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，在广阔区域内催生了全新的森林群落。研究团队在哈佛森林（Harvard Forest）内受飓风严重破坏的林分（其中多数在飓风灾后遭到采伐）设立永久样地，以开展森林演替评估。绝大多数样地聚焦于冰碛物（glacial till）或冰水沉积土壤（outwash soils）上的白松风倒区的森林演替过程。分别于1940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更新幼苗快速在样地定植；飓风发生10年后，铁杉（hemlock）成为唯一成功完成自然更新的乔木物种，而绝大多数乔木物种在灾后2至4年内便已出现。至1978年，灰桦（gray birch）与苦樱桃（pin cherry）等先锋物种逐渐衰退乃至消失，红枫（red maple）、白松（white pine）、纸桦（paper birch）及红栎（red oak）成为样地的优势树种。至1991年，飓风发生前存在的绝大多数林下物种已恢复，但仍有一小部分林下物种对干扰更为敏感，未能完成恢复。