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ŠUMARSKI LIST 7-8/2018 str. 29     <-- 29 -->        PDF

Influence of the ecological conditions on the productive potential of Grey alder
Utjecaj ekoloških uvjeta na proizvodni potencijal sive johe
Michal Bugala, Zuzana Parobeková, Ján Parobek
The aim of the study is to analyse the productive potential of grey alder (Alnus incana (L.) Moench) along an altitudinal gradient to verify coincidence of productive and ecological optimum and to identify climatic factors that control the growth. Along the altitudinal gradient of the river basin, dendrometric data has been analysed on the eight permanent research plots at the altitude of 525–705 m. Correlations between standard chronology and average monthly climate characteristics were calculated for the period 1969–2015. Significant differences in the average basal area increments have been recognized among the investigated altitudinal zones. The highest basal area increment (1661±975 mm2y-1) was detected in the zone of altitude 605 m. and the average annual volume increment of the model grey alder stand was 4.59 m3. The radial growth of grey alder has been positively affected only by the temperature of the current April and negatively by precipitation of the previous growing season. Based on the pointer year analysis can be claimed that condition of the root system is the most influential factor in relation to the radial growth and is dependent on water stress in the previous year. Investigated relationships may significantly influence decision making process in the forest management focused on grey alder re- or afforestation.
Key words: production, ecological optimum, basal area increment, dendrochronology, climate-growth relationships
Grey alder (Alnus incana (L.) Moench.) is an important component of riparian vegetation with great regulatory and retention ability during high water levels. In the spring areas alder stands are a specific habitat most commonly found on the upper parts of watercourses (Lukáčik, 1996; Lukáčik and Bugala, 2005; Vukelić et al., 2012). These stands not only affect the steadfastness of the watercourses and retain their natural character, but they are significant landscape element. Grey alder belongs to the fast-growing tree species with ameliorative function and considerable tolerance to various climatic and edaphic environmental conditions (Rodríguez-González et al., 2010; Pernar et al., 2012; Vacek et al., 2016). It is often used for the biological site preparation and serves for the soil stabilization, regulation of the microclimate (mitigation of temperature extremes), and improvement of the physical, chemical and biological soil properties. Symbiotically N2-fixing and litter decomposition significantly improve the quality of the soils where it grows. During the last decades this unique combination of properties has made grey alder as the tree species of an increasing importance in Europe (Rytter and Rytter, 2016).