南亚热带红锥和马尾松人工林生长对穿透雨减少的响应

为了预测和评估全球气候变化背景下森林生长和生产力对降水格局变化和季节性干旱的响应,以南亚热带红锥和马尾松人工林为对象,设置穿透雨减少50%和不减雨(对照)处理,开展连续3年(2015-2017年)的模拟试验,研究降雨减少对人工林胸径生长、凋落物量和叶面积指数的影响.结果表明: 与对照相比,穿透雨减少导致红锥2017年胸径增长量显著降低31.8%,而对马尾松无影响;红锥叶面积指数平均降低8.8%,马尾松叶面积指数降低7.2%或者不变;红锥林2015年枝凋落量和2017年凋落物总量分别增加29.6%和35.8%,马尾松林2015年其他树种(除了马尾松以外)叶凋落量显著减少50.7%,而其他凋落物组分无显著变化.短期穿透雨减少对人工林产生了干旱胁迫作用,这种作用存在年际变异和树种差异.

Growth responses of Castanopsis hystrix and Pinus massoniana plantations to throughfall reduction in subtropical China.

To better predict and evaluate responses of tree growth and forest productivity to the changes of precipitation pattern and seasonal drought under global climate change scenarios, throughfall reduction experiments including 50% of throughfall and natural rainfall (control) treatments were conducted in Castanopsis hystrix and Pinus massoniana plantations of warm subtropical region over a three-year period (2015-2017). Diameter at breast height (DBH), litterfall production and leaf area index of both plantations were investigated, respectively. The results showed that throughfall reduction resulted in a 31.8% decrease of annual increment of DBH of C. hystrix in 2017 and had no significant impact on that of P. massoniana. Leaf area index under throughfall reduction decreased by 8.8% in C. hystrix plantation and decreased by 7.2% or remained unchanged in P. massoniana plantation. Branch litterfall in 2015 and total litterfall in 2017 of C. hystrix increased by 29.6% and 35.8% by throughfall reduction, but leaf litterfall of other tree species (except for P. massoniana) in P. massoniana plantation declined by 50.7% in 2015, with no significant difference for other litterfall components. In conclusion, throughfall reduction had consequences of drought stress in both C. hystrix and P. massoniana plantations, with inter-annual variation and inter-specific differences.