Changing perspectives on regeneration ecology and genetic diversity in western quaking aspen: implications for silviculture

2012 ◽  
Vol 42 (12) ◽  
pp. 2011-2021 ◽  
Author(s):  
James N. Long ◽  
Karen Mock
Keyword(s):  
Genetic Diversity ◽  
Populus Tremuloides ◽  
Stand Development ◽  
Quaking Aspen ◽  
Conventional View ◽  
High Severity ◽  
Low Expectations ◽  
Recent Developments ◽  
Regeneration Ecology ◽  
Silvicultural Practice

A conventional view of regeneration ecology of quaking aspen ( Populus tremuloides Michx.) in western North American holds that reproduction is strictly vegetative and, except on some marginal sites, only successful following high-severity disturbance. This view has strongly influenced silvicultural treatment of western aspen and has led to low expectations concerning genetic diversity of stands and landscapes. However, recent discoveries are fundamentally altering our understanding of western aspen regeneration ecology and genetics. For example, there are clearly multiple pathways of aspen regeneration and stand development. Research on a variety of fronts indicates that seedling establishment is common enough to be ecologically important and that genetic diversity is substantially greater than previously thought. We review conventional understanding of western aspen and put this into the context of silvicultural practice. We then review recent developments in aspen research and assess the silvicultural implications of these insights.

Cytotype differences in radial increment provide novel insight into aspen reproductive ecology and stand dynamics

2015 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R. Justin DeRose ◽  
Karen E. Mock ◽  
James N. Long
Keyword(s):  
Genetic Diversity ◽  
Populus Tremuloides ◽  
Ring Width ◽  
Stand Development ◽  
Quaking Aspen ◽  
Radial Increment ◽  
Management Actions ◽  
Tree Ring Data ◽  
Development Processes ◽  
Insight Into

High rates of triploidy have recently been described in quaking aspen (Populus tremuloides Michx.) of the Intermountain West, raising questions about the contributions of triploidy to stand persistence and dynamics. In this study, we investigated cytotype differences between diploid and triploid aspen clones using dendrochronological techniques. We used tree-ring data collected from stems within an aspen stand near Fish Lake, Utah, to test for differences in stem age, population structure, growth, and response to climate. This stand contains the well-known Pando clone, which is purported to be the largest organism documented on earth. Our results show that triploid aspen stems grew more rapidly than diploids, and that this difference was most pronounced early in stand development. Growth response to climate varied little between triploids and diploids, where wide rings were associated with cool, moist years, and narrow rings were associated with above-average growing season temperatures. Stand development processes and inherent genetic differences are mechanisms possibly controlling the observed differences in aspen ring width between triploids and diploids. Regardless of the mechanism, the results have specific management implications. Conventional regeneration methods involving coppicing and the associated intermediate treatments will promote asexually reproducing triploids, leading to static or reduced genetic diversity. Enhanced genetic diversity will be favored by management actions that explicitly account for (i) the potential existence of multiple cytotypes within a stand and (ii) the observed differences in growth rates between diploid and triploid individuals.

scholarly journals Surface Fire to Crown Fire: Fire History in the Taos Valley Watersheds, New Mexico, USA

Fire ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 14
Author(s):  
Lane Johnson ◽  
Ellis Margolis
Keyword(s):  
Populus Tremuloides ◽  
Fire History ◽  
Historical Context ◽  
Fire Regimes ◽  
High Elevation ◽  
Severe Drought ◽  
Quaking Aspen ◽  
Conifer Forests ◽  
High Severity ◽  
Historical Photographs

Tree-ring fire scars, tree ages, historical photographs, and historical surveys indicate that, for centuries, fire played different ecological roles across gradients of elevation, forest, and fire regimes in the Taos Valley Watersheds. Historical fire regimes collapsed across the three watersheds by 1899, leaving all sites without fire for at least 119 years. Historical photographs and quaking aspen (Populus tremuloides Michx.) ages indicate that a high-severity fire historically burned at multiple high-elevation subalpine plots in today’s Village of Taos Ski Valley, with large high-severity patches (>640 ha). Low-severity, frequent (9–29-year median interval) surface fires burned on the south aspects in nearby lower elevation dry conifer forests in all watersheds. Fires were associated with drought during the fire year. Widespread fires commonly burned synchronously in multiple watersheds during more severe drought years, preceded by wet years, including fire in all three watersheds in 1664, 1715, and 1842. In contrast, recent local “large” wildfires have only burned within single watersheds and may not be considered large in a historical context. Management to promote repeated low-severity fires and the associated open stand structures is within the historical range of variability in the dry conifer forests of these watersheds. In the high-elevation, subalpine forests, different management approaches are needed, which balance ecological and socioeconomic values while providing public safety.

