Peak radial growth of diffuse-porous species occurs during periods of lower water availability than for ring-porous and coniferous trees

Abstract

Climate models project warmer summer temperatures will increase the frequency and heat severity of droughts in temperate forests of Eastern North America. Hotter droughts are increasingly documented to affect tree growth and forest dynamics, with critical impacts on tree mortality, carbon sequestration, and timber provision. The growing acknowledgement of the dominant role of drought timing on tree vulnerability to water deficit raises the issue of our limited understanding of radial growth phenology for most temperate tree species. Here, we use well-replicated dendrometer band data sampled frequently during the growing season to assess the growth phenology of 610 trees from 15 temperate species over six years. Patterns of diameter growth follow a typical logistic shape, with growth rates reaching a maximum in June, and then decreasing until process termination. On average, we find that diffuse-porous species take 16–18 days less than other wood-structure types to put on 50% of their annual diameter growth. However, their peak growth rate occurs almost a full month later than ring-porous and conifer species (ca. 24 ± 4 days; mean ± 95% credible interval). Unlike other species, the growth phenology of diffuse-porous species in our dataset is highly correlated with their spring foliar phenology. We also find that the later window of growth in diffuse-porous species, coinciding with peak evapotranspiration and lower water availability, exposes them to a higher water deficit of 88 ± 19 mm (mean ± SE) during their peak growth than ring-porous and coniferous species (15 ± 35 mm and 30 ± 30 mm, respectively). Given the high climatic sensitivity of wood formation, our findings highlight the importance of wood porosity as one predictor of species climatic sensitivity to the projected intensification of the drought regime in the coming decades.

Relating the Growth Phenology and Biomass Allocation in Seedlings of 13 Acadian Tree Species With Their Drought Tolerance

“…Impacts to height phenology patterns may additionally have increased importance in understanding vulnerabilities and survival of seedlings, given the role shoot extension plays in the competition for light resources. These findings are in line with previous works (Zapater et al, 2013;Vanhellemont et al, 2019;D'Orangeville et al, 2021), that demonstrate a drought avoidance strategy whereby species have altered growth phenology patterns, avoiding active growth during the drought season. In addition, the high level of interspecific variation in growth phenology reported here suggests that drought could have variable impacts.…”

“…The phenological traits of species are increasingly recognized to play an important role in their relative drought tolerance levels through the maximization or completion of annual growth prior to the regular drought season during late summer D'Orangeville et al, 2021). The timing of drought affects drought vulnerability in trees, since the process of cambial cell division at the heart of primary and secondary growth is highly sensitive to water availability (Gruber et al, 2010;Foster et al, 2014;Lempereur et al, 2015), though the productivity of coniferous forests may be less sensitive to changing phenology patterns than deciduous forests (Richardson et al, 2010;Carnicer et al, 2013).…”

“…In these experiments, traits are often used as a proxy for other fundamental characteristics, and help inform species vulnerabilities, conservation practices, and adaptive management approaches (McKay et al, 2001;de Villemereuil et al, 2016;Housset et al, 2018). Drought stress affects many functional traits in seedlings, including phenology patterns (Nguyen et al, 2017;D'Orangeville et al, 2018), wood anatomical traits (Crous et al, 2012;D'Orangeville et al, 2021), and biomass allocation (Møller and Jennions, 2002;Niinemets and Valladares, 2006;Markesteijn and Poorter, 2009), however, it is still unclear which traits are most important for understanding and predicting species drought tolerances (Moran et al, 2017).…”

Limitation by vapour pressure deficit shapes different intra‐annual growth patterns of diffuse‐ and ring‐porous temperate broadleaves

“…4c) might mirror differences in leaf and cambial phenology. Ring‐porous species partly compensate for their sensitivity to VPD by an early onset of cambial activity (D’Orangeville et al ., 2021). The formation of the first xylem layers occurs before leaf unfolding in Q. robur (Sass‐Klaassen et al ., 2011) when the stem water content is not negatively affected by stomatal transpiration.…”

Coupling of Tree Growth and Photosynthetic Carbon Uptake Across Six North American Forests

“…Our findings here further support the importance of previous year's carbon uptake (and climate variables) for WBI at US‐Ho1. We predicted uptake occurring late in the growing season would be strongly associated with WBI in the following year because wood formation in northern forests largely occurs in the spring and early summer (D'Orangeville et al., 2021; Rossi et al., 2006) and ends well before carbon uptake slows down in the winter (Zweifel et al., 2010). Our findings here suggest that uptake from the previous year's summer months was strongly linked to WBI the following year in this evergreen‐dominated northern forest, but this does not necessarily translate to other temperate (or conifer‐dominated) forests.…”