Ecology Suitability Regions Of Pinus Koraiensis In Northeast China Based On The Maxent Model

Broad-leaved Korean pine(Pinus koraiensis)forest is one of the main forest types in Northeast China.As a key constructive species of broad-leaved Korean pine forest,Pinus koraiensis has high ecological and economic value.However,the broad-leaved Korean pine forests have suffered severe damages after experiencing the wars before the founding of New China and the unreasonably high-strength clear cuts after the founding of New China,large-sized broad-leaved Korean pine forests are replaced by broad-leaved mixed forests.The number of key tree species,Pinus koraiensis,has sharply decreased.With the continuous development of society,economy,and science in China,people gradually realize the importance of protecting the ecological environment.The implementation of a series of major projects such as the natural forest protection project and the total prohibition of commercial logging in state-owned forest areas has played a key role in the protection of forest ecosystems,especially for broad-leaved Korean pine forest,its further degradation is effectively inhibited.However,for broad-leaved Korean pine forests that have been severely degraded to broad-leaved miscellaneous forests,how to restore scientifically and reasonably to broad-leaved Korean pine forests on the basis of comprehensive protection against logging,especially the recovery of Pinus koraiensis population is the key.The first step in the restoration of Pinus koraiensis population is to reasonably evaluate the regional environmental adaptability of Pinus koraiensis,and scientifically predict the ecologically suitable area of Pinus koraiensis,in order to identify the limiting environmental factors in the restoration process of Pinus koraiensis,scientific guidance the suitable recovery area of the Pinus koraiensis population.In view of this,this study used the Pinus koraiensis as the research object,used the northeast plant and habitat database to extract the data of the Pinus koraiensis distribution point,the environmental factors in Northeast China were selected from the interpretation of long-term environmental monitoring data from 97 meteorological stations in the Northeast.MaxEnt model was used to analyze the potential distribution area of Pinus koraiensis in the forest area of Northeast China,and the main environmental factors affecting the distribution of Pinus koraiensis were revealed,and the ecological suitability of Pinus koraiensis was compared.The main conclusions are as follows:(1)The model test results show that the MaxEnt model can predict the geographical distribution of Pinus koraiensis ideally,and the AUC value in the ROC test is 0.923,which is an“excellent”level.(2)The top 6 dominant climatic factors affecting the distribution of Pinus koraiensis are:annual average precipitation(30.8%),extreme low temperature(17.4%),forest type(16.8%),and the growing season average temperature from April to September(10.6%),average relative humidity(8.7%),soil type(5.1%).(3)The analysis of the main environmental factors affecting the distribution of Pinus koraiensis shows that:Pinus koraiensis is suitable to be distributed in areas with an average annual rainfall of 545.45mm-1018.18mm.The low temperature range that Pinus koraiensis can adapt to is between-35℃-28℃.The average temperature of the growing season that can be adapted to Korean pine is between 13.6℃-18.0℃.The average annual relative humidity range of suitable distribution of Pinus koraiensis was between 66.7%-70.72%.The suitable soil types for Pinus koraiensis were brown soil,brown coniferous forest soil,aquatic soil and primary culture soil.(4)According to the distribution-environmental relationship model of Pinus koraiensis in Northeast China,the probability of existence of Pinus koraiensis in the study area(p),p≤0.1 is the unsuitable area;0.1<p≤0.3 is the low suitable area;0.3<p≤0.5 is the edge of the suitable area;0.5<p≤0.7 is the suitable area;p>0.7 is the most suitable area,according to the above criteria,it is divided into the suitable areas of the Korean pine.The unfavorable area of Pinus koraiensis is approximately 1.0821×10~4 km~2,accounting for 74.3%of the total study area;the low suitable area is approximately 10.41×10~4 km~2,accounting for 7.17%of the total study area;the marginal suitable area is approximately 9.63×10~4 km~2,accounting for the study area.6.63%of the area;suitable area is approximately 10.64×10~4 km~2,accounting for 7.33%of the study area;the most suitable area is approximately 6.68×10~4 km~2,accounting for 4.6%of the study area.The suitable area above 0.5 is mainly distributed in Xiaoxing’anling-Changbai Mountain,including Yichun City,Hegang City,Qitaihe City,Mudanjiang City,Yanbian Prefecture,Jilin City,Baishan City,Tonghua City,and Fushun City.These areas can develop Pinus koraiensis fruit forests,and should restore degraded forests to coniferous and broad-leaved mixed forests as much as possible.