Silver fir sapling bank in seminatural stand: Individuals architecture and vitality

The relations between age, crown architecture, height and height increment of silver fir (Abies alba Mill.) saplings were analysed using a multivariate method. Individuals from the saplings bank in mixed, unevenly aged, seminatural stands in Western Poland were investigated. Examined features were analysed with respect to light availability, which varied between 5.9 and 25.8% of full sunlight. The age of firs in the saplings bank varied from 11 up to 101 years. Under shade, growth is suspended and saplings tend to form a flat crown. Reduction of growth of a sapling did not influence its mortality, and did not diminish its ability to vigorously grow for up to 90-year-old saplings. Results of the PCA showed that age was not connected with sapling size, growth or crown morphology. Height increment is related to the relative crown length (RCL) and to the size of the sapling. In looking for an objective and quantitative indicator of growth potential, results suggest the RCL as a feature not influenced by sapling size. It should be pointed out that the vitality defined in this way reflects only the current growth, but not the potential to survive or the ability for rapid growth along with a changing light environment. The apical dominance ratio (ADR) value seems to be an indicator of light conditions in the understorey, but this trait is influenced by the height of the sapling.