Hain F P
Department of Entomology, Box 7626, North Carolina State University, Raleigh, NC 27695, USA.
Tree Physiol. 1987 Mar;3(1):93-102. doi: 10.1093/treephys/3.1.93.
Hypotheses of forest decline are summarized. Stressed trees may be a more suitable food source for invertebrate herbivores than unstressed trees because stress causes an increase in the tissue content of soluble nitrogenous compounds. There is reasonable correlative evidence that air pollutants influence the outbreak patterns of forest insect species. In some cases, formerly innocuous insects may become pests. The occurrence of specific insect pests with specific air contaminants is reviewed. Emphasis is placed on the decline of Fraser fir (Abies fraseri (Pursh) Poir.) in the southern Appalachians and the occurrence of the balsam woolly adelgid. Variable mortality patterns of Fraser fir may be caused by locally distributed air pollutants acting in combination with other types of stress including that caused by the adelgid.
对森林衰退的假说进行了总结。与未受胁迫的树木相比，受胁迫的树木可能是无脊椎食草动物更适宜的食物来源，因为胁迫会导致可溶性含氮化合物的组织含量增加。有合理的相关证据表明，空气污染物会影响森林昆虫物种的爆发模式。在某些情况下，以前无害的昆虫可能会变成害虫。综述了特定害虫与特定空气污染物的发生情况。重点关注了阿巴拉契亚山脉南部弗雷泽冷杉（Abies fraseri (Pursh) Poir.）的衰退以及香脂冷杉球蚜的发生情况。弗雷泽冷杉不同的死亡模式可能是由局部分布的空气污染物与包括香脂冷杉球蚜造成的胁迫在内的其他类型胁迫共同作用引起的。
