【作者】 雷静品；

【导师】 肖文发；

【作者基本信息】 中国林业科学研究院 ， 生态学， 2009， 博士

【摘要】 全球气候变化是人类生存所面临的重大问题,而三峡库区因地形复杂,物种丰富、群落多样,一直是我国乃至世界研究关注的热点地区,因此三峡库区主要树种的生长与气候因子之间的关系以及其森林健康问题成为本研究的主要内容。树木年轮气候学是以植物生理学为基础,以树木年轮生长特性为依据,研究气候对树木生长影响的程度。本研究试图通过树木年轮学的方法,解释三峡库区主要树种生长与气候因子之间的关系,从森林经营的角度通过影响森林生态系统的结构、环境因子,试图改善森林健康状况,提高森林结构多样性,增强森林抵御外界干扰的能力,实现三峡库区森林的健康、持续、稳定发展。本研究利用库区森林资源二类清查资料和国家气象局气象网站多年历史数据,调查库区主要县市的森林虫害发生历史记录,对其森林健康状况进行了评价和分类,对虫害发生和危害等级进行了划分,并建立了地理信息系统。通过样地调查和树木年轮资料的获取,分析主要树种生长趋势,建立主要树种不同地域、不同海拔高度树木生长与气候因子之间的关系模型。通过一定的经营措施,试图通过改变林分微环境控制和改善叶蜂危害状况。分析结果表明:1.马尾松生长不同海拔对气候的响应不同,海拔600m时,马尾松生长主要受5,6月份的降雨和5,6月份的湿度指数影响,而海拔900m时受5,6月份温度和上年11月份降雨和湿度指数影响。2.库区中游云阳县分布上限的马尾松树轮宽度指数变化幅度大于下限,且上限树轮样本的信噪比、样本总体代表性要高于下限的。总体来讲,上限树木的生长对环境的敏感性高于下限的。进一步分析表明上限马尾松生长受前一年温度和降水的影响,而分布在生长下限的马尾松生长只与当年降水有关,这表明云阳分布在上限的马尾松和分布在下限的马尾松生长与气候因子之间的关系不同;气候因子对分布在上限的马尾松生长的影响存在滞后效应。3.运用相关函数及单年分析等树木年轮气候学方法,研究三峡库区上游马尾松径向生长与气候变化的关系,结果表明,马尾松的生长对环境变化比较敏感,不同海拔马尾松对降雨量和气温的响应不同,海拔600 m处马尾松生长与5,6月份的降雨和湿润指数显著相关,而海拔900 m处马尾松与环境的关系相对复杂,除受当年5,6月份温度影响外,还受上年11月份湿润指数的影响,说明同一地区不同海拔梯度的马尾松对气候的响应具有不同特征。最后用多元回归模型回归了马尾松径向生长与气候因子之间的关系。4.利用虫害发生的历史记录,按照单位时间内虫害发生的频率划分为频发区、偶发区和安全区。秭归为湖北库区病虫害发生频率最严重的县,频发区为茅坪镇;偶发区为郭家坝镇和归州镇;除此外基本属于安全区域。而夷陵县马尾松毛虫则在太平溪镇、乐天溪镇和小溪塔镇为频发区;三斗坪镇和雅雀岭镇为偶发区;其他地区均为安全区。5.各种气象因子综合作用于马尾松毛虫的发生,秭归县马尾松毛虫的发生主要受受温度和日照的影响比较显著,其次为风速,马尾松毛虫的发生面积主要与当年4月份的平均温度、最高温度、最低温度和日照时数相关。6.通过主成分分析,影响夷陵地区马尾松毛虫发生的主要是降雨、日照和温度,通过月份气象因子的分析,4月份的平均温度、4月份日照时数和5月份总降雨量与马尾松毛虫发生面积之间存在显著正相关关系。7.不同带宽改造后对林分径级组成的影响主要在小径级林木,即改造后无论哪种带宽,都表现出低径级林木株数增多的现象,而对高径级则影响不大。不同树种改造带柏木更新幼苗数量都比未改带有明显的增加,而不同树种在改造带内所产生的环境条件的不同,导致柏木幼苗数量的差异。8.带状改造后对Simpson指数的影响不同,20m带宽改造对于灌木层来讲,Simpson指数改造带平均0.4813,未改带为0.6078,未改带高出改造带20.8%,而草本却恰恰相反,改造带0.6478,未改造0.4393,改造带高出未改带32.2%。6m改造后灌木层生物多样性指数D,H与20m结果一致,S则是改造带小于柏木带,与20m处理的结果相反。20m带宽改造后Shannon-Wiener指数与Simpson指数的结果相似,改造带灌木:0.985,未改带灌木1.2609,未改带比改造带高21.8%,改造带草本1.3403,未改带0.8767,改造带比未改带高出34.6%。9. 6m带宽改造后9,10月份平均温度分别比20m带宽高0.85℃,0.62℃,最高温度之间分别相差0.39℃和0.77℃,6m带宽的较差要比20m的低,说明改造带窄,整个林分的郁闭度比20m的高,土壤温度由于太阳辐射影响而产生的温度差异要小。10.带状改造后改造带内部与边缘叶蜂幼虫的数量存在显著差异,而不同带宽之间没有产生显著差异,带宽改造带内叶蜂入土的数量显著高于林分边缘,而不同带宽之间没有显著差别。叶蜂入土主要集中在5月9-18日的10天之间。6m带宽、20m带宽及20m改造林缘在这10天内截获的幼虫数量分别占截获幼虫总数量的85%,88%和79%。即平均84%的叶蜂幼虫是在5月9-18日之间入土。11.不同带宽改造对土壤理化性质的影响不同,土层深度20～40cm的土壤容重降低的幅度20m带宽要高于6m带宽改造,而土层0～20cm土壤容重降低的幅度6m带宽要高于20m带宽改造;6m改造带土层0～20cm和20～40cm土壤总孔隙度分别提高4.7%、1.6%,而20m改造带土层0～20cm土壤总孔隙度提高23.4%,土层20～40cm土壤总孔隙度比对照则降低了29.4%。土壤有机质由于改造后林分环境条件的不同,使有机质积累和分解的速度不同,导致20m带宽改造后土层0～20cm和20～40cm有机质含量比对照分别提高了15.0%、28.4%。6m带宽改造土层20～40cm有效N含量增加32.779mg·kg-1,20m带宽改造后速效N、速效K、全P、全K含量有不同程度的提高。带宽改造对改良土壤结构,提高土壤理化性质都有不同程度的改善。通过对三峡库区主要树种林木生长与气候因子关系分析以及森林健康经营研究,可以为三峡库区生态建设规划布局、工程模式选择等提高科学依据。更多还原

【Abstract】 In this paper, the forest health conditions were classified using the forest inventory data and historical documentation about forest insects of the main counties/cities in the Three Gorges Reservoir Area. The geographic information system of forest insect frequency was established based on the different classification and gradation of forest insect and frequency. The growth trends of main tree species were analyzed and the correlation model of main tree species in different regions and elevation gradients was simulated. Forest health management measures have been adopted to control the harm of Chinolyda flagellicorn through changing forest environment. The results are shown as follows:1. The relationship of Pinus massoniana radial growth with climatic factors of different elevations was assessed by dendrochronological techniques including correlation functions and single-years analysis. Finally the correlation model of tree ring width index and climatic factors in different elevations was simulated by multi-factor regression. The results showed that the character of ring width index of Pinus massoniana is different because of the altitude gradients due to complex topography. And growths in different elevations had significantly different responses to temperature and precipitation. In normal climatic conditions, the growth at the elevation of 300m was significantly affected by mean monthly precipitation and humid index of last June and October, and there is no significant correlation to climatic factors of the current year. The growth