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Herb-rich forests are often considered biodiversity hotspots in the boreal zone but their fungal assemblages, particularly those of wood-decaying fungi, remain poorly known. We studied herb-rich forests as habitats for polypores, a distinct group of wood-decaying fungi, and assessed the importance of tree- and stand-scale variables for polypore species richness, abundance, and diversity, including red-listed species. The data include 71 herb-rich forest stands in Finland and 4797 dead wood items, on which we made 2832 observations of 101 polypore species. Dead-wood diversity was the most important variable explaining polypore species richness and diversity, whereas increasing latitude had a negative effect. Red-listed species showed a positive response to the abundance of large-diameter dead wood, which, especially birch, supported also high general abundance of polypores. The composition of polypore assemblages reflected their host-tree species. The red-listed species did not show explicit patterns in the ordination space. Compared to old-growth spruce forests, herb-rich forests seem to host lower polypore species richness and less red-listed species. However, because of high proportion of deciduous trees in the dead wood profile, herb-rich forests have a clear complementary effect on polypore assemblages in boreal forest landscapes.

Deadwood quality can be a highly significant factor in determining the occurrence of deadwood-dependent organisms such as saproxylic fungi. Rare deadwood substrates that are produced only after a lengthy senescence such as kelo trees may have unique deadwood qualities. Using high-performance liquid chromatography, we compared the phenolic composition of six types of Scots pine (Pinus sylvestris L.) substrates: living mature trees with no fungal sporocarps, living mature trees with Phellinus pini sporocarps, fallen non-kelo trees, soon-to-be kelo (standing), standing kelo, and fallen kelo. The fungal-infected living trees and fallen kelos were found to have more similarities in their phenolic composition when compared with the living and fallen trees and the standing kelos, which gets further pronounced with increasing decay. The results also highlight the uniqueness of the fungal-infected living trees and the fallen kelos and illustrate a possible correlation between fungal infection and the heartwood phenolic composition of Scots pine. However, it remains unclear to what extent the differences in phenolic compositions are caused by fungal infection and fungal decomposition. We also observed a previously undocumented correlation between the phenolic groups and fire scars on the trunks of the trees. The variation in substrate quality warrants further consideration when deadwood restoration activities are planned, as the quality of the deadwood could be as equally important as the quantity. Key words: boreal forest, chemical diversity, deadwood, fungal decay, heartwood phenolics, substrate quality, tree resistance. La qualite du bois mort peut etre un facteur tres important pour determiner l'occurrence des organismes qui dependent du bois mort tels que les champignons saprophytes. Les substrats de bois mort rares qui sont produits seulement apres un long processus de vieillissement, tels que les arbres kelo, peuvent avoir des caracteristiques particulieres. A l'aide de la chromatographie liquide a haute performance, nous avons compare la composition phenolique de six types de substrat de pin sylvestre (Pinus sylvestris L.) : arbres matures vivants sans sporophores de champignon, arbres matures vivants avec des sporophores de Phellinus pini, arbres non kelo tombes au sol, arbres sur le point de devenir kelo (sur pied), arbres kelo sur pied et arbres kelo tombes au sol. La composition phenolique des arbres vivants infectes par des champignons ressemblait davantage a celle des arbres kelo tombes au sol comparativement aux arbres vivants sains, aux arbres tombes au sol et aux arbres kelo sur pied, et les similitudes s'accentuaient a mesure que la carie progressait. Les resultats font aussi ressortir le caractere unique des arbres vivants infectes par les champignons et des arbres kelo au sol et illustrent une correlation potentielle entre l'infection fongique et la composition phenolique du bois de coeur du pin sylvestre. Il demeure toutefois difficile de determiner dans quelle mesure les differences dans la composition phenolique sont dues a l'infection ou a la decomposition fongique. Nous avons egalement observe une correlation jamais rapportee auparavant entre les groupes phenoliques et les cicatrices de feu sur le tronc des arbres. La variation de la qualite du substrat merite un examen plus pousse lorsque des activites de restauration du bois mort sont planifiees etant donne que la qualite du bois mort pourrait etre aussi importante que sa quantite. [Traduit par la Redaction] Mots-cles : foret boreale, diversite chimique, bois mort, decomposition fongique, composes phenoliques du bois de coeur, qualite du substrat, resistance des arbres., Introduction Forest deadwood substrates, comprised mostly of snags, fallen dead trunks, and stumps (Hagemann et al. 2009), are of high ecological value, as they maintain a large part of the [...]

