Canopy cover and species' climatic niche shape Pinus sylvestris regeneration after drought-induced die-off
Chowdhury, Faqrul Islam (Universitat Autònoma de Barcelona)
Espelta Morral, Josep Maria (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Sánchez-Mejía, T. (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Margalef Marrasé, Jordi (Centro de Investigaciones sobre Desertificación)
Jaime, Luciana (Universitat de Lleida. Departament de Ciència i Enginyeria Forestal i Agrícola)
Lloret Maya, Francisco (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Date:	2026
Abstract:	Drought-induced die-off alters canopy structure and understory microclimatic conditions, but its consequences for tree regeneration remain unclear. We assessed how canopy-driven microclimate filtering and climatic suitability influenced Pinus sylvestris regeneration across developmental stages (seedlings, young saplings, and old saplings) following drought-induced die-off in forests across Catalonia (NE Spain). We analysed recruit densities with linear mixed models incorporating forest condition (die-off vs. control), canopy type (closed, defoliated, and open gaps), survey year (2013, 2017, and 2022), and climatic-niche metrics as fixed effects, while site and plot were considered as random effects. In closed habitats, die-off lowered both young and old saplings relative to controls. Defoliated habitats consistently failed to support regeneration across all stages, even in climatically favourable sites, likely due to impaired propagule supply. Open habitat enhanced seedling and sapling densities in die-off plots. Regarding the position in the climatic niche, old saplings persisted in closed habitats at climatically marginal sites, likely benefiting from canopy-mediated microclimate control. Canopy buffering also protected young saplings in closed habitats during the periods with strong interannual climate fluctuations. In open habitats, young and old saplings were sensitive to climatic position in species' niche, with their densities declining with increasing distance to the optimum, core niche. Overall, seedlings' density was higher near the climatic optimum in die-off plots than in controls. Also, nearly a decade after the drought, only young sapling densities increased in die-off plots, likely reflecting disturbance legacies and favourable climatic fluctuations. Our results highlight the silvicultural value of maintaining a mosaic of canopy structures, retaining open habitats in climatically optimal sites to enhance seedling establishment and progression, while preserving closed canopy refugia in marginal climatic sites to buffer climate extremes, thus, favouring saplings survival against increasing drought stress.
Grants:	"la Caixa" Foundation 100010434 Agencia Estatal de Investigación PID2020-115264RB-I00 Agencia Estatal de Investigación PID2023-152644NB-I00 European Commission 101000574 Generalitat de Catalunya 2021/SGR-00849 Generalitat de Catalunya 2021/SGR-00889
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Canopy buffering ; Drought legacy ; Species niche ; Regeneration density ; Tree mortality
Published in:	Forest ecology and management, Vol. 603 (March 2026) , art. 123438, ISSN 1872-7042

DOI: 10.1016/j.foreco.2025.123438

11 p, 4.2 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles