Che Cunwei, Xiao Shengchun, Ding Aijun, Peng Xiaomei, Su Jingrong
Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2022 Apr 8;13:862529. doi: 10.3389/fpls.2022.862529. eCollection 2022.
Understanding the temporal-spatial variability of tree radial growth and ecological response is the basis for assessing forest vulnerability in sight of climate change. We studied stands of the shrub Kom. at four sampling sites (natural forest CL and plantation forests XZJ, CK and TPX) that spanned the different precipitation gradient (180-415 mm) across China's western Loess Plateau, and demonstrated its radial growth dynamics and ecological response. We found that the growth of natural in arid regions have adapted and cope with regional environmental changes and radial growth was less affected by drought stress. However, the growth of planted was significantly affected by drought stress in arid and semi-arid regions, especially during the growing season (from June to September). Variations in radial growth rates and growth indicators such as shrub height, canopy area are consistent with the climate-growth relationship. With increase of precipitation, the limiting of drought on the growth of planted gradually decreased and the amount of radial growth variation explained by drought decreased from 53.8 to 34.2% and 22.3% from 270 to 399 and 415 mm of precipitation, respectively. The age-related radial growth trend shows that radial growth increased until 4 years of age, then decreased rapidly until 12-14 years of age, and then eventually tend to stabilized. In the context of climate warming and humidification, increased precipitation and regular branch coppicing management at around 12 years old will help to mitigate the limitation of drought on the growth of . Moreover, the initial planting density should be tailored to local precipitation conditions (below 5,000 shrubs per hectare). The above results have important practical significance for the maintenance of the stability and sustainable management of plantation forests in the western Loess Plateau.
了解树木径向生长的时空变异性及其生态响应是从气候变化角度评估森林脆弱性的基础。我们研究了中国西部黄土高原不同降水梯度（180 - 415毫米）的四个采样点（天然林CL以及人工林XZJ、CK和TPX）的柠条锦鸡儿林分，展示了其径向生长动态和生态响应。我们发现，干旱地区天然柠条锦鸡儿的生长已经适应并应对区域环境变化，其径向生长受干旱胁迫的影响较小。然而，干旱和半干旱地区人工柠条锦鸡儿的生长受到干旱胁迫的显著影响，尤其是在生长季节（6月至9月）。径向生长速率以及诸如灌木高度、冠幅面积等生长指标的变化与气候 - 生长关系一致。随着降水量增加，干旱对人工柠条锦鸡儿生长的限制逐渐降低，干旱解释的径向生长变化量分别从降水量270至399毫米时的53.8%降至降水量415毫米时的34.2%和22.3%。与年龄相关的径向生长趋势表明，径向生长在4岁前增加，然后在12 - 14岁迅速下降，最终趋于稳定。在气候变暖和湿润的背景下，增加降水量以及在12岁左右定期进行平茬管理将有助于减轻干旱对柠条锦鸡儿生长的限制。此外，初始种植密度应根据当地降水条件进行调整（每公顷低于5000株灌木）。上述结果对黄土高原西部人工林稳定性的维持和可持续经营具有重要的现实意义。
