中国橡胶种植北界

Apreliminary study of the northern planting boundary of rubber tree cultivation in China

基于中国橡胶的地理分布信息及其相应的气候资料,结合最大熵模型,明确了影响中国橡胶种植的5个主导气候因子,即最冷月平均温度、极端最低温度平均值、月平均温度≥18℃月份、年平均气温和年平均降水量。在此基础上,给出了80%气候保证率下中国橡胶树稳产高产的种植北界,该北界准确覆盖了目前中国橡胶主产区的实际种植区域。研究结果可为中国橡胶种植优势区域布局规划及防灾减灾提供科学决策依据。

The rubber tree（ Hevea brasiliensis） originated in Brazil and was a typical tropical plant with thermophilic and hygrophilous characteristics,sensitive to strong winds. As an untraditional planting area,South China frequently sees tropical cyclones and cold-weather damage to plants. Thus,the climatic conditions were the key factor affecting the planting of the rubber tree in China. The safe northern planting boundary of the rubber tree was guided by the desire to effectively avoid cold-weather damage and strong winds. Various studies（ since 1980s） on the suitability of rubber tree planting in China have discussed the northern planting boundary of the rubber tree and provided a rationale for the planting,which promoted development of the rubber tree industry in China. Rubber production was concentrated in the suitable climatic conditions,and regional layout was becoming more suitable gradually. Chinese researchers have developed cold- and windresistant strains of the rubber tree and a good base of rubber production. Nowadays,Hainan,Yunnan,and Guangdong Provinces in South China are suitable for rubber tree cultivation,and the amount of rubber trees is increasing continuously.Nevertheless,climate change has seriously influenced temperature and precipitation on the global and regional scale and is expected to affect the rubber tree cultivation system. The existing research on Chinese rubber tree cultivation has been limited by the shortage of early climatic data and by the insufficient number of meteorological stations. Particularly,climatic factors that affect rubber tree cultivation have been mainly selected in accordance with practical experience,and researchers did not consider the comprehensive effects of all climatic factors on cultivation of the rubber tree. These factors influencedthe boundary of rubber tree cultivation and are important for accurate assessment of suitability of rubber tree planting,for planning of rubber tree plantations,and for formulating response measures to climate change decision-making. Accordingly,the five main climatic factors,i.e.,mean temperature of the coldest month,mean extremely low temperature,the number of monthly days with mean temperature ≥18 ＂C,mean annual temperature,and mean annual precipitation,were confirmed by the maximum entropy model based on the geographical distribution of rubber tree cultivation and the corresponding climatic data. The northern planting boundary of the rubber tree was selected at the 80% rate of climate guarantee,which is believed to correspond to a high and stable yield of rubber cultivation. This boundary covered the actual main production area of rubber tree plantations in China. The maximum entropy model that we used to confirm the northern planting boundary of rubber tree plantations in China has certain advantages over other methods according to comparison with the existing research results. The maximum entropy model can fully take into account the intrinsic interactions of various factors,to a certain extent,it can overcome the interference by the artificial division factor range and then more objectively predict the potential spatial distribution of Chinese rubber tree planting. This model can prevent blind planting of rubber trees with consequent waste of human labor,materials,and financial resources. Therefore,the maximum entropy model should help to rationally choose a geographic location for rubber production. Nevertheless,the northern planting boundary of the rubber tree was ascertained to offer the 80% rate of climate resource guarantee. Thus,the northern boundary has essentially been a rubber stable and a high-yield planting boundary. Our results should facilitate scientific decision-making regarding distribution of rubber tree planting as well as disaster prevention and mitigation in China.