Effects of individual size, local competition and canopy closure on the stem volume growth in a monoclonal Japanese cedar (Cryptomeria japonica D. Don) plantation

Abstract

We studied how the dominant factor affecting stem volume growth changes during stand development in a monoclonal stand of Cryptomeria japonica D. Don. Stem analysis was used to compare growth history of trees in an unthinned plot (closed canopy) and a thinned plot (open canopy). In the unthinned plot, the dominant factor affecting stem volume growth was basal area (BA) before canopy closure, whereas neighborhood competition index (CI) was the dominant factor after canopy closure. In contrast, the dominant factor affecting stem volume in the thinned plot was BA throughout stand development. Spearman's rank correlation coefficient between BA and CI continued to increase after canopy closure and size rank among individuals became increasingly fixed. Our results indicated that stem volume growth shifts from size-dependent to competitiondependent growth at canopy closure. The apparent correlation between tree size and growth rate observed in many previous studies may be the result of competitionmediated positive feedback between size and growth.

Individual-tree radial growth in a subtropical broad-leaved forest: The role of local neighbourhood competition

“…The dbh was only weakly (C. fargesii) or not at all (Q. fabri) related to age, because the older trees experienced one or more periods of severe growth suppression. Competition is generally known to affect height growth of trees only when it is extremely low or high (Ammer et al, 2005;Simard and Zimonick, 2005;Inoue et al, 2008). The lack of a relationship between height and radial growth supports the view that height growth is less sensitive to competition than diameter growth because it is a higher priority for carbon allocation (Simard and Zimonick, 2005;Pretzsch, 2009), and suggests that the intensity of local neighbourhood competition is currently at a level that closely regulates radial growth, but does not suppress height growth.…”

Derivation of two-way volume equation for bamboo, Phyllostachys pubescens

“…Toshima, located in the eastern part of Kumamoto City, Kumamoto Prefecture, western Japan. The average annual temperature and annual rainfall in Kumamoto City were 16.8°C and 2,060 mm, respectively (Inoue et al 2008 (Hayashi and Yamada 2008). The study site was located on a south-facing gentle slope and the altitude ranged from 80 to 90 m. According to the local residents, this site was originally used for upland farming until a few decades ago, and is now being turned into a P. pubescens stand because of the planting of bamboo and subsequent abandonment.…”

Deriving a reduction factor for woody part of culm for bamboo Phyllostachys pubescens

“…Toshima, located in the eastern part of Kumamoto City, Kumamoto Prefecture, western Japan. The mean annual temperature and rainfall in Kumamoto City was 16.8°C and 2,060 mm, respectively (Inoue et al 2008). Bamboo species such as P. pubescens and P. bambsoides were distributed from the foot to the mountainside of Mt.…”