Forest Sciences Prince Rupert Forest Region
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Forest Sciences Prince Rupert Forest Region Extension Note # 25 The Effects of Timber Harvesting on Mushrooms and December, 1997 Mycorrhizae of the Date Creek Research Forest Harvesting of mushrooms, especially harvesting on mushrooms and Research Issue Groups: pine mushrooms, is an important part mycorrhizal communities. of local economies in the Prince Forest Biology Rupert Forest Region and other parts Mushrooms and mycorrhizae of British Columbia. However, most Many commerically valuable Forest Growth commercial mushrooms are found in mushrooms, such as pine mature forests, where timber mushrooms, chanterelles, and Soils harvesting and silvicultural practices boletes, are mycorrhizal fungi. such as thinning or fertilizing can Mycorrhiza (literally fungus root) Wildlife Habitat affect mushroom production. Many means that these fungi live in people would like to better symbiosis (as partners) with trees. Silviculture understand how forest management Each feeder root of coniferous trees can affect alternative forest products is covered in a dense layer of fungal Timber Harvesting such as mushrooms. In this note we hyphae, forming a mantle, which will discuss what mushrooms are and penetrates roots to directly connect their relationship to trees, and with root cells (Figure 1). A Ecosystem Inventory and secondly, summarize research that mycorrhizal fungus extends from a Classification examines the effects of timber root into the surrounding soil, Biodiversity Ecosystem Management Hydrology Geomorphology Extension Figure 1. Mycorrhizal fungi covering root tips of western hemlock (magnified 10X) Forest Sciences, Prince Rupert Forest Region Bag 5000, Smithers, BC V0J 2N0 847-7500 (FAX 847-7217) absorbs nutrients and water, and on mycorrhizal communities and mushrooms from growing. brings them back to share with the mushroom production. Date Creek However, because mushrooms are tree. The tree photosynthesizes, has a tremendous community of only the fruiting part of the fungus, producing enough sugars to share mycorrhizal fungi. Mushroom we were not yet certain what effect with the fungus. The feeder roots surveys during one period in the gaps had on the mycorrhizal and fungal symbiont are found September revealed at least 80 community. throughout the forest floor and upper mycorrhizal species, and other mineral soil, creating a very large species exist that we were unable to The gaps are filled with young living biomass in the soil. identify or that were fruiting at seedlings colonized by mycorrhizae, Mushrooms are the only part of this different times of the year (Table 1). which we can compare to the fungus/tree root symbiosis that we mycorrhizal community of the commonly see. Mushrooms are the In addition to the mature stands at adjacent mature forest. We fruiting stage of mycorrhizal fungi, Date Creek, we searched different examined western hemlock seedlings needed to disperse fungal spores for sized stand openings (gaps ranging across some large gaps (50-75 m colonizing other tree roots. Picking from 28 m² to 4526 m²) for diameter) to determine fungal a mushroom should not be harmful mycorrhizal mushrooms. The richness and distribution (Figure 3). to mycorrhizae if the forest floor is smallest gaps, where only a few trees Seedlings under the canopy had the undisturbed, since the feeder roots had been removed, still had many most mycorrhizae (38 fungal and fungal mantle will survive. mushrooms (Figure 2). The number morphotypes), while seedlings near Raking the forest floor, however, can of species dropped considerably as the edge had 21% less (30 fungal break off tree roots and kill the the gaps grew larger. The production types). Seedlings furthest into the fungal symbionts responsible for of mushrooms was reduced to a few gap openings had 25 ectomycorrhizal mushrooms. species fruiting very infrequently at types, 34% less than the seedlings in gap sizes greater than approximately the mature forest. The decrease in There are other mushrooms in forests 600m² (20x30 m). Clearly the fungal richness suggests that not all which are not mycorrhizal. For removal of enough trees to form mycorrhizal fungi persist in soils example, black morels and the large gaps in the stand has stopped common supermarket mushroom are saprophytic (live off dead stuff) and can be found growing in burned or disturbed areas. These fungi live in soils by decomposing organic matter rather than by colonizing root tips. Timber harvesting effects on mycorrhizae and mushrooms Its should be clear that removing trees will affect mycorrhizal mushroom fruiting because of the symbiotic connection between fungus and trees. We have been conducting studies at the Date Creek research forest, near Hazelton, to examine the effect of stand openings Figure 2. Gap area vs. species richness of mycorrhizal mushrooms per 100 m north/south transect. 