Feasibility of implementing thinning in even-aged Larix olgensis plantations to develop uneven-aged larch-broadleaved mixed forests

• Published in: Journal of forest research Vol. 15; no. 1; pp. 71 - 80
• Main Authors: Zhu, Jiaojun, Yang, Kai, Yan, Qiaoling, Liu, Zugen, Yu, Lizhong, Wang, Hexin
• Format: Journal Article
• Language: English
• Published: Japan Japan : Springer Japan 01.02.2010; Taylor & Francis; Springer Japan; Taylor & Francis Ltd
• Subjects: Acer; Biodiversity; Biomedical and Life Sciences; Broad leaved tree species; Cornus controversa; Environmental impact; Forestry; Forestry Management; Forests; Fraxinus; Land degradation; Larix; Larix olgensis; Larix olgensis plantation; Life Sciences; Litter; Mixed forests; Natural regeneration; Pinus koraiensis; Plant Ecology; Plant Sciences; Plant species; Plantations; Planting density; Quercus mongolica; Seedlings; Special Feature: Original article; Stems; Sustainable development; Thinning; Timber; Tree Biology; Trees; Uneven aged forest; Vegetation cover; Thinning; Uneven aged forest; plantation; Broad leaved tree species; Natural regeneration
• ISSN: 1341-6979; 1610-7403
• DOI: 10.1007/s10310-009-0152-6

Thinning experiments were conducted in larch (Larix olgensis) plantations to assess the feasibility of converting even-aged plantation stands to uneven-aged forests with more complex stand structures. Stands established in 1965 and 1960 were thinned in 2004 (Regime A, for determining the effect of recent thinning on emergence of seedlings) and 1994 (Regime B, for examining the effects of the past thinning on establishments of recruitments), respectively, at two intensities each. Natural regeneration, together with litter depth, canopy openness and vegetation cover, was surveyed in the thinned plots. Results indicated that larch seedlings started to emerge in May, reached a peak in June, decreased from June through September, and then disappeared in October. No larch seedlings exceeded 1 year old in the thinned plots because of the low levels of light and dense litter and vegetation cover. However, there were many naturally regenerated seedlings (5-50 cm in height) and saplings (50-500 cm in height) of broadleaved tree species such as Acer spp., Fraxinus spp., Cornus controversa, Quercus mongolica, and even the climax tree species, Pinus koraiensis, in the thinned plots. The mean density of regenerated seedlings reached 6.7 and 4.5 stems m⁻² in Regimes A and B, respectively, whilst the mean density of regenerated saplings reached 4,595 stems ha⁻¹ in Regime B. These results suggest that it is impractical to turn even-aged larch plantations to uneven-aged larch forests, but it may be feasible to develop uneven-aged larch-broadleaved forests from even-aged larch plantations through thinning.