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Variations in stem radii of Larix principis-rupprechtii to environmental factors at two slope locations in the Liupan Mountains, northwest China
Journal of Forestry Research ( IF 3.4 ) Pub Date : 2020-04-11 , DOI: 10.1007/s11676-020-01114-w
Jing Ma , Jianbin Guo , Yanhui Wang , Zebin Liu , Di Gao , Liu Hong , Ziyou Zhang

Relationships between stem growth and climatic and edaphic factors, notably air temperatures and soil moisture for different slopes, are not completely understood. Stem radial variations were monitored at the bottom and top slope positions in a Larix principis-rupprechtii plantation during the 2017 and 2018 growing seasons. Total precipitation during the growing season in 2017 and 2018 was 566 mm and 728 mm, respectively. Stem contractions typically occurred after mid-morning followed by swelling in the late afternoon in both plots, reflecting the diurnal cycle of water uptake and loss. Trees at the two locations showed the same growth initiation (mid-May) because of the small differences in air and soil temperatures. There were no significant differences in cumulative stem radial growth between the bottom plot (1.57 ± 0.34 mm) and the top plot (1.55 ± 0.26 mm) in 2018. However, in 2017, the main growth period of the bottom plot ceased 17 days earlier than in the top plot, while cumulative seasonal growth of the bottom plot (1.08 ± 0.25 mm) was significantly less than the top plot (1.54 ± 0.43 mm). Maximum daily stem shrinkage was positively correlated with air and soil temperatures, solar radiation, vapor pressure deficits, and negatively correlated with volumetric soil moisture content. The maximum daily shrinkage reflected transpiration rates as affected by environmental factors. Daily radial stem increment was correlated with precipitation and volumetric soil moisture in both years, but with air temperatures only in 2017. The seasonal growth of L. principis-rupprechtii Mayr thus shows interannual dynamics, while precipitation constitutes a key driving factor.



中文翻译:

六盘山两个坡地华北落叶松茎半径与环境因子的变化

茎的生长与气候和生态因素之间的关系,尤其是不同坡度的气温和土壤湿度之间的关系,还没有被完全理解。在华北落叶松的底部和顶部坡度位置监测茎的径向变化2017年和2018年生长季节的人工林。2017年和2018年生长季节的总降水量分别为566毫米和728毫米。茎收缩通常发生在上午中旬之后,随后在两个地块都在下午膨胀,这反映了水摄取和损失的昼夜周期。由于空气和土壤温度的微小差异,两个地点的树木显示出相同的生长开始时间(5月中旬)。底部图(1.57±0.34 mm)和顶部图(1.55±0.26 mm)之间的累积茎径向生长在2018年没有显着差异。但是,在2017年,底部图的主要生长期提前了17天底部区域的累积季节性增长(1.08±0.25 mm)明显小于顶部区域(1.54±0.43 mm)。每日最大茎干收缩与空气和土壤温度,太阳辐射,蒸气压不足呈正相关,与土壤水分含量呈负相关。每日最大收缩量反映了受环境因素影响的蒸腾速率。两年中,日radial茎的日增重与降水量和土壤水分含量相关,但仅在2017年与气温相关。因此,L。principis-rupprechtii Mayr表现出年际动态,而降水是关键的驱动因素。

更新日期:2020-04-11
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