at the elevation of 600m was significantly correlated to the temperature of last June and mean monthly precipitation and humid index of current July. At 900m the growth was not only affected by the temperature of current February, but also affected by the mean precipitation and humid index of December. The relationship was verified by single year analysis.2. Tree-ring cores were collected from the low and upper altitude limits of Pinus massoniana in Yunyang County, Chongqing City. Two tree-ring width chronologies were established using standard dendrochronological methods, respectively. The two sampling sites are located close to each other but at different elevations. Results indicated that the chronology fluctuation of the upper altitude limit is higher than that of the low limit. The statistical character of the chronology shows that signal to noise ratio (SNR.) and express population signal (EPS) of upper limit are higher than those of low limit. Therefore, the sensitivity of trees’response to the climatic changes increased with increasing altitude. In order to understand the varying response of tress at different elevations to environmental changes, the correlations between the chronology indices and precipitation and between air temperature in different seasons and different months were calculated. The results show that the growth of Pinus massoniana of upper limit was affected by temperature and precipitation of previous year, and that of low limit was only affected by precipitation of current year. It showed that there is lag-effect of the growth of upper limit in response to climate factors.3. The relationship of Pinus mussoniana radial growth in upper reaches of the Three Gorges Reservoir Area in China with climate change was assessed by dendrochronological techniques including correlation functions and single-years analysis. The results showed that Pinus mussoniana growths at high and low elevations had significantly different responses to temperature and precipitation. At low elevation, Pinus mussoniana growth was significantly correlated to the mean precipitation and the humid indices of May and June, but at high elevation, it had a more complicated relationship with the environment. Besides the mean temperature of May and June, the humid index of last November was significantly correlated with the Pinus mussoniana tree-ring width. Therefore, it was not the same relationship of the same tree species with different environmental gradients. Finally the correlation model at different elevations of tree ring width index and climatic factors was simulated by multi-factor regression.4. The frequent area, accidental area and safety area were classified in Hubei province of the Three Gorges Reservoir Area (TGRA) according to frequency of forest insects and diseases based on documented records. Zigui County is the most serious county in TGRA. In Zigui County the frequent area is Maoping Town; accidental areas include Guojiaba Town and Guizhou Town, and the other areas are safety area. In Yiling Couty, the frequent areas are Taipingxi Town, Letian Town and Xiaoxita Town; accidental areas are Sandouping Town and Yaqueling Town, while others are safety areas.5. Various climate factors have an integrated effect on the occurring of Dendrolimuspunctatus Walker. Air temperature and sunlight time are the premier driving factors and wind speed is secondary in Zigui county; The occurring area of Dendrolimuspunctatus Walker is significantly related to air temperature, temperature maximum and minimum and sunlight time of current April.6. The relationships between Dendrolimuspunctatus Walker occurring area and climate factors are same in Yiling County with Zigui County. Precipitation, sunlight time and air temperature significantly affect the insect occurring area in Yiling County. The occurring area was found to be mainly positively correlated with the average temperature and sunlight time of April, and total monthly precipitation of May.7. We try to control Chinolyda flagellicornis by changing forest environment with the measure of strip reform. The result showed that: the