Ungulate-Forest Interactions in Partially Harvested Oak-Pine Stands in Central Massachusetts 2009

Ungulates are attracted to forest openings created by natural disturbance and timber harvesting due to the abundance of high quality browse in these openings. Despite the increased activity and browsing of ungulates in forest openings, the importance of browsing relative to abiotic factors such as light on forest regeneration is often unclear. In southern New England, medium-intensity harvesting is the predominant forest disturbance attracting white-tailed deer and moose. Oaks are the foundation hardwood taxon and predominant timber tree in the region and are in decline. Hence, the effects of ungulate browsing on oak forests are of great interest to ecologists, conservationists and forest and wildlife managers. We sampled tree regeneration and ungulate foraging activity across a range of canopy disturbances (35-90% basal area removed) in 34 stands of the Quabbin and Ware River Watershed Forests. Browsing was very high across the plots with about 80% of red maple and oak stems browsed. Taller stems were generally browsed more frequently than shorter stems. Oak regeneration in the smaller size classes was generally lower in stands with higher percent cover of hay-scented fern. The proportion of browsed red maples and oaks generally increased with increasing density of these taxa. Despite intensive herbivory, oaks appear to be regenerating well with increased light in these partially harvested stands.有蹄类动物（Ungulates）会被自然干扰与木材采伐形成的林隙所吸引，因为这些林隙中分布着大量优质适口的可啃食植被。尽管林隙内有蹄类动物的活动与啃食行为显著增加，但相较于光照等非生物因子，啃食对森林更新的相对重要性往往尚不明确。在新英格兰南部地区，中等强度采伐是吸引白尾鹿与驼鹿的主要森林干扰类型。橡树是该地区核心的阔叶树分类群与主导用材树种，目前正处于衰退态势。因此，有蹄类动物啃食对栎林的影响，受到了生态学家、保护工作者以及森林与野生动物管理者的高度关注。本研究团队在夸本与韦尔河流域森林的34个林分中，针对一系列林冠干扰梯度（伐除35%-90%的胸高断面积）开展了树木更新与有蹄类动物觅食活动的调查采样。所有样地的啃食压力均较高，约80%的红枫与栎树幼茎遭到啃食。通常而言，较高的幼茎比较低矮的幼茎被啃食的频率更高。在香蕨（hay-scented fern）盖度较高的林分中，小型径级的栎树更新量普遍较低。遭啃食的红枫与栎树占比，通常会随该类群的种群密度升高而增加。尽管存在高强度的植食性啃食，但在这些经部分采伐的林分中，随着光照条件的改善，栎树似乎能够实现良好的更新。