Predicting the distributions of suitable habitat for three larch species under climate warming in Northeastern China

The larch ( Larix) genus is the most important species group in the forest ecosystems in Northeastern China, occupying about 25% of the forest areas. The high tolerance to coldness and relatively fast growth rate make this genus the main species group for forestation. According to the predictions of the global circulation model CGCM3, temperature could rise by 2–4 °C over the next 100 years. Few studies have been conducted on the response of larch species to climate warming in Northeastern China. Such studies are becoming increasingly needed due to the economic and ecological significance of this genus. This paper studies the potential distribution ranges of three larch species under the current and the warming climate conditions. A new classification and regression tree technique, Random Forest, was used to investigate the potential distributions of three larch species, based on 18 environmental variables which reflect the climate, topography and soil conditions of Northeastern China. The results showed that the biological coldness index (BCI) is the most important factor for Dahurian larch, annual precipitation (AP) is the most important factor for Korean larch and elevation (DEM) is the most important factor for Prince Rupprecht larch. Under the current climate regime, in general, the prediction accuracy for the training dataset is much higher than that of testing dataset. The prediction accuracy for Dahurian larch is much higher than that of other two larch species. Under three climate warming scenarios, the southeast boundary of suitable habitat of Dahurian Larch was modeled to retreat northwestward by 90 km (CGCM3-B1) via 105 km (CGCM3-A1B) to 140 km (CGCM3-A2) scenario. The potential area would thus decrease from 25.5 million ha currently to 13, 9.5 and 7.2 million ha, correspondingly. The northwest boundary of suitable habitat for Korean larch was modeled move northwestward by 100 km (CGCM3-B1) via 125 km (CGCM3-A1B) to 340 km (CGCM3-A2), while the southern boundary may move northeastward 125 km via 170–200 km, respectively. The modeled potential area thus decreased from 14.6 million ha to 14.5, 12.6 and 9.7 million ha, correspondingly. The suitable habitat of Prince Rupprecht Larch was modeled to disappear under each of the three scenarios.