Closer-to-nature forest management

What

Closer-to-Nature Forest Management is a concept proposed in the EU Forest Strategy for 2030, which aims to improve the conservation values and climate resilience of multifunctional managed forests in Europe. It encompasses management systems acknowledging the natural ranges of variability in forest ecosystems as complex adaptive systems, such as variable retention forestry, disturbance-based forest management, continuous-cover forestry and restorative forest management.

Where

Closer-to-nature forestry can be a NBS in both private and public forests.

Why

We need forest management approaches that can achieve a balance between intensive forest management aiming to efficiently deliver economic values and natural ecosystem dynamics that foster nature diversity, biodiversity, carbon sequestration, resilience and adaptive capacity. The growing role of forest ecosystems in human well-being is an important societal driver for change in forestry practices.  

The forests in the Nordic countries have been under intensive and long-lasting forest management. The focus on wood production has resulted in a simplification and homogenization of forests, mostly represented as even-aged and single-species tree stands. In natural forests, disturbances are caused by fire, wind, insects and fungi, and they occur at varying spatial scales, from deaths of single trees or groups of trees, to stand-replacing and large-scale impacts. The natural disturbance regime creates a dynamic mosaic of forests characterized by multi-scale structural diversity of habitats for forest-dwelling organisms.  

Closer-to-Nature Forest Management addresses multiple societal challenges, first of all enhancing biodiversity, climate change adaptation and mitigation as compared to conventional intensively managed forests. Closer-to-nature managed forests are more resilient, and consequently the NbS accounts well for disaster risk and preparedness and contributes to human health and wellbeing. Closer-to-nature managed forests along water bodies positively affect water quality and thus are a good NBS to address the societal challenge water management.  

How

Closer-to-Nature Forest Management is an overarching “umbrella” term summarizing the idea “to follow and support nature” in forestry. Different regions need different adaptive management approaches. Closer-to-Nature Forest management is not a quick-fix but is built on long-term measures. Forest ecosystem responses to management interventions need to be regularly monitored and evaluated to adjust management strategies accordingly.  

Variable retention forestry refers to management, in which living trees, undergrowth and deadwood are intentionally left on cutting areas to maintain ecological processes and to enhance biodiversity. It can be successfully applied in any forest ecosystem. 

Disturbance-based forest management aims to emulate natural disturbance dynamics at stand and landscape scales through silvicultural manipulations of forest structure and landscape patterns. This management is grounded on the premise that natural disturbance is a key process maintaining diversity of ecosystem structures, species and functions, and adaptive and evolutionary potential, which functionally link to sustainability of ecosystem services supporting human well-being. Forest management treatments include leaving retention tree groups, deadwood, as well as emulating wildfire by prescribed burning. 

Continuous-cover forestry is a sustainable forest management approach that maintains a permanent forest canopy. It involves selective harvesting of individual or small groups of trees, allowing light to reach the forest floor and enabling new seedlings to grow. 

The closer-to-nature forest management is based on the following main principles: 

  • All forest management activities are intended to create and maintain heterogeneous forest stands and landscapes. Regeneration areas follow natural ecosystem boundaries. 

  • Natural regeneration is preferred to planting. Soil preparation on regeneration sites is avoided.  

  • When retaining living trees, tree groups are usually better than individual trees, to support continuity of microclimate. Groups of trees of various species, age and size with tree undergrowth and deadwood are ideal. Preferably old, large, damaged or weakened trees providing microhabitats (cavities, bird nests etc.) for different organisms, or trees that have potential to become old or large and develop microhabitats, should be retained. All standing and downed deadwood, including high stumps, as well as dying and dead trees should be spared in final fellings.  

  • Preserving key habitats and ecologically functioning buffer zones along water bodies and in forested peatland ecotones in managed forests is an essential part of biodiversity-oriented forest management.  

  • In juvenile tree stand management, seedlings, understorey and shrubs inside retention tree groups, on rocky outcrops, and in paludified spots are preserved. Monocultures should be avoided. Existing seedlings of junipers, goat willows, hazels, rowan, linden, oak, ash, elms and maple should not be removed if they do not significantly disturb the development of crop seedlings. 

  • In commercial thinnings (intermediate fellings), retention trees including both healthy trees and habitat trees (trees with cavities, damaged and decaying trees), as well as all standing dead trees (snags), logs and stumps should be left untouched. It is recommended to maintain tree species mixtures, as well as to keep open growth space and preserve existing thickets for game management.  

  • Deadwood in form of snags, logs or high stumps should be preserved or created at all stages of forest management under all systems. 

  • Uneven-aged forest management practices – e.g. selective and gap felling – mimic natural disturbance patterns and natural structural variability in forest stands and landscapes better than conventional intensive even-aged forest management. The same principles apply: valuable habitats should be excluded from fellings, retention trees and thickets should be left and tree species admixture should be favoured. All existing deadwood should be preserved. 

