Effects of climate change on distribution of suitable area of Pinus tabuliformis plantation in China

Objective Chinese pine (Pinus tabuliformis) is one of the most important conifer species for afforestation in the northern region of China, with well-developed roots and strong abilities in soil and water conservation, playing an important role in ecological protection. Studying the ecological characteristics and distribution boundaries of Chinese pine, exploring the optimal afforestation area and understanding the changes in the distribution of suitable area under climate change are prominent to formulate reasonable afforestation and management plan for Chinese pine, and to understand the adaptability of Chinese pine plantations to climate change.

Method Based on 221 effective distribution records of Chinese pine plantation in China and 22 environmental variables, combined with ArcGIS, the MaxEnt model was used to predict the potential distribution of Chinese pine plantation under background of climate change. Meanwhile, the key environmental variables and suitable ranges that constrain the distribution of Chinese pine plantation were determined and the geographical distribution and area changes of Chinese pine plantation in different future climate scenarios were also predicted.

Result (1) The area under curve (AUC) value of the Maxent model reached 0.955, indicating the reliability of the simulation results. (2) The current suitable area of Chinese pine plantation in China was 98.90 × 10⁴ km², concentrated in the north of Qinling Mountains, Taihang Mountains, the Loess Plateau, Yan Mountains of northern China and western Liaoning Mountains of northwestern China. The main environmental variables affecting the distribution of Chinese pine plantation were the precipitation of the warmest quarter, mean temperature of the driest quarter, min. temperature of the coldest month and altitude. Among them, precipitation of the warmest quarter was the primary variables affecting the distribution of Chinese pine plantation, with a suitable range from 223 to 389 mm. Mean temperature of the driest quarter ranged from −5 to 5 ℃, and min temperature of the coldest month ranged from −14.5 to −3.5 ℃. The suitable altitude for the growth of Chinese pine plantation ranged from 100 to 2100 m. (3) From the trend of changes in the past 90 years (1931−2020), the southern boundary of suitable area for Chinese pine plantation had remained basically unchanged, along the line of Minshan-Qinling-Daba Mountains, reaching the southern end of the Qilian Mountains and the southern side of the Helan Mountains to the west, without expanding to the northwest. However, the northern boundary of the suitable area for Chinese pine plantation had been extending northward, approximately 3.5° northward, and the center of gravity of the high suitability area had also migrated northward. Therefore, the area of suitable habitat for Chinese pine plantation had been increasing. From the perspective of future climate change scenarios, in the two periods of 2041−2060 and 2061−2080, the potential suitable area of Chinese pine plantation continued to show a trend of northward migration, and the area of high suitable area increased firstly and then decreased.

Conclusion Climate change will lead to the expansion of suitable area for Pinus tabuliformis to the north, while high suitability area in the Loess Plateau and Qinling Mountains are fragmented. Therefore, caution should be exercised when introducing and cultivating Pinus tabuliformis. The high suitability areas in the northern part of Yanshan Mountain and the western part of Liaoning Province are relatively stable and suitable for further expansion of planting.