Forest biomass is a sustainable source of renewable energy and a valuable alternative to finite fossil fuels. However, its overharvesting may lead to soil nutrient depletion and threaten future stand productivity, as well as affect the habitat for biodiversity. This paper provides quantitative data on biomass removal, fine woody debris [d ≤ 7 cm], and coarse woody debris [d > 7 cm] left on the forest floor in whole tree harvesting systems. Using tree allometric equations and inventory field methods for woody debris estimation, we assessed biomass removal on nine fuelwood harvesting sites in Central France, as well as fine and coarse woody debris left on the sites. The aboveground biomass estimates showed a high variability between the studied sites, it varied between 118 and 519 Mg ha⁻¹. However, less variability was found among sites managed as coppice-with-standards 174 ± 56 Mg ha⁻¹. Exported biomass was 107 ± 42 Mg ha⁻¹ on average, including 35 ± 9% of fine wood. The amounts of both fine and coarse woody debris left on sites were generally less than 10% of the total harvested biomass in 2/3 of the studied sites. These amounts are lower than the minimum retention levels recommended by the sustainable forest biomass harvesting guidelines. Therefore, more technical effort and additional management measures should be taken to ensure more woody debris, especially in poor forest soils and thus, to guarantee a sustainable biomass harvesting.

中文翻译：

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评估全树收获系统中的生物质去除和木本碎片：是否确保建议的残留水平？

森林生物质是可再生能源的可持续来源，是有限化石燃料的宝贵替代品。然而，过度采伐可能导致土壤养分枯竭，威胁未来林分生产力，并影响生物多样性的栖息地。本文提供了关于在整个树木采伐系统中残留在森林地面上的生物量清除、细木屑 [d ≤ 7 cm] 和粗木屑 [d > 7 cm] 的定量数据。我们使用树木异速生长方程和清单现场方法进行木质碎片估计，评估了法国中部 9 个薪材采伐场的生物量清除情况，以及遗留在现场的细木屑和粗木碎片。地上生物量估计值显示出研究地点之间的高度可变性，在 118 和 519 Mg ha ^-1之间变化. 然而，在按照标准 174 ± 56 Mg ha ^-1管理的场地中发现的变异性较小。出口的生物量平均为 107 ± 42 Mg ha ^-1，包括 35 ± 9% 的细木。在 2/3 的研究地点，遗留在场地上的细木屑和粗木屑的数量通常不到总收获生物量的 10%。这些数量低于可持续森林生物量采伐指南推荐的最低保留水平。因此，应该采取更多的技术努力和额外的管理措施来确保更多的木质碎片，特别是在贫瘠的森林土壤中，从而保证可持续的生物质收获。