Ecological perspectives on variable retention forestry

Abstract

Forest management globally affects the ecosystem services, especially those related to ecosystem functioning and biodiversity conservation, by altering forest structure and composition. The degree of alteration was related to the intensity and type of harvesting; therefore, the major silvicultural challenge is to develop alternatives to mitigate climate change and maintain forest functions and biodiversity while also providing acceptable levels of timber production. Variable retention forestry (VRF) is a highly flexible concept, with continuity of forest cover, structure, function, and species composition, thereby supporting multiple economic, environmental, and cultural goals. This special issue provides an overview of the concepts and applications related to VRF implementation around the world. It shows that VRF has been applied globally for several decades, with varying levels and retention types, depending on local conditions and the economic importance of forestry. The challenges of VRF seem to differ to some extent on different continents, yet the general aims have been accepted in most of the continents. VRF has been successful in mitigating many effects of intensive harvesting, though in some forests of the world, the retention levels are too low to maintain acceptable levels of biodiversity and ecosystem functions. We conclude that an active collaboration between scientists and forest practitioners is needed to realize all of the opportunities provided by VRF in solving global forestry-related issues.

Natural Disturbance-Based Forest Management: Moving Beyond Retention and Continuous-Cover Forestry

“…In managed forests, leaving retention trees has globally become a common approach in reconciling the conflicting goals of timber production and biodiversity conservation (Gustafsson et al, 2010(Gustafsson et al, , 2012(Gustafsson et al, , 2020bLindenmayer et al, 2012;Martínez Pastur et al, 2020). The ecological impact of logging depends on retention level and its range of variability (Table 1).…”

“…In many cases the retention levels are too low and applied too monotonously at the stand and landscape scale to benefit the native species that are threatened by current forest management (Kuuluvainen et al, 2019;Koivula and Vanha-Majamaa, 2020). Nevertheless, retention forestry continues to be the globally dominant avenue for reconciling the economic, ecological and social goals in forest management (Martínez Pastur et al, 2020). Recently, continuous-cover forest management, with its roots in the classical model of uneven-aged silviculture (Dauerwald in German), has started to gain more attention as an alternative to clear-cutting based low-retention management, and as a tool in landscape-scale forest ecosystem management (Diaci et al, 2011;Puettmann et al, 2015;Peura et al, 2018).…”

“…Nevertheless, the boreal forest still harbors a large share of the world's intact landscapes and also terrestrial carbon (Bradshaw et al, 2009;Potapov et al, 2008). In boreal forests managed for timber production, the dominating silvicultural approach is intensive even-aged management (Duncker et al, 2012), with some ecological considerations such as leaving retention trees (Martínez Pastur et al, 2020) and protecting valuable key habitats (Timonen et al, 2011). However, management is driven by relatively short clear-cut harvesting cycles compared with natural, usually much longer and also more diverse, cycles of natural disturbance (Kuuluvainen, 2009;Jõgiste et al, 2017Jõgiste et al, , 2018.…”

Social Forestry: The Balance between Welfare and Ecological Justice

“…The forest functions to support life, affect the functioning of ecosystems, and biodiversity conservation (Martínez Pastur, et al 2020). At present about thirty percent of the earth's land surface is still covered by forests, but a forest crisis occurs due to the significant narrowing of the forest area due to various human activities, such as land clearing for settlements or industry (Kumari et al 2020).…”

Using “management mosaics” to mitigate the impacts from extreme wildfires

“…In many semi-natural and managed forest ecosystems, to avoid catastrophic megafires, "fuel treatments" need to adopt the "management mosaics" approach across the target landscapes (Pastur et al 2020), something similar to "intercropping" used to promote agricultural productivity and mitigation of drastic environmental changes (Vandermeer 1992). In other words, different treatments (e.g., thinning, prescribed burning and grazing, fuel breaks, clear-cutting, or their combination as mixed treatments) could be used in the same areas (or patches) but in different years (temporal turnover) or in different patches but in the same year (spatial turnover).…”