The Clonal Growth Habit of American Aspens

Abstract

Bigtooth and trembling aspens (Populus grandidentata and P. tremuloides) typically occur in Michigan and throughout much of their native range in natural clones of several to many genetically identical individuals. A clone is initiated by the establishment of a seedling (the ortet); suckers (ramets) arise from the root system of the ortet. Death of ramets and decay of root connections may result in formation of several independent root systems within the same clone. Average size of individual clones of both species on the research sites in Michigan was approximately 0.007 acre. Male and female clones did not differ in size. Clones are established, expand, intergrow, and coalesce depending upon the ease of seedling establishment, rapidity of root expansion, inherent suckering ability, and amount of disturbance. Although the aspens are typically recognized as pioneer species, they may be more permanently part of the habitat than most of their non—clonal associates. Recognition of the clonal structure of most aspen stands is important in many aspects of research.

Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales

“…They occur in mixed forests as well as monospecific stands that can extend continuously over broad areas; the largest individual organism known to science, the Pando genet, covers 44.3 ha in southern Utah, USA [42]. Western US aspen are often triploid and form expansive genets of genetically identical ramets [43][44][45]. Conversely, aspen in the Great Lakes region of the USA are rarely triploid [44], and form small genets that are often interspersed with mixed northern hardwood species.…”

Aspen mortality in the Colorado and southern Wyoming Rocky Mountains: Extent, severity, and causal factors

“…This species is dioecious, and both male and female flowers form as catkins (Jones, 1985). Barnes (1966) determined that aspen seedlings may initiate suckering soon after establishment. The number of original seedlings (or 'ortets') in an aspen stand has been found to be inversely proportional to the clone size, regardless of site conditions (Barnes, 1966).…”

“…Barnes (1966) determined that aspen seedlings may initiate suckering soon after establishment. The number of original seedlings (or 'ortets') in an aspen stand has been found to be inversely proportional to the clone size, regardless of site conditions (Barnes, 1966). Other differences, such as varied width: length ratio and serration patterns of leaves may vary with genotype (Barnes, 1975).…”

“…Removal, wounding, or death of the adult trees results in rapid declines in root auxin levels, which initiates suckering (Eliasson, 1971(Eliasson, , 1972Sandberg, 1951). Aspen clone size has been shown to be inversely proportional to the number of original seedlings (or 'ortets'), regardless of site conditions (Barnes, 1966).…”

Determination de l age de l epinette noire (picea mariana) en sous-etage de peupliers faux-trembles (populus tremuloides) dans la foret boreale Quebec

“…Selon Zasada et al (1992), les racines latérales pouvant s'étendre sur de grandes distances, la surface occupée par le clone pourrait augmenter immédiatement après chaque perturbation. Le drageonnement confère également un avantage au peuplier faux-tremble sur les espèces compétitrices, les drageons pouvant atteindre plus d'un mètre de hauteur dès la première année (Perala 1990), et arriver à maturité bien avant un semis du même âge grâce aux hydrates de carbone et hormones transférés par le système racinaire ayant survécu au feu (Barnes 1966 La régénération par graine du peuplier faux-tremble est assez méconnue.…”