How do trees deal with late spring frosts?

Late spring frosts have always been a risk for deciduous trees. Especially if it appears when new leaves emerge, because stage most sensitive to temperature changes and especially for freezing.

“While there is a lot of talk about frost damage, it’s not clear how much it affects our trees,” says one of the researchers, Frederik Baumgarten. It is also unclear why some trees shed their leaves early, let alone the risk of freezing. How might climate change affect this situation in the future?. Baumgarten and his colleagues set out to find out.

To do this a outdoor experiment. They planted 960 two-year-old trees from four local species in pots: wild cherry (Prunus avium), oak (Quercus robur), hornbeam (carpinus betulus) and there (Fagus sylvatica).

Baumgarten placed them in a heat chamber for several days at weekly intervals to simulate a spring period and have them bloom at different times, a little earlier or a little later than control trees left in natural conditions.

Resistance of cherry and oak trees

Shortly after the leaves began to sprout, the researcher artificial frost in a cold room of two different densities, which causes the death of leaves. He then transplanted all the trees outside and supervised them. to get better For one year.

Later deciduous trees were more affected by artificial frost. Even without any freezing process, development and growth is delayed in relation to what has already developed. “In a forest, these specimens cannot compete with other individuals and species,” the report says.

Samples poured a few days ago gained more biomass., but some species have experienced aphid attacks. This shows that, according to the study’s authors: The optimal time for leaf appearance in spring was determined for each tree species during the evolution between these two boundaries..

Frost damage weakens trees, but experimentation showed that frost is not an equal problem for all species. “I was surprised at how well some species were able to recover from frost damage,” says Baumgarten.

this is true all the frozen trees grew less fast more than unfrozen ones, but in the case of wild cherry trees and oaks, good strategies to deal with the frost.

Wild cherry trees formed new shoots, and oak trees formed many replacement buds that could open quickly when the first leaves died. Mortality in these two species was insignificant.

On the contrary, 32% of hornbeams could not stand the frost. In-laws were also greatly affected: the mortality rate stood at 12%. The survivors formed smaller leaves and their crowns became thinner than usual.

Danger of ‘false bow’

The study showed that the ability to survive frost allows species such as oak and wild cherry to develop leaves earlier in the year despite the risk of frost.

HE climate change may make this ability even more important in the future. “It’s usually warmer earlier in the year, and some deciduous trees are defoliating significantly earlier today, which means ‘false springsThe authors draw attention to the phrases “”, which pose a danger to some species.

risk of descent extreme eventsScientists predict that it will stay at least as high as late frosts. “This means that frost-resistant species will be able to defend themselves better than sensitive species These future events, especially when another stressor occurs within the same year, for example extreme drought‘, the researchers report.

It can change forests in the long run. “Over time, a new community of species better adapted to frost can establish itself,” says Baumgarten. The results of the experiment were published in the journal ‘Functional Ecology’.

frosts cause vegetables weakening of functional activity, by reducing enzymatic actions, respiratory intensity, photosynthetic activity and water absorption rate. there is also a displacement of biological balances: Respiration, photosynthesis, transpiration, water absorption and upward circulation cease.

Finally, cell death and tissue destruction are recorded. The most vulnerable phenological stages to cold are flowering and fruit set.

Reference report: https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.14243

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Contact details of the environment department: crisisclimatica@prensaiberica.es