The effects of thinning on within-stand light conditions and the composition and structure of saplings in a mixed stand of sugi (Cryptomeria japonica) and deciduous hardwood species in Iwate Prefecture, northern Japan
2009
Kunisaki, T.(Iwate Univ., Morioka (Japan). Faculty of Agriculture) | Sugawara, S. | Ando, R.
The effects of thinning on within-stand light conditions and the composition and structure of saplings in a mixed stand of Cryptomeria japonica and deciduous hardwood species, located in Iwate Prefecture, northern Japan, were investigated. In 2002, thinning was carried out in part of the mixed stand. In 2006, four 0.04-ha plots each were established in thinned and control blocks of the mixed stand, and stand structure, sapling characteristics and within-stand light condition were studied. The relative photon flux density (rPFD) was 12.1% in the thinned block 4 years after thinning and was estimated to be 25% immediately after thinning. The mean rPFD in the thinned block was significantly higher than in the control block. Within-stand light conditions were found to be improved by low thinning of Cryptomeria japonica and selected cutting of dominant hardwoods. The number of species and the upper height of saplings positively correlated with rPFD. In conclusion, thinning of mixed stands effectively promotes colonization and the growth of saplings.
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