Energy wood harvesting should be avoided as much as possible because removal of biomass means removal of substrates and habitats for a large group of forest dwelling species, as well as nutrients and carbon, with negative impacts for biodiversity, nutrient balance as well as carbon sequestration and other ecosystem services in forested landscapes.   

Below you can see examples of closer-to-nature forest management.

Outcomes

The positive effects include improved multiple ecosystem services in forest ecosystems, e.g. water quality, soil health, aesthetic recreational values of forest landscapes.  

Possible negative side effects can be related to risks of pests and diseases, failure in tree regeneration and less economic outcome per area. This can result in more intensive management in other areas if total economic yield is politically decided to be constant or to increase.  

In a changing climate, post-disturbance forest stages may face increased risk of regeneration failure. Management options may include assisted species migrations and leaving natural disturbance legacies, such as deadwood, that enhance tree regeneration.  

Retained habitat trees as well as fresh logs and snags can be colonized by pests in the case of susceptible species (e.g. Norway spruce and bark beetle). This can bring economic losses to forest owners. However, in a variable forest landscape with deadwood in different decay stages there is larger populations of the natural enemies to bark beetles, making large outbreaks less probable. It should be an aim to avoid all harvesting of dying and wind-thrown trees.  

ATTENTION

  • People’s safety should be kept in mind when performing different tree fellings. 

  • The use of forests is mainly guided by forest legislation, forest certification criteria and forest management guidelines. In many Nordic countries, forest legislation and forest management guidelines have recognized uneven-aged forest management practices, as well as promoted the retention of critical structural elements in forest management operations from the 1990s onwards. However, the closer-to-nature forest management principles should be better taken into consideration in forest management to safeguard biodiversity. 

  • There is a need to review existing subsidy and taxation regimes affecting private forestry, and to consider how these might be changed to further the uptake of Closer-to-Nature Forest Management. 

  • In forestry laws in the Nordic countries it is stated that volumes of recently dead spruces exceeding 10 m3/ha shall be removed before mid-July to avoid damage by the European spruce bark beetle (Ips typographus), and that volumes of recently dead pines exceeding 20 m3/ha shall be removed before the beginning of July to avoid damage by the pine shoot beetle (Tomicus piniperda) and the lesser pine shoot beetle (T. minor). Old deadwood does not constitute a risk of spreading bark beetles to living stands, and should be retained. 

Costs 

  • Closer-to-Nature Forestry might result in lower yield of the harvest at the stand level. However, there is a potential loss of financial revenue as the retention of individual trees or tree groups may involve trees of larger diameters aimed at timber production.  

  • If the political goal is to maintain the same or higher volumes of timber harvest, there will be a need to conduct harvest on slightly larger areas. This might result in higher costs for building forestry roads, transport etc. New harvesting systems in combination with more forest protection can however open opportunities for income from other ecosystem services than timber production, such as various recreation opportunities etc. Natural regeneration is cheaper as compared to regeneration by planting, but can result in slower regeneration and possibly prolong time to next harvest. 

Specific location: southern Finland (Isojärvi research area, Kuhmoinen) and east-central Finland (Ruunaa research area, Lieksa) 

Which ecosystem type: Forests    

Title/name of the NbS: Disturbance-Based Forest management 

Summary: A large-scale and long-term research and development project Forest management inspired by natural disturbance dynamics (DISTDYN) was initiated in Finland in 2009. The aim is to examine how variation in spatial and temporal scales of felling affects forest structure and biota. Harvesting methods applied in this project include selection, gap, partial and clear felling with variable retention. Rehabilitation is also applied as dead wood is intentionally increased while harvesting. The motivation of the project lies in the growing interest in using natural disturbances as an inspiration of forest-ecosystem management and in the recognition that mid- to small-scale disturbances are a characteristic feature of unmanaged Fennoscandian forests. The effects of felling methods are studied at the stand scale. However, a unique aspect of the project is the focus on landscape-scale impacts of different harvesting alternatives by comparing ca. 150-ha landscape units with varying harvesting regimes. Overall, the project aims at creating a long-lasting multidisciplinary research infrastructure. It also addresses core issues of forest-ecosystem management, including ecological, timber-production, economic and socio-cultural performances of alternative harvesting practices. 

Contact: Prof. Koivula Matti (LUKE), Natural Resources Institute Finland, matti.koivula@luke.fi 

Relevant links to documentation: Forest management inspired by natural disturbance dynamics (DISTDYN) – a long-term research and deve (tandfonline.com) 

Specific location: Municipality of Oslo 

Which ecosystem type: Forest 

Title/ name of the NbS: Multifunctional forestry 

Summary: The municipality of Oslo aims to do economically profitable forestry that also protects biodiversity values, allows for versatile outdoor recreation possibilities, as well as contributes to climate change mitigation both through carbon sequestration in the forest ecosystem and through providing wood biomass for substitution of fossil-based materials. While the dominant harvest form in Norway is clear-cutting, the municipality of Oslo applies continuous-cover forestry where site conditions are appropriate for it. Clear-cutting is applied in sites not well suited for continuous-cover forestry. Nitrogen fertilizer is not used in forestry because of the uncertainty of its impacts on biodiversity. Much of the regeneration is natural, but planting is done in clear-cut sites and is also used to complement natural regeneration. The forests in Oslo municipality are currently in a transition phase from clear-cutting dominance to a larger share of continuous-cover forestry, as it takes time to convert traditionally managed forests into forests with greater variation in both structure, age and tree species. 

