环境因子对华北落叶松树干径向变化的影响

Environmental impact of stem radial variation of Larix principis-rupprechtii in Liupan Mountains

为深入了解环境变化下树木生长和水分特征,2019年5—10月,利用带状树干径向变化测量仪连续监测了六盘山叠叠沟小流域华北落叶松的树干径向变化,分析了不同生长阶段树干日增量、收缩量和水分亏缺量与环境因子的关系,分析短时树干径向变化对环境因子的响应。结果表明:在湿润年,华北落叶松树干半径生长结束于7月20日[日序(DOY)201],在快速生长阶段(≤DOY 201),降水量是影响树干日增量的主要因子,太阳辐射强度和饱和水汽压差是影响树干日收缩量的主要因子,饱和水汽压差是影响树干水分亏缺量的主要因子;在生长停滞阶段(>DOY 201),降水量和太阳辐射强度是影响树干日增量的主要因子,气温、空气相对湿度和太阳辐射强度是影响树干日收缩量的主要因子,气温、空气相对湿度和饱和水汽压差是树干水分亏缺量的主要影响因子。树干日增量主要受降水和太阳辐射强度的影响,而树干日收缩量和水分亏缺量主要受气象条件和土壤水分的影响。

It is extremely important to analyze the response of short-time radial change of tree stems to environmental factors for understanding tree growth and water characteristics under changing environment. The radial variations of Larix principis-rupprechtii were continuously monitored using dendrometers from May to October 2019 to analyze the relationship between stem daily increment, shrinkage and water deficit, and environmental factors at different growth stages. The results showed that the stem radius growth of Larix principis-rupprechtii in the study year(wet year) ended on 20 July 2011[the day of year was 201(DOY 201)]. During the rapid growth stage(≤DOY 201), precipitation was the main factor affecting the daily increment in stem radius. Solar radiation intensity and vapor pressure difference were the main factors affecting daily shrinkage, while saturated vapor pressure was the main factors affecting the stem water deficit. During the growth stagnation stage(>DOY 201), precipitation and solar radiation intensity were the main factors affecting the daily increment in stem radius. Air temperature, relative humidity, and solar radiation intensity were the main factors affecting the daily shrinkage in stem radius, while air temperature, relative humidity, and vapor pressure difference were the main factors affecting the stem water deficit. In conclusion, stem increment is affected by precipitation and solar radiation intensity, and stem shrinkage and water deficit are mainly affected by meteorological condition and soil water content.