ABSTRACT A large portion of planted forests in Japan have recently reached maturity. These trees have grown larger than previous stands, and are more difficult to log using current techniques. This study aimed to develop an improved logging system for logs with relatively larger diameters and lengths in Japan. In a moderate-slope mountain forest in Toyama Prefecture, we evaluated the productivity of final cutting and compared the productivity of each log length class (4 m, 6 m, and 8 m) using both current-sized and larger-sized machine harvesting systems. Moreover, different felling techniques for large diameter trees were assessed using a mechanical wedge that is commonly used in central Europe. We found that felling using the mechanical wedge had additional safety benefits. Furthermore, the productivity using the larger machine system was higher than those using the current techniques and systems; however, the productivity was only marginally higher for larger machines across log length classes.

中文翻译：

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日本山林最后伐木时采伐大直径原木和长原木的生产力

摘要 日本的大部分人工林最近已经成熟。这些树木比以前的林分长得更大，并且使用当前技术更难以采伐。本研究旨在为日本直径和长度相对较大的原木开发改进的测井系统。在富山县的中等坡度山林中，我们评估了最终切割的生产力，并比较了每个木材长度等级（4 m、6 m 和 8 m）使用当前尺寸和更大尺寸的机器采伐系统的生产力. 此外，使用中欧常用的机械楔子对大直径树木的不同砍伐技术进行了评估。我们发现使用机械楔子进行砍伐具有额外的安全优势。此外，使用较大机器系统的生产率高于使用当前技术和系统的生产率；然而，对于跨日志长度类别的大型机器，生产率仅略高。