Statistical analysis of temperatures on both the upper and lower boundaries of sub-alpine dark conifer forests in china

Abstract

Temperature of every month on both the upper and lower boundaries of sub-alpine dark conifer forests at various sites in China are estimated in terms of their distributions and temperature records. Based on these estimated data, the heat factors to influence and control the distribution and growth of sub-alpine dark conifer forests in China are discussed. It is found that the most important heat index to influence and control the distribution and growth of sub-alpine dark conifer forests is neither the mean temperature in the warmest month, nor the maximum or minimum temperatures, but monthly accumulated temperature of >0°C or monthly effective accumulated temperature of >5°C. When monthly accumulated temperature of >0°C is more than 40°C, or monthly effective accumulated temperature of >5°C is over 50°C, sub-alpine dark conifer forests cannot grow well. When monthly accumulated temperature of >5°C is less than 60°C, sub-alpine dark conifer forests can not grow at all. When monthly effective accumulated temperature of >5°C is in the range 15°C–45°C, sub-alpine dark conifer forests in China can grow well. The ecological significance of temperature in May and September, and in summer half year are discussed.