Abstract
<jats:p>In order to understand the interactions of the fungi that harm the decomposition of the wood of the forest species of Alnus acuminata, the objective of this study was to identify the characteristics of the fungi that attack the species Alnus acuminata located in the Lindero 2 de Mayo valley. The methodological design used in this study was descriptive, since it focused on the observation and characterization of the pathogenic fungi that affect Alnus acuminata. The fungus, Fomes fomentarius presents sporangia with a globular shape and mycelial structures that spread dispersely on the substrate. For this reason, the wood of Alnus acuminata affected by this fungus presents collapsed and deformed areas, indicative of the enzymatic action of the fungus. Conduits of interrupted porosity can be seen, where the fungus selectively degrades lignin, leaving a matrix rich in cellulose. While the fungus Stereum rugosum shows in its shape globose sporangia with smooth walls, which are connected to thin and branched hyphae, where both pathogens cause significant damage to the species Alnus acuminata, having a negative impact on the forest. The study identified the fungi Fomes fomentarius and Stereum rugosum as pathogens that affect Alnus acuminata, weakening its structure through the decomposition of lignin and wood. The microscopic characterization highlighted its adaptive capacity and reproduction mechanisms.</jats:p>