Effects of residual overstory on aspen development in Minnesota

1999 ◽  
Vol 29 (2) ◽  
pp. 284-289 ◽  
Author(s):  
Ronald D Huffman ◽  
Mary Ann Fajvan ◽  
Petra Bohall Wood
Keyword(s):  
Populus Tremuloides ◽  
Canopy Cover ◽  
Basal Area ◽  
Multiple Regression Model ◽  
Coefficient Of Determination ◽  
Stand Age ◽  
Stem Density ◽  
Stand Development ◽  
Quaking Aspen ◽  
Accurate Representation

The effects of different amounts of residual canopy on stand development of quaking aspen (Populus tremuloides Michx.) were examined in a chronosequence of 32 stands spanning 6-10 years since harvest. Residual canopy covers ranged from 0 to 65%, and residual basal areas ranged from 0 to 14.4 m2/ha. Aspen regeneration densities ranged from 7130 to 43 672 stems/ha. Regeneration stem density was affected primarily by residual canopy cover (R2 = 0.27, P = 0.0001) and secondarily by stand age (R2 = 0.09, P = 0.004). Aspen density decreased significantly with increasing residual canopy cover for 7-year-old and 8-year-old regeneration. Residual canopy cover did not significantly affect aspen density in 9-year-old regeneration (R2 = 0.02, P = 0.579) but was negatively related to total height of 9-year-old codominant aspens (R2 = 0.49, P = 0.002). Canopy cover was a more accurate representation of the amount of shade the regeneration received than the density or basal area of residual trees. However, the low value of the coefficient of determination from a multiple-regression model indicates that considerable variation in stem densities and height was unexplained by residual canopy cover, even though it was the best predictor of the variables measured.

scholarly journals Continental-scale assessment of genetic diversity and population structure in quaking aspen (Populus tremuloides )

2013 ◽  
Vol 40 (9) ◽  
pp. 1780-1791 ◽  
Author(s):  
Colin M. Callahan ◽  
Carol A. Rowe ◽  
Ronald J. Ryel ◽  
John D. Shaw ◽  
Michael D. Madritch ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Populus Tremuloides ◽  
Quaking Aspen ◽  
Continental Scale ◽  
Scale Assessment

scholarly journals Polyploidy influences plant–environment interactions in quaking aspen (Populus tremuloides Michx.)

2017 ◽  
Vol 38 (4) ◽  
pp. 630-640 ◽  
Author(s):  
Burke T Greer ◽  
Christopher Still ◽  
Grace L Cullinan ◽  
J Renée Brooks ◽  
Frederick C Meinzer
Keyword(s):  
Populus Tremuloides ◽  
Quaking Aspen ◽  
Plant Environment

Canopy and edge activity of bats in a quaking aspen (Populus tremuloides) forest

2012 ◽  
Vol 90 (7) ◽  
pp. 798-807 ◽  
Author(s):  
T.W. Pettit ◽  
K.T. Wilkins
Keyword(s):  
Populus Tremuloides ◽  
High Frequency ◽  
Regression Tree ◽  
Low Frequency ◽  
Tree Height ◽  
Quaking Aspen ◽  
Activity Levels ◽  
Forest Canopies ◽  
Bat Activity ◽  
Cart Analysis

Characteristics of edges affect the behavior of species that are active in and near edges. Forest canopies may provide edge-like habitat for bats, though bat response to edge orientation has not been well examined. We sampled bat activity in quaking aspen ( Populus tremuloides Michx.) forest canopies and edges in Heber Valley, Utah, during summer 2009 using Anabat detectors. Categorization and regression tree (CART) analysis of echolocation characteristics (e.g., frequency, duration) identified two guilds based on characteristic frequency (i.e., high- and low-frequency guilds). We used linear regression to compare characteristics of canopy and edge vegetation (e.g., tree height, diameter at breast height) to bat activity levels. Activity levels of high-frequency bats did not respond differentially to edge vegetation; low-frequency bat activity seemed to respond to canopy height. Activity levels of high-frequency bats were significantly greater than low-frequency bats in both edges and canopies. We detected significantly more bat activity in forest edges than in forest canopies, indicating the importance of edges to bats in forests.

