Structure and regeneration of canopy species in an old-growth evergreen broad-leaved forest in Aya district, southwestern Japan

Abstract

The population structure and regeneration of canopy species were studied in a 4 ha plot in an old-growth evergreen broad-leaved forest in the Aya district of southwestern Japan. The 200 m x 200 m plot contained 50 tree species, including 22 canopy species, 3,904 trees (dbh > 5 cm) and a total basal area of 48.3 m2/ha. Forty one gaps occurred within the plot, and both the average gap size (67.3 m 2) and the total area of gap to plot area (6.9 %) were small. Species found in the canopy in the plot were divided into three groups (A, B, C) based on size and spatial distribution patterns, and density in each tree size. Group A (typical species: Distylium racemosum, Perseajaponica) showed a high density, nearly random distribution and an inverse J-shaped size distribution. Species in group B (Quercus salicina, Quercus acuta, Quercus gilva) were distributed contagiously with conspicuous concentration of small trees (< 5 cm dbh) around gaps. However, the species in this group included few trees likely to reach the canopy in the near future. Group C included fast-growing pioneer and shade intolerant species (e.g. Comus controversa, Carpinus tschonoskii, Fagara ailanthoides), which formed large clumps. Most gaps were not characterized by successful regeneration of group B and C but did appear to accelerate the growth of group A. Group B species appear to require long-lived or large gaps while group C species require large, catastrophic disturbances, such as landslides, for regeneration.

Silviculture for old-growth attributes

“…Instead, it may be better to manage forests for conservation based on their degree of oldgrowthness, their local and landscape functions in recognition of the expected opportunities for, and constraints to obtaining desirable levels of old-growthness. However, practically, it could be extremely difficult and costly to evaluate and assign a specific Angers et al, 2005;Ansley and Battles, 1998;Dyne, 1991;Franklin et al, 2002;Franklin and Van Pelt, 2004;Holt et al, 1999;Kneeshaw and Gauthier, 2003;Meyer et al, 2003;Mosseler et al, 2003;Nilsson et al, 2002;Pollman, 2003;Salas et al, 2006;Siitonen et al, 2000;Tanouchi and Yamamoto, 1995;Trofymow et al, 2003;Tyrrell and Crow, 1994 degree of old-growthness to each stand. Instead, a third category, partial old-growth or regrowth forests with some level of oldgrowthness, may be identified between true old-growth and intensively managed regrowth forests, a manageable approach to improve conservation planning (Fig.…”

Stand Dynamics and Biomass Increment in a Lucidophyllous Forest over a 28-Year Period in Central Japan

“…Ohsawa [3] suggested that the tropical lower montane forests that are mainly dominated by evergreen Fagaceae (especially Castanopsis) can be correlated to the horizontal subtropical/warm-temperate zone of East Asia as lucidophyllous forests, and the latitudinal northern limit reaches sea level at 35 • N of central Japan. There have been several long-term studies that investigated the structure and the dynamics of the unique forests using large permanent quadrats in southwestern Japan; e.g., Aya Research Site from 1989 [4][5][6] or Tatera Forest reserve from 1990 [7][8][9]. These studies have revealed that diverse gap-forming processes created environmental heterogeneity in the forest floor and contributed to the maintenance of the species-rich evergreen broad-leaved forests.…”

A Phytosociological Study on the Community of Palaquium gutta(Hook.f.) Baill. (Sapotaceae) at Ayer Hitam Forest Reserve, Selangor, Malaysia

“…This factor suggests that the tropical forest consists of many aggregated species and small numbers of randomly distributed species (Hubbell 1979;Masaki et al 1992;Tanouchi & Yamamoto 1995;Yamamoto et al 1995). The distribution of 73% of tree species in a 52 ha forest dynamics plot in Bornean mixed dipterocarp forest were significantly aggregated on one of the four soil types which were sandy loam, loam, fine loam and clay (Russo et al 2005).…”