Effects of advance regeneration and germinated seedlings on forest recovery after clearcutting of Chamaecyparis obtusa plantations in Southern Kyushu, Southwestern Japan
Effects of advance regeneration and germinated seedlings on forest recovery after clearcutting of Chamaecyparis obtusa plantations in Southern Kyushu, Southwestern Japan
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日本西南部九州南部扁柏人工林砍伐后提前更新和发芽苗对森林恢复的影响
DOI：
10.1007/s11355-021-00485-4
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发表时间：
2021
影响因子：
2
通讯作者：
Hirata Ryoko
中科院分区：
文献类型：
--
作者：
Yamashita Kazuhiro;Yamagawa Hiromi;Kondo Hiroki;Ito Satoshi;Hirata Ryoko
我们阐明了在中期观察期(允许形成林冠的12-1400年)采伐针叶林后，提前更新对天然林恢复的影响。我们建立了林下完好区(UI-PLOT)，其中保留了提前更新(AR；砍伐前胸径超过1厘米)，以及林下清除区(UC-PLOT)，在砍伐针叶树作物时，所有AR都被移除。我们调查了采伐后1年、12年或14年不同更新起点的个体密度、物种丰富度和树高。然后，我们比较了UI-PLOT和UC-PLOT的结构变化。在中期恢复过程中，UC-Plot中重新萌发的AR与UI-Plot中保留的AR在形成高度分布格局和分层方面提供了相同的效果。采伐后新植苗木个体的个体密度和物种丰富度对两个样地的林分生长都有一定的促进作用。此外，在树木密度和物种数量方面，SE对森林恢复的贡献很大，但对重力散布的亮叶乔木恢复的意义有限。研究结果表明，AR保留的优势仅限于采伐后早期林分结构的快速恢复，只要有充足的提前更新积累和周围种源的有效保障，在中期观察期内基本消失。
We clarified the effect of advance regeneration on natural forest recovery after clearcutting of conifer plantations over the mid-term observation period (12–14 years to allow formation of the forest canopy). We established understory-intact plot (UI-plot), where advance regeneration (AR; DBH more than 1 cm before clearcutting) were retained, and understory-cleared plot (UC-plot), where all ARs were removed at felling of conifer crops. We surveyed individual density, species richness, and tree height with reference to different regeneration origins 1 year after and 12 or 14 years after clearcutting. Then, we compared the structural changes in UI-plot with that in UC-plot. The resprouted AR in UC-plot has provided the same effect as the retained AR in UI-plot in forming their height distribution patterns and stratification over a mid-term recovery process. We also found that individual density and species richness attributed by the individuals of newly established seedlings after clearcutting (SE), have contributed to the stand development in the both plots. Furthermore, SE was found to have a large contribution to forest recovery in terms of tree density and species number, while its significance for the recovery of gravity-dispersal, lucidophyllous trees was limited. We concluded that the advantage of AR retention is limited to the fast recovery of forest structure at the early stage after clearcutting, and mostly disappeared over a mid-term observation period as far as abundant advance regeneration was sufficiently accumulated and surrounding seed sources were effectively secured.