不同径级红松径向生长对气候变化的响应

运用树木年轮气候学方法,研究原始阔叶红松林分布区内白石砬子自然保护区(40.9° N)、长白山自然保护区(42.4° N)、凉水自然保护区(47.2° N)和胜山自然保护区(49.4° N)4个纬度样地的2个径级红松径向生长对气候变化的响应,分析不同径级红松对气候因子响应的异同,以及影响不同纬度红松径向生长的关键气候因子,探讨气候变化显著的40多年中红松径向生长的变化动态.结果表明: 2个径级红松对气候因子的响应具有很大的相似性,但是小径级(胸径为10～20 cm)红松对当年生长季的平均最低气温以及上一年的气候因子更敏感,而大径级(胸径>40 cm)红松对当年生长季的平均最高气温和平均相对湿度更敏感.影响4个纬度样地红松径向生长的关键气候因子存在一定差异:在最南端的白石砬子自然保护区是当年生长季的季均气温和季均最高气温;最北端的胜山自然保护区是低温因子,包括所有季节的平均最低气温、冬季的平均最高气温,以及除上一年生长季末期和当年生长季以外所有季节的平均气温;中间纬度的长白山自然保护区是当年生长季和生长季末期的帕尔默干旱指数(PDSI)和当年生长季的降水量;凉水自然保护区是当年生长季的平均气温.在气温不断上升的40多年,最南端的2个径级红松径向生长均显著下降,最北端均显著上升,中间2个纬度样地变化均不显著.

Response of radial growth to climate change in Pinus koraiensis with different diameter classes

Dendrochronological techniques were used to study the response of radial growth of Pinus koraiensis with different diameter classes to climate change throughout the natural range of broad-leaved Korean pine forests, including Baishilazi Nature Reserve (40.9° N), Changbai Mountain Nature Reserve (42.4° N), Liangshui Nature Reserve (47.2° N), and Shengshan Nature Reserve (49.4° N). We investigated the similarities and differences of growth responses of different diameter classes to climate factors and clarified the key climate factors affecting the growth of P. koraiensis at different latitude sites. We explored the dynamic changes of the radial growth of P. koraiensis from the latitudinal gradient over the past 40 years. The results showed many similarities in the response of two diameter classes to local climate factors. Small diameter (diameter at breast height of 10-20 cm) trees were more sensitive to the changes of average minimum temperature of the current growing season and the meteorological factors of the previous year, whereas large diameter (diameter at breast height >40 cm) trees were more sensitive to the changes of average maximum temperature and average relative humidity of the current growing season. The key meteorological factors that affecting radial growth of P. koraiensis differed along the latitude gradient. In Baishilazi Nature Reserve, the southernmost plot, the key climate factors were the average maximum temperature and the average maximum temperature in the current growing season. In Shengshan Nature Reserve, the northernmost sample plot, the key climate factors were low temperature factors, such as the minimum temperature in all seasons, the average maximum temperature in winter, the average temperature of all seasons except for the end of previous growing season and the current growing season. The Palmer drought severity index (PDSI) in the current growth season and the end of the current growth season and the precipitation in the current growth season were the key climate factors in Changbai Mountain Nature Reserve. The average temperature of the current growing season was the key climate factor of Liangshui Nature Reserve. In recent four decades, with the rising of temperature, the radial growth of P. koraiensis of two diameter classes significantly decreased in the southernmost point, significantly increased in the northernmost point, and had no significant variation in middle latitudes.