Conversion of Norway spruce monocultures need for sustainable forest management in the Czech Republic

Transcription

1 Conversion of Norway spruce monocultures need for sustainable forest management in the Czech Republic E. Klimo 1), J. Sou ek 2), J. Kulhav 1), V. Tesa 1) 1) Mendel University of Agriculture and Forestry, Brno 2) Forest and Game Research Institute, Research Station Opo no

2 Forestry in the Czech Republic Forest area 2.6 mill. ha (33.7% of the area) State forests (62%), private owners (19%) 75% production forests, 22% special purpose forests, 3% protection forests 71% of forests certificated (mainly PEFC) Mean growing stock 259 m 3.ha -1, mean rotation 115 year Cutting mill. m 3 ( m 3 per person, m 3.ha -1 ), mean increment m 3.ha -1.y -1, the last 2 years mean cuttings higher than increment! Motor/manual system of cuttings with wheel tractor skidding dominates, share of harvesters gradually increase Natural regeneration on 14 17% of regenerated area, broadleaves in regeneration 35% Forest health conditions are affected by climatic extremes (2003, 2007), winds (Kyrill, Emma), air-pollution (60% of forest area), soil acidification and biotic factors (wildlife, bark beetles, rodents, fungi) - salvage cuttings limit management

3 100 Composition of tree species (% of forest land area) % Natural Current Recommended Spruce Fir Pine Other conifers Oak Beech Other broadleaves

4 Presence of spruce stands in the Czech Republic

5 History of stand conversions Intuitive attempts to transform conifer monocultures before the 2nd WW were mostly unsuccessful, next attempts in 1950s were based on forest typology and knowledge about natural species composition. In 1970s redirection of system due to air-pollution and use of mechanization New forest law (1995) sustainable forest management law amendment in 2000 (harmonisation with EU) National forestry programme (NFP II ) - performance of EU forestry strategy, succession on former NFP ( )

6 Different tendency to the management in NFP II Issue Clearcutting Stand structure, species composition Introduced species Sustainable management Limited usage Mixed stands with preference of economically important species Possible Close-to-nature management Exclusion of clearcuttings Potential natural species composition Only native species

7 Even-aged Norway spruce monocultures outside of their natural area have high risk of damage (low stability, soil changes) and induced important changes negatively affected forest sustainability. Accumulation of organic matter on the soil surface in spruce monocultures can change element cycle towards its deceleration. Proper silvicultural techniques can partly reduce negative consequences of spruce monocultures. Introduction of broadleaves species reduce acidification processes in soil, improve decomposition of upper humus horizons and element cycle Conversion of stands to more stable and close-to-nature forests should not results in the exclusion of spruce from stand composition. Tolerable proportion of Norway spruce in new forests must be found to reduce any risks for the condition and development of future ecosystems. Conversion of spruce monocultures has to be started by stand stabilization.

8 Methods of conversion Basic system of attached cuttings in appointed system (time and spatial arrangement). The modification of species composition of a subsequent stand attainable at a short time, required proportion of soil-improving and reinforcing species at the regeneration of stands.

9 Methods of conversion Maximal - transition to the continuous cover forestry in the course of a long transformation period (40+ years) is close to the principle of sustainable forest management. Require good stand stability, high demands for stand arrangement and planings.

10 Between both points plenty of transitive possibilities according to the species and age stand composition, structure and soil conditions (mainly humus horizons). Most common stage - the combination of advanced regeneration elements with the gradual regeneration of mature stands.

11 Example plots of close-to-nature management First mapping of example plots in CR in 1995, revision in 2001, Plots differentiated according to the site and stand conditions, history, methods and length of forest management. Number of plots gradually increased 41 plots (1995) 78 plots (2001) 100+? (2009). 48 plots in stands with spruce dominance on the area of hundreds hectares. Various research activities on plots, internal and international excursions for foresters, students.

12 Example plots with conversion of spruce stands Thanks you for your attention.