| Summary: | Understanding species-specific responses to climate change allows a better assessment of the possible impact of global warming on forest growth. We studied the responses of the shrub species <i>Corylus avellana</i> L., <i>Corylus maxima</i> Mill. and intermediate forms, together stated as the <i>Corylus</i> taxa, and <i>Cornus sanguinea</i> L. upon periodically elevated temperatures in spring and/or in summer–autumn. Experiments were performed in a common garden, with Belgian and Pyrenean provenances for <i>Corylus avellana</i> and <i>Cornus sanguinea</i>. In the <i>Corylus</i> taxa, a warmer spring resulted in a reduction in height and diameter growth. Remarkably, the reduced diameter increment was restored with full compensation in the following year. The height increment for <i>Cornus sanguinea</i> was larger upon a warmer summer–autumn, concurring with a later leaf senescence. Our results suggest that <i>Corylus</i> is more sensitive to spring warming, influencing growth negatively, whereas <i>Cornus</i> is more sensitive to summer–autumn warming, influencing height growth positively. These deviating responses can be explained, at least partly, by their diverging ecological niches, with the <i>Corylus</i> taxa being more shade-tolerant compared to <i>Cornus sanguinea.</i> The warm spring conditions advanced bud burst in all studied taxa, whereas the warm summer–autumn advanced leaf senescence but prolonged its duration in the <i>Corylus</i> taxa, as well as delayed this phenophase in <i>Cornus sanguinea</i>. Little to no after-effects of the temperature treatments were detected. Although <i>Corylus avellana</i> and <i>Cornus sanguinea</i> plants originated from similar origins, their growth and phenological responses in the common garden diverged, with <i>Corylus</i> being more stable and <i>Cornus</i> displaying more variation between the Belgian and Pyrenean provenances.
|
|---|