Ning Peng, Zhang Min, Bai Tianyu, Zhang Bin, Yang Liu, Dang Shangni, Yang Xiaohu, Gao Runmei
College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China.
Zhongtiaoshan Forestry Bureau of Shanxi Province, Houma, Shanxi, China.
Front Plant Sci. 2023 Mar 30;14:1147229. doi: 10.3389/fpls.2023.1147229. eCollection 2023.
Global climate change can affect the sensitivity of tree radial growth to climate factors, but the specific responses of tree radial growth to microclimate along the altitudinal gradient in the long term are still unclear.
In this study, the tree-ring width chronologies of Carr. in Shanxi Province of China were studied at three altitude gradients (1200-1300 m (low altitude), 1300-1400 m (medium altitude) and 1400-1500 m (high altitude)) during 1958-2017.
The results showed that (1) the climate background could be divided into two periods based on the Mann-Kendall test analysis: 1958-1996 was a stable period (mean annual temperature (MAT)=10.25°C, mean annual precipitation (MAP)=614.39 mm), and 1997-2017 was a rapid change period (MAT=10.91°C, MAP=564.70 mm), indicating a warming and drying trend in the study region. (2) The radial growth of at different altitudes showed inconsistent variation patterns. The tree radial growth at low and medium altitudes (CV=27.01% for low altitude and CV=24.69% for medium altitude) showed larger variation amplitudes during the rapid change period than that in the stable period (CV=12.40% for low altitude and CV=18.42% for medium altitude). In contrast to the increasing trend, the tree radial growth rates at the high altitude showed a decreasing trend across years. (3) In the stable period, the radial growth of at the low altitude showed a significantly negative response to temperature and a positive response to precipitation in May and June. The tree radial growth at the medium altitude was positively related to precipitation in June and minimum temperature in February. The tree growth at the high altitude was mainly positively correlated with the temperature in May and August. In the rapid change period, the radial growth of at the low altitude was affected by more meteorological factors than that in the stable period. Medium-altitude trees were positively influenced by precipitation in June and minimum temperature in January, whereas high-altitude trees responded positively to wind speed in February. (4) Along altitudinal gradients, tree radial growth was more related to temperature than precipitation in the stable period. The tree radial growth at the high altitude during the rapid change period was only affected by wind speed in February, whereas the tree radial growth at low and medium altitudes was mainly affected by temperature to a similar extent during the two periods.
The study indicated that tree growth-climate response models could help deeply understand the impact of climate change on tree growth adaptation and would be beneficial for developing sustainable management policies for forest ecosystems in the transition zone from warm-temperate to subtropical climates.
全球气候变化会影响树木径向生长对气候因子的敏感性，但长期来看，树木径向生长沿海拔梯度对小气候的具体响应仍不明确。
本研究对中国山西省1958 - 2017年期间3个海拔梯度（1200 - 1300米（低海拔）、1300 - 1400米（中海拔）和1400 - 1500米（高海拔））的辽东栎树木年轮宽度年表进行了研究。
结果表明：（1）基于曼肯德尔检验分析，气候背景可分为两个时期：1958 - 1996年为稳定期（年平均温度（MAT）=10.25℃，年平均降水量（MAP）=614.39毫米），1997 - 2017年为快速变化期（MAT = 10.91℃，MAP = 564.70毫米），表明研究区域存在暖干化趋势。（2）不同海拔的辽东栎径向生长呈现出不一致的变化模式。低海拔和中海拔树木的径向生长（低海拔变异系数CV = 27.01%，中海拔CV = 24.69%）在快速变化期的变异幅度大于稳定期（低海拔CV = 12.40%，中海拔CV = 18.42%）。与增加趋势相反，高海拔树木的径向生长速率逐年呈下降趋势。（3）在稳定期，低海拔辽东栎的径向生长对温度呈显著负响应，对5月和6月的降水量呈正响应。中海拔树木的径向生长与6月降水量和2月最低温度呈正相关。高海拔树木生长主要与5月和8月的温度呈正相关。在快速变化期，低海拔辽东栎的径向生长受气象因子的影响比稳定期更多。中海拔树木受6月降水量和1月最低温度的正向影响，而高海拔树木对2月风速呈正响应。（4）沿海拔梯度，在稳定期树木径向生长与温度的相关性大于与降水量的相关性。快速变化期高海拔树木的径向生长仅受2月风速影响，而低海拔和中海拔树木的径向生长在两个时期受温度影响的程度相近。
该研究表明，树木生长 - 气候响应模型有助于深入理解气候变化对树木生长适应性的影响，有利于制定暖温带向亚热带过渡区森林生态系统的可持续管理政策。
