长白山白桦径向生长季节动态及其对环境因子的响应

Seasonal dynamics of radial growth of Betula platyphylla and its response to environmental factors in Changbai Mountains

白桦(Betula platyphylla)作为温带次生林的典型先锋树种,在森林生长研究中具有重要意义。该研究利用微树芯法连续监测了长白山两个生长季(2020-2021年)白桦径向生长的季节动态,并分析了其与环境因子的响应关系。结果表明,白桦形成层于5月中下旬开始活动,6月和7月为快速生长期,9月下旬木质化结束。2021年早春温度升高导致白桦径向生长提前开始,但两年径向生长停止的时间无显著差异。在快速生长期,白桦径向生长速率与平均气温、最低气温、相对空气湿度和土壤温度呈显著正相关关系,与饱和水汽压差呈显著负相关关系;而在慢速生长期,白桦径向生长速率仅与最低气温和土壤温度呈显著正相关关系;在较干燥年份,土壤含水量降低显著抑制了白桦径向生长,温度始终是影响白桦年内径向生长的主要气候因子。研究结果对白桦林的经营和可持续管理具有参考价值。

Aims Betula platyphylla,as a typical pioneer tree species in temperate secondary forests,has important significance in forest growth research.Methods In this study,microcoring method was used to continuously monitor the seasonal dynamics of radial growth of B.platyphylla in Changbai Mountains during two growing seasons(2020-2021),and the relationship between radial growth and environmental factors was analyzed.Important findings The results indicated that the cambium of B.platyphylla became active in mid to late May,with June and July being the periods of rapid growth,and the lignification ended in late September.The increase of temperature in early spring in 2021 led to an early onset of cambial activity,but there was no significant difference in the time of radial growth cessation between the two years.During the rapid growth period,the radial growth rate of B.platyphylla showed a significant positive correlation with mean air temperature,minimum air temperature,relative air humidity and soil temperature,while it exhibited a significant negative correlation with the saturation vapor pressure deficit.During the slow growth period,the radial growth rate showed a significant positive correlation only with the minimum air temperature and soil temperature.In the drier year,the decrease of soil water content significantly inhibited radial growth of B.platyphylla.Temperature was the main factor affecting intra-annual radial growth.The findings of this study provide valuable insights for the sustainable management of B.platyphylla forests.