Combined dendroecological and normalized difference vegetation index analysis to detect regions of provenance in forest species. (Special Issue: Innovation and new horizons in tree nursery stock production and forest restoration - from research to business.)

摘要

In the past 15 years several European countries have defined regions of provenance for forest species, to achieve better management of genetic resources and to detect and certificate plant material origin. The main methods involved the use of ecological parameters (e.g. pedological, phytoclimatic), presumed to be homogeneous within each area, thus identifying ecoprovenances for a species as a consequence of evolutionary differentiation according to the effects of natural selection. In this study a dendroecological approach in defining regions of provenance was tested in Latium (Italy) and combined with the phenological responses of forests. Previous dendroclimatic research demonstrated the relationship between plant growth and climatic parameters; in Latium, similar bioclimatic responses from different forest stands growing at similar elevations were statistically grouped into three homogeneous altitudinal belts using principal component analysis and hierarchical cluster analysis. Phenological patterns of forest species were quantified using the photosynthetic activity signals expressed in the normalized difference vegetation index (NDVI). Through a beech tree-ring network, NDVI was compared with dendroecological results using Geographical Information System analysis, obtaining high correspondence in overlapping, and underlying the relevance of altitude as a main factor defining homogeneous spatial vegetation dynamics, thus delimiting ecological regions of provenance based on tree responses to climate.