A Model of Stand Dynamics for Holm Oak-Aleppo Pine Forests
The paper deals with the dynamics of structure, diversity and growth of natural pine stands without direct human impact during the ten-year period in Nature Reserve (NR) Kostelecké bory, Czech Republic. The objective was to determine the main characteristics of the spontaneous development of Scots pine (Pinus sylvestris L.) forest stands in relation to their naturalness, ecological stability and adaptation to climate change and air pollution stress. Horizontal and vertical structure and species
... ructure and species diversity of the tree layer, dead wood and natural regeneration of each permanent research plot (PRP) were evaluated (n = 6, 50 × 50 m /0.25 ha/, Northern Bohemia, 410-425 m above sea level). The average ring series of PRPs were correlated with the climatic data (precipitation, temperature) according to individual years from the Doksy climatic station, and the air pollution data (SO 2 in 1988-2015, NO X and AOT40F -ozone exposure in 1992-2015) from Radimovice station. In 2016, the stand volume increased by 26.0% to 136 m 3 ha −1 (108 m 3 ha −1 in 2006) and the volume of dead wood increase by 127.2% to 27 m 3 ha −1 (12 m 3 ha −1 in 2006). The horizontal structure of tree layer and natural regeneration was predominantly aggregated to random. More distinct changes in biodiversity and structural characteristics occurred in the natural regeneration (21.5%) compared to tree layer (2.8%). The precipitation had a significantly higher effect on radial growth compared to temperature. The lack of precipitation in growing season and high temperature in previous autumn and winter were limiting factors for growth. Climatic factors had significant effect on diameter increment in July of the current year (P < 0.01) and June of the current and previous year (P < 0.05). Radial growth was negatively correlated with SO 2 concentrations (P < 0.01) and ozone exposure (P < 0.05). NO X concentrations had low effect on radial growth. The natural stand dynamics had positive effect on biodiversity and functional integrity of natural pine ecosystems.