Abstract: Understanding the suitable habitat distribution of Korean pine (Pinus koraiensis) is significant for genetic resource conservation of Korean pine and vegetation restoration of broadleaved Korea pine mixed forest. In this study, we optimized the parameters (such as feature combination and regularization multiplier) of MaxEnt model. Using 168 geographical distribution records of Korean pine and 22 environmental factors, we simulated the habitat suitability of Korean pine and identified the major environmental factors controlling its distribution. The results showed that the complexity and degree of overfitting of the model were relatively low. The model was more accurate when the feature combination was linear, quadratic, hinge and product equation, and regularization multiplier was 3. Korean pine was mainly distributed in the eastern mountain area of Northeast China. The highly suitable area, low suitable area, and unsuitable area accounted for 19.24%, 28.54% and 52.22% of the total area, respectively. Annual precipitation, precipitation seasonality, elevation, and annual mean temperature played important roles in regulating the distribution of Korean pine, with the suitable threshold of each factor being 630-1090 mm, 86%-97%, 210-1140 m and 0.3-4.3 ℃, respectively.

Key words: treated water, sewage sludge, emergy, environmental service, waste disposal, sustainability.