numerous wildlife and plants. Scientific evaluation of forest health not only helps to protect and manage natural resources, but also effectively maintains biodiversity and promotes regional sustainable development. This article takes the border area among  China, North Korea, and Russia as the object, uses subjective and objective weighting methods to determine the initial weights of each evaluation indicator, and uses game theory to combine and optimize the weights. After determining the weights, based on the principle of extension, a matter-element extension model is constructed to evaluate the long-term forest health status. This research has shown that: 1) The weight allocation optimized through game theory shows that the vitality indicator dominates the four major categories of indicators in the indicator system, with a weight of 51.85%. This highlights the importance of vitality in forest health assessment, followed by indicators of system resilience (18.16%), site condition (16.43%), and soil quality (13.56%). 2) The results of the three periods in 2000, 2010, and 2020 show that the forest in the research area has the highest proportion of moderate health status, followed by good health status, and the lowest proportion of unhealthy status, with 16.50%, 15.53%, and 15.42%, respectively, showing a downward trend. This reflects that although some areas are in an unhealthy state, the forest health status is developing towards a better direction. 3) For many years, the multi-temporal and spatial characteristics of forest health in the research area have been dominated by a moderate health steady state, reflecting the stability of forest health. However, there are significant regional differences. In some regions of China, fluctuations coexist with high-quality steady states. While in North Korea, low steady states dominate but show signs of improvement. The health status of the western and eastern regions of Russia is diverse.

Key words: forest health assessment, game theory, matter-element extension model, multi-temporal and spatial dynamics