1. An experimental approach for crown to whole-canopy defoliation in forests
- Author
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Fahey, Robert T., Tanzer, Danielle N., Alveshere, Brandon C., Atkins, Jeff W., Gough, Christopher M., and Hardiman, Brady S.
- Subjects
Ecosystem components -- Environmental aspects ,Defoliation -- Environmental aspects ,Plant canopies -- Environmental aspects ,Earth sciences - Abstract
Canopy defoliation is an important source of disturbance in forest ecosystems that has rarely been represented in large-scale manipulation experiments. Scalable crown to canopy level experimental defoliation is needed to disentangle the effects of variable intensity, timing, and frequency on forest structure, function, and mortality. We present a novel pressurewashing-based defoliation method that can be implemented at the canopy-scale, throughout the canopy volume, targeted to individual leaves or trees, and completed within a timeframe of hours or days. Pressure washing proved successful at producing consistent leaf-level and whole-canopy defoliation, with 10%-20% reduction in leaf area index and consistent leaf surface area removal across branches and species. This method allows for stand-scale experimentation on defoliation disturbance in forested ecosystems and has the potential for broad application. Studies utilizing this standardized method could promote mechanistic understanding of defoliation effects on ecosystem structure and function and development of synthetic understanding across forest types, ecoregions, and defoliation sources. Key words: defoliation, experiment, herbivory, canopy, disturbance. La defoliation du couvert forestier est une source importante de perturbation dans les ecosystemes forestiers qui a rarement ete etudiee dans des experiences de manipulation a grande echelle. Une defoliation experimentale transposable de l'echelle de la cime a celle du couvert forestier est necessaire pour distinguer les effets de la variation de l'intensite, du moment et de la frequence sur la structure, la fonction et la mortalite de la foret. Nous presentons une nouvelle methode de defoliation fondee sur le lavage a la pression qui peut etre : appliquee a l'echelle du couvert forestier, a tout le volume du couvert forestier, appliquee a des arbres ou des feuilles individuellement et realisee a l'interieur d'une periode de quelques heures a quelques jours. Le lavage a la pression a reussi a produire une defoliation constante a l'echelle des feuilles et de l'ensemble du couvert forestier avec une reduction de 10-20 % de l'indice de surface foliaire et l'elimination d'une surface foliaire constante parmi les branches et les especes. Cette methode permet d'experimenter a l'echelle du peuplement avec les perturbations causees par une defoliation dans les ecosystemes forestiers et pourrait avoir un vaste champ d'application. Des etudes utilisant cette methode standardisee pourraient faciliter la comprehension mecaniste des effets de la defoliation sur les fonctions et la structure des ecosystemes ainsi que la comprehension synthetique des types forestiers, des ecoregions et des sources de defoliation. [Traduit par la Redaction] Mots-cles: defoliation, experimentation, broutage, couvert forestier, perturbation., 1. Introduction Large-scale experimental manipulations have been essential to advancing knowledge about ecosystem processes (e.g., Ainsworth and Long 2005; Templer et al. 2017). For example, experiments emulating variable disturbance severity, [...]
- Published
- 2022
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