重庆酸雨区马尾松林凋落物特征及对干旱胁迫的响应  

The litter-fall characteristics and their response to drought stress in the Masson pins forests damaged by acid rain at Chongqing,China

作　　者：王轶浩[1,2] 王彦辉[1] 于澎涛[1] 熊伟[1] 李振华[1] 郝佳[1] 段健 

机构地区：[1]中国林业科学研究院森林生态环境与保护研究所,国家林业局森林生态环境重点实验室,北京100091 [2]重庆市林业科学研究院,重庆市三峡库区森林生态保护与恢复市级重点实验室,重庆400036 [3]重庆市铁山坪林场,重庆400026

出　　处：《生态学报》2013年第6期1842-1851,共10页Acta Ecologica Sinica

基　　金：中挪合作项目(193725/S30);林业公益性行业科研专项(200904005,200904056,201104005-02);国家林业局森林生态环境重点实验室和重庆市三峡库区森林生态保护与恢复市级重点实验室联合资助

摘　　要：气候变化导致干旱等极端气象事件增多,这将和酸雨等环境胁迫一起影响森林健康。在重庆铁山坪于2010年监测了酸雨区受害马尾松林的凋落物数量和组分特征及其对土壤水分的响应。结果表明:马尾松林月凋落物量呈"双峰"模式,第1高峰出现在8—9月份伏旱期,第2高峰出现在冬季休眠的12月份;枯死针叶占年凋落物总量的48.42%,凋落物组分比例为针叶>树枝>阔叶>有机碎屑>树皮及球果;除阔叶凋落物外,其它组分凋落物在伏旱期均明显增加,与土壤湿度显著负相关,特别是30—40 cm和40—50 cm土层;此外,马尾松林凋落物量还与表征气象干旱的气象指标显著相关。和健康森林相比,酸雨区受害林木的细根数量变少和分布变浅导致马尾松林针叶的年形成量与凋落量减少,但枝凋落量及其占总凋落量的比例增大;凋落发生对干旱胁迫更加敏感,年凋落物量的时间分布更集中在伏旱期;酸雨和干旱的双重胁迫将进一步恶化研究地区的森林健康状况。The health condition of forests especially those already damaged in the acid rain region will be increasingly influenced by the increasing extreme drought events caused by climate change. Understanding the forest health response to multiple stresses is a new challenge. The characteristics of litter-fall can be used as an important indicator to reflect forest health condition and its response to environmental stresses. The aim of this study is to detect how drought stress affect the litter-fall characteristics of forests for a better understanding and more precise prediction of the forest health decline in the acid rain region of south China. Masson pine （Pinus massoniana） is a native and widely distributed tree species in south China. it is also one of the most important tree species used for forestation and widely damaged by acid rain. The litter-fall quantity and its components （dead needles, green needles, twigs, debris, bark and cones, and broad leaves of other tree species） in the Masson pine forest stands were monitored at Tieshanping of Chongqing in 2010, and their responses to soil moisture was analyzed through Pearson correlation. The results showed that the monthly variation of litter-fall presented a ＂two-peak＂ pattern. The highest peak appeared in the dry-summer period of August-September with the lowest soil moisture and amounted to 2.30 t/hm2; the second peak appeared during the dormancy period of December and was only 0.65 t/hm2; the amount of litter-fall in the two peak periods accounted for 49.56% of the annual total （5.96 t/hm2） in 2010. The annual dead needle was 2.89 t/hm2; it accounted for 48.42% of the annual total of litter-fall. The order of weight percentage of the litter-fall components was： needles 〉 twigs 〉 broad leaves 〉 debris 〉 bark and cones. The variation of monthly dead needle amount well presented the variation of total litter-fall amount. The monthly proportion of dead needle to total litter-fall was almost the highest in the whole year and fluctuated

关 键 词：酸雨 干旱胁迫 马尾松林 凋落物 森林健康 

分 类 号：S714[农业科学—林学]