Hurricane Recovery Plots at Harvard Forest since 1937

The New England hurricane of 1938, by destroying many acres of mature and semi-mature forests, initiated new forest associations over a large area. Permanent plots were established across the Harvard Forest in severely damaged stands (many of which were logged subsequent to the hurricane) to assess forest succession. Most of the plots involved successions following the blowdown of white pine on glacial till or outwash soils. From 1940 to 1948, and in 1978 and 1991, tree density and presence or absence of herb and shrub species were tallied. Pioneer species regenerating from seed and advance regeneration of longer-lived species quickly established at the sites; hemlock was the only species successfully regenerating after year 10, and most tree species were present within 2-4 years of the hurricane. By 1978, pioneer species such as gray birch and pin cherry declined or disappeared and red maple, white pine, paper birch and red oak dominated the plots. By 1991, most understory species present before the hurricane had returned, although there was a small group of understory species that apparently were more sensitive to disturbance and did not recover.

1938年新英格兰飓风摧毁了大片成熟与半成熟森林，在广袤区域内催生了全新的森林群丛（forest association）。研究团队在哈佛大学森林（Harvard Forest）内受飓风破坏严重的林分（其中多数在灾后遭到采伐）设立永久样地，以评估森林演替过程。绝大多数样地的演替均发生在冰碛物（glacial till）或冰水沉积土（outwash soils）上的北美白松（white pine）风倒区域。研究人员分别于1940年至1948年，以及1978年、1991年，对样地内的树木密度，以及草本、灌木物种的存在与否进行了统计。由种子萌发的先锋物种与长寿物种的预先生成幼株迅速在样地定植；铁杉（hemlock）是唯一在飓风发生10年后仍成功完成更新的树种，多数乔木树种则在灾后2至4年内便已出现。至1978年，灰桦（gray birch）与山樱桃（pin cherry）等先锋物种已衰退或消失，红枫（red maple）、北美白松、纸皮桦（paper birch）以及红栎（red oak）成为样地的优势物种。至1991年，飓风发生前存在的多数林下物种均已恢复，但仍有一小部分林下物种对干扰较为敏感，未能完成恢复。