Aspen

Nesting site for

• Great Spotted WoodpeckerDendrocopos major

  Excavates nest holes in Aspen more readily than in oak. The soft, fast-decaying wood requires significantly less effort. Aspen stands are disproportionately important for woodpecker nesting density relative to tree abundance.

• European Green WoodpeckerPicus viridis

  Excavates nest cavities in soft aspen heartwood, especially where fungal heart-rot is present; Aspen's rapid decay makes it a preferred nesting substrate in mixed woodland.

• WryneckJynx torquilla

  Obligate secondary cavity nester, strongly associated with aspen woodpecker holes.

• Spotted FlycatcherMuscicapa striata

  Uses Black Woodpecker and Great Spotted Woodpecker cavities in large aspens.

• Lesser Spotted WoodpeckerDryobates minor

  Nests in dead or dying Aspen, particularly where Tinder Fungus has softened heartwood.

Parasitised by

• Willow BracketPhellinus igniarius

  A primary heart-rot pathogen of living Aspen, creating decay columns that are subsequently excavated by woodpeckers as nest cavities. A documented fungus → bird facilitation chain.

• Aspen BracketPhellinus tremulae

  Obligate host-specific white-rot parasite of Aspen; causes the heartwood decay essential for cavity-nesting birds.

Host of

• Tinder FungusFomes fomentarius

  Saprotrophic and weakly parasitic on Aspen in boreal and montane woodland.

• Poplar FieldcapCyclocybe cylindracea

  Also commonly found on Aspen stumps and standing deadwood.

Mycorrhizal partner of

• Orange Birch BoleteLeccinum aurantiacum

  Near-obligate ectomycorrhizal partner; Aspen is the primary host throughout the European range.

• Poplar KnightTricholoma populinum

  Also forms ectomycorrhiza with Aspen in riparian and lowland woodland.