2 after harvesting, to recolonize new seedlings. Instead, some mycorrhizae re-enter the harvested area by slowly spreading from roots of mature trees to roots of seedlings in the openings. Some fungi may also not occur in gaps because they can only grow in the moister, cooler soil conditions found in the mature forest. The decline in fungal richness across the gaps is likely temporary, as we expect the rest of the mycorrhizae community will recolonize the gaps over time. What we noticed, however, was that the mycorrhizae community in the gaps was more diverse than was indicated Figure 3. Mycorrhizal communities found on western hemlock across gaps at Date by the mushrooms found in the gaps. Creek. The fungal types are ranked in order of abundance (% root colonized). Canopy refers to seedlings under mature trees; Edge are The reduction in mushroom fruiting seedlings 5 to 10 m into the gap; Open are seedlings 15 to 20 m into the in the gaps is therefore not from a lack of mycorrhizal fungi. One Future research give us more information about other possible reason for the reduction in Partial cutting is perhaps the best choice edible mushrooms in this mushrooms is that seedlings are too strategy to maintain some level of region. Many of these species could small to supply fungi with enough timber harvesting concurrent with become more valuable in the future if energy to grow mushrooms. A mushroom production. At Date wild mushrooms continue to grow in second possibility is that warmer and Creek, the light removal treatment popularity. drier (lower relative humidity) soil has 30% of the forest volume conditions in gaps are not suitable removed through single-tree Mycorrhizae and mushroom research for stimulating mushroom growth by selection and small gaps. We will was initiated by Elaine Wright in the mycorrhizal fungi. As trees begin monitoring parts of the single- cooperation with Melanie Jones and mature, they will be able to supply tree removal stands for mushroom Dan Durall (Okanagan College sugars needed by fungi and influence production. This phase of the University), Marty Kranabetter the microclimate of soils. research will also look at amounts of (Regional soil scientist), Tara Wylie Plantations might begin to show mushrooms produced, rather than and Paul Kroeger (consulting more mushroom diversity at about just diversity, since this is important biologists). age ten, but full re-establishment of in assessing the impact to the mushroom production might not mushroom industry. The research occur until ages 30 or 40. It is fairly will also assess a wide range of clear that in the short-term, fungal species to better understand mushroom production will require how the mycorrhizal community is enough mature trees to support affected, rather than just valuable mycorrhizae and to maintain suitable species such as pine mushrooms. microclimates. This baseline monitoring will also 3 Table 1. Date Creek mycorrhizal mushroom list, September 1996 Amanita porphyria Hydnellum spp. Russula decolorans Boletus mirabilis Sarcodon imbricatum Russula densifolia Cantharellus infundibuliformis Hygrophorus bakerensis Russula emetica Chroogomphus rutilus Hygrophorus cf. erubescens Russula flaviceps Chroogomphus tomentosus Hygrophorus piceae Russula fragilis Clavariadelphus ligula Hygrophorus saxatilis Russula cf. gracilis Clitocybe spp. Hygrophorus tephroleucus Russula laurocerasi v. tephroleucus Cortinarius cf. Alboviolaceus Hygrophorus spp. Russula occidentalis (Sericeocybes) Cortinarius cf. Armeniacus Inocybe geophylla Russula cf. olivacea (Telamonia) Cortinarius armillatus (Telamonia) Inocybe geophylla v. lilacina Russula virescens Cortinarius cinnamomea Inocybe spp. Russula xerampalina (Dermocybe) Cortinarius cf. Cotoneus Laccaria bicolor Russula spp. (Compactae) (Leprocybe) Cortinarius cf. deceptivus Laccaria laccata Russula spp. (Telamonia) Cortinarius glaucopus Lactarius affinis v. affinis Suillus tomentosus (Phlegmacium) Cortinarius mutabilis Lactarius deliciosus Thelephora terrestris (Phlegmacium) Cortinarius phoeniceus Lactarius glyciosmus Tricholoma pardinum v. occidentalis (Dermocybe) Cortinarius semisanguineus Lactarius mucidus Tricholoma pessundatum (Dermocybe) var fuscogriseus Cortinarius cf. Speciosissimus Lactarius pseudomucidus Tricholoma platyphyllum (Leprocybe) Cortinarius traganus Lactarius resimus Tricholoma cf. saponaceum (Sericeocybe) v. resimus Cortinarius vanduzerensis Lactarius rufus (Myxacium) Cortinarius vibratilis (Myxacium) Lactarius scrobiculatus Cortinarius spp. (Bulbopodium) Lactarius torminosus v. normandensis Cortinarius (Dermocybe) spp. Lactarius uvidus Cortinarius (Phlegmacium) spp. Lactarius spp. Cortinarius