Alnus glutinosa

Alnus glutinosa, or black alder, is a deciduous tree in the birch family native to Europe, western Asia, and northern Africa. It thrives on wet ground and enriches soil through a symbiosis with nitrogen-fixing bacteria.

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Betulaceae: A family of flowering trees and shrubs that includes birches, alders, hazels, and hornbeams. Black alder belongs to this family alongside birches and hazels.
Riparian forest: A forest community growing alongside rivers, streams, or other waterways. Black alder often forms a defining tree layer along European waterways.
Grey alder: Alnus incana, a pale-barked alder native to much of Europe and northern Asia. It is a close European relative, generally associated with cooler and drier sites.
Alder cone: A small woody, cone-like fruiting structure produced by alder trees. Black alder's persistent, dark fruiting structures are conspicuous after leaf fall.
Alder decline: The widespread deterioration or death of alder trees caused by disease and environmental stress. Black alder populations have been affected by disease and altered river conditions.
Alnus: A genus of trees and shrubs in the birch family, commonly called alders. Black alder is one species within this genus.
Floodplain: Low-lying land beside a river that is periodically inundated by floods. The species tolerates the waterlogged and periodically flooded soils common there.
European white birch: Betula pendula, a deciduous birch native to Europe and parts of Asia. It shares the birch family with black alder but favors less waterlogged ground.
Alder leaf beetle: Agelastica alni, a leaf-feeding beetle whose larvae and adults consume alder foliage. Its feeding can leave black alder leaves visibly skeletonized.
Phytophthora disease: Plant diseases caused by oomycetes in the genus Phytophthora. The broader disease group helps frame the threat posed by Phytophthora alni.