Close to nature forestry

Mixed and irregular deciduous forest in Catalonia

Close to nature forestry is a theory and practice that takes the forest as an ecosystem and manages it as such. It is based оn reduced human intervention, that should be directed to accelerate the processes that nature would do by itself more slowly. It aims at overcoming the divorce between forestalist and ecologist management systems of forest. As an important consequence, it concludes that if properly applied, it would render the segregation of forest lands into "productive" and "reserves" or national parks unnecessary.^[1]

History

Europe

The Arbeitsgemeinschaft für Naturgemässe Waldwirtschaft (ANW) (German: Working Group for the Close to Nature Forestry) was established in Germany in 1950. In recent years this association has increased a lot its membership. The main reasons being the increase of ecological consciousness, the growing demand for forest products or services other than wood, the damages suffered by regular forest stands, the forest death fear.^[1] Another term often used to describe a close to nature approach to forest management, especially in Britain and Ireland, is Continuous Cover Forestry.^[2]

Because of a 1948 forest law, Slovenia has many forests managed according to the principles of close to nature forestry. In 1989 ANW promoted a meeting at Robanov Kot, in the Julian Alps, and the ProSilva organization was created, with representatives of 10 countries. At present the organization headquarters are in the French region of Alsace.^[1]

North America

In the United States professor Thom McEvoy has published the book Positive Impact Forestry,^[3] that recommends forestry practices similar to those of the "close to nature" movement. He thinks that the precursors of this type of forestry are to be found in Europe, mainly in Germany, and particularly makes mention of Heinrich Cotta, and his famous Cotta's Preface,^[4] that highlighted the importance that the study and understanding of nature should have for the foresters. As a more immediate precursor he makes reference to American forester and ecologist Aldo Leopold.

The Ecoforestry Institute consists on educational, non profit and non governmental organizations operating in US and Canada. They propose a forestry based on ecological principles, very similar to those of Pro Silva.

Forest management/ecosystem management

The close to nature approach intends to bridge the discrepancies, or even antagonisms between the silvicultural and ecological visions on the single reality of forest, considering the forest as an ecological system that produces wood. The sought after solution is not to segregate the territory into areas devoted to either forestry or ecology, but to integrate all functions.^[3]

Objective

The management has to obtain healthy and stable forest systems that produce wood with a minimum human intervention. The products to obtain, other than wood, are fauna habitats, biodiversity, recreational, aesthetics, and water management. The human action has the object of accelerating natural processes, but not substitute them.^[1]

Silvicultural models

Forest with irregular structure and mixed composition, in NE Germany.

ProSilva recommends to use the uneven-aged forest system, in which the ages, and consequently sizes, of trees in a forest are different. It has the advantage to offer a stable structure regarding natural disasters and plagues, and is very adequate for fauna habitat and biodiversity promotion. It provides a better soil protection, since there is a permanent tree cover.^[1]

McEvoy considers that in spite of being the most close to nature system, it is difficult to implement, and proposes to use the high regular forest model, in which all trees are of the same age/size, but recommends using a regeneration system with a generous cover, to avoid soil erosion, and prevent excessive light entrance, that would promote the growth of a potent understorey.^[3]

The Ecoforestry Institute, similarly to Pro Silva, recommends multi-aged and multi-species forests.

Recommended practices

Proposed thinning frequency is about ten years, and intensity low, in order to limit the ingress of excessive light, that could promote too much understory, or the growing of epicormic shoots. It has to be directed to favor the trees that show good prospect for the future. The operations have to be done in a way that will avoid soil compaction or damage to the trees that will remain standing.^[5]

Native/introduced species

When foresters plant trees, they may use either native or introduced species. Whenever foresters decide to use a species that is not native, they do it because they think that there are silvicultural advantages linked to this choice, be they the wood quality, ease of management, adaptation to the climatic conditions, shorter production delay, etc. It may be that there is information available about the behavior of this species in the habitat, or the forester is ready to make a trial.

From the ecological point of view, the introducing species is considered as a threat. The introduced species risks being invasive. Invasives displace local species, resulting in a reduction of biodiversity, a condition also to be expected if great extensions are forested using introduced species.

Professor McEvoy^[3] is very clear and strict: introduced species can not be used at all when working in a close to nature forestry system. Pro Silva makes some distinctions, based on species and conditions.^[1] Natural forest systems are to be preserved, but the enrichment with certain introduced species may be positive, depending on circumstances.

ProSilva recommendations^[6]

The natural vegetation systems for each region are an asset to maintain, and constitute an important basis for the silvicultural planning.
Introduced species can, depending on circumstances, supplement natural species, and add economical revenue.
The forest species that are introduced to a region are termed exotic.
The introduction of exotic species should only be permitted after trials conducted from the qualitative and quantitative point of view.

Herbivore fauna management

The herbivore fauna, be it domesticated or wild, acts on tree seedlings and small trees. In high regular forests, the regeneration periods are chosen by the forester, and therefore it is possible to establish some control over fauna action, particularly domesticated fauna, avoiding grazing during regeneration. The un-even aged forest is continuously regenerating, and therefore it is difficult to make it compatible with grazing, and does not admit a high density of wild herbivore fauna. The pressure of herbivore fauna, mainly cervids, in some European forests, has reached an intensity that is threatening the practice of close to nature forestry.^[1]

Economic aspects

Forestry's economic profitability has progressively diminished in developed countries, beginning at the end of the 20th century. This has been the result of lower lumber prices and higher operating costs. Because it requires less human intervention, the close to nature forestry has lower labor costs.^[1] Also, it encourages the evolution of forests toward higher ecologic and landscape value structures. This is in demand by society, and the payment for ecosystem services is being considered.