The Impact of Light Availibility on the Functional Traits of Quercus Robur L. And Acer Platanoides L. First-year Seedlings by Direct and Indirect Methods

The resource strategy of seedlings is an important key for understanding the adaptation of trees at this ontogenetic phase to abiotic changes. In this study, we tried to determine the patterns of response of functional traits of shade-tolerant and shade-intolerant species along natural environmental light gradients, using an entire-level, trait-based approach by direct and indirect methods in the Arboretum at Kórnik (Poland). Differences between the two species were found for some variables. Analysis of phenotypic plasticity indices of leaf, stem and root traits of seedlings had high values ​​for both species. The values of plasticity indices of A. platanoides root traits were lower compared to the corresponding traits for Q. robur. Relationships between measures obtained from individual-level trait data were stronger than relationships with measures obtained from community-level trait data. The data obtained from the direct method revealed the closest relationships between functional traits of seedlings and light changes at the individual level trait data for both species. Correlation links between LAI and leaf (LMA, SLA) and stem (SSL, SMR) traits were less tight for Q. robur compared to A. platanoides. The indirect phytoindicative method revealed relationships between LC and LMA, and S/R of seedlings based on community-level trait data. Close relationships between LC and LMF, and SLA were not established in contrast to LAI and DIFN. Internal (closest) and external links between the leaf, stem, and root functional traits at the community-level trait data were established.