Regeneration of forest stands on permanent research plots in the Krkonoše Mts.

Abstract

ABSTRACT:The article describes natural, combined and artificial regeneration on 38 permanent research plots in both Czech and Polish part of the Krkonoše Mts. The attention is paid to species composition, spatial (horizontal and vertical) and age structure of forest regeneration according to different stand and site conditions. Concerning the structure and dynamics of forest stands and their regeneration, the potential and prospects of regeneration according to particular developmental stages and stand types (beech stands; mixed stands: spruce-beech, fir-beech, spruce-firbeech; spruce stands, stands in the ecotone of the upper forest limit and relict pine woods) were evaluated. In many aspects the plots show several similarities, nevertheless the regeneration in different site and stand conditions show clear differences in dynamics of development. The main differences are result of different ecological conditions, environmental limits and biological characteristics of dominant tree species.Keywords: forest ecosystem; forest regeneration (natural, combined, artificial); Krkonoše Mts.; site and stand conditions; structure and development of forest stands Increasing the ratio of natural regeneration is in present days considered as one of the main challenges of the Czech forestry and nature protection. The use of natural regeneration is commonly accepted as essential part of close-tonature forest management based on ecological principles. Beside lower establishment cost, natural regeneration is important measure in conservation of forest genetic resources and establishment of forest stands with appropriate tree species composition and ecological stability. In the Krkonoše National Park the ratio of natural regeneration is constantly increasing (Fig. 1) with simultaneous decrease of artificially regenerated areas, usually of conifers (mainly spruce). Issue analysisNatural regeneration, its age, species and height structure have a key role in regeneration of tree layer in forest ecosystems. Regeneration processes and their dynamics largely influence stability and functionality of forest stands. The advantages of natural regeneration lie mainly in maintaining of autochthonous or well-established allochthonous populations of forest woody plants with presupposition of preserving desirable qualities of maternal forests, i.e. individuals of regeneration that well adapted to more extreme site conditions; it enables to use effectively differences in site conditions (Korpeľ et al. 1989;Vacek et al. 2010a).The regeneration development in forests with natural or near-natural structure is related to the occurrence of disturbances in the forest development. The success of natural forest regeneration depends on a number of factors. Worsening conditions for existence of a forest in mountain areas (climatic and soil extremes) result in decreasing generative reproduction ability of forest woody plants. Continuous regeneration is dependent on

Changes in horizontal structure of natural beech forests on an altitudinal gradient in the Sudetes

“…Man-made forest stands mostly have lower volumes of dead wood (standing and fallen) - (Christensen et al 2005), simplified DBH and age structure and regular distribution of trees, while natural forest stands that originate from natural regeneration (from seeds, vegetative sprouts or by layering) usually have an aggregated or randomly irregular initial distribution (Vacek et al 2010a(Vacek et al , 2010b and generally higher structural heterogeneity (Rademacher et al 2001;Rozas 2006). In the course of stand development this type of distribution changes toward moderately regular distribution in favourable environmental conditions (Korpeľ 1995;Wolf 2005), while in less favourable conditions more irregular or aggregated structures are expected (Vacek et al 2010b).…”

Belowground ectomycorrhizal communities in three Norway spruce stands with different degrees of decline in the Czech Republic

“…Pure spruce forests declined extensively and then largely failed to regenerate. Although the air quality has improved in the Krkonose Mountains and the stand states have generally stabilized or improved since the 1990s (Vacek and Matějka 1999), many forest sites are still heavily damaged and only a few percent of trees have survived; most show extensive defoliation and no regeneration.…”

Cluster reforestation near the timber line

“…The surveys made in 2009 indicate that 43% of trees from the original stand died of which 13% of trees died in the last few years due to the feeding of spruce bark beetle. Comparable results of stand development under air-pollution and bark beetle pressure near the timber line published Vacek and Matějka (1999).…”