American Marten (Martes Americana)


American Marten In the past, the cutting of vast areas of mature conifer forests destroyed much of the American marten habitat in the Sierra Nevada. While the amount of older, undisturbed forest is the Sierra Nevada is continually diminishing, the young-growth forests replacing them are not able to support viable marten populations as the original forests once did. Habitat loss and fragmentation has contributed to the decline in abundance of the marten. Zielinski et al (2005) found a simultaneous decline in the amount of old growth forests along with fragmentation of marten population in the northern Sierra since 1945.  As a consequence of the habitat type marten prefer, they are often found in forests that are highly used for logging and as a result often find their habitat fragmented by these activities.


The American marten lives in mature, dense conifer forests or mixed conifer-hardwood forests with a high percentage canopy cover and large amounts of coarse woody debris on the forest floor. These forests provide prey, protection, den sites and the large snags and downed logs utilized during rest. Furthermore, based upon the elevational ranges suitable for marten in the Sierra Nevada, the overwhelming majority of potential marten habitat in California is contained within the eleven National Forests of the Sierra Nevada. Experts in marten biology have determined that the best habitat for marten currently exists in the forests surrounding Lassen Volcanic National Park. Unfortunately, this region is also the focus of some of the most intensive clearcut logging in the state.


The protection of large trees and closed canopy forests provides the shelter and habitat required for the survival of the American marten. The original Sierra Nevada Framework Plan ensured the protection of these critical attributes and represented the lowest possible risk to the marten by retaining these large trees and minimally required canopy cover. These provisions from the Framework were gutted however in the 2004 Framework revisions that are currently guiding Forest Service policy. The new plan allows for a significant increase in the level of fuels reduction treatments with has much lower canopy cover requirements. The 2004 revisions also set forth a plan to harvest old growth eastside pine trees, up to 30” diameter on the eastern side of the Sierra Nevada, a key structural feature for marten habitat.

Enjoy this great presentation by researcher Katie Moriarty at Sage Creek Field Station, UC Berkeley.


While the American marten is not protected under the Endangered Species Act it is considered  a sensitive species by the Forest Service and is listed as a Management Indicator Species (MIS) for seven Sierra Nevada national forests including the Inyo, Lassen, Modoc, Plumas, Sierra, Stanislaus, and Tahoe National Forests. The State of California lists the American marten as a “species of special concern” and trapping the Marten is illegal in both California and Nevada.

Scientific Research

Buskirk, S.W., and L.F. Ruggerio. 1994. The Scientific Basis for Conserving Forest Carnivores: American Marten, Fisher, Lynx and Wolverine in the Western United States USDA Forest Service, Rocky Mountain Research Station.  RM-GTR-254: Chapter 2: American Marten. Pp. 7-37. (884KB PDF)

Buskirk, S.W., and W.J. Zielinski. 1997. American marten (Martes americana) Ecology and Conservation. In: Mesocarnivores of Northern California: Biology, Management, & Survey Techniques. Pp. 17-22. (57KB PDF)

Green, R.E. 2007. Distribution and Habitat Associations of Forest Carnivores and an Evaluation of the California Wildlife Habitat Relationships Model for American Marten in Sequoia and Kings Canyon National Parks. Masters Degree Thesis, Humboldt State University. Arcata, CA. (2MB PDF)

Hargis, C.D., J.A. Bissonette, and D.L. Turner. 1999. The Influence of Forest Fragmentation and Landscape Pattern on American Martens. Journal of Applied Ecology 36, 157-172. (1013KB PDF)

Kirk, T. and W. Zielinski. In press. Functional Habitat Connectivity of the American Marten (Martes americana) in Northeastern California Using Least-cost Corridor Modeling. (3.42 MB PDF)

Kucera, T.E., W.J. Zielinski, And R.H. Barrett. 1995. Current Distribution of the American Marten, Martes Americana, in California. California Fish and Game81(3) 96-103. (129KB PDF)

Poole, K.G., A.D. Porter, A. de Vries, C. Maundrell, S.D. Grindal, and C.C. St. Clair. 2004. Suitability of a young deciduous-dominated forest for American marten and the effects of forest removal. Canadian Journal of Zoology 82, 423–435. (700KB PDF)

Powell, R.A., S.W. Buskirk, and W.J. Zielinski. 2003. Fisher and Marten. In: Wild Mammals of North America: Biology, Management, and Conservation. Johns Hopkins University Press. Pp. 635-649. (3MB PDF)

Rustigian-Romsos, H. and W.D. Spencer. 2010. Predicting Habitat Suitability for the American Marten on the Lassen National Forest. Produced by Conservation Biology Insitute (CBI) for Lassen National Forest. (6.0 MB PDF)

Slauson, K.M., W.J. Zielinski, and J.P. Hayes. 2002. Ecology of American Martens in Coastal Northwestern California. U.S. Forest Service, Pacific Southwest Research Station, Redwood Sciences Laboratory. Arcata, California. (1.5MB PDF)

Slauson, K.M. 2003. Habitat Selection by American Martens (Martes americana) in Coastal Northwestern California. Masters Degree Thesis, Oregon State University. Corvalis, Oregon. (2.73MB PDF)

Zielinski, W.J., R.L. Truex, C.V. Ogan, and K. Busse. 1997. Detection Surveys for Fishers and American Martens in California, 1989-1994: Summary and Interpretations. In: Martes: Taxonomy, Ecology, Techniques, and Management, Pages 372-392. Provincial Museum of Alberta, Edmonton, Alberta, Canada. (441KB PDF)

Zielinski, W.J., and N.P. Duncan. 2004. Diets of Sympatric Populations of American martens (Martes americana) And Fishers (Martes pennanti) in California. Journal of Mammalogy 85(3), 470–477. (105KB PDF)

Zielinski, W.J., R.L. Truex, F.V. Schlexer, L.A. Campbell, and C. Carroll. 2005. Historical and Contemporary Distributions of Carnivores in Forests of the Sierra Nevada, California, USA. Journal of Biogeography 32, 1385–1407. (33KB PDF)

Zielinski, W.J., J. Werren, and T. Kirk. 2005. Selecting Candidate Areas for Fisher (Martes pennanti) Conservation that Minimize Potential Effects on Martens (M. americana). U.S. Forest Service, Pacific Southwest Research Station, Redwood Sciences Laboratory. (7.89MB PDF)

Supporting Resources

California Department of Fish and Game Natural History Information --This California state website contains rather limited and old information but is a good basic background composite for the species. Choose from a drop-down list to select the animal you are interested in.

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