Effects of thinning and extraction on advance regeneration (Wykeham 2007)

Extensive damage to and mortality of understorey seedlings during overstorey thinning could prevent the use of natural regeneration as a method of restocking. Experiments carried out on three upland conifer sites in Britain assessed the short-term impact of thinning operations on survival and damage to advance regeneration seedlings of different heights. At two sites dominated by Sitka spruce, the number of small-sized (<50 cm) and medium-sized (50 – 200 cm) seedlings lost during harvesting was significantly higher than the number of large seedlings (>200 cm) which tended to be damaged rather than lost. At the Scots pine/Japanese larch site, damage and loss were not related to seedling size. Survival or damage was significantly related to the distance from the nearest extraction rack (striproad). At two of the sites, survival or damage was related to distance to the nearest felled tree stumps. The seedlings in 25 – 30 per cent of the area were lost due to clearing the extraction racks prior to harvesting. In the stand matrix, 40 – 80 per cent of the regeneration survived and was not severely damaged; the remaining regeneration was likely to be sufficient to restock at all three sites, although distributions were clumped. There were no marked differences between motormanual and harvester felling.
See also: Stokes, V., Kerr, G., and Ireland, D. (2009.) Seedling height and the impact of harvesting operations on advance regeneration of conifer species in upland Britain. Forestry. 82 (2): 185-198 Attribution statement: If you use this data you must cite: Stokes, V., Kerr, G., and Ireland, D. (2009.) Seedling height and the impact of harvesting operations on advance regeneration of conifer species in upland Britain. Forestry. 82 (2): 185-198.

在林冠疏伐过程中，对林下层幼苗的广泛损害及死亡率可能阻碍自然更新作为补植方法的运用。在英国三个高原针叶林地点进行的实验评估了疏伐作业对不同高度幼苗的短期存活和损害影响。在以 Sitka 针叶树为主的两个地点，收获过程中损失的小型（<50厘米）和中型（50-200厘米）幼苗数量显著高于大型幼苗（>200厘米）的数量，后者往往受损而非丢失。在苏格兰松/日本落叶松地点，损害和损失与幼苗大小无关。存活或损害与最近提取架（采伐道）的距离显著相关。在两个地点，存活或损害与最近砍伐树桩的距离相关。25-30%区域内的幼苗因在收获前清理提取架而丢失。在林分矩阵中，40-80%的更新幼苗存活且未严重受损；剩余的更新幼苗可能足以在所有三个地点进行补植，尽管分布较为聚集。在人工和机械采伐之间没有明显的差异。参见：Stokes, V., Kerr, G., and Ireland, D. (2009.) 种苗高度与英国高原针叶树种收获作业对更新幼苗的影响。林业。82 (2): 185-198。引用声明：如使用此数据，必须引用：Stokes, V., Kerr, G., and Ireland, D. (2009.) 种苗高度与英国高原针叶树种收获作业对更新幼苗的影响。林业。82 (2): 185-198。