The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees

Abstract

The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees.

“Green pointillism”: detecting the within-population variability of budburst in temperate deciduous trees with phenological cameras

“…Quantifying WPVbb with ground phenological observations is time-consuming. Indeed, in order to derive a robust estimate of WPVbb, one needs to observe at least 30 trees (Denéchère et al , 2019), with a typical amplitude of around 20 days from the first to the latest tree to burst buds (Delpierre et al , 2017); note that we attained a 35 days amplitude in Orsay 2012, corresponding to our maximum standard deviation of budburst, Fig. 3b).…”

“…Interestingly, WPVbb varies across tree populations (Salmela et al , 2013), and across years for a given population (Denéchère et al , 2019). The within-population standard deviation of budburst averaged 4.0 days, but ranged from 1.7 to 9.7 days in 14 populations of nine temperate deciduous tree species (Denéchère et al , 2019). This variability was related to temperature conditions during the budburst period, with colder conditions associated to an increased WPVbb (Denéchère et al , 2019).…”

“…The within-population standard deviation of budburst averaged 4.0 days, but ranged from 1.7 to 9.7 days in 14 populations of nine temperate deciduous tree species (Denéchère et al , 2019). This variability was related to temperature conditions during the budburst period, with colder conditions associated to an increased WPVbb (Denéchère et al , 2019). Whatever their causes, the year-to-year variations of WPVbb have potentially strong ecological implications, influencing the competition of trees for resource (light, water and nutrient) acquisition and transfer throughout the food web (van Dongen et al , 1997; Thackeray et al , 2016).…”

“…Whatever their causes, the year-to-year variations of WPVbb have potentially strong ecological implications, influencing the competition of trees for resource (light, water and nutrient) acquisition and transfer throughout the food web (van Dongen et al , 1997; Thackeray et al , 2016). Unfortunately, WPVbb has seldom been documented to date in natural tree populations (but see Denéchère et al , 2019), probably because its quantification remains laborious based on ground phenological observations, which are still needed for observing individual trees (Chesnoiu et al , 2009; Cole & Sheldon, 2017; Delpierre et al , 2017). Indeed, quantifying WPVbb requires observing bud development on a relatively high number of trees per population ( ca .…”

“…Indeed, quantifying WPVbb requires observing bud development on a relatively high number of trees per population ( ca . 30, see Denéchère et al , 2019), which is rarely attained in most phenological studies. Beside this sampling requirement, it is also more demanding in terms of the number of observations campaigns during spring, since one has to “wait” for all trees to burst buds, whereas classical phenological studies typically record the date at which 50% trees of the surveyed population have reached budburst.…”