Because many currently protected forests are former timber production areas, restoration activities are often used to re-establish their natural structures. In this experimental study, we monitored the establishment of tree seedlings in previously managed but currently protected Scots pine (Pinus sylvestris L.) dominated stands in boreal forests 5 years after restoration measures. The study included eight study areas (115 sample plots) in southern Finland. We compared seedling abundance between five study groups: untreated control forest, unburned canopy gap, burned full-canopy forest, burned canopy gap, and thinned and burned forest. Density of tree seedlings was highest in burned canopy gaps (mean 25.4 seedlings/100 [m.sup.2] compared with 6.0 seedlings/100 [m.sup.2] in control sites). In particular, birch (Betula spp.) and Scots pine were significantly more abundant within burned canopy gaps than in unburned gaps. We conclude that opening within-stand canopy gaps, especially in combination with prescribed burning, can be useful in forest restoration as the gaps diversify age-class structure and tree species composition of single-cohort pine stands. Key words: controlled burning, forest regeneration, restoration fire, Scots pine. Puisque plusieurs forets actuellement protegees sont d'anciennes aires de production ligneuse, des activites de restauration sont souvent utilisees pour retablir leur structure naturelle. Dans cette etude experimentale, nous avons suivi l'etablissement de semis d'arbres dans des peuplements de la foret boreale domines par le pin sylvestre (Pinus sylvestris L.), precedemment amenages mais maintenant proteges, cinq ans apres l'application de mesures de protection. L'experience comportait huit aires d'etude (115 placettes echantillons) situees dans le sud de la Finlande. Nous avons compare l'abondance des semis parmi cinq groupes d'etude: foret temoin non traitee, trouee non brulee, foret avec un couvert ferme brulee, trouee brulee et foret eclaircie et brulee. La plus forte densite de semis d'arbres a ete observee dans les trouees brulees (moyenne de 25,4 semis/100 [m.sup.2] comparativement a 6,0 semis/100 [m.sup.2] dans le groupe temoin). En particulier, le bouleau et le pin sylvestre etaient significativement plus abondants dans les trouees brulees comparativement aux trouees non brulees. Nous concluons que les ouvertures du couvert d'un peuplement, surtout si elles sont combinees a un brulage dirige, peuvent etre utiles a la restauration forestiere parce que les trouees diversifient la structure des classes d'age et la composition arborescente des pinedes constituees d'une seule cohorte d'arbres. [Traduit par la Redaction] Mots-cles: brulage dirige, regeneration forestiere, utilisation du feu pour restaurer la foret, pin sylvestre., Introduction Conversion of natural forests into single-cohort stands (Esseen et al. 1997; Ostlund et al. 1997) and the decline of forest fires (Zackrisson 1977; Linder et al. 1997; Wallenius 2011) [...]

Riparian forests often have a more diverse tree species composition and more woody debris than neighboring upland forests, but little is known about their importance for the conservation of deadwood-dependent species. We studied the forest characteristics and the diversity of wood fungi (poroid Aphyllophorales) in lakeside riparian (flat and sloping topography) and upland boreal forests in eastern Finland. Riparian forests had a higher density of broadleaved trees and broadleaved debris than did upland forests. A total of 48 species of wood fungi were recorded, including eight red-listed or old-growth forest indicator species. Overall, more species and records and greater diversity were observed in the flat riparian sites than in the sloped riparian and upland sites. The mean species richness did not differ significantly among site categories, indicating greater β diversity among the flat riparian sites. Species composition was more similar between the two riparian categories than between the riparian and upland sites. Riparian sites also hosted more fungal species associated with broadleaved trees. The results show that riparian forests support the diversity of wood fungi in managed boreal forests. Diversity of deadwood-dependent organisms can be promoted by leaving wider and completely unharvested riparian buffer zones. Les forets riveraines ont une composition en especes arborescentes plus diversifiee et plus de debris ligneux que les memes forets en milieu sec mais on ne connait pas leur importance pour la conservation des especes qui dependent du bois mort. Nous avons etudie les caracteristiques de la foret et la diversite des champignons lignicoles (Aphyllophorales poroides) dans les forets riveraines d'un lac (terrain de niveau et en pente) et dans les forets boreales correspondantes en milieu sec dans l'est de la Finlande. Les forets riveraines avaient une plus forte densite de feuillus et de debris d'especes feuillues que les forets en milieu sec. Au total, 48 especes de champignons lignicoles ont ete observees, incluant huit especes sur la liste rouge ou indicatrices de vieilles forets. Dans l'ensemble, plus d'especes, une plus grande frequence et une plus forte densite ont ete observees dans les stations riveraines de niveau que dans les stations riveraines en pente ou dans les stations en milieu sec. La richesse en especes moyenne n'etait pas significativement differente entre les categories de stations, indiquant que la diversite beta etait plus grande dans les stations riveraines de niveau. La composition en especes etait plus semblable entre les deux categories riveraines qu'entre les stations riveraines et les stations en milieu sec. Les stations riveraines etaient aussi l'hote de plus d'especes fongiques associees aux especes feuillues. Les resultats montrent que la diversite des champignons lignicoles dans les forets boreales amenagees depend des forets riveraines. On peut favoriser la diversite des organismes qui dependent du bois mort en laissant des zones tampons riveraines plus larges et en n'y faisant aucune recolte. [Traduit par la Redaction], Introduction Unharvested buffer zones are generally left adjacent to lakes, streams, and rivers to protect waters from sediment and nutrient flow from adjacent harvested areas (Blinn and Kilgore 2001). Riparian [...]

Abstract: Effective fire suspension in Fennoscandian boreal forests has caused a number of species to become threatened. To compensate for the negative ecological impacts of fire elimination, prescribed burning of [...]

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