Griffiths, R. 2011. Association of ectomycorrhizal mats with Pacific yew and other understory trees at the Andrews Experimental Forest and the southern and western Cascades, Oregon, 1992-1994 Long-Term Ecological Research Andrews Forest LTER Site. [Database]. Available: https://andrewsforest-stage.forestry.oregonstate.edu/data/fsdb-data-catalog/SP022 Accessed 2026-05-10.

This study was designed to determine if ectomycorrhizal mats are more likely to be present in soils at the base of common understory trees than in soils distant from trees and to determine if there is a relationship between the occurrence of mats and tree size. The understory trees studied included the Pacific yew (Taxus brevifolia Nutt.) western hemlock (Tsuga heterophylla (Raf.) Sarg) and vine maple (Acer circinatum Pursh). Twelve sites were studied representing a range of climatic conditions and management histories. More than 2,900 plots were surveyed over an 18-month period. It was found that the incidence of ectomycorrhizal mats was higher at the base of all three species of trees when compared with control plots. A statistically significant positive correlation was also observed between the incidence of mats and tree size. When comparing saplings with larger trees, the saplings consistently had a lower incidence of mats. These observations are not consistent with the hypothesis that ectomycorrhizal mats are required for T. brevifolia establishment or survival.

Temporal coverage: 1992-01-07 to 1994-01-07

Geographic coverage: N/A

Bounds: W N/A, E N/A, N N/A, S N/A

• A group of ectomycorrhizal fungi that form dense fungal mats in the litter layer and A horizon of forest soils can make up to 50% of the mass of mineral soils (Ingham et al., 1991). Because of the density of fungal material in these mats, they have proven to be excellent systems for measuring mycorrhizal function in forest soils (Griffi­ths et al., 1990). Studies comparing the chemistry and biology of mat-colonized soils and adjacent soils without obvious mat colonization have shown that these fungi are capable of increasing nutrient availability to trees by weathering mineral soil and decomposing soil organic material (Griffiths et al., 1990; Griffiths et al., 1991b; Griffiths and Caldwell, 1992; Aquilera and Griffiths, 1993; Griffiths et al., 1994). In addition, these mats have the ability to enhance Douglas-fir seedling survival under low-light conditions (Griffiths et al., 1991a).
• Because of the commercial importance of yew bark for the production of the anticancer drug taxol and an increased interest in vegetation associated with old-growth Douglas-fir forests, there has been renewed interest in determining which factors influence the establishment and survival of Pacific yew. We have informally observed that Pacific yew in Douglas-fir old-growth forests is usually associated with ectomycorrhizal mats. This observation is all the more curious since T. brevifolia usually forms symbiotic relationships with vesicular arbuscular mycorrhizal (VAM) fungi but not with ectomycorrhizal fungi (Trappe, pers. comm.). The same is generally true of other Taxus species found in Canada and Europe (Prat, 1934; Bakshi, 1960), however there is one report of ectomycorrhizal colonization of Canadian yew roots (Boullard and Ferchau, 1962). Establishment of Taxus plants from seed is thought to be plagued by low seed germination rates. High seedling losses are also due to fungal root disease caused by Cylindrocarpon radicicola Manka et al. (1968) and other fungal pathogens. Since ectomycorrhizal fungi are known to protect trees from root pathogens (Marx, 1970) we hypothesized that these ectomycorrhizal mats relate to T. brevifolia seedling establishment and survival in coniferous forests of the Pacific Northwest. Because of the implications of this relationship, we initiated a study to determine if T. brevifolia was always associated with ectomycorrhizal mats and to determine if these mats were more likely to be associated with seedlings or larger trees.

Title: Long-Term Ecological Research

• Robert P. Griffiths
  Role: Principal Investigator
  Oregon State University;Dept. of Forest Science;321 Richardson Hall, Corvallis, OR, 97331-5752, USA
  Phone: (541) 737-6559
  Email: bbgriff@peak.org, griff@for.orst.edu
• Robert P. Griffiths
  Role: Abstractor
  Oregon State University;Dept. of Forest Science;321 Richardson Hall, Corvallis, OR, 97331-5752, USA
  Phone: (541) 737-6559
  Email: bbgriff@peak.org, griff@for.orst.edu
• Robert P. Griffiths
  Role: Creator
  Oregon State University;Dept. of Forest Science;321 Richardson Hall, Corvallis, OR, 97331-5752, USA
  Phone: (541) 737-6559
  Email: bbgriff@peak.org, griff@for.orst.edu

• Information Manager
  Andrews Forest LTER Program, US Forest Service Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR, 97331
  Email: hjaweb@fsl.orst.edu
  URL: http://andrewsforest.oregonstate.edu/
• Robert P. Griffiths
  Oregon State University;Dept. of Forest Science;321 Richardson Hall, Corvallis, OR, 97331-5752, USA
  Phone: (541) 737-6559
  Email: bbgriff@peak.org, griff@for.orst.edu

• Andrews Forest LTER Site
  Role: Publisher
  Forest Ecosystems and Society Department in Forestry, Oregon State University, 201K Richardson Hall, Corvallis, OR, 97331-5752
  Phone: (541) 737-8480
  Email: lterweb@fsl.orst.edu
  URL: http://andrewsforest.oregonstate.edu/

