Silviculture as a disturbance regime: the effects of clear-cutting, planting and thinning on polypore communities in mixed forests

Abstract

The structure of modern forest landscapes is profoundly affected by human-caused disturbances, particularly forest management; however, the effects and prospects of individual silvicultural techniques are insufficiently understood. This study distinguishes the effects of clear-cutting, planting and thinning on species richness and community composition of polypore fungi. In 2008-2009, 181 forest compartments (ranging from naturally regenerated deciduous stands to planted Picea abies stands and 0-137 years post clear-cutting) were explored in a hemiboreal landscape subjected to even-aged management. Altogether 104 polypore species were recorded. For species richness, time since clear-cutting was the most influential factor at both stand and landscape scales, followed by thinning. Clear-cuts had distinct polypore communities (including several red-listed species) whose species richness declined in time. Following 20 years post clear-cutting, species richness started to increase along different community-composition pathways determined by regeneration type. The communities developed after planting were moderately species rich at stand scale but homogeneous over larger areas. Thus, at landscape scale, mature unmanaged naturally regenerated stands hosted most species; thinning reduced species richness by approximately 15%, and among thinned stands, planted areas had a further 9-22% fewer species than naturally regenerated areas. In such variably managed landscape, silviculture appeared to create particularly distinct communities in young stands on nutrient-rich soils, which naturally provide polypores with a rich supply of small deciduous snags absent from stands artificially planted with P. abies and intensively thinned.

The impacts of thinning on the fruiting of saprophytic fungi in Cryptomeria japonica plantations in central Taiwan

“…Although thinning provided extra substrates for wood-inhabiting fungi, the wood-inhabiting macrofungal richness was diminished in the thinned plots with disappearance of minor species and the delay of fruiting. Lohmus (2011) also found that the number of polypore species declined during the first 20 years after cutting, rebounding afterward. The post-harvest time interval should rank among the most important factors determining the species richness of woodinhabiting macrofungi.…”

Polypore communities in broadleaved boreal forests

“…In most forest compartments we sampled the majority of coarse woody debris, and in addition the old living trees which may also host some polypore species. It can be presumed that the great majority of the species which were fruiting were detected by the method we used, but the abundances may be skewed towards the species with large and visible fruit bodies and the species that fruit on charismatic substrates (Lõhmus 2009). Therefore we used only presence/absence data at the forest compartment scale in this study.…”

“…Hottola and Siitonen 2008, Komonen et al 2008, Lõhmus 2011a, but the studies have been conducted in young stands or in forests dominated by coniferous trees. The few studies focusing on the polypores occupying broadleaved trees have been targeted only at aspen-dependent species (Lõhmus 2011b) or alder-dominated forests (Strid 1975). In addition, there are some studies conducted on clear-cuts and focusing on retention trees (Lindhe et al 2004, Junninen et al 2007).…”

“…Similarly spruce-dominated lakeside riparian forests (Komonen et al 2008) and woodland key habitats (Hottola and Siitonen 2008) have been found to host more polypore species than control forests because of the higher proportion of broadleaved trees and broadleaved dead wood. Aspen, especially hosts unique species assemblages and is considered to be a keystone tree species also for polypores (Miettinen 2001, Junninen et al 2007, Lõhmus 2011b. In addition, one biogeographical study has discussed the ecology of wood-inhabiting fungi living in alderdominated boreal forests (Strid 1975).…”

The effects of habitat degradation on metacommunity structure of wood-inhabiting fungi in European beech forests

“…Recently there have been several studies focusing on the impacts of modern forest management actions (see e.g. Lõhmus 2011;Toivanen et al 2012) as well as restoration measures (Olsson et al 2011) on wood-inhabiting fungi. These studies have, for practical reasons, shown mostly the results on the earliest decay stages.…”