influence on forest composition structure mostly focuses on smaller diameter class. Whatever width the strip reform was taken to, the number of smaller diameter class increases significantly, and there is no great effect on larger diameter class. As the sunlight becomes stronger after strip reform, the temperatures of soil and air in forest are higher, and air humidity is lower. All these changes affect the regeneration of Cupressus funebris.8. Effects of strip reform to cypress plantation were analyzed in the view of biodiversity and forest stand environment including index of biodiversity of undergrowth vegetation species, air temperature in stands, and soil temperature of different strip width treats. The result showed that: there were different effects on undergrowth biodiversity by strip reform to different width. For 6 m width strip reform, only index of D, H from shrub layer has increased and there was no significant effect on S and D, H, S of herb layer. , The species composition was not significantly changed after 20 m width strip reform except different importance values. Mbawmagyabceij of Rhamnaceae replaced Rosaceae plants and became the dominant species in 6 m width strip reform in shrub layer identically, and biological diversity of shrub layer was different at different strip width. Monocotyledon was replaced by dicotyledon gradually as the dominant species as the sun plants increasing as the result of the forest stand environment change. The influences on air temperature and soil temperature of different strip reforms are different. The soil temperature variance is lower than in 20m width strip and air temperature variance of 6m width strip is higher than 20m width strip.9. The average air temperature of September and October in 6m strip reform was 0.85℃, 0.62℃higher than in 20m strip reform respectively. The maximum temperature difference between the two strip widths was about 0.39℃and 0.77℃respectively which means the temperature difference in 6m strip width is lower than in 20m strip reform. All these were resulted from the difference of shade density caused by the different width strip. The soil temperature difference is lower than air temperature after strip reform operation in either width.10. There is significant difference of the number of larva of Chinolyda flagellicorn in the strip and the edge of the strip, and no significant difference with the width of strip. The number of larva in soil inside the strip is larger than that in forest edge, and there is no significant difference with the width of strip. The time of larva going into earth is consistent with the different width strip, mainly during 9-18 of May. There are about 85% and 78% larva going into the earth respectively in 6m and 20m width strip during the ten days. 84 percent of total larva goes into earth during 9-18 of May averagely.11. The soil physical and chemical properties have been comparatively studied with different width strip reforms. The result showed that: decrease extent of soil capability in the depth of 20-40cm soil layer in 20m width strip reform is much higher than in 6m, but the result is converse in 0-20cm soil layer. The total soil porosity increased by 4.7%, 1.6% in 0-20cm and 20-40cm respectively in 6m width strip, and by 23.4% in 0-20cm in 20m width strip, while the total soil porosity decreased by 29.4% in 20-40cm soil layer to the contrary. The soil organic matter increased by 15.0%、28.4% in 0-20cm and 20-40cm soil layer respectively after 20m width strip reform because of the difference of decomposition speed. Available N increased 32.779mg·kg-1 in 20～40cm soil layer after 6m width strip reform. Available N Available N, available K, total P and total K increased to certain extent in 20m width strip reform. The soil structure and its physical and chemical properties have been improved after strip reform. It will provide a scientific basis for the ecological improvement planning and the choice of project model for the Three Gorges Reservoir Area through the research on growth of Pinus massoniana and Cupressus funebris plantation and health management.更多还原