Contact: Esben Kirk Hansen, esben.kirk.hansen@bym.oslo.kommune.no, Lisa Näsholm, lisa.naesholm@bym.oslo.kommune.no, Knut Johansson, knut.johansson@bym.oslo.kommune.no, Bymiljøetaten, municipality of Oslo 

Relevant links to documentation: Inkludering-av-klimahensyn-i-Oslo-kommunes-skoger.pdf 

Specific location: Municipality of Eidskog 

Which ecosystem type: Forest 

Title/name of the NbS: Variable retention forestry 

Summary: The municipality forest of Eidskog aims to carry out active forestry and at the same time facilitate for higher biodiversity. Their approach, the so-called Eidskog-method, represents variable retention forestry that they implement in all kinds of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) stands.  

Before logging, employees in the municipality forest manually mark all the future retention trees in each stand. They select the retention trees so that they are scattered all over the stand, which is in considerable contrast to traditional clear-cuts, where the retention trees are most often set aside in groups and clusters. On-site individual selection of the future retention trees enables targeting the largest and most vital trees in the stand. In addition, they set aside a minimum of one extra (relative to the requirement of the Norwegian PEFC forest standard) retention tree per 1000 m2, so that stands harvested using the Eidskog-method contain at least two living retention trees per 1000 m2. All dead trees are also retained. As an additional contribution to maintain forest biodiversity in some of the stands, they set aside small areas with particularly high biological value. For instance, areas with extraordinary old and/or big trees, humid microclimate as well as parts that considerably deviate from the rest of the stand, for example areas with big stones and boulders which affects tree species composition and their age structure.    

After the first three years of implementing the Eidskog-method, the harvested stands differ visually considerably from traditional clear-cuts, the amounts of dead wood have increased substantially and the retention trees are remarkably stable. So far only a small fraction of the >1500 retention trees set aside have fallen down because of heavy wind or snow.  

Contact: John Wirkola Dirksen, the municipality of Eidskog, jwd@eidskog.kommune.no 

Relevant links to documentation: https://www.eidskog.kommune.no/tjenester/teknikk-plan-og-naring/skog-og-landbruk/skogbruk/kommuneskogen/ 

Ecological background: characteristic features of old-growth forests  

Guidelines and principles 

  • Larsen, J. B., Angelstam, P., Bauhus, J., Carvalho, J. F., Diaci, J., Dobrowolska, D., ... & Schuck, A. (2022). Closer-to-Nature Forest Management. From Science to Policy 12 (Vol. 12, pp. 1-54). EFI European Forest Institute. (EFI_fstp_12_2022.pdf (unito.it) Scientific book 

  • Korhonen, K.T., Huuskonen, S., Kolström, T., Kurttila, M., Punttila, P., Siitonen, J. & Syrjänen, K. 2021. Closer-to-nature forest management approaches in Finland. Natural resources and bioeconomy studies 83/2021. Natural Resources Institute Finland. Helsinki. 25 p. Closer-to-nature forest management approaches in Finland (luke.fi) Scientific report 

  • Messier, C., Puettmann, K.J. and Coates, K.D. eds., 2013. Managing forests as complex adaptive systems: building resilience to the challenge of global change. Routledge. Scientific article 

  • Metsänhoidon suositukset - Tapio Webpage, handbook on closer-to-nature forest management in private forests in Finland according to the recommendations by Tapio, in Finnish and Swedish 

Scientific evidence on the impact of NBS, case studies 

  • Koivula, M., Louhi, P., Miettinen, J., Nieminen, M., Piirainen, S., Punttila, P. & Siitonen, J. 2022. Talousmetsien luonnonhoidon ekologisten vaikutusten synteesi. Luonnonvara- ja biotalouden tutkimus 60/2022. Luonnonvarakeskus. Helsinki. 83 s. Talousmetsien luonnonhoidon ekologisten vaikutusten synteesi (luke.fi) Scientific report, in Finnish  

  • Larsen, J.B., 2012. Close-to-nature forest management: the Danish approach to sustainable forestry. Sustainable forest management—current research, pp.199-218. Scientific article 

  • Coll, L., Ameztegui, A., Collet, C., Löf, M., Mason, B., Pach, M., ... & Ponette, Q. (2018). Knowledge gaps about mixed forests: What do European forest managers want to know and what answers can science provide?. Forest Ecology and Management, 407, 106-115. content (udl.cat) Scientific article , includes a methodology of creating mixed forests