Based on a broad approach to sustainability, PRO SILVA presents in the following pages policy statements on four issues of major importance to present-day forest management. These issues concern:
- the basic principles of responsible forest management and forest utilisation,
- the maintenance of biodiversity,
- the use of exotic species, and
- the ecological role of forests in the landscape.
Together with this emphasis on sustainability, PRO SILVA promotes forest use which follows natural processes. By these means, ecological and economic risks are reduced.
PRO SILVA is convinced that it is possible to commence the change from a regimented type of forest management to the type of management and silviculture advocated by PRO SIL.VA at almost any stage of stand development. Within a range of stand types, forest protection, management and utilisation can assist in regenerating and conserving the forest.
Pro Silva supports the implementation of such management in the following ways:
- Exchange of information within regional working groups;
- Establishment of demonstration forests;
- Meetings and excursions in demonstration forests;
- Cooperation with educational and scientific institutions, and other bodies.
These policy statements are the result of many discussions held among members of the Board of PRO SILVA Europe. The objective of these policies is to increase the benefit derived from the forest, by present and future generations.
Pro Silva Forestry Principles
PRO SILVA promotes forest management strategies which optimise the maintenance, conservation and utilisation of forest ecosystems in such a way that the ecological and socio-economic functions are sustainable and profitable. The general approach to management which is advocated by PRO SILVA, includes market and non-market objectives, and takes the whole forest ecosystem into consideration.
With reference to sustainability in its broadest sense PRO SILVA believes that forests provide four categories of benefit to society. These are:
Principle 1: Conservation of ecosystems
The maintenance of ecosystems provides a basis for the protective, productive and recreational functions of forests, and however society may wish to utilise the forest, the vitality and inter-relation of life forms within the forest ecosystem provides the foundation for all the other functions of the forest. The preservation, and if necessary the restoration, of the ecosystem is, therefore, the first priority.
Elements of ecosystems are:
- Local and regional diversity of flora and fauna (species diversity);
- Genetic diversity within the local population of each species, providing the possibility for evolutionary development (genetic diversity);
- Local and regional diversity of ecosystems (spatial and temporal diversity in structure);
- The occurrence of ecological processes (natural and semi-natural forest dynamics);
- The ecological network;
- The ecological interactions of forests in relation to the environment (world-, regional- and local climate, and interaction with surrounding landscape).
PRO SILVA recommends the following essential methods to allow forest ecosystems to function:
- Paying serious attention to (i.e. maintaining or restoring) the natural forest vegetation pattern, while making use of the forest;
- Maintenance of soil productivity, through continuous cover and through the maintenance of biomass in the forest (including dead wood);
- Propagation of mixed forest with special attention to rare and endangered species;
- Restricting the use of exotics to cases where this is an economic necessity, and then only if the exotics can be mixed with the indigenous vegetation pattern within certain quantitative and qualitative limits;
- In special cases, forgo any harvest.
The elements of the conservation of forest ecosystems, as stated above, correspond to the declaration on biodiversity which was made at the Rio conference in 1992.
The protection, production and recreational functions of the forest are all based on the conservation of the ecosystem; and they are all, in their own way, important to society.
Principle 2: protection of soil and climate
Essential elements of the protective function are:
- Protection or restoration of the natural soil fertility and soil structure (soil protection);
- Protection of natural forest types (biotope protection);
- Protection of typical and rare or endangered species (species protection);
- Protection against erosion (erosion protection);
- Protection and cleaning of water (water protection);
- Protection or improvement of forest climate and its impact on surrounding landscape (local and regional climate protection);
- Maintenance and improvement of carbon storage (world climate protection);
- Protection or improvement of air quality (emission protection);
- Protection against noise (noise protection);
- Concealment of visually disturbing elements in the landscape (visual protection).
Most elements of the protective function are, at the same time, an integral part of the conservation function of forest ecosystems. They cannot be considered or dealt with separately.
PRO SILVA considers the following methods essential to achieve the benefits from the protective functions of the forest:
- Adopt a holistic approach involving perpetual forest cover;
- Establish a regional network of protected forest areas of various kinds, including some non-intervention areas;
- Adopt specific strategies for physical protective functions such as prevention of erosion, conservation of water supplies, visual aspects, and capture of pollutants.
