Relationship between climatic suitability and productivity of Larix gmelinii forest

Objective Larix gmelinii is an important constructive tree species in the forests of northeastern Inner Mongolia of northern China. Global warming leads to great uncertainty on the potential geographical distribution and the productivity of L. gmelinii forest. Therefore, accurately assessing the potential climate suitability for L. gmelinii and its relationship with the forest productivity in northeastern Inner Mongolia plays an important role in the sustainable development of forest ecosystems in northeastern China.

Method Based on field inventory data from 68 sample plots in the natural forest area of northeastern Inner Mongolia and eight climatic variables, the MaxEnt model was used to simulate and predict the potential geographical distribution of L. gmelinii forest. The climate suitable geographical distribution and the area of L. gmelinii forest were determined. Based on the distribution probability of measured points, combining with the forest productivity and stand structure factors, the relationship among climatic suitability, forest productivity and its influencing factors was clarified.

Result The suitable area for L. gmelinii forest was mainly distributed in the northeast of Inner Mongolia, the north and southeast of Heilongjiang Province, and the southeast of Jilin Province of northeastern China. The area of suitable area was sorted from large to small as low suitable area (6.050 × 10⁵ km²) > high suitable area (4.087 × 10⁵ km²) > medium suitable area (3.534 × 10⁵ km²). There was a significant negative correlation between climate suitability and productivity of L. gmelinii, and the productivity of the low suitable area was significantly higher than that of the high suitable area. Stand age had a significant moderating effect on the relationship between climate suitability and productivity of L. gmelinii. The negative correlation between climatic suitability and productivity was enhanced by low stand age, while the relationship between climatic suitability and productivity was weak when stand age was high.

Conclusion This study confirms the significant negative relationship between climatic suitability and productivity of L. gmelinii forest, but this negative relationship may be affected by stand age. When studying the relationship between habitat suitability and productivity, the effects of climatic factors and stand structure should be considered.