Populus grandidentata

Big Tooth Aspen

Big Tooth Aspen
Photo courtesy Wisconsin State Herbarium and
Kenneth J. Sytsma

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The natural history of the northwoods


  • Populus, from the Latin for poplar
  • grandidentata, from the Latin, grandis, "great, large", and dentatus, "toothed"
  • Common Name from the strongly toothed leaf margins
  • Other common names include Largetooth Aspen
  • , Canadian Aspen


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Magnoliopsida, the Dicotyledons
      • Subclass Dilleniidae
        • Order Salicales
          • Family Salicaceae, the Willows, with aspen and poplars
            • Genus Populus, the Poplars
  • Taxonomic Serial Number: 22463
  • Along with five other aspen species, assigned to the subsection Trepidae of the section Leuce in the genus Populus. Because of their similarities, these six species are sometimes considered a single super species.
  • Bigtooth Aspen and Quaking Aspen (Populus tremuloides) are the only North American aspen species.


  • Native, short-lived, dioecious, medium-sized deciduous tree with a straight trunk and gently ascending branches.
  • Fruit a two-valved capsule.
  • Bigtooth aspen has 19 pairs of chromosomes (2n=38).
  • Height at maturity 60'-80' with diameters of 8'-10'; grows rapidly.
  • Age: Stands begin to deteriorate after 50-70 years on good sites, but individuals may live as long as 100 years.
  • Clonal species. Clones resemble small groves of many individual stems.
  • Roots shallow and wide spreading; lateral root spread in a forest may be 33'-66'. Generally, four to five lateral roots originate from the tree and then branch within 2'; vertical, penetrating roots near the base anchor the tree.
  • Bark of young trees smooth; after 30 years rough with grooves.


  • Identifiable as an Aspen by its characteristic aspen leaf.
  • Distinguished from Quaking Aspen (Populus tremuloides) by having slightly larger leaves with large irregular teeth on the leaf edges. Quaking Aspen has finely toothed leaf edges.


  • Southeastern Manitoba to Nova Scotia, south to North Dakota, Minnesota, Iowa, Missouri, Tennessee, and North Carolina.
  • Primarily NE United States, SE Canada, and the Great Lakes Region.


  • Most commonly floodplains, gently rolling terrain, and the lower slopes of uplands. Large stands grow on sands, loamy sands, and light sandy loams. Lower soil pH limit of 4.0.
  • Tolerates drier conditions than Quaking Aspen (Populus tremuloides). However, for good growth on upland sites the watertable must be at least 2', but not more than 5', below the surface. Soil must be moist but well aerated for good growth.
  • Very shade intolerant; most shaded stems die.
  • Pioneer species on disturbed sites, persisting in successional communities until senescence.
  • Rapid height growth of suckers allows it to outcompete other sprouting species such as Red Oak (Quercus rubra) and Red Maple (Acer rubrum) on many sites.
  • In the absence of disturbance, replaced by conifers and hardwoods. On dry sites by Red Pine (Pinus resinosa), oak, and Red Maple; on intermediate sites by White Pine (Pinus strobus); and on mesic sites by northern hardwoods, spruce (Picea spp.), and Balsam Fir (Abies balsamea).
  • In the Great Lakes Region at the turn of the century, many mature pine forests were logged and burned. Bigtooth Aspen and Quaking Aspen frequently dominated the postdisturbance forests. Without fire or other disturbance, these forests are being replaced by later successional, shade-tolerant species.
  • Usually grows in even-aged mixed stands, most commonly with Quaking Aspen. Codominant in both hardwood and conifer forests; does not occur as a subdominant because of its extreme shade intolerance.
  • Quaking Aspen (Populus tremuloides) is the predominant species in aspen stands in the Great Lakes Region, but Bigtooth Aspen dominates on the drier upland sites. Aspen stands dominated by Bigtooth Aspen are generally more open than those dominated by Quaking Aspen.
  • More disease resistant than Quaking Aspen. The most serious disease is Hypoxylon Canker (Hypoxylon mammatum). Other rots, fungi, and root decay affect this species. A preferred host of gypsy moth. Death occurs when nearly complete defoliation by gypsy moth is followed by a fungal infection by Armillaria spp. Ambrosia beetle (Xyleborus saxesceni) attacks fire-damaged bigtooth aspen.
  • Commonly occurs in areas that frequently burn, such as large upland areas distant from water and upwind of natural fire breaks such as lakes.