Principle 3: Production of timber and other products
PRO SILVA regards sustainable forest ecosystems as the proper basis of economic sustainability. Protection and production are both important to society. For sustainability in the broadest sense, continuing and optimal productivity is only possible if the protective function remains intact. This precludes production strategies that ignore the protective function.
PRO SILVA supports the management of forests and the use of renewable resources of timber.
With regard to the general principles of sustainability, the following are essential elements of the productive function:
- Maintenance of the soil fertility;
- Guaranteed continuity of the forest ecosystems and timber production;
- Maintenance of the natural energy and mineral cycles.
As methods for achieving the functioning of these elements PRO SILVA recommends:
- Continuous forest cover to protect soil productivity;
- Full use of natural dynamic forest processes;
- Adding value by selection felling and tending at all stages of development;
- Maintaining growing stock at an optimal level;
- Working towards a balance between increment and harvesting in each management unit (i.e. in each compartment);
- Increase forest stability, and consequently reduce production risks, through stabilisation of single trees and groups of trees;
- Paying attention to the function of every single tree in tending and harvesting;
- Avoidance of clearcuts and other methods which destroy forest conditions;
- Abolition of rotation age as the instrument for determining when a tree should be cut;
- Undertaking renewal of the forest as an integral part of forest tending.
- Spontaneous forest renewal and forest development, through single tree harvesting and group harvesting with long regeneration periods, involving:
- use of natural regeneration,
- use of natural stem number reduction;
- Harvesting methods which do not harm the soil or the stand;
- Use of appropriate machines, which suit the structure and features of the forest;
- Minimise the use of additional materials (fertilisers, plant protection materials);
- Restoration of densities of game species to levels which are in balance with the carrying capacity;
Tending and harvesting should be the main features of management, and these should not be unduly influenced by the need to obtain regeneration.
Principle 4: Recreation, amenity, and cultural aspects
PRO SILVA recognises the increasing importance of the forest for physical and mental health, especially in densely populated countries in Europe.
Essential elements of the recreational function of forests are:
- Suitability of forests for quiet, “ceo-friendly” forms of physical and mental recreation;
- Suitability of forests as part of traditional emotional attachment of people to forests and nature (forest of secrets, myths, fairy tales);
- Suitability of forests as custodian of cultural traditions (forest as a theme in painting, poetry, music).
PRO SILVA recommends the following methods for development of forests for their recreational function:
- Giving priority to quiet forms of recreation, by providing appropriate trails and other facilities;
- In so far as is needed, the concentration of recreational facilities in specific zones;
- Establishment of quiet areas of the forest, for experiences of the senses (a place for consciousness, for thinking, for dreaming, for becoming absorbed by nature);
- Encourage attractive trees, groves and other features (colours, flowers, fruits, shrubs, herbs etc.);
- Maintenance and creation of attractive forests by varied forest structures;
- Establishment of non-intervention areas where nature is left to follow its course;
- Maintenance of forest meadows, valleys, rocky outcrops, water features, views, etc..
PRO SILVA is convinced that the recreational function generally stems automatically from the type of forest management which is proposed above. Only in exceptional circumstances will extra measures be needed.
Paying attention to the recreational function in forest management may assist in providing a counterweight to the living conditions of modem man, who is living in an increasingly urban and technical society.
Pro Silva and Biodiversity
One of the most important objectives of PRO SILVA is the preservation and development of all values of the forest, including the value of the forest to society and its intrinsic value. An important part of this value is the full spectrum of life forms and organisms of the forest ecosystem.
These various organisms and life forms are associated with the different development and successional phases of the forest, including degradation phases, open areas, standing and flowing water, and others. The totality of all organisms living in a particular forest ecosystem is a reflection of its specific biodiversity, being a part of the broader concept of global biodiversity.
Biodiversity includes higher and more primitive plant and animal species, whether or not they have a commercial value or use to society.
The preservation of species diversity as part of global biodiversity, is regarded as a prime function of the forest. This is the case irrespective of any recognisable link with human needs.
The preservation of species diversity has, in addition to its intrinsic value, considerable relevance to the use of the forest ecosystem by society. Beside the traditional use of timber and many other forest products, one should keep in mind potential products which might have a market value in the future.
