Forest Investment Account (FIA) - Forest Science Program
FIA Project Y071310

    Developing Molecular Tools for Identifying Pine Mushroom Infected Short Roots in Derived Stand Level Remnants
Project lead: Chapman, Bill
Contributing Authors: Chapman, Bill K.; Bravi, Becky
Imprint: [BC] : University of British Columbia; Ministry of Forests and Range, 2007
Subject: Forest Investment Account (FIA), Pine Mushroom, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
The focus of this research proposal is to develop tools that will allow us to more effectively monitor the effects of the current mountain pine beetle epidemic on the spatial distribution of pine mushrooms. In the mid 1980ís pine mushrooms were found in commercial quantities in many parts of British Columbia and the pine mushroom harvest and export industry was developed (Betty Shore, personal communication, September 1999). Since that time the Pine Mushroom (Tricholoma magnivelare) has become the most valuable non-timber forest product in British Columbia (Wills and Lipsey, 1999). It is highly prized in Japan and commands top dollar at auctions where the mushrooms are sold to wholesalers and then distributed to the general public for sale individually or in sets (Wills and Lipsey, 1999). Annual revenues to pickers from this industry provincially exceed $50 million (based on historical yield and price data) and provide many small rural communities (primarily First Nations communities) with an important source of income. The current Mountain Pine Beetle epidemic and the associated salvage harvest operations threaten the sustainability of the pine mushroom industry at an unprecedented scale across the province. Some productive areas are experiencing direct loss of habitat as mature to old pine stands die or are salvage harvested while others are experiencing the indirect effect of increased harvest pressure as pickers concentrate on the remaining patches. Managing and monitoring management practices associated with the pine mushroom are crucial at this time to ensure the sustainability of this resource and to protect the economic benefits pine mushroom harvesting brings to many rural first nationsí communities. Pine mushroom producing patches have been studied intensively in the West Chilcotin for about 8 years, as a joint effort between the Ulkatcho First Nation and the BC MOFR. One of the primary types of ecological data collected describes stand character. Virtually all the stands in which our sixty transect plots are located, have been attacked to varying degrees by mountain pine beetle because the pine mushroom occupies mature to old stands. These are the same stands preferred (initially) by the beetle. Data collected during the pine mushroom study and again in 2005 after severe MPB attack shows that many of the attacked mushroom patches retain the same sort of complex structure that they had before attack, i.e., some large escape trees, many dead snags, a reasonably intact understory and considerable smaller regeneration. We suspect that many of the MPB affected patches may continue to produce mushrooms, or will begin to produce mushrooms again very soon if they are not salvage harvested. Monitoring the effects that mountain pine beetle has had on the structural and spatial diversity of pine mushrooms and determining the effects of large scale changes to seral distribution on pine mushrooms is crucial to sustaining pine mushroom presence on the landscape. As a result of the research efforts, management recommendations have been made at both the landscape and stand level in the West Chilcotin. Landscape level management focuses on the retention and recruitment of suitable pine mushroom producing habitat across the landscape. Stand level recommendations include maintaining patches of known production or suitable habitat within the stand as well as adjacent patches of young or immature trees in an effort to ensure mushroom spores or mycelium will inoculate the immature stand. Some of the beetle affected pine mushroom-producing areas have been recommended for exemption from salvage harvesting. However, a major challenge to monitoring and managing pine mushroom production in pine mushroom patches is the fact that T. magnivelare does not fruit on an annual basis and sporocarp production in this species is still not well understood. In some patches throughout the province pine mushrooms have not produced fruit bodies for >5 years with production beginning again after that time period and pine mushroom production does not begin in stands until they have reached 70 years of age or older. Because mountain pine beetle salvage operations will occur over a relatively short time period it is probable that large areas of pine mushroom habitat could be rendered non-productive if they are not identified very soon. Hence, monitoring tools are required that allow us to identify the presence of pine mushroom independently of sporocarp production so that these stands can be considered for protection from salvage harvesting. In 2005 a project was implemented using provincial mountain pine beetle funding to determine if it is possible to use T. magnivelare infected short roots to identify pine mushroom persistence in MPB affected patches where fruiting was not observed in the fall of 2005. Pine mushroom associated root morphologies from the fall of 2002 to 2005 were described and four characteristic features consistently expressed (Matchstick Roots, Blackened Roots, Cortical Cell/Epidermal Deterioration and Cottony Association), were identified as possible indicators of pine mushroom persistence. Five known producing sites were identified where no mushroom production was observed in 2005 and host tree root samples were collected and observed for the 4 characteristic root morphologies. The overall conclusion of the study was that root morphologies could be used to monitor persistence in stands where production had been previously confirmed. However, complexity of the technique limits its utility to trained technicians who are experienced in root morphology descriptions. Also questions arose as to whether or not other fungal root associations in the area form the same morphologies. These limitations make the root morphology technique inadequate as the sole tool for assessing pine mushroom presence in the short term. Genetic analysis used in the study to confirm the findings of the morphologies was conducted but was inconclusive. A non-specific fungal primer of the ITS region was used for the analysis as it is currently the only available primer for sequencing. Problems associated with using a general fungal primer are that it is not pine mushroom specific and may not identify its presence adequately or in all cases. This could lead to false negative results for presence (Berbee, personal communication, 2006). Increasing our ability to easily and accurately determine pine mushroom persistence and presence can be achieved through the development of two molecular tools, a pine mushroom specific primer for use in genetic analysis and a monoclonal antibody stain. The development of these tools as well as an assessment of their utility is the focus of this research proposal. Monoclonal antibody stains have been effectively used for some time to identify fungi in roots and soil (Kumer et al,1986) and species-specific primers are the current best tool for distinguishing fungal species from small samples (Martin and Rygiewicz, 2005). Approaches for developing these tools are well documented and will be used to guide the process for developing pine mushroom specific stains and primers. The monoclonal antibody stain technique is relatively simple and can be applied relatively rapidly and easily. The species-specific primers would be used to spot check fungal identifications made using the staining technique. Tools used to monitor mushroom persistence in stands known to produce mushrooms could also be used to identify pine mushroom presence in stands where production was not previously known to occur. Being able to find new areas to harvest pine mushroom could expand the industry and could help mitigate the effects from the predicted timber shortfall as pine mushroom patches can be very valuable. The use of predictive maps such as the one developed in the West Chilcotin by Chapman and Bravi (Bravi, 2006) could be used to identify areas of suitable habitat for pine mushrooms and point to areas that should be more intensively surveyed for pine mushroom presence using the tools developed through this research. The ability to identify young stands that are infected by pine mushroom mycelium but have not begun mushroom production will greatly assist pine mushroom management efforts which are aimed at maintaining and sustaining pine mushroom presence across the landscape. Having timely and cost effective tools that can be employed to accurately survey persistence and presence is paramount
Related projects:  FSP_Y082310
Contact: Chapman, Bill, (250) 398-4718,


Executive Summary (21Kb)

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Updated August 16, 2010 

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