Natural disturbance regimes as a guide for sustainable forest management in Europe

Abstract

In Europe, forest management has controlled forest dynamics to sustain commodity production over multiple centuries. Yet over-regulation for growth and yield diminishes resilience to environmental stress as well as threatens biodiversity, leading to increasing forest susceptibility to an array of disturbances. These trends have stimulated interest in alternative management systems, including natural dynamics silviculture (NDS). NDS aims to emulate natural disturbance dynamics at stand and landscape scales through silvicultural manipulations of forest structure and landscape patterns. We adapted a "Comparability Index" (CI) to assess convergence/divergence between natural disturbances and forest management effects. We extended the original CI concept based on disturbance size and frequency by adding the residual structure of canopy trees after a disturbance as a third dimension. We populated the model by compiling data on natural disturbance dynamics and management from 13 countries in Europe, covering four major forest types (i.e., spruce, beech, oak, and pine-dominated forests). We found that natural disturbances are highly variable in size, frequency, and residual structure, but European forest management fails to encompass this complexity. Silviculture in Europe is skewed toward even-aged systems, used predominately (72.9% of management) across the countries assessed. The residual structure proved crucial in the comparison of natural disturbances and silvicultural systems. CI indicated the highest congruence between uneven-aged silvicultural systems and key natural disturbance attributes. Even so, uneven-aged practices emulated only a portion of the complexity associated with natural disturbance effects. The remaining silvicultural systems perform poorly in terms of retention compared to tree survivorship after natural disturbances. We suggest that NDS can enrich Europe's portfolio of management systems, for example where wood production is not the primary objective. NDS is especially relevant to forests managed for habitat quality, risk reduction, and a variety of ecosystem services. We suggest a holistic approach integrating NDS with more conventional practices.

A new paradigm for sustainable forest management: closeR to nature forest management

“…4). È opportuno evidenziare che già attualmente circa l'80% delle utilizzazioni forestali a scala continentale possono essere configurate come una imitazione di processi naturali (Aszalós et al 2022). Questo vale sia per un taglio saltuario per piede d'albero Fig.…”

A matter of size and shape: Microclimatic changes induced by experimental gap openings in a sessile oak–hornbeam forest

“…Within the framework of even-aged forest management, clear-cutting and shelterwood cuts applied over a short period of time recurrently create large and homogenous reductions in canopy cover over extensive areas (Aszalós et al, 2022;Gresh and Courter, 2021), which induce substantial changes in microclimate conditions (Keenan and Kimmins, 1993;Kermavnar et al, 2019). The microclimate of cut areas is characterized by increased incident shortwave radiation, higher and more variable air and soil temperatures, increased vapour pressure deficit and wind speeds compared to adjoining closed stands (Chen et al, 1999).…”

Enhancing the structural diversity between forest patches—A concept and real‐world experiment to study biodiversity, multifunctionality and forest resilience across spatial scales

“…Forest management has shaped these structural components. A focus on timber production has shaped both α‐diversity and β‐diversity of forests for centuries (Aszalós et al, 2022). In the Middle Ages (500–1500 CE), multi‐purpose forest management created a heterogeneous forest landscape of native tree species with coppicing, promoting early‐successional stages and pastures, interspersed with veteran trees that harboured old‐growth specialists (Miklín et al, 2018).…”

“…In the Middle Ages (500–1500 CE), multi‐purpose forest management created a heterogeneous forest landscape of native tree species with coppicing, promoting early‐successional stages and pastures, interspersed with veteran trees that harboured old‐growth specialists (Miklín et al, 2018). In contrast, particularly in the Northern Hemisphere, modern forestry since the late 18th century, has focused increasingly on timber production (Rackham, 2008; Schelhaas et al, 2003) often at the expense of structural and biological diversity via planting even‐aged conifer‐dominated forests (Aszalós et al, 2022). In addition, since the early 19th century, forest management has systematically removed dying and dead trees as a precautionary measure against pest outbreaks, with the subsequent disappearance of forest specialists, including many birds, beetles, true bugs, lichens and fungi (Abrego et al, 2015; Seibold, Brandl, et al, 2015).…”

“…In general, the ESC strategy appears promising for promoting biodiversity and presumably enhancing the diversity of ecosystem functions, but this concept lacks an explicit β‐diversity component. More recently, the increase in natural disturbances in homogenized forests has also stimulated interest in alternative management systems, such as natural dynamics silviculture (Aszalós et al, 2022) that aim to emulate natural disturbance dynamics at stand‐ and landscape scales through silvicultural interventions. However, evidence for a causal chain from natural disturbances to BEF across scales is still limited, mainly because studies on natural disturbances often lack a properly replicated design, and simply do not often combine changes in β‐diversity with variation in ecosystem functioning.…”