Impact of successive spring frosts on leaf phenology and radial growth in three deciduous tree species with contrasting climate requirements in central Spain

Abstract

Rear-edge tree populations forming the equatorward limit of distribution of temperate species are assumed to be more adapted to climate variability than central (core) populations. However, climate is expected to become more variable and the frequency of climate extremes is forecasted to increase. Climatic extreme events such as heat waves, dry spells and spring frosts could become more frequent, and negatively impact and jeopardize rear-edge stands. To evaluate these ideas, we analyzed the growth response of trees to successive spring frosts in a mixed forest, where two temperate deciduous species, Fagus sylvatica (European beech) and Quercus petraea (sessile oak), both at their southernmost edge, coexist with the Mediterranean Quercus pyrenaica (Pyrenean oak). Growth reductions in spring-frost years ranked across species as F. sylvatica > Q. petraea > Q. pyrenaica. Leaf flushing occurred earlier in F. sylvatica and later in Q. pyrenaica, suggesting that leaf phenology was a strong determinant of spring frost damage and stem growth reduction. The frost impact depended on prior climate conditions, since warmer days prior to frost occurrence predisposed to frost damage. Autumn Normalized Difference Vegetation Index (NDVI) data showed delayed leaf senescence in spring-frost years and subsequent years as compared with pre-frost years. In the studied forest, the negative impact of spring frosts on Q. petraea and especially on F. sylvatica growth was considerably higher than the impacts due to drought. The succession of four spring frosts in the last two decades determined a trend of decreasing resistance of radial growth to frosts in F. sylvatica. The increased frequency of spring frosts might prevent the expansion and persistence of F. sylvatica in this rear-edge Mediterranean population.

No risk—no fun: Penalty and recovery from spring frost damage in deciduous temperate trees

“…Fagus resprouted from adventive buds and produced smaller leaves (personal observations) and a visibly reduced canopy found also by Menzel et al (2015) and Rubio‐Cuadrado, Camarero, et al (2021). Higher chlorophyll content of frozen leaves which remained longer in autumn presumably compensated for assimilation losses to some extent (Vander Mijnsbrugge et al, 2021; Zohner et al, 2019).…”

“…The pronounced lag effect of frost on growth increments (during the second growing season) reflects mainly the difference in saplings' stature caused by the frost treatments during the first growing season. It is likely, that such a carry‐over effect diminishes with increasing tree size and maturation as indicated by the high resilience to frost found in tree ring studies (Príncipe et al, 2017; Vitasse et al, 2019), though this carry‐over effect has also been found in adult beech population in central Spain (Rubio‐Cuadrado, Camarero, et al, 2021).…”

“…At the level of the individual tree, damaging frost effects are well reflected in the form of impaired annual rings. Since damaging spring frosts fall at the beginning of the growing season, the tree ring losses are usually as significant or even greater than the ones induced by extreme summer droughts (Rubio‐Cuadrado, Camarero, et al, 2021; Vitasse et al, 2019). Although tree ring widths of beech are largely reduced during years with damaging spring frosts, no carry‐over effects are generally observed in the following years (Príncipe et al, 2017).…”

Cold-season freeze frequency is a pervasive driver of subcontinental forest growth

“…Because snow cover insulates and prevents soil freezing in winter and buffers against cold snaps in autumn and spring, root injuries are most severe when snow cover is low ( 21 – 23 ). In the same way the legacy effects of summer water stress can cause episodes of mass tree mortality, freezing can lead to growth loss, permanently damaging trees and potentially resulting in death several years later ( 13 , 24 – 28 ). While the most extreme freezes can damage many species, and trees of all sizes, over vast areas, freeze damage often varies both among and within species ( 6 , 11 , 29 , 30 ).…”

European Beech Spring Phenological Phase Prediction with UAV-derived Multispectral Indices and Machine Learning Regression

“…The copyright holder for this this version posted December 30, 2022. ; https://doi.org/10.1101/2022.12.30.522283 doi: bioRxiv preprint A potential threat for European beech (Fagus sylvatica L.) in central Europe, when growing seasons are extended, is the earlier onset of budbreak and leaf-unfolding. When followed by sudden freezing temperatures, also known as episodic frost or "late frost", newly unfolded leaves can be susceptible to the damage of cell tissue (Rubio-Cuadrado et al, 2021). Damage to the entire leaf or also partial damage, can have considerable effects on growth (Menzel et al, 2015;Sakai & Larcher, 1987).…”