Effects of stand age and litter removal on the regeneration of Populus tremuloides

Abstract

Abstract. The objective of this study was to demonstrate the regeneration by root suckering of Populus tremuloides (quaking aspen) along a successional sere at Lake Duparquet in NW Québec with six sites of different ages ‐ 46, 74, 120, 143, 167 and 230 yr since last fire. In 1990, in each of the sites, one 20 m x 20 m plot was cut. In each plot, 4‐m2 plots were selected, both control and with litter removed. The number of suckers and their height were estimated for each plot in 1991, 1992 and 1993. Results showed that sucker production was not related to the number of P. tremuloides before the clearcut, but it was related to litter whereby increasing cover lowered the production. The number of suckers produced in the control plots did not show any significant difference along the successional sere for any of the three years. Scarified plots had more suckers than control plots, and this increase was more pronounced and significantly different for the younger stage. Regression analysis for the 1991 and 1992 data showed that sucker number in scarified plots decreased with increasing seral stage age. Mortality, after three growing seasons, was about 60% for all plots and was not affected by seral stage and treatment. We suggest that removal of litter in scarified plots exposed the roots to higher temperatures and caused wounds, both of which may have stimulated the production of suckers in young seral stages.

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

“…The effect of vegetation cover may suppress regeneration in two ways: by increasing competition for available growing space and soil moisture; by lowering soil temperatures beneath heavily-vegetated areas, which in turn may prevent auxin levels in underlying aspen roots to be altered, and thus fail to initiate suckering (MacIsaac, et al, 2006). This is supported by the findings of Lavertu, et al, (1994), who showed that litter removal enhanced regeneration production in aspen stands in northwestern Quebec. Late spring frost may also suppress regeneration (Wolken, et al, 2009).…”

Structure, spatial distribution and competition in mixed jack pine (Pinus banksiana) stands on clay soils of eastern Canada

“…White birch stem patterns is expected to be clumpy due to its stump sprout origin and that of aspen is expected to be more random since it can root sprout as individual stems at a long distance from the other trees of its parent clone [27]. Consequently, aspen stems will be competing with a greater number of jack pine than birch stems.…”

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

“…Le peuplier faux-tremble, qui se régénère très rapidement et efficacement par drageonnement après feu (Horton et Hopkins 1965;Heeney 1980;Brown et Debyle 1987;Lavertu et al 1994), a tôt fait de surpasser en hauteur les espèces qui lui sont associées (Ahlgren 1959;Bartos et al 1991;Bergeron et Charron 1994). Malgré l'absence d'étude portant précisément sur la période d'établissement de l'épinette noire présente sous le peuplier en peuplements mixtes, quelques auteurs suggèrent une installation contemporaine des deux espèces, l'étagement étant créé par des taux de croissance différents et non par une invasion en sous-couvert de l'épinette (MacLean 1960;Dix et Swan 1971;Day et Woods 1977;Kelsah étal.…”

“…La mort des tiges stimule la production de drageons en altérant l'équilibre hormonal du système racinaire ainsi que les régimes de température et de lumière au sol (Farmer 1962;Hungerford 1988). Selon Bartos et al (1983), Mercier (1992) et Lavertu et al (1994), l'installation des drageons est complétée en deux ans. Ils apparaissent en groupes de 1 à 15 tiges à proximité des tiges mortes, où la densité des racines est élevée (Schier 1975).…”

“…Malgré le fait que l'espèce semble avoir un grand potentiel d'ensemencement, avec une production très abondante de petites graines se disséminant sur de grandes distances (Perala 1990), l'installation par graine est assez rare (MacLean 1960;Barnes 1966;Lavertu et al 1994). Ceci est probablement dû au fait que les graines ne demeurent viables que pendant une très courte période de temps et qu'elles sont très sensibles aux variations d'humidité, comme les jeunes semis (Moss 1938).…”