Differences in Leaf Morphology Between Alnus glutinosa (L.) Gaertn. and Its Subspecies barbata

Abstract

Alnus glutinosa (L.) subsp. barbata from Türkiye and Alnus glutinosa (L.) Gaertn. from Morocco represent the two edges of the range populations within the species distribution. Limited prior research on their morphological differences prompted this study, which focuses on comparative leaf trait analysis. The primary goals were to (1) assess variations in leaf morphology and (2) identify the most divergent traits between the taxa. Leaves were sampled from ten trees per population during summer in Morocco and Türkiye, with 30 sun-exposed leaves collected from each tree’s upper crown. Twenty-two traits related to size, structure, and shape were measured. Descriptive statistics and nested ANOVA revealed significant inter- and intra-taxon differences across all traits. Principal component analysis highlighted leaf size as the most distinguishing feature between the taxa, with altitude emerging as a key influencing factor. Given the ecological and economic importance of these populations, and the increasing threats Mediterranean forests face from climate change, their conservation warrants urgent attention. Cite this article as: Sahli, A., Akpulat, H. A., & Ater, M. (2025). Differences in leaf morphology between Alnus glutinosa (L.) Gaertn. and its subspecies barbata. Forestist, 75, 0109, doi:10.5152/forestist.2025.24109.