This study was designed to determine if ectomycorrhizal mats are more likely to be present in soils at the base of common understory trees than in soils distant from trees and to determine if there is a relationship between the occurrence of mats and tree size. The understory trees studied included the Pacific yew (Taxus brevifolia Nutt.) western hemlock (Tsuga heterophylla (Raf.) Sarg) and vine maple (Acer circinatum Pursh). Twelve sites were studied representing a range of climatic conditions and management histories. More than 2,900 plots were surveyed over an 18-month period. It was found that the incidence of ectomycorrhizal mats was higher at the base of all three species of trees when compared with control plots. A statistically significant positive correlation was also observed between the incidence of mats and tree size. When comparing saplings with larger trees, the saplings consistently had a lower incidence of mats. These observations are not consistent with the hypothesis that ectomycorrhizal mats are required for T. brevifolia establishment or survival. A group of ectomycorrhizal fungi that form dense fungal mats in the litter layer and A horizon of forest soils can make up to 50% of the mass of mineral soils (Ingham et al., 1991). Because of the density of fungal material in these mats, they have proven to be excellent systems for measuring mycorrhizal function in forest soils (Griffi­ths et al., 1990). Studies comparing the chemistry and biology of mat-colonized soils and adjacent soils without obvious mat colonization have shown that these fungi are capable of increasing nutrient availability to trees by weathering mineral soil and decomposing soil organic material (Griffiths et al., 1990; Griffiths et al., 1991b; Griffiths and Caldwell, 1992; Aquilera and Griffiths, 1993; Griffiths et al., 1994). In addition, these mats have the ability to enhance Douglas-fir seedling survival under low-light conditions (Griffiths et al., 1991a). Field Methods - SP022

Purpose: A group of ectomycorrhizal fungi that form dense fungal mats in the litter layer and A horizon of forest soils can make up to 50% of the mass of mineral soils (Ingham et al., 1991). Because of the density of fungal material in these mats, they have proven to be excellent systems for measuring mycorrhizal function in forest soils (Griffi­ths et al., 1990). Studies comparing the chemistry and biology of mat-colonized soils and adjacent soils without obvious mat colonization have shown that these fungi are capable of increasing nutrient availability to trees by weathering mineral soil and decomposing soil organic material (Griffiths et al., 1990; Griffiths et al., 1991b; Griffiths and Caldwell, 1992; Aquilera and Griffiths, 1993; Griffiths et al., 1994). In addition, these mats have the ability to enhance Douglas-fir seedling survival under low-light conditions (Griffiths et al., 1991a).

Method Steps

Sampling

No software entries listed in this EML file.

• LTER controlled vocabulary: primary production (theme), inorganic nutrients (theme), mycorrhizae (theme)
• Andrews Experimental Forest site thesaurus: Long-Term Ecological Research (LTER) (theme)
• LTER core research areas: primary production (theme), inorganic nutrients (theme)

• All Organisms: All Organisms
• Highest common category (ca. kingdom): Fungi
• Division or Phylum: Basidiomycota
• Division or Phylum: Basidiomycetes
• Order: Polyporales
• Family: Atheliaceae
• Genus: Piloderma
• Order: Phallales
• Family: Gomphaceae
• Genus: Gautieria
• Family: Hysterangiaceae
• Genus: Hysterangium
• Highest common category (ca. kingdom): Plantae
• Division or Phylum: Coniferophyta
• Class: Pinopsida
• Order: Taxales
• Family: Taxaceae
• Genus: Taxus
• Species: Taxus brevifolia
• Order: Pinales
• Family: Pinaceae
• Genus: Tsuga
• Division or Phylum: Magnoliophyta
• Class: Magnoliopsida
• Subclass: Rosidae
• Order: Sapindales
• Family: Aceraceae
• Genus: Acer

No related dataset codes found in the EML text fields.

No publication citations found in this EML file.

No related files listed in this EML file.

Data Use Agreement:

The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. This Data Set is released under the Creative Commons license CC BY "Attribution" (see: https://creativecommons.org/licenses/by/4.0/). Creative Commons license CC BY - Attribution is a license that allows others to distribute, remix, tweak, and build upon your work (even commercially), as long as you are credited for the original creation. This license accommodates maximum dissemination and use of licensed materials.

It is considered professional conduct and an ethical obligation to acknowledge the work of other scientists. The Data User is asked to provide attribution of the original work if this data package is shared in whole or by individual parts or used in the derivation of other products. A recommended citation is provided for each Data Set in the Andrews LTER data catalog (see: http://andlter.forestry.oregonstate.edu/data/catalog/datacatalog.aspx). A generic citation is also provided for this Data Set on the website https://portal.edirepository.org in the summary metadata page. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

While substantial efforts are made to ensure the accuracy of data and associated documentation, complete accuracy of data sets cannot be guaranteed and all data are made available "as is." The Data User should be aware, however, that data are updated periodically and it is the responsibility of the Data User to check for new versions of the data. The data authors and the repository where these data were obtained shall not be liable for damages resulting from any use or misinterpretation of the data.

General acknowledgement: Data were provided by the HJ Andrews Experimental Forest research program, funded by the National Science Foundation's Long-Term Ecological Research Program (DEB 2025755), US Forest Service Pacific Northwest Research Station, and Oregon State University. If data used in publication, the PI will be listed as a coauthor. Whenever these data are presented in whatever form, the PI will be acknowledged.

License: N/A

Maintenance update frequency: irregular

Description

• An update history is logged and maintained with each new version of every dataset.

Change History

• Version1 (2001-04-30)
  Original metadata creation.
• Version2 (2002-02-08)
  Metadata restructured and moved into SQLServer metadata database LTERMETA. Data moved into SQLServer database FSDBDATA.