Development of a novel provenance test using the example of the tree species Castanea sativa Mill. and a model approach for the preselection of provenances in climate change

The speed of anthropogenic climate change makes a similarly rapid adaptation of forests without human intervention unrealistic. Sometimes thermophilic tree species from drier natural areas are increasingly becoming the focus of the discussion on the development of climate-resilient forests. The search for suitable options should not be limited to the species level: In particular, if differentiated ecotypes exist within a species over a wide geographical area and climatic amplitude, which have evolved in adaptation to the prevailing environmental conditions, the targeted manner of introducing certain provenances can be a proven means of mitigating the negative effects of climate change on forests.

The sweet chestnut(Castanea sativa Mill.) is currently often articulated as a potentially suitable tree species for climate change. With its natural distribution centered in southern and southeastern Europe, it is still a largely rare tree species in Germany. The places of origin of the occurrences in this country are generally unknown. At the same time, the literature shows that several ecotypes can be distinguished within the natural distribution area of the sweet chestnut, which occur under significantly different climatic conditions. Against this background, there is a knowledge gap as to which provenances are better suited to cultivation in certain locations under climate change than others.

Conventional provenance trials test a variety of provenances on a variety of sites over at least a decade. The pre-selection of provenances is to be rationalized using a systematic approach and the test period shortened through targeted manner in the germination and establishment phase. The focus on the early life phase allows the inclusion of a large sample in a relatively small area and statistically evaluable results after just a few vegetation periods. The basic possibility of being able to draw conclusions about the growth behavior in later stages at a young stage based on certain characteristics is known from early tests.