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It has recently become clear that the regeneration density of serotinous species within a burned area declines with local fire intensity. It is assumed that this occurs because variation in local fire intensity leads to variation in incident heat fluxes and, ultimately, seed necrosis. We argue here that this same relationship between incident heat flux and seed necrosis is important at the scale of individual plant crowns. Using Picea mariana (Mill.) B.S.P. (black spruce), we show that postfire seed viability increases with crown height, depth into the crown, and angle from wind direction (with the windward side enjoying greater viability). All three effects are what one would expect given the physics of buoyant plumes, interactions of moving fire lines with wake flow around cylinders, and heat transfer in porous bodies such as a tree crown. We conclude by discussing the broader consequences of cone cluster size and global change on regeneration in serotinous species. Key words: Picea mariana, fire, seed viability, cone clustering, abscission, establishment. Il est recemment devenu clair que la densite de la regeneration des especes serotineuses dans une zone brulee diminue avec l'intensite locale du feu. On assume que cela se produit parce qu'une variation de l'intensite locale du feu entraine une variation des flux de chaleur incidente et, ultimement, la necrose des graines. Nous pretendons ici que cette meme relation entre le flux de chaleur incidente et la necrose des graines est importante a l'echelle de la cime des individus. A partir de l'etude de Picea mariana (Mill.) B.S.P. (epinette noire), nous montrons que la viabilite des graines apres feu augmente avec la hauteur de la cime, la profondeur dans la cime et l'angle forme avec la direction du vent (le cote expose au vent profitant d'une plus grande viabilite). Les trois effets correspondent a ce a quoi on s'attendrait etant donne les caracteristiques physiques des panaches flottants, les interactions des lignes de feu mobiles avec le sillage de l'ecoulement autour de cylindres et le transfert de chaleur dans les corps poreux tels que la cime des arbres. Nous concluons en discutant des consequences plus larges de la taille des grappes de cones et des changements globaux sur la regeneration des especes serotineuses. [Traduit par la Redaction] Mots-cles : Picea mariana, feu, viabilite des graines, regroupement des cones, abscission, etablissement., Introduction In biomes where the prevailing natural disturbance regime is dominated by large, stand-replacing fires (Doerr and Santin 2016), serotiny is a primary adaptation for postfire sexual reproduction of plants [...]

Abstract: The mechanisms governing tree mortality in surface fires are poorly understood, owing in large part to the absence of a process-based framework for defining and evaluating these mechanisms. This [...]

Abstract: The Van Wagner crown scorch model is widely used to estimate crown component necroses in surface fires. The model is based on buoyant plume theory but accounts for crown [...]