全球变暖背景下西藏高原高海拔地区木本植物分布限制因子分析

Analysis on Limiting Factors of Woody Plant Distribution in High Altitude Area of Tibet Plateau Under the Background of Global Warming

【目的】探明在气候变化条件下木本植物在西藏高原高海拔地区分布的主要限制因子及适应途径。【方法】参照林线相关理论及青藏高原针叶林树线热量条件,比较青藏高原生态条件最为接近的那曲镇与阿里地区狮泉河镇的热量因素在全球变暖条件下的变化趋势,分析木本植物在西藏高原高海拔地区分布的主要限制因子。【结果】夏季温度是北半球非热带林线的主要限制因素之一,在全球变暖背景下,那曲镇各热量指标均显著上升,热量条件基本能满足木本植物的生存需要。那曲镇木本植物分布的限制因子为大风日数多,在持续且强烈的大风环境中其新梢或叶片往往脱水枯死。【结论】风是限制西藏高寒高海拔地区木本植物生存的主要因子,在做好防风措施后,应选择抗风能力强的植物作为那曲镇的城镇绿化树种。

【Objective】The main limiting factors and adaptive approaches of woody plants in high altitude areas of Tibet Plateau under the condition of global warming were explored.【Methods】Accord-ing to the theory of forest line and the heat condition of coniferous forest line in Qinghai Tibet Plateau,the change trend of heat factors in Naqu Town and Shiquanhe town in Ali area under the condition of global warming was compared,and the main limiting factors and adaptive ways of woody plants in high altitude areas of Tibet were analyzed.【Results】Summer temperature is one of the main limiting factors of the forest line outside the tropical zone in the northern hemisphere.Under the background of global warming,the heat index of Naqu Town increased significantly,and the current heat condition can basically meet the survival needs of woody plants.The limiting factors of woody plant distribution in this area is that the number annual gale days(97.4 days/year)in Naqu Town is very large,and the shoots and leaves of woody plants are easy to dry and die in case of gale.【Conciusion】Gale is the limiting factor for the sur-vival of woody plants in high altitude and cold areas of Tibet.On the premise of wind prevention mea-sures,the construction of urban green plants in Naqu Town is feasible.