We explored whether, and to what extent, variable retention (VR) forestry has been applied in European boreal forests in northwestern Russia. Our survey revealed VR since 1910. Between 1910 and the 1960s, the statistics showing how much was retained are largely missing. However, for example, in the 1950s, on a large scale in the Republic of Karelia, up to 200-ha-sized harvesting areas, 18–33%, were retention patches with a mean growing stock of 30–40 m3 ha−1. In the fellings defined as “incomplete clear fellings,” which were the most common final felling type at that time, 11–40% of the growing stock was left. Between the 1960s and the early 1990s, with more efficient harvesting and skidding techniques, conventional clear fellings with a much lower amount of retention were practiced. Concern about the regeneration of harvested areas gradually led to smaller (maximum 50 ha) harvesting areas and the increase of silvicultural activities. Until now, to ensure natural regeneration, patches of understory and 20–25 seed trees (i.e., ca. 15–25 m3) per ha have been left permanently in harvesting areas. Landscape-scale retention for protecting ecosystem functions and biodiversity was legislated in 1978 by preserving key biotopes up to 1000 ha in size. Since 2001, promoted by forest certification, the key biotopes, such as paludified forest patches, buffers around water bodies, and habitats of red-listed species, have also been retained in harvesting areas, together with a dispersed retention of different elements. Quantitative estimates of the amount of key biotopes are largely missing. However, estimates of 1–13% in harvesting areas and 23% in whole managed landscapes have been given. VR applied during the last century has emulated natural disturbances and created diverse uneven-aged forest structures with high amounts of diverse coarse woody debris. We conclude that an analysis of past and current retention practices is essential for estimating the global role of Russian forestry. Further decisions on the general direction of Russian forestry and, specifically, retention practices are important to address the global challenges of biodiversity loss and climate change.

中文翻译：

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俄罗斯欧洲北方森林中的可变保留林业

我们研究了可变保留（VR）林业是否已应用到俄罗斯西北部的欧洲北方森林中，以及在多大程度上适用于此。我们的调查显示自1910年以来的VR。在1910年至1960年代之间，丢失了保留多少数据的统计数据大部分丢失了。但是，例如，在1950年代，卡累利阿共和国大规模种植了面积为200公顷的采伐区，占18–33％，是保留斑块，平均蓄积量为30–40 m3 ha-1 。在当时被定义为“不完全清除砍伐”的砍伐活动中，砍伐是当时最常见的最终砍伐类型，其中剩余的11％至40％的剩余库存。在1960年代至1990年代初之间，由于采伐和打滑技术更加有效，人们进行了常规的伐木，其截留量大大降低。对收割区再生的担忧逐渐导致收割面积变小（最多50公顷），并使造林活动增加。迄今为止，为了确保自然更新，每公顷的林木和每公顷20至25棵种子树（即约15至25立方米）被永久留在收割区。为了保护生态系统功能和生物多样性，在1978年立法通过保留最大1000公顷的关键生物群落来立法保护景观。自2001年以来，在森林认证的推动下，重要的生物群落（例如，森林茂密的斑块，水体周围的缓冲区以及列入红色名录的物种的栖息地）也保留在了采伐区中，并且分散地保留了各种元素。关键生物群落数量的定量估计在很大程度上缺失。然而，估计收割面积为1-13％，整个管理景观中为23％。在上个世纪应用的虚拟现实技术已经模拟了自然干扰，并创造了具有大量多样的粗木屑的多样的不均匀老化的森林结构。我们得出结论，对过去和现在的保留做法进行分析对于估算俄罗斯林业的全球作用至关重要。关于俄罗斯林业总体方向的进一步决定，特别是保留做法，对于应对生物多样性丧失和气候变化的全球挑战很重要。我们得出结论，对过去和现在的保留做法进行分析对于估算俄罗斯林业的全球作用至关重要。关于俄罗斯林业总体方向的进一步决定，特别是保留做法，对于应对生物多样性丧失和气候变化的全球挑战很重要。我们得出结论，对过去和现在的保留做法进行分析对于估算俄罗斯林业的全球作用至关重要。关于俄罗斯林业总体方向的进一步决定，特别是保留做法，对于应对生物多样性丧失和气候变化的全球挑战很重要。