Increased autumn productivity permits temperate trees to compensate for spring frost damage

Abstract

Summary Climate warming is leading to earlier budburst and therefore an increased risk of spring frost injury to young leaves. But to what extent are second‐cohort leaves, which trees put out after leaf‐killing frosts, able to compensate incurred losses? To investigate whether second‐cohort leaves behave differently from first‐cohort leaves, we exposed saplings of beech (Fagus sylvatica), oak (Quercus robur), and honeysuckle (Lonicera xylosteum) to experimental treatments mimicking either a warm spring or a warm spring with a leaf‐killing frost. Refoliation took 48, 43, and 36 d for beech, oak and honeysuckle, respectively. In beech and oak, autumn Chl content and photosynthesis rates were higher in second‐ than in first‐cohort leaves, senescence in second‐cohort leaves occurred c. 2‐wk‐later, and autumn bud growth in beech was elevated 66% in frost‐damaged plants compared with the warm spring treatment. No differences in autumn phenology and growth were observed for honeysuckle. Overall, in beech and oak, delayed Chl breakdown in second‐cohort leaves mitigated 31% and 25%, respectively, of the deficit in growing‐season length incurred by spring frost damage. These results reveal an unexpected ability of second‐cohort leaves of beech and oak to compensate for spring frost damage, and demonstrate that long‐lived trees vary their autumnal phenology depending on preceding productivity.

Contrasting resistance and resilience to extreme drought and late spring frost in five major European tree species

“…Interestingly, our results show no carry over effect of the impact of damaging frost for the two broadleaved species on radial growth of the next 2 years, as also found recently for beech in Germany after local spring frosts (Príncipe et al, ). This is likely because trees are able to produce a new cohort of leaves during the same growing season, allowing to refill carbon reserve later in autumn (Zohner, Rockinger, & Renner, ). However, a secondary bud flush later in the same growing season may cause a depletion of plant carbon reserves at a time when water and nutrient availability is generally lower, which may weaken tree defenses against diseases and insect pests (McDowell et al, ), an aspect that has remained largely unconsidered so far.…”

Differentiation and Non-Linear Responses in Temporal Phenotypic Plasticity of Seasonal Phenophases in a Common Garden of Crataegus monogyna Jacq.

“…There is no consensus concerning the factors controlling the leaf senescence process [29,35]. Leaves that emerged after a late spring frost in beech and oak displayed higher photosynthesis rates and a delayed leaf senescence in autumn, compensating for spring frost damage and demonstrating that long-lived trees can adapt their autumnal phenology depending on preceding productivity [36]. The spring phenophases of bud burst and flowering, and the timing of leaf senescence and leaf abscission are most probably strongly auto-correlated.…”

Abiotic genetic adaptation in the Fagaceae

“…Interestingly, some tree species seem to be able to compensate for spring frost damage by increasing their autumn productivity (Zohner et al . ). In F. sylvatica and Q. robur autumn chlorophyll content and photosynthesis rates were higher in second‐cohort leaves (leaves developed after leaf‐killing frosts) compared to first‐cohort leaves, and senescence in second‐cohort leaves occurred about 2 weeks later (Zohner et al .…”

“…In F. sylvatica and Q. robur autumn chlorophyll content and photosynthesis rates were higher in second‐cohort leaves (leaves developed after leaf‐killing frosts) compared to first‐cohort leaves, and senescence in second‐cohort leaves occurred about 2 weeks later (Zohner et al . ).…”