Polypores in the parks and forests of the City of Helsinki

Authors: Erkkilä, Reijo & Niemelä, Tuomo
Journal: Karstenia, Volume 26 (1986), Issue 1, pages 1-40.
Doi: https://doi.org/10.29203/ka.1986.242
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Abstract:  The polypores of the Helsinki municipal area in South Finland were studied with regard to their microdistributions, host relationships, abundances and economic importance. Altogether 120 species are reported. Five site types were defined, ranging from urban to rural environments: parks proper, tree rows, park forests, forests proper and idle land areas. Distinct differences were found in the species compositions of urban environments (parks proper and tree rows), as compared with more natural wooded areas (park forests and forests proper). Polypores which prefer urban growth sites (the centric species) are southern in Finland (Fistulina hepatica Schaeff. : Fr., Laetiporus sulphureus (Bull.: Fr.) Murr., Spongipellis spumeus (Sow.: Fr.) Pat.) or have a scattered general distribution (Phaeolus schweinitzii (Fr.) Pat., Polyporus squamosus Huds.: Fr., Rigidoporus populinus (Schum.: Fr.) Pouz.). Species preferring rural environments (peripheral) are mostly the basic, common forest species of southern and central Finland. A third group of polypores (indifferent) occurs evenly in all environmental types, but often varies in pathological properties between areas: for instance, Bjerkandera adusta (Willd .: Fr.) Karst., Ganoderma lipsiense (Batsch) Atk. (G. applanatum) and Fomitiporia punctata (Karst.) Murr. are more readily parasitic when growing in the inner city. The mechanisms and reasons for the fungal infections in park trees are discussed, and some commoner polypores causing rot in park trees are studied more closely. The most harmful park-tree decaying polypores in Helsinki are Ganoderma lipsiense, Bjerkandera adusta, Inonotus obliquus (Pers.: Fr.) Pil. , Laetiporus sulphureus, Ochroporus igniarius (L.: Fr.) Schroet., Polyporus squamosus and Rigidoporus populinus.
The Helsinki municipal area is divided into 1-km2 squares and the distributions of 30 representative species are mapped accordingly. Some typical parks, forests and polypores are illustrated.
The delimitation and species of the genus Oligoporus are discussed. The following polypores are reported as new to Finland: Oligoporus cerifluus (Berk. & Curt.) Gilbertson & Ryv., Polyporus badius (Pers.) Schw. and Schizopora radula (Pers.: Fr.) Hallenb. The presence of Oligoporus balsameus (Peck) Gilbertson & Ryv. in Finland is confirmed.