Differential response of naturally regenerated European shade tolerant tree species to soil type and light availability

The effect of soil type and light availability on a natural regeneration community comprising of several shade tolerant species was studied in 120-year-old managed, beech-dominated, forest in the Czech Republic. Full inventory of natural regeneration was conducted and a light climate (canopy openness, DSF, ISF, TSF) determined from hemispherical photographs on 81 sampling plots (3.14 m^2 each) belonging to two distinctly different soil types (Calcaric regosol and Calcaric cambisol). The effect of light and soil on basal diameter and height of nine naturally regenerated tree species was examined. The mean density of natural regeneration was about 160 000 ind./ha, which is several times higher than recommended afforestation rates. Density of natural regeneration was independent of soil type and negatively regressed to canopy openness, probably as a result of increased competition with herbal vegetation in open spots. Mean height of natural regeneration was significantly related to soil type and available light. Although species composition of the regeneration community was similar on both soil types, the partitioning of species differed greatly. Influence of soil and light availability on seedling diameter and height differed among species. Soil had significant effect on height of elm and sycamore maple and on basal diameter of elm. Light climate had significant effect on height of beech and diameter of beech and Norway maple. Browsing by deer was found to be an important factor determining natural regeneration community development. Ash, maple and elm were the most preferred with up to 100% of individuals being browsed while less than 15% of beech seedlings were damaged.