Index of Species Information

SPECIES:  Taxus canadensis


SPECIES: Taxus canadensis
AUTHORSHIP AND CITATION : Sullivan, Janet. 1993. Taxus canadensis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].

ABBREVIATION : TAXCAN SYNONYMS : Taxus minor Brit. Taxus baccata L. var. canadensis Gray Taxus baccata L. var. minor MIchx. Taxus baccata L. var. procumbens Loud SCS PLANT CODE : TACA7 COMMON NAMES : Canada yew American yew ground hemlock TAXONOMY : The accepted scientific name for Canada yew is Taxus canadensis Marsh. [9,19]. There are no subspecies, varieties, or forms. LIFE FORM : Shrub FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Taxus canadensis
GENERAL DISTRIBUTION : Canada yew is found from Newfoundland west to Manitoba, south to Virginia, Tennessee, Illinois, and Iowa [9,34,45]. ECOSYSTEMS : FRES10 White - red - jack pine FRES11 Spruce - fir FRES18 Maple - beech - birch FRES19 Aspen - birch STATES : CT IL IN IA KY ME MD MA MI MN NY NC OH PA TN VT VA WV WI MB NB NF NS ON PE PQ BLM PHYSIOGRAPHIC REGIONS : NO-ENTRY KUCHLER PLANT ASSOCIATIONS : K093 Great Lakes spruce - fir forest K094 Conifer bog K095 Great Lakes pine forest K096 Northeastern spruce - fir forest K097 Southeastern spruce - fir forest K102 Beech - maple forest K103 Mixed mesophytic forest K104 Appalachian oak forest K106 Northern hardwoods K107 Northern hardwoods - fir forest K108 Northern hardwoods - spruce forest SAF COVER TYPES : 1 Jack pine 5 Balsam fir 12 Black spruce 13 Black spruce - tamarack 17 Pin cherry 19 Gray birch - red maple 20 White pine - northern red oak - red maple 21 Eastern white pine 22 White pine - hemlock 23 Eastern hemlock 24 Hemlock - yellow birch 25 Sugar maple - beech - yellow birch 26 Sugar maple - basswood 27 Sugar maple 28 Black cherry - maple 30 Red spruce - yellow birch 31 Red spruce - sugar maple - beech 32 Red spruce 33 Red spruce - balsam fir 34 Red spruce - Fraser fir 35 Paper birch - red spruce - balsam fir 37 Northern white-cedar 38 Tamarack 60 Beech - sugar maple 108 Red maple SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : Canada yew is a shrub-layer component of many forest associations, including spruce-fir, mixed conifer-northern hardwoods, and northern hardwoods [13]. It is indicative of cool and moist, old-growth conditions [7]. Common understory associates in many forest types include mountain maple (Acer spicatum), striped maple (A. pensylvanicum), beaked hazelnut (Corylus cornuta), leatherwood (Dirca palustris), prickly gooseberry (Ribes cynosbati), prickly currant (R. lacustre), red currant (R. triste), red raspberry (Rubus idaeus), serviceberries (Amelanchier spp.), American fly honeysuckle (Lonicera canadensis), partidgeberry (Mitchella repens), and scarlet elder (Sambucus pubens) [7,20,40]. In addition to the above-mentioned species, shrub layer associates in climax, eastern hemlock forests include alternate-leaved dogwood (Cornus alternifolia) and hobblebush (Viburnum alnifolium) [28]. Ground layer associates in many forest types include shining clubmoss (Lycopodim lucidulum), common woodsorrel (Oxalis montana), wild lily-of-the-valley (Maianthemum canadense), woodfern (Dryopteris spinulosa), and yellow beadlily (Clintonia borealis) [7,24]. Bryophytes and lichens that are common in the climax forests in which Canada yew occurs are feathermoss (Pleurozium schreberi), dicranum mosses (Dicranum spp.), Ptilidium pulcherrimum, and reindeer mosses (Cladonia spp.) [3]. Publications naming Canada yew as an indicator or shrub-layer dominant include the following: The principal plant associations of the Saint Lawrence Valley [7]. Wilderness ecology: virgin plant communities of the Boundary Waters Canoe Area [29].


SPECIES: Taxus canadensis
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Canada yew provides year-round browse for moose and is an important winter food for white-tailed deer where it is available [44]. The fleshy aril of Canada yew is eaten by many birds, including ruffed grouse, pheasants, and various nongame birds, such as cedar waxwings, robind, and starlings [25,35,43]. All parts of Canada yew, except for the aril, are poisonous to horses and cattle [5]. PALATABILITY : Canada yew is highly preferred by moose and white-tailed deer [17]. NUTRITIONAL VALUE : NO-ENTRY COVER VALUE : NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES : NO-ENTRY OTHER USES AND VALUES : The aril of Canada yew can be eaten by humans [25]. Native American tribes in Michigan and Quebec used the foliage to make a beverage [44]. Canada yew is suggested for conservation planting, though it would probably not do well except on shady, moist sites [35]. It is planted as an ornamental but is more often used as parental stock for the formation of new hybrids. It is not as versatile as other species of yew for ornamental purposes. Numerous horticultural varieties are available [15,25]. OTHER MANAGEMENT CONSIDERATIONS : Canada yew is intolerant to moderate or heavy browsing by moose or deer [23,30,38]. Browse availability can be classified as follows on the basis of use of balsam fir (Abies balsamea), Canada yew, and paper birch (Betula papyrifera): if Canada yew is highly or moderately used, the range is below carrying capacity; if balsam fir is heavily browsed, Canada yew has already been browsed to extirpation [31]. Canada yew was once abundant on Isle Royale, Michigan, occurring with 67 percent frequency on plots recorded by surveyors in 1847 [16]. Since colonization of the island by moose, Canada yew has become rare and is increasing only in moose exlosures [1,17,26]. In Nova Scotia, removal of the hemlock overstory destroys Canada yew; it is recommended that some old-gowth stands be preserved to maintain the presence of Canada yew as deer browse [36]. Any removal of the overstory is likely to be detrimental to Canada yew [23]. In a mixed conifer-hardwood forest in New Hampshire, Canada yew cover was "inconsequential" 8 years after a light, selective cut. Heavier levels of harvest resulted in it being eliminated [21]. Canada yew is more cold hardy that English yew (Taxus baccata) or Japanese yew (T. cuspidata), which are also used for ornamentals [25].


