Regeneration process of coniferous forests in northern Hokkaido I. Abies sachalinensis forest and Picea glehnii forest

Abstract

Regeneration of natural forests was studied in the Nakagawa Experiment Forest of Hokkaido University using age distribution surveys made by the clear felling method.In Plot 1 (30 m • 65 m), Abies sachalinensis dominated the canopy layer but there were also a few Betula ermanii trees. Sasa senanensis densely covered the forest floor. Most of the canopy trees were from 122 to 195 years old. Seedlings younger than 50 years old of A. sachalinensis were found on fallen logs and root bases. There were, however, few trees from 50 to 120 years old. The present canopy trees seemed to have regenerated after competitive pressure from old canopy and Sasa disappeared 180 years ago. Plot 2 (50 m • 100 m) on serpentinite soil was dominated by Picea glehnii. Sasa kulirensis covered the floor but not as densely as S. senanensis in Plot 1. The ages of P. glehnii ranged from 1 to 586 years old, and the age distribution ofA. sachalinensis was L-shaped.A small gap in the canopy formed about 290 years ago, and it gradually extended. Conifers regenerated continuously in the extending gap but B. ermanii did not. One hundred thirty years ago, part of Plot 2 was again destroyed and A. saehalinensis and B. ermanii regenerated. Thus, two types of regeneration were found. One regenerated both conifers and Betula after a sudden disturbance of canopy layer or death of Sasa, and the other, under an extending gap, regenerated only conifers.

Effect of bryophytes on survival of conifer seedlings in subalpine forests of central Japan

“…This phenomenon is reported for Picea sitchensis-Tsuga heterophylla forests (Harmon & Franklin 1989) and other forests (Harmon et al 1986) in North America, Nothofagusfusca forests in New Zealand (Ogden 1985), Picea jezoensis var. hondoensis forests (Yatoh 1963), Tsuga diversifolia-Abies veitchii forests (Nakamura & Obata 1985;Nakamura 1987) and Picea glehnii-Abies sachalinensis forests (Suzuki et al 1987) in Japan. The logs may be advantageous to the colonization of tree seedlings.…”

Plastic Response of Crown Architecture to Crowding in Understorey Trees of Two Co-dominating Conifers

“…Longevity of Abies sachalinensis is approx. 100-200 years, while that of Picea glehnii is 400-500 years (Suzuki et al, 1987). Average tree ages of canopy trees taller than 10 m in this study site were 94n7 years for Abies sachalinensis and 260n5 years for Picea glehnii (Hiura, Sano and Konno, 1992).…”

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).…”