【作者】 王晓春；

【导师】 周晓峰；

【作者基本信息】 东北林业大学 ， 生态学， 2004， 博士

【摘要】 本文采用树木年轮气候学、树干解析、地统计学以及遥感影像解译等方法并结合当地气候资料分析，以中国东北地区亚高山林线与全球气候变化之间的关系为核心，依照现代生态学的层次观，以吉林省长白山和黑龙江省老秃顶子林线为例，从个体、种群、生态系统和景观水平系统地分析了亚高山林线过渡带中树木年轮宽度、高生长、径生长、材积生长、种群年龄结构和种群个体空间分布格局等对全球变暖的响应，并且应用不同时期TM图像分析了全球变暖对林线位置、形状、宽度，以及林线景观格局指数和NDVI植被指数等景观特征的影响，得出如下结论： 1、近50年中国年平均气温以0.04℃／10a的速率上升，这一趋势与全球变暖的趋势相一致。就地区而言，东北地区升温趋势最明显。大海林和长白山地区近几十年来气温呈上升趋势，尤其是月最低温、寒冷时期和温暖时期温度升高非常明显，积温也有所增加；月均温中，以2月份增温幅度最大，季节均温中，以冬季增温最明显；季节热幅减少，但全年的总量有所增加。降水资料分析结果表明，大海林地区年降雨量波动性略有增加，但不是十分明显。长白山林线区夏季降水量呈下降趋势，春季、秋季和冬季的降水量都呈轻微的上升趋势，年降水量也呈下降趋势。 2、年轮指数与气候因子相关性分析表明，温度对高山林线树种的影响明显，而降雨的影响相对较弱，6～9月温度和积温与年轮指数呈正相关，寒冷时期的温度与年轮指数呈负相关。对1905年以来老秃顶子地区的夏季平均温度进行了重建，重建值和实测值的基本趋势非常一致，表现出明显的上升趋势。 3、对林线过渡带内树木年轮结构进行分析，结果表明中年树木对气候变暖最为敏感，岳桦对气候变暖的敏感性要比云冷杉大，在不同的岳桦个体中又以林线的中上部敏感度最好。气候变暖造成树木直径生长增加，年轮指数的变化趋势与气候变暖非常一致，表明气候变暖已经在林线树木个体生长中得到响应。 4、岳桦解析木分析表明，随着全球气候变暖，年径生长量增大；高生长也增加，但增加的幅度非常小，材积生长指数也增加。通过相关分析可知，径生长、高生长、材积生长与温度的相关性较强，与降水的相关较弱；在温度中与6～9月的平均温度相关较大，在测树因子中，径生长与温度的相关较大，表明径生长对气候变化更为敏感。 5、通过传统的数理统计分析和地统计学分析，结果表明气候变暖使得林线过渡带中上部的幼苗、幼树增多，径级和年龄分布呈倒J字型，种群呈聚集分布，空间异质性由空间自相关引起，对空间占据能力相对较弱，种群呈增长趋势；在林线过渡带的中下部和岳桦的典型分布区，岳桦大树较多，种群呈随机分布，空间异质性主要由随机性因素引起，对空间占据能力较强，种群呈稳定态势；整个岳桦种群随着全球气候变暖有一种整体向上迁移的趋势，岳桦向苔原侵入的程度加强。全球变暖导致林线上部更新增多，从林线上部到林线下部树木的密度降低，而树高增大，树木年龄增高。 6、通过对不同时期老秃顶子林线区域的景观变化分析，结果表明随着全球气候变暖林线上升，北坡相对较快，其它坡向相对较慢。全球变暖使林线形状更趋于复杂化，全球变暖还对岳桦郁闭林与疏林之间的过渡带和岳桦疏林灌丛与山顶裸地之间的过渡产生影响，使得峭度降低，过渡更为缓慢，整个林线的宽度加宽。 7、林线区域的景观格局分析表明，从1985年到1997年，老秃顶子林线区域景观中阔叶林面积有所增加，山顶裸地的面积减少，斑块数量增多，斑块密度加大，平均斑块大小减少，斑块间的毗连程度减弱，但是斑块的形状逐渐趋于相对规则，斑块的边界趋于简单化，说明全球变暖使林线向山顶裸地侵入加剧，异质性增强，斑块的连通度减弱，整个林线景观逐渐趋于破碎化。 8、通过对老秃顶子林线两个时相NDVI的变化分析中得出，全球变暖使山顶裸地的NDVI植被指数增加，尤其是在有植被与无植被的交错区NDVI变化明显，表明从1 985年到1997年林线向上迁移，使得裸地边缘的植被指数增加;因此，可以得出全球变暖己经对林线区域的景观产生了影响。更多还原

【Abstract】 According to the hiberarchy of modern ecology, focusing on the relationship of global climate change and the subalpine timberline in northeast China, a case study was carried out at the timberlines of Changbai Mountain in Jilin Province and Laotudingzi Mountain in Heilongjiang Province. The responses of ring width, growth in high, diameter and volume, population age structure and spatial distribution of trees at the timberline to global warming at individual, population, ecosystem and landscape scales were studied by using the methods of dendroclimatology, stem analysis, geostatistics, remote sensing image and the local climate data analysis. The effects of global warming on the location, shape, width, pattern index and NDVI of the timberlines landscape character were analyzed. The main results are as follwing:The annual mean temperature increases as 0.04C/10a in China in recent 50 years. This trend is consistent with global warming. In terms of region, the warming in Northeast is clear, and the trend of subalpine timberline in Northeast is more significant.The climate data in Changbai Mountain and Dahailin region show that the global warming was very obvious in recent several decade years, especially the lowest month temperate, cold and warm periods temperature. The accumulated temperature increased slightly. February was the month with the greatest increaseing magnititude in a year. As to seasonal changes, winter was the most obvious. The seasonal thermal amplitude decreased, while the whole year heat increased. The rainfall data show that annual rainfall in Dahailin fluctuated with sightly increase, but there was no clear trend. The rainfall in Changbai Mountain showed that there was a decreasing trend in summer, and aslight increase in spring, autumn and winter. However, the annual rainfall exhibited decreasing trend.The correlation analysis between the ring index and the climate factors suggests that the ring index at timberline was strongly correlated with the temperature and slightly with precipitation. However, the warm period temperature and accumulated temperature were the positively correlated with the ring index, and the cold period temperature and mean annul temperature were negatively correlated with the ring index. According to the relationship between annual ring index and summer mean temperature, the summer temperature has been reconstructed in Laotudingzi region since 1905. Though there were some offset between reconstruct value and observed value, the increase trend was consistent.The results of tree annual ring analysis at timberline shows that trees with different age structure response to global change differently, and the middle-aged tree were the most sensitive. The different species and location were also different. With comparision, the sensitivity of Betula ermanii was better than that of spruce-fir, and it is mainly related with the location, and the middle-aged tree had the better sensitivity. The global warming resulted in the increase of diameter growth, and the trend of annual index was consistent with the trend of temperature.Through stem analysis, the growth in diameter, height and volume increased with global warming, but the height growth trend was the lowest. With the correlation analysis among measured trees and climate factors, the growth index of height, diameter and volume correlated with temperature strongly, with rainfall slightly or irrelative. Among the temperature factors, the mean temperature from June to September was more important, and the diameter growth was the clearest in the measured tree factors. The result indicates that the individual trees at timberline have been response to global warming.The effects of global climate change on timberline have been demonstrated by the difference of distribution and dynamics of structure with traditional statistics and geostatistics. The results show that the seedling and young tree predominated in upper timberline with global warming, the class structure showed inverse J type, and the population pattern exhibited更多还原