Editing Polypore (section)

===Threats===
Almost all polypores are dependent on trees for their survival. Deforestation and intensive forest management cause declines in polypore abundance and diversity. For many species the changes can be too much, and they start a slow slide towards extinction. Since most polypore species are relatively widespread, this process is typically slow. Regional extinctions can happen relatively quickly and have been documented (for instance ''Antrodia crassa'' in North Europe<ref>Junninen K (2009) Conservation of ''Antrodia crassa''. ''Metsähallituksen luonnonsuojelujulkaisuja, sarja A'' 182: 1–51.</ref>).

Polypores can decline for many reasons. They can be dependent on a single host or a very special habitat. For instance ''[[Echinodontium ballouii]]'' has been found only in [[Atlantic white cedar]] swamps in the Northeastern USA.<ref>Gilbertson RL, Ryvarden L (1986) ''North American polypores 1, ''Abortiporus ''to'' Lindtneria. Oslo, Fungiflora.</ref><ref>{{Cite web | url=http://www.mushroomhunter.net/ballouii.htm | title=査定の前にすべきこと – 鉄道模型の買取でBトレインショーティーの買取}}</ref> Species can be dependent on very old tree individuals like ''[[Bridgeoporus nobilissimus]]'' of the Northwestern USA.<ref name="Ledo 2007"/> Both of these species also have a rather restricted range, making them more vulnerable to extinction.

In addition to the host tree individual, the characteristics of the surrounding habitat also matter. Some species prefer closed-canopy forest with a moist, even microclimate that could be disturbed for instance by logging (e.g. ''[[Skeletocutis jelicii]]''). Others suffer from lack of open forest-fire habitat in areas where fire suppression is done (e.g. ''[[Gloeophyllum carbonarium]]'' in Nordic countries where forest fires are part of the natural forest dynamics).<ref name="Olson 2010"/>

For most declining species the main problem is lack of dead wood in the forest. When suitable tree trunks are too sparse in the landscape, not all species are able to spread to new trunks after old ones have been consumed, causing the population to decline and eventually vanish. Thus, species that are abundant in [[old-growth forests]] with abundant dead wood can be totally absent from managed forests. For instance ''[[Amylocystis lapponica]]'' and ''[[Fomitopsis rosea]]'' are dominant species in North European old-growth spruce forests from Poland to Norway, but absent in managed forests.

Climate change may cause a problem for polypores that are already dependent on a few fragments of old-growth forests and may be unable to migrate with changing vegetation.