东亚地区夏季干旱、强台风事件与松树枯萎病的关系

松树枯萎病的发生和流行给东亚的日本、中国和韩国带来了不小的损失,引起许多国家的重视. 本文应用实地观测和气象数据分析等方法,研究了东亚地区松树枯萎病的发生和流行特点，以及与灾害气象事件之间的关系.结果表明: 在日本、中国和韩国，持续的夏季干旱少雨和强台风等极端气象事件能够诱发松树枯萎.在极端干热的环境中,松树常出现能量代谢失调, 以至于受胁迫的松树整株枯萎；而在低温多雨的年份，松树枯萎少,甚至没有发生枯死现象.在松材线虫及其媒介昆虫侵染之前，松树的活力业已下降.松树枯萎病似乎应该局限在台风频发和持续干热的地区.在自然环境优越、少有台风和干热事件出现且没有不当扩大松树栽培范围的地区，松树枯萎病大面积发生的可能性不大.

Responses of grassland net primary productivity in western Songnen Plain of Northeast China to climate change and human activity

By the methods of correlation analysis and buffer analysis,and taking two main climate factors(air temperature and precipitation) and two main human activity areas(road and residential land) into account,this paper studied the effects of climate change and human activity on grassland net primary productivity(NPP) in western Songnen Plain in 2000-2009.In the past ten years,the mean air temperature in the study area was 5.39 ℃,which increased from north to south,and the mean precipitation was 378 mm,which decreased from northeast to southwest.The grassland NPP increased with the increase of air temperature and precipitation.Compared with air temperature,precipitation affected NPP more obviously,which accorded with the special climate conditions of water shortage in western Songnen Plain.The difference in the NPP was not significant at yearly scale but extremely significant at monthly scale,indicating that time scale had remarkable effects on the statistical significance.The effects of road and residential land on the NPP were completely opposite.The closer to the road,the larger area the grassland with good plant growth,which could related to the appropriate management measures and the ways of local human activities;while the further to the residential land,the weaker the human activities intensity or their capabilities in affecting the grassland,the better the plant growth on the grassland.Compared with road,residential land had more obvious effects on the grassland NPP,possibly due to the higher density of residential land and the more frequent building construction,reclamation,and grazing caused by population increase.