Abstract Although impacts of intensive forest harvesting practices such as removing logging residue and stumps for bioenergy on forest ecosystem has been extensively studied, no information is available about the long-term effects of stump harvesting on the health status of young Norway spruce stands. In the present study, we surveyed damage caused by the large pine weevil (Hylobius abietis L.) and other causal agents as well as the height growth of the Norway spruce seedlings for 12 years in stump-harvested and non-harvested experimental plots. The overall effect of stump harvesting combined with mounding on the health and survival of spruces was positive: 70% of spruce seedlings in stump-harvested plots were spared any damage, while 58% of seedlings remained undamaged in undisturbed control plots. The positive effect of stump removal and mounding on tree health was mainly due to reduced pine weevil damage. In all, 14.8 and 24.6% of spruce seedlings were gnawed by pine weevil in stump-harvested and control plots, respectively. In stump-harvested plots, pine weevil damage was slighter and lasted for a shorter time than in control plots. In addition, damage caused by Hylastes spp., black root beetles, was significantly less on stump-harvested plots. By contrast, vole damage was most frequent in stump-harvested plots during the population peak when the vole density was exceptionally high. Irrespective of whether stumps were harvested or not, stump roots provided a source of Heterobasidion inoculum in the next spruce regeneration. During this early stage of stand development only a few spruce seedlings were killed by Heterobasidion root rot and there were neither temporal nor quantitative treatment-related differences between the treatments. From the third year onwards the height growth of undamaged seedlings was more rapid in stump-harvested than non-harvested plots. Our results suggest that the overall risk of damage in young Norway spruce stands can be reduced by stump harvesting. Thus, stump harvesting and mounding seem to decrease the need for supplementary planting, which reduces regeneration costs that represent a considerable financial investment for a forest owner.

中文翻译：

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树桩清除是否会减少挪威云杉再生过程中的松象虫和其他损害？– 12 年监测期的结果

摘要 尽管森林集约化采伐做法（如清除伐木残留物和树桩以获取生物能源）对森林生态系统的影响已得到广泛研究，但尚无关于树桩采伐对挪威云杉幼树健康状况的长期影响的信息。在本研究中，我们调查了大松象鼻虫 (Hylobius abietis L.) 和其他病原体造成的损害，以及 12 年来在树桩收获和未收获的试验田中挪威云杉幼苗的高度增长。树桩收获结合堆垛对云杉的健康和存活的总体影响是积极的：在树桩收获地块中 70% 的云杉幼苗没有受到任何损害，而在未受干扰的控制地块中，58% 的幼苗没有受到损害。树桩清除和堆垛对树木健康的积极影响主要是由于减少了松树象鼻虫的损害。总共有 14.8% 和 24.6% 的云杉幼苗在树桩收获地和对照地被松象虫啃食。在树桩收获地块中，与对照地块相比，松树象鼻虫的损害较轻且持续时间较短。此外，黑根甲虫 Hylastes spp. 造成的损害在树桩收获地块上显着减少。相比之下，当田鼠密度异常高时，在种群高峰期间，在树桩收获地块中田鼠损伤最为频繁。无论树桩是否被收获，树桩根都为下一次云杉再生提供了异型担子菌接种物的来源。在林分发展的这个早期阶段，只有少数云杉幼苗被 Heterobasidion 根腐病杀死，并且处理之间既没有时间上也没有数量上的差异。从第三年开始，有树桩收获的地块的未受损苗的高度增长比未收获的地块更快。我们的结果表明，砍伐树桩可以降低年轻的挪威云杉林分受损的总体风险。因此，树桩采伐和堆垛似乎减少了补充种植的需要，这降低了再生成本，这对森林所有者来说是一笔可观的财务投资。从第三年开始，有树桩收获的地块的未受损苗的高度增长比未收获的地块更快。我们的结果表明，砍伐树桩可以降低年轻的挪威云杉林分受损的总体风险。因此，树桩采伐和堆垛似乎减少了补充种植的需要，这降低了再生成本，这对森林所有者来说是一笔可观的财务投资。从第三年开始，有树桩收获的地块的未受损苗的高度增长比未收获的地块更快。我们的结果表明，砍伐树桩可以降低年轻的挪威云杉林分受损的总体风险。因此，树桩采伐和堆垛似乎减少了补充种植的需要，这降低了再生成本，这对森林所有者来说是一笔可观的财务投资。