长白山红松不同树高处径向生长特征及其对气候的响应

利用长白山红松不同树高(0.3、1.3、4、10、15、20、25 m)处的径向生长资料,分析各树高处径向生长特征,建立红松生长与气候因子的相关关系,以期完善红松种群对气候变化的响应机制。结果表明:(1)红松不同树高处年径向生长量变化趋势基本一致,除在1980年前后,20 m处径向生长量出现异常增加外,其他各高度径向生长均出现下降趋势,红松基部和顶端(0.3、1.3 m和20 m)处径向生长年际变化更明显。随着树高增加,各处年径向生长率有所降低,0.3m处生长速率最大,且与10 m和15 m处径向生长差异显著(P < 0.05)。(2)不同树高处径向生长对气候因子的响应存在明显差异,10 m树高是红松径向生长对温度和降水响应差异的分界线。10 m以下红松径向生长主要受到生长季温度的负作用,尤其是4 m处,与当年生长季初期(4月和5月)温度显著负相关(P < 0.05)。0.3 m和1.3 m处径向生长分别与上年9月平均温度显著正相关(P < 0.05),当年6月平均和最高温度显著负相关(P < 0.05)。随着树高上升,降水对径向生长的促进作用增强,而温度对径向生长的作用也发生改变。10 m(含)以上则受到温度和降水的共同作用。10 m处径向生长对气候因子响应最敏感,受到当年生长季高温的抑制作用,还与上年和当年生长季末(9月)降水显著正相关(P < 0.05)。15 m处径向生长与上年9月最低温度和降水显著正相关(P < 0.05),而与当年5月月平均温度显著负相关(P < 0.05)。20 m处径向生长与当年3月月平均、最低和最高温度,当年7月月平均温度以及当年5月降水显著正相关(P < 0.05),而与当年1月降水显著负相关(P < 0.05)。

Characteristics of Korean pine (Pinus koraiensis) radial growth at different heights and its response to climate change on Changbai Mountain

Understanding the relationship between climate and growth at different heights gives insight into the mechanisms by which trees respond to climate change. In this paper, tree-ring data at different heights (0.3, 1.3, 4, 10, 15, 20, and 25 m,) on the north side of Korean pine (Pinus koraiensis) trees on Changbai Mountain were collected from 155 cores, taken from 25 Korean pine trees. Dendrochronology and a multiple comparison method (LSD) were used to analyze the radial growth characteristic and the climate-growth relationship. The results show that the trends in annual radial growth of Korean pine at different heights were essentially identical. Apart from an abnormal increase in the annual radial growth at a height of 20 m around 1980, the annual radial growths at other heights showed a downward trend. The most obvious variations were found at the base (0.3 m and 1.3 m) and crown (20 m) of Korean pines. With increasing tree height, the annual growth rates at different heights were all reduced. The maximum growth rate was observed at a height of 0.3 m, which was significantly different from the annual growth rates at 10 m and 15 m (P < 0.05). We identified a differential response of radial growth to temperature and precipitation at different heights, depending on whether the height was above or below 10 m. Radial growth at heights below 10 m was mainly controlled by temperature, particularly at a height of 4 m. The radial growth at 0.3 m and 1.3 m was significantly positively correlated with monthly mean temperature in September of the previous growing season (P < 0.05) and significantly negatively correlated with the monthly mean and maximum temperatures in June of the current growing season (P < 0.05), respectively. At a height of 4 m, the radial growth was significantly negatively correlated with the temperature at the beginning of current growing season (May and June) (P < 0.05). The positive influences of precipitation on radial growth became stronger and the impact of temperature on growth also changed with increasing tree height. Radial growth at heights above 10 m was strongly affected by both temperature and precipitation. The radial growth of Korean pine at a height of 10 m was much more sensitive to the climate than that at other heights. Radial growth at a height of 10 m was significantly negatively correlated with the temperature in the current growing season, and significantly positively correlated with precipitation at end of the previous and current growing seasons (September) (P < 0.05). The radial growth at a height of 15 m was significantly positively correlated with the monthly minimum temperature and precipitation in September of the previous season (P < 0.05), but negatively correlated with the monthly mean temperature in May of the current season (P < 0.05). At a height of 20 m, radial growth was significantly positively correlated with the monthly mean and maximum and minimum temperatures in March of the current season, and with the monthly mean temperature in July of the current season (P < 0.05).