Sustainable development and management of beech forests

Abstract

Beech is a very widespread species on the entire Eurasian continent. It grows and develops in different ecological and habitat conditions in a wide horizontal and vertical amplitude. It can be found at altitudes below 100 and above 2,000 m. Beech forests develop in different age stands from young to very old (old-growth forests). They can be pure or mixed with other species or they can be very different in origin (generative or vegetative). They develop as eaven-aged or uneaven-aged stands, and some of the beech forests have the characteristics of forests with high natural values and are very important for the conservation of biodiversity. Their natural regeneration process is of essential importance for the survival and sustainable development of beech forests. Restoration of beech forests can be achieved naturally or artificially. In modern forestry science and practice, natural forest regeneration is always preferred. The processes of natural regeneration have different development depending on whether they take place under the protection of the parent stand or take place in an open canopy in the forest or on uncultivated terrain. The density of the canopy has a great influence, so that with the increase of the canopy of the parent stand during the natural renewal, there is a decrease in the number of regeneration individuals(offsprings) in all developmental stages. During the natural regeneration in different conditions of the stand canopy and the size of the openings within the forest, the most abundant and best regeneration is observed in the openings up to 500 m², then for openings within 500 and 1,000 m², and least in openings between 1,000 and 1,500 m². This clearly indicates that large openings within the forest are not suitable for the natural regeneration of beech because the number of offsprings, which are very necessary in the younger developmental stages, is continuously decreasing. The natural renewal that develops in the conditions of circular openings within the size of up to 500 m² has the best quality structure of the offspring. In such openings, about 60% of the offspring is of good quality, about 25% is of medium quality and about 15% is of poor quality. In openings between 500 and 1,000 m2 , the number of good quality natural regeneration is reduced to 41%, the number of medium quality natural regeneration is increased to 38% and from poor quality to 21%. The quality structure of natural regeneration is further reduced in openings between 1,000 and 1,500 m² where only about 20% of the offsprings is of good quality, about 30% is of medium quality and about 50% is ofpoor quality. With openings larger than 500 m², weeds are very common. Beech stands in different habitats have large differences in their productivity, caused by the wide range of the beech forests in different habitat conditions and in different cultivation forms. Aboveground biomass in beech forests varies depending on the age of the forest, the way it is managed and used, as well as numerous environmental factors. High values of aboveground biomass in preserved oldgrowth beech forests above 750 t·ha-1 are known. Moderate values in commercial forests range between 200 and 400 t·ha-1 . In dominant trees, the largest biomass is found in tree crowns, while in subdominant and suppressed trees, the largest biomass is in the trunk, which is the result of a smaller crown due to the lack of solar radiation. Generally, 1/3 or slightly less of the aboveground biomass comes from the branches, the leaves cover about 1-2%, while the largest biomass (60- 70%) is concentrated in the tree. Dead biomass in beech forests consists of dead biomass accumulated in the forest floor, as well as in standing and lying dead biomass. Forest biomass varies in European beech forests: beech forests in the north show less biomass of 3-12 t·ha-1 , while high values (25-75 t·ha-1 ) are registered for the southeastern parts. Standing dead biomass in forests amounts to 1.2-6.0% of living aboveground biomass or 2-5 t·ha-1 . Lying dead biomass in European beech forests varies to a very large extent depending on the conservation of beech forests and their developmental stage. The European range is 32-310 m3 ∙ha-1 , and values above 130 m3 ∙ha-1 belong to the preserved beech forest reserves. When choosing methods of beech forest management, one should always take into account the biological characteristics of beech in relation to the ecological conditions in the area where beech develops. Today, various and professionally supported methods of forest management with the aim of their sustainable development demand great importance for beech forests.