In addition, it is important to note that the preservation of biodiversity generally results in a reduction of ecological and economic risks.
Foresters can make use of the following approaches as a means of preserving and developing natural biodiversity:
- Use of indigenous tree species: because numerous animal and plant species are connected to the indigenous trees in their co-evolutionary development;
- Enhancement of diversity in forest structure through forest regeneration, tending and exploitation as a means of obtaining appropriate occurrence of niches in space and time;
- Acceptance of standing and fallen dead trees, hollow trees, old groves, etc. in sufficient quantities and distribution;
- Protection of special biotopes in the forest (wetlands, rocky outcrops, dunes, etc.);
- Regulation of unnaturally high game densities, and other populations of herbivores which over-use the forest over large areas.
Forestry according to PRO SILVA principles serves biodiversity in general and species diversity in particular.
Together with economic planning, the preservation and maintenance of biodiversity in the forest must be an integral element of the forestry objectives.
Conservation of biodiversity must be included and facilitated within the medium-term management plans.
The question of non-indigenous forest species
1. Basic principles
- The vegetation pattern which evolved in European forests during the postglacial migration of forest species, forming the existing forest regions, is regarded as a precious natural asset, which must be maintained. It should be respected as the most important basis of all silvicultural measures.
- Non-indigenous species (exotics) can, under some circumstances, supplement the indigenous vegetation pattern and increase the economic yield of forestry.
- All forest species which did not previously form part of a given natural plant association and which have been introduced from distant locations must be considered as exotic species.
- The introduction of exotic species should only be allowed after critical qualitative and quantitative tests.
2. Basic conditions
- Intact natural forests:
In forest regions with natural forests or natural tree composition and with good potential timber production there is no reason to introduce exotics.
- Forest regions with insufficient natural capital:
In certain forest regions of Europe, where post glacial migration of tree species could not be achieved and the number of indigenous tree species is low, bearing in mind the climate and site conditions, and where yield from the indigenous species is unsatisfactory, exotics might present a valuable enrichment.
- Devastated forests:
In forest regions where historical influences have weakened the genetic fitness of tree populations and where soils have been harmed by human activities, and where indigenous species under the given circumstances can not be reintroduced and the natural succession will not take place, an introduction of exotics might contribute to the restoration of such forests.
- Denuded forest land:
In places where former forests have been totally destroyed, and where a forest climate no longer exists, and where indigenous species under the given circumstances can not be reintroduced at the present time and the natural succession will not take place, exotic species might play an important pioneer role.
- Niche invasion:
Certain exotics may expand into ecological niches which are currently only weakly exploited by native species and thereby suppress indigenous species.
- Site deterioration:
Some exotics may impoverish the productivity of some soils by poor litter decomposition, acidification and insufficient depth of rooting.
- Disease transport:
The introduction of some exotics into existing indigenous vegetation may bring the risk of introducing disease, which could harm the indigenous plants.
- Disease in the tree crop:
Some exotics may themselves suffer from pathogenic organisms or other risks which are present in the indigenous vegetation.
- Inadequate ecological network:
Some exotics may not fit well within the indigenous ecosystem, as they do not allow the natural vegetation to establish and develop, and/or indigenous animals avoid them.
- Lack of natural regeneration:
Some exotics are not able, or not sufficiently able, to propagate by natural regeneration, and require planting on a perpetual basis.
4. Conditions for introduction
- In every forest region each indigenous forest association should be represented to an extent which guarantees all its ecological functions. This means that no major introduction of exotics which would reduce or prevent such an extent should be admitted.
- An introduced species should not be so aggressive in its competitive behaviour and its natural regeneration as to suppress indigenous tree species or eliminate other indigenous species.
- An introduced species should be adapted to the local climate and soils. It must not impoverish soils, and its litter should decompose easily.
- An introduced species must not spread diseases or contribute to increased instability of ecosystems.
- An introduced species must not run an abnormal risk of being itself affected by biotic or abiotic hazards.
- An introduced species should become integrated into the indigenous vegetation in a modest way. It must be able to merge with, without excluding, the indigenous flora and fauna.
- An introduced species should be able to regenerate naturally, together with indigenous tree species.
- Niche invasion: