Ectomycorrhizal fungal communities in young forest stands regenerating after clearcut logging

Abstract

Contents Summary399 Introduction400 Population biology and inoculum potential of ectomycorrhizal fungi401 Ectomycorrhiza development on seedlings regenerating after clearcut logging402 Which is the most important factor driving changes in the ECM fungal community after clearcut logging: inoculum loss or change in the below‐ground environment?406 Possible consequences for regenerating stands of species shifts in ectomycorrhizal fungi414 Conclusions416 Summary The effects on the ectomycorrhizal fungal community of clearcut logging, which is used to harvest millions of hectares of ectomycorrhizal forest annually, has been studied for a number of years. Here, we review current knowledge of inoculum sources for ectomycorrhizal fungi in forests and then re‐examine earlier studies of ectomycorrhizas on young trees in regenerating stands. We conclude that, taken separately from the effects of site preparation, the major impact of clearcut logging is to change the species composition of the ectomycorrhizal fungal community rather than to reduce the percentage of roots colonized. A thorough examination of site preparation treatments suggests that the changes in fungal species composition are driven by changes in the biology and chemistry of the soil environment after clearcutting as much as they are by loss or change in fungal inoculum. This is an important conclusion because it implies that these new ectomycorrhizal fungal communities are better adapted to the new conditions than the ones in the forest would have been. The shift in fungal species composition and diversity will have implications for seedling establishment and competition. The effects of individual fungi or diverse assemblages of fungi on seedling growth, and effects of changes in the ability of young trees to associate with a common mycelium are discussed.

Long-term dynamics of aboveground fungal communities in a subalpine Norway spruce forest under elevated nitrogen input

“…It is possible that the observed community change is partly a consequence of this land-use conversion. During afforestation on land that previously was colonized only by non-ectomycorrhizal plants, ectomycorrhizal fungi undergo primary succession (Jones et al 2003). In our site the fungal community structure probably started to change immediately after afforestation, i.e.…”

The effects of fire severity on ectomycorrhizal colonization and morphometric features in Pinus pinaster Ait. seedlings

“…For example, seedling root distribution and length varies according to soil depth (Wallander et al, 2004), in this sense postfire seedlings tend to extend their root system vertically as seen in our results by increasing mainly taproot length therefore also changing the distribution and structure of the lateral roots (Palfner et al, 2008). Also the mycelium of ECM fungi which is usually most abundant in the superficial organic soil layers in undisturbed ecosystems (Visser, 1995, Neville et al, 2002, Wallander et al, 2004 may influence root morphology and architecture through the formation of short lateral roots and root tips (Ostonen et al, 2009, Kubisch et al, 2015, therefore affecting seedling growth (Jones et al, 2003). There is also evidence of the stratification of fungal communities (Dickie et al, 2002, Rosling et al, 2003Anderson et al, 2007) between the 0-10 and 10-20 cm sections of soil profile, but is not always the case as reported by Anderson et al (2007) where non stratified homogeneous ECM communities were present within the 20 cm of soil depth after two years after fire.…”

Below-ground ectomycorrhizal community in natural Tuber melanosporum truffle grounds and dynamics after canopy opening

“…This decrease may be due to loss of EM inocula provoked by pine mortality, but this factor does not seem relevant since nonmycorrhized active tips are scarce throughout all the monitoring. This indirectly points to the effect of the soil environment on the EM fungi (Jones et al 2003a) or on the fine roots. In a subtropical forest, Jones et al (2003b) found that the fine roots of pine and those of understorey species replaced each other over a pine density gradient, but when the understorey was removed the pine root density was primarily driven by abiotic factors.…”

“…However, the effects of these cuttings on the below-ground EM community remain largely unexplored, and the abundance of fruiting bodies is considered to poorly reflect the composition of the below-ground EM community (Gardes and Bruns 1996). It is known that clearcutting alters the abundance of roots and changes the soil environment, affecting the EM community of the regenerating forest stand (Parsons et al 1994;Jones et al 2003a) even in the advance regeneration (Hagerman et al 2001). On the other hand, in the patches of retention trees the EM community does not seem to change in the short term (Jones et al 2008).…”