Impact of extrafloral nectar availability and plant genotype on ant (Hymenoptera: Formicidae) visitation to quaking aspen (Salicaceae)

2015 ◽  
Vol 148 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Jonathon R. Newman ◽  
Diane Wagner ◽  
Patricia Doak
Keyword(s):  
Populus Tremuloides ◽  
Late Summer ◽  
Early Summer ◽  
Quaking Aspen ◽  
Plant Genotype ◽  
Free Living ◽  
Natural Induction ◽  
Formica Fusca ◽  
Time Of Year ◽  
Nectar Availability

AbstractFor quaking aspen (Populus tremuloides Michaux; Salicaceae) the rate of extrafloral (EF) sugar secretion is increased by defoliation and decreased by drought. Although wholesale blocking of EF nectar has been shown to reduce ant (Hymenoptera: Formicidae) visitation to aspen, the effect of more subtle and realistic variations in nectar availability on ant recruitment is unknown. Working in Alaskan boreal forest (United States of America), we reduced and supplemented EF nectar availability on potted aspen ramets of three genotypes and surveyed visitation by free-living Formica fusca (Linnaeus) (Hymenoptera: Formicidae). Ants were more responsive to a subtle increase in sugar availability than to a decrease. While nectar reduction had no effect on ant visitation, nectar supplementation increased ant visitation to one aspen genotype by 70% during an early summer trial. Average ant visitation to different aspen genotypes varied during the late summer, indicating that aspen genotype can influence attractiveness to ants. We conclude that natural induction of EF secretion in response to herbivory may benefit aspen through improved ant recruitment, though the response is dependent on aspen genotype and time of year. Differences among aspen genets in attractiveness to ants could influence the relative success of genotypes, especially in settings in which aspen regenerates from seed.

scholarly journals Distribution, Morphology, Survival, and Genetics of Aspen (Populus Tremuloides) Seedlings Following the 1988 Yellowstone Fires

1996 ◽  
Vol 20 ◽  
pp. 118-122
Author(s):  
Monica Turner ◽  
Rebecca Reed ◽  
William Romme ◽  
Gerald Tuskan
Keyword(s):  
Populus Tremuloides ◽  
Yellowstone National Park ◽  
National Park ◽  
Plant Competition ◽  
Mineral Soil ◽  
Rare Event ◽  
Weather Conditions ◽  
Elevational Gradient ◽  
Quaking Aspen ◽  
Burned Areas

An unexpected consequence of the 1988 Yellowstone fires was the widespread establishment of seedlings of quaking aspen (Populus tremuloides) in the burned forests, including areas outside the previous range of aspen (Kay 1993; Romme et al. 1997). Although aspen is the most widely distributed tree species in North America (Powells 1965), it is relatively uncommon and localized in distribution within Yellowstone National Park (Despain 1991). Most aspen stands in Yellowstone are found in the lower elevation landscapes in the northern portion of the park, and the species was absent - prior to 1988 -- across most of the high plateaus that dominate the southern and central park area. Aspen in the Rocky Mountain region reproduces primarily by means of vegetative root sprouting. Although viable seeds are regularly produced, establishment of seedlings in the wild is apparently a rare event due to the limited tolerance of aspen seedlings for desiccation or competition (e.g., Pearson 1914; McDonough 1985). In the immediate aftermath of the 1988 Yellowstone fires, there was a brief "window of opportunity" for aspen seedling establishment, as a result of abundant aspen seed production, moist weather conditions in spring and summer, and bare mineral soil and reduced plant competition within extensive burned areas (Jelinski and Cheliak 1992; Romme et al. 1997). We initiated this 3-year study in 1996 to address four questions about the aspen seedlings now growing in burned areas across the Yellowstone Plateau: (1) What are the broad-scale patterns of distribution and abundance of aspen seedlings across the subalpine plateaus of Yellowstone National Park? (2) What is the morphology and population structure -- e.g., proportions of genets (genetic individuals that developed from a single seed) and ramets (vegetative root sprouts produced by a genet) of various ages - in aspen seedling populations? (3) What are the mechanisms leading to eventual persistence or extirpation of seedling populations along an elevational gradient, particularly with respect to ungulate browsing and plant competition? (4) What is the genetic diversity and relatedness of the seedling populations along gradients of elevation and substrate?

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