SPECIES: Taxus canadensis
GENERAL BOTANICAL CHARACTERISTICS : Canada yew is a native, evergreen, coniferous shrub. It grows from 1 to 3 feet (0.3-0.9 m) and occasionally up to 6 feet (2.8 m) tall. It is rarely arborescent [5,9]. The dense, spreading branches can grow up to 6.6 feet (2 m) long, spreading from the base for about one-third of their length. The bark is nearly smooth. The fruit is a fleshy, cuplike aril surrounding a single seed [35]. RAUNKIAER LIFE FORM : Phanerophyte REGENERATION PROCESSES : Canada yew is monoecious, producing a single seed per female strobilus [44], but under certain conditions it is dioecious. Size appears to influence sex expression. Small Canada yews tend to be male, but if monoecious, they tend to have more female strobili than male stroboli. Large Canada yews are typically monoecious but with male-biased strobilus ratios. Stresses such as browsing increase the proportion of individual males in the population; however, the number of female strobili in the population is greater than that of male strobili. The adaptive significance of this differential sex expression is unclear [2]. Most yews produce some seed almost every year. The seeds are disseminated by birds. Natural germination usually does not take place until the second year. The seeds exhibit a strong but variable dormancy that can be broken by combined warm and cold stratification [35]. Canada yew commonly reproduces by layering, forming a continuous population of genetically identical plants. The connections between genets usually rot [2]. SITE CHARACTERISTICS : Canada yew occurs in humid, continental climates. It grows on moist, poszolic, or leached loam soils; growth is best on well-drained silt loams of pH 5.0 to 7.5 [5,13,25,40]. Canada yew occurs in cool, rich, damp woods and wooded swamps; on banks; along bog margins; and ravines [34,44,45]. Elevational range of Canada yew in the Adirondack Mountains of New York is from 100 to 2,300 (30-700 m) [19]. SUCCESSIONAL STATUS : Obligate Climax Species Canada yew does not occur in early seral of mid-seral communities. It is a slow-growing, shade-tolerant species that grows best in the stable environmental conditions of climax forests [25,33]. Growth is best in at least partial shade [25]. Canada yew appears to have a competitive advantage over intolerant species only under a well-developed canopy [33]. On Isle Royale, Michigan, Canada yew occurred in moderate shade, densely populating some sites, but it did not occur under the very dense shade of balsam fir. Balsam fir, in turn, does not reproduce where Canada yew forms dense ground layers. Canada yew populations migrate; they increase in size by layering, and die back in older portions of the genet, which then allows other plants to come in [6,13,34,43]. Disturbances tend to exclude Canada yew. In the early part of this century, a virgin forest in Connecticut that had reamined free of fire for more than 300 years had a well-established population of Canada yew. Second-growth forests in the same area had no Canada yew in their understory [27]. SEASONAL DEVELOPMENT : Male and female strobili open from April to May in the upper midwestern states. The aril ripens the same year from July through September [35].


SPECIES: Taxus canadensis
FIRE ECOLOGY OR ADAPTATIONS : Canada yew is not well adapted to fire. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY : Shrub without adventitious-bud root crown


SPECIES: Taxus canadensis
IMMEDIATE FIRE EFFECT ON PLANT : Canda yew is probably easily killed by fire. Specific information on its degree of sensitivity is lacking. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Canada yew was locally abundant in a birch-aspen-spruce community on Isle Royale, Michigan, 36 years after a wildfire. In the same area it was present in an old-growth forest that had been free of fire for 80 to 120 or more years[13]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : Fire is likely to result in decreased Canada yew populations; any disturbance that opens the canopy reduces the competitive advantage of the shade-tolerant Canada yew [33]. The decline of Canada yew on Isle Royale, Michigan, has bee partly atrributed to fire [16].


SPECIES: Taxus canadensis
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The hemlock-white pine-northern hardwood region of eastern North America. Ecology. 16(3): 403-422. [8867] 29. Page, C. N.. 1986. The strategies of bracken as a permanent ecological opportunist. In: Smith, R. T.; Taylor, J. A., eds. Bracken: Ecology, Land Use and Control Technology; 1985 July 1 - July 5; Leeds. Lancs: The Parthenon Publishing Group Limited: 173-181. [9721] 30. Peek, J. M. 1974. A review of moose food habits studies in North America. Le Naturaliste Canadien. 101: 195-215. [7420] 31. Pimlott, Douglas H. 1963. Influence of deer and moose on boreal forest vegetation in two areas of eastern Canada. In: Transactions of the 6th congress, International Union of Game Biologists. London: The Nature Conservancy: 105-116. [21413] 32. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843] 33. Risenhoover, Kenneth L.; Maass, Steven A. 1987. The influence of moose on the composition and structure of Isle Royale forests. 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