Microsites for seedling establishment of subalpine conifers in a forest with moss‐type undergrowth on Mt. Fuji, central Honshu, Japan

Abstract

We examined microsites for the seedling establishment of Tsuga diversifolia, Abies veitchii and Abies mariesii in a subalpine coniferous forest with moss-type undergrowth dominated by Hylocomium splendens and Pleurozium schreberi on Mt. Fuji, a lesssnowy mountain located on the Pacific Ocean side of the central part of Honshu Island, Japan, and compared these microsites with cases in other regions of Japan with different undergrowth vegetation (herb type, dwarfbamboo type) under snowier conditions. L-shaped size structures with abundant seedlings and small trees were identified for all three species. Established seedlings of T. diversifolia showed remarkable preference for elevated microsites such as fallen logs and convex ground (i.e. ground raised around trunk bases), while A. veitchii and A. mariesii indicated no significant bias toward such elevated microsites in the large seedling stage. However, the relative frequency of T. diversifolia seedlings established on flat ground reached high values of 54-77%, since the relative occupation area of the flat ground was large (85-89%). Such a large share suggests that flat ground should be regarded as the most important microsite for the seedling establishment of T. diversifolia in forests with moss-type undergrowth. This preference trait for T. diversifolia observed with moss-type undergrowth has not been reported in previous studies examining forests with herb-and dwarf bamboo-type undergrowth, where T. diversifolia seedlings are scarce on the ground and restricted to elevated microsites. We conclude that the major microsite for T. diversifolia seedling establishment changes according to the undergrowth vegetation type: a large ground share for moss-type undergrowth and a small ground share for herb-and dwarf bamboo-type undergrowth.

Regeneration in windthrow areas in hemiboreal forests: the influence of microsite on the height growths of different tree species

“…Residual vegetation coverage and height can significantly decrease seedling establishment potential (Harrington and Bluhm 2001;Bell et al 2000;Wohlgemuth et al 2002;Sugita and Nagaike 2005). The vegetation in the plots of this study was investigated by Ilisson et al (2006), who found no significant difference between the heavily and moderately disturbed areas, although only the vegetation on undisturbed soil was studied.…”

Effects of surface and light conditions of fallen logs on the emergence and survival of coniferous seedlings and saplings

“…In boreal forests, many coniferous tree species regenerate on fallen logs (Harvey et al 1987;Suzuki et al 1987;Taylor et al 1990;Szewczyk and Szwagrzyk 1996;Nakagawa et al 2001;Sugita and Tani 2001;Mori et al 2004;Sugita and Nagaike 2005). In Hokkaido, northern Japan, two dominant evergreen conifers, Abies sachalinensis and Picea jezoensis, emerge and grow on both fallen logs and the forest floor, and exclusively on fallen logs, respectively (Natsume 1985;Kubota et al 1994;Takahashi 1994).…”

The influence of storm-induced microsites to tree regeneration patterns in boreal and hemiboreal forest

“…Nevertheless, thick moss layers, increasing in height with wood decay, could be detrimental for seedling establishment (Sugita and Nagaike 2005;Iijima et al 2007). Relatively more regeneration is found on larger diameter logs (Takahashi 1994).…”

“…Nevertheless, roots of some species are able to adapt to the microsite conditions, e.g. by developing stilt roots (Canham et al 1996;Sugita and Nagaike 2005). Other species, such as black birch (Betula lenta L.), are able to adapt to more shaded conditions, e.g.…”