  • Easily top-killed by fire, but extensive vegetative reproduction, prolific off-site seed production, and the tenacity and lateral extent of its roots enable it to perpetuate after fire. Removal of the overstory and heating of the soil stimulate root sprouting. Fire also creates a suitable seedbed and reduces competition.
  • Almost always retains or extends its range following fire. The extensive root system allows it to dominate the postfire forest, even if aspen was only a minor component of the prefire stand. Aspen roots persist an undetermined length of time in the absence of canopy aspen, making it possible to regenerate in a stand where aspen was not even represented in the prefire overstory.
  • Aspen-dominated forests do not readily burn, especially when young and healthy. Slow burning, low-severity surface fires are typical; decadent stands contain more fuel and are more likely to burn than younger stands. An understory of conifers increases the flammability of aspen stands. However, aspen is generally incapable of supporting a severe fire. Crown fires in the surrounding forest generally drop into surface and ground fuels when they enter aspen stands.
  • Very susceptible to fire, although roots are very fire resistant. Bark is thin and does not protect the cambium from heat damage. If there is sufficient fuel in a young sapling stand for a fire to burn, the fire will kill the sapling. An average scorch height of 0.6' will kill most stems under 6" in diameter.
  • Since most fires in aspen are of low severity, mature trees do not always succumb to fire. However, basal wounds caused by low-severity fire serve as entry points for disease organisms.
  • Prolonged drought and large amounts of slash are required to raise the soil temperature high enough to kill the roots of aspen. Bigtooth Aspen roots are deeper in the soil than Quaking Aspen roots, making root damage from fire highly unlikely. Roots are stimulated to sprout if the soil is heated. The soil is heated not only by the fire, but also by blackening of the soil surface and removal of overstory and duff.
  • Density and growth of suckers is dependent in part on fire severity. A low-severity fire that does not kill all of the overstory does not result in suckers as dense or vigorous as those produced after a moderate severity fire.
  • Fire also prepares a favorable seedbed. Seeds from off-site sources may blow onto burned sites and establish if there is sufficient moisture and if the competition is not severe.
  • Most shrub species in the understory of aspen forests are able to sprout after fire, as are many hardwood associates.


  • Trees: Balsam Poplar (Populus balsamifera), Quaking Aspen (Populus tremuloides), Black Cherry (Prunus serotina), White Oak (Quercus alba), Bur Oak (Quercus macrocarpa), Basswood (Tilia americana), In the northern part of its range, common tree associates are quaking aspen, balsam poplar, balsam fir (Abies balsamea), paper birch (Betula papyrifera) gray birch (B. populifolia), jack pine (Pinus banksiana), red pine (P resinosa), red maple (Acer rubrum), and white spruce (Picea glauca).
  • Shrubs: Speckled Alder (Alnus incana), Juneberries (Amelanchier spp.), Sweetfern (Comptonia peregrina), Dogwood (Cornus spp.), American Hazel (Corylus americana), Beaked Hazel (Corylus cornuta), Low Bush Honeysuckle (Diervilla lonicera), Chokecherry (Prunus virginiana), Willows (Salix spp.) Common shrub associates are chokeberry (Prunus virginiana), downy serviceberry (Amelanchier arborea), dogwood (Cornus spp.), willow (Salix spp.), beaked hazel (Corylus cornuta), speckled alder (Alnus rugosa), highbush cranberry (Viburnum trilobum), American hazel (Corylus americana), and Sweetfern (Comptonia peregrina). Common ground flora are blueberry (Vaccinium spp.), teaberry (Gaultheria procumbens), bracken (Pteridium aquilinum var. latiusculum), fly honeysuckle (Lonicera canadensis), smooth sumac (Rhus glabra), dwarf bushhoneysuckle (Diervilla lonicera), and strawberry (Fragaria spp.)
  • Herbs: Bracken Fern (Pteridium aquilinum)
  • Ground Covers:
  • Mammals:
    • Moose and White Tail Deer browse.
    • Beaver eat bark, leaves, twigs, and branches. By cutting trees and damming waterways, beaver can destroy large aspen stands.
  • Birds:
    • Ruffed Grouse feed on the highly palatable leaves in the summer, staminate flower buds in the winter, and catkins prior to the breeding season.
    • Approximately 116 nongame bird species breed in aspen-birch forests. Cavity nesters use Bigtooth Aspen.


  • Used by the Ojibwe -Cambium layer scraped, boiled and eaten, something like eggs.


  • Wood light colored, straight grained, finely textured, and soft. Used primarily for pulp, but also to make particle board and structural panels. Minor uses include log homes, pallets, boxes, match splints, chopsticks, hockey stick components, and ladders.
  • Bark is pelletized for fuel and supplemental cattle feed.


  • Regenerates by seed and vegetative reproduction.
  • Seed production prolific; a single tree may produce more than 1.5 million seeds. Generally has good or better crops 2 out of every 3 years.
  • The light seeds are dispersed long distances by wind.
  • Germination rates high. Seeds germinate under a wide range of temperatures as long as there is sufficient moisture. They will even germinate when submerged in water. Despite high seed production and high germination rates, seedling establishment is uncommon. Few seedlings reach more than a few inches in height. Bare moist soil free of competition is necessary for seedling establishment. Short seed viability (2-3 weeks) also limits establishment. A seedling may grow 6"-8" the first year.
  • Most Bigtooth Aspen forests regenerate vegetatively. When the parent tree is killed or the soil is heated, suckers develop from extensive, shallow lateral roots. A sucker grows 3'-6' the first year, considerably more than a seedling. After a mature stand is destroyed by fire or logging, roots may produce 3,200 to 24,000 suckers per acre. Root suckers are initially dependent on the parent roots for water and nutrients. This dependence decreases with time but is still substantial after 25 years, when the parent roots still contribute the nutrient requirements for approximately half the yearly growth.
  • Multiple suckers result in a clone, a multistemmed, vegetatively reproduced "individual."
  • Roots may remain alive in a forest long after the last tree has died.
  • Bigtooth Aspen flowers, foliates, and disperses seeds about 1 to 3 weeks later than Quaking Aspen in the same location
  • Natural hybrids of bigtooth aspen and quaking aspen do occur, but less frequently than might be expected, because of differences in time of flowering. When hybridization occurs, it is most likely to be between male quaking aspen and female bigtooth aspen


  • By seed


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Because of its low flammability, recommended for use in fire breaks, especially on droughty, sandy sites.



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Last updated on 4 March, 2006