温度和降水对宁夏六盘山自然保护区蒙古栎年内木质部生长的影响

Effects of Temperature and Precipitation on Intra-Annual Xylem Growth of Quercus mongolica in Liupan Mountain Nature Reserve,China

了解我国干旱半干旱地区树木木质部生长动态及其与气候因子之间的关系,对于评估和预测气候变化背景下的森林生产力和固碳潜力十分重要。通过微树芯采样技术,在2个生长季(2019年和2020年)监测了宁夏六盘山自然保护区内4棵蒙古栎(Quercus mongolica)年内木质部生长动态,并采用混合线性模型分别探索温度和降水对其生长速率的影响。研究发现蒙古栎的年内木质部生长动态在2个生长季内无显著差异(P>0.05),均于4月初开始生长,9月中下旬停止生长,生长季长度为(177±17)d(2019年)和(165±24)d(2020年)。混合线性模型结果显示,蒙古栎年内木质部的生长速率与采样前7、10、15天的最高、最低、平均温及总降水量均呈现显著正相关关系(P<0.01)。全球气候变化背景下,宁夏六盘山自然保护区蒙古栎年内木质部生长可能受益于未来增温湿润的气候条件。

Understanding the growth dynamics of tree xylem in arid and semi-arid areas of China and its response to climatic factors is crucial for assessing and predicting forest productivity and carbon sequestration potential under climate change.In this study,the intra-annual xylem formation of four Quercus mongolica in Liupan Mountain Nature Reserve of Ningxia were monitored by micro-core sampling technique in two growing seasons(2019 and 2020),and mixed linear model was used to explore the effects of temperature and precipitation on xylem growth rates.The results showed that there was no significant difference in intra-annual xylem formation dynamics between the two years(P>0.05).The onset of xylem formation started from early April and ceased from mid-to-late September,resulting in a growing season length of(177±17)days(2019)and(165±24)days(2020).The results of the mixed linear model showed that the annual xylem growth rate of Q.mongolica was positively correlated with the maximum,mean,minimum temperatures,as well as total precipitation in the preceding 7,10 and 15 days(P<0.01).Under global change,the xylem growth of Q.mongolica may benefit from future warm and humid climate conditions in Liupan Mountain Nature Reserve,