Sycamore maple (Acer pseudoplatanus L.) stands on former agricultural land in the Sudetes – evaluation of ecological value and production potential

Sycamore maple (Acer pseudoplatanus L.) is a fast-growing tree species that produces economically attractive timber, provides ecological services and has high site adaptability, but it is only a minor component of European forests. This paper describes production, structure and diversity of sycamore-dominated forest stands that originated by succession on former agricultural lands in the Orlické hory Mts., the Czech Republic. The partial objectives were to determine impact of climatic factors on the radial growth of sycamore maple and evaluate the effect of game on natural regeneration. The number of sycamore seeds on the ground was on average 9–34 seeds m–2 and seedling mortality reached on average 89% caused by damage of hare and drought. Density of natural regeneration ranged from 1,532 to 4,244 recruits ha–1, but growth dynamic was strongly influenced by ungulate browsing (69%) with the largest losses in sycamore (96%). Analyses of climatic effects showed a significantly close relationship with growth of sycamore in submontane areas, being especially sensitive to extremely dry and cold winters or very high summer temperatures. Radial growth was more significantly influenced by monthly temperatures compared to precipitation, but increasing sum of annual precipitation was main positive driver factor of diameter increment. Radial growth had the strongest relationship with weather conditions in July and October of previous year and March of the current year. Stand volume ranged from 378 to 545 m3 ha–1 at age around 75 years, while sycamore accounted for 32–82%. The horizontal structure of the tree layer was mostly random to aggregated; resembling the clumped spatial pattern of natural regeneration. Besides their wood production, these stands fulfil many ecosystem functions that are associated with high ecological stability, high structural differentiation and medium to high species diversity.