DOI: 10.5061/dryad.f7m0cfxtq
title: Data from: Linking radial growth patterns and moderate-severity disturbance dynamics in boreal old-growth forests driven by recurrent insect outbreaks: a tale of opportunities, successes, and failures

description: In boreal landscapes, emphasis is currently placed on close-to-nature
 management strategies, which aim to maintain the biodiversity and
 ecosystem services related to old-growth forests. The success of these
 strategies, however, depends on an accurate understanding of the dynamics
 within these forests. This study aims to reconstruct the disturbance and
 post-disturbance dynamics in boreal old-growth forests that are driven by
 recurrent moderate-severity disturbances. We studied eight old-growth
 forests in Québec, Canada, that has recorded recurrent and moderate to
 severe spruce budworm (Choristoneura fumiferana [Clem.]) outbreaks over
 the 20th century. To reconstruct the disturbance history and the
 post-disturbance dynamics of the study sites, we used dendrochronological
 data and k-means clustering to identify growth releases and growth
 patterns in the studied trees. We identified nine growth patterns; these
 patterns represented trees differing in age, size, and canopy layer, and
 indicated different tree histories. Spruce budworm outbreaks caused
 recurrent moderate-severity disturbances within the study sites. The
 canopy gaps created by these disturbances were filled mainly by
 understorey trees, which responded by single and significant increases in
 radial growth and height. In contrast, overstorey trees had little
 influence on gap filling; thus, trees were mostly from the dominant and
 codominant canopy layers. Our study underlines the resistance of boreal
 old-growth forests to recurrent and moderate-severity disturbances, as
 understorey trees can rapidly fill the resulting gaps. However, trees that
 are unable to attain the canopy following the disturbance then tend to
 remain in the lower canopy layers. Therefore, reaching the canopy
 represents a once-in-a-lifetime opportunity, where success or failure
 depends on a relatively short window of time. This gap-filling dynamic
 produces, however, a vertical structure that is often similar to the
 expected structure in even-aged forests. Our results highlight the
 efficacy of identifying tree growth patterns to reconstruct stand
 disturbance dynamics and contribute to developing closer to nature forest
 management strategies.
description: These data are those used in the article "Linking radial
 growth patterns and moderate-severity disturbance dynamics in boreal
 old-growth forests driven by recurrent insect outbreaks: a tale of
 opportunities, successes, and failures" published in Ecology and
 Evolution by Martin, M., Krause, C. & Morin H.
 The dataset is divided into two parts: field survey data
 (<em>Dataset_Field_Survey_Martin_et_al_2020_Ecology_and_Evolution.txt</em>) and dendrochronological data (<em>Dataset_Dendrochron_Martin_et_al_2020_Ecology_and_Evolution.txt</em>). An ID has been assigned to each tree and each site to facilitate navigation between the two datasets. The name of each variable and each class has been made to be as self-explanatory as possible. For more details on the sampling method, please refer to the article. Missing values are presented as "NA." If you have any questions or problems, please do not hesitate to contact the authors.