Pits and rocky microsites in a subalpine forest stand facilitate regeneration of spruce saplings by suppressing dwarf bamboo growth inside a deer-proof fence

Abstract

We determined patterns of microsite suppression in dwarf bamboo Sasa nipponica when grazing deer were absent. This bamboo species is able to outcompete Hondo spruce (Picea jezoensis var. hondoensis) saplings under many environmental circumstances. We set up two 10 9 100 m plots inside a deer-proof fence within a subalpine forest on Mt. Ohdaigahara, central Japan, and two similarly sized plots outside the fence. Within the plots, we surveyed microsites where spruce saplings grew. We measured height and shoot elongation of all spruce saplings, and culm height and cover ratios of dwarf bamboo growing around each spruce sapling. Spruce sapling density and average height were higher inside the deer-proof fence than outside, as were bamboo height and cover. Thus, there was a negative effect of deer browsing on vegetation parameters outside the fence and a suppression of the negative effect of bamboo on spruce sapling growth inside the fence. Spruce sapling height was higher in tree-fall pits than in other microsites inside the fence, whereas both dwarf bamboo height and cover were lower in pits and rocky sites than elsewhere. In soil and collar microsites, spruce sapling shoot growth was lower and bamboo height and cover were higher than in pits and rocky sites. Inside the fence, dwarf bamboo cover was high, but pits and rocks suppressed its growth, allowing spruce saplings to flourish. To restore heavily damaged spruce forests with advanced saplings, it will be necessary to construct deer-proof fences and create and maintain microsites with pits and rocks.

Removing aboveground vegetation facilitates survival but slows height growth of spruce saplings in a fenced, degraded sub-alpine forest in central Japan

“…Thus, catastrophic events such as those that form large canopy gaps are considered essential for regeneration of the species (Mori and Takeda 2004a). However, despite the presence of large canopy gaps within our study area, deer browsing outside and dwarf bamboo suppression inside the fence inhibited the growth of spruce saplings (Kisanuki et al 2009). Our results, which show that sapling survival is facilitated by removal of surrounding dwarf bamboo, are in accordance with those of a previous study on the increased survival of A. homolepis seedlings on excluding deer and removing dwarf bamboo (Itô and Hino 2004).…”

“…dwarf bamboo, which can negatively affect seedling establishment and growth Hino 2004, 2005). Therefore, installing deer-proof fencing and removing the above-ground portions of dwarf bamboo are necessary for tree regeneration in a dwarf-bamboo field after forest degradation by deer grazing (Itô and Hino 2004;Kisanuki et al 2009). …”

Features of formation of micromosaic structure of dark coniferous forests of the Northern Urals

“…В зависимости от характера гибели дерева (слом или вывал) образуется либо ветровально-почвенный комплекс (ВПК), включающий яму, бугор и валежину, либо ветроломный комплекс (ВК), состоящий только из валежины и пня. В настоящее время в литературе достаточно широко освещена биоценотическая роль ВПК, в результате которых создается максимальное разнообразие контрастных экотопических условий, значимых для сохранения и поддержания биоразнообразия [7,16,23,29,32,34], роль ВК в естественных процессах изучена недостаточно [1,8]. Вероятно, в спонтанно развивающихся лесах должны присутствовать оба типа комплексов, поскольку ни один из них не формирует всех потенциальных микросайтов.…”