scholarly journals Herbivory and advance reproduction influence quaking aspen regeneration response to management in southern Utah, USA

2016 ◽  
Vol 46 (5) ◽  
pp. 674-682 ◽  
Author(s):  
Justin M. Britton ◽  
R. Justin DeRose ◽  
Karen E. Mock ◽  
James N. Long
Keyword(s):  
Populus Tremuloides ◽  
Stand Structure ◽  
Site Index ◽  
Site Preparation ◽  
Quaking Aspen ◽  
Preparation Technique ◽  
Primary Control ◽  
Before And After ◽  
Regeneration Response ◽  
Management Recommendations

Recent concern regarding the potential decline of quaking aspen (Populus tremuloides Michx.) forests in the western United States has sparked concern over whether the species can be effectively regenerated. Using a retrospective approach, we quantified the response of regenerating aspen stems to an ordinary set of silvicultural treatments conducted over approximately the past decade in southern Utah, USA. A suite of variables describing stand structure and composition, stand vigor, physiographic factors, herbivore pressure, and treatment types were measured to predict the possible controls, as well as their relative importance, on aspen regeneration. Results suggested that aspen regeneration was most strongly related to browsing pressure, site preparation technique, and the presence of advance reproduction before treatment, which is a novel finding. Secondary predictors included elevation, site index, and overstory conditions, which are generally characteristics of stand vigor. Management recommendations based on our results should recognize the strong primary control that browsing pressure exerts on regeneration. First, the height of advance reproduction is inherently dependent on antecedent herbivory and also indicative of present browsing and should be assessed before treatment. Second, the most effective site preparation techniques, namely broadcast burning and browsing reduction, will directly reduce browsing pressure, assuming ungulate populations are not too large. Any management targeting timely and effective aspen regeneration should incorporate monitoring and (or) controlling browsing pressure, both before and after treatment.

Development of the pistillate flower of Populus tremuloides following controlled pollination

1972 ◽  
Vol 50 (12) ◽  
pp. 2503-2509 ◽  
Author(s):  
Gilbert H. Fechner
Keyword(s):  
Populus Tremuloides ◽  
Pistillate Flower ◽  
Natural Material ◽  
Quaking Aspen ◽  
Controlled Pollination ◽  
Sectioned Material ◽  
Before And After ◽  
Unfertilized Ovules

Quaking aspen branches bearing female inflorescences were forced, artificially pollinated, and grown in water in the laboratory at 25 °C. The pistillate flowers developed normally to produce normal seeds in about 2 weeks. Sectioned material, which had been fixed at different times before and after pollination, revealed that the megagametophyte was in the four-nucleate stage at receptivity of the stigmas, and that it developed through the stages that Nagaraj (1952) described for natural material. Fertilization probably occurred between 72 and 120 h after pollination. Unfertilized ovules within ovaries containing one or more fertilized ovules developed normally for 1 week after pollination, but they began to degenerate soon thereafter.

Fungal colonization of aspen roots following mechanical site preparation

2003 ◽  
Vol 33 (12) ◽  
pp. 2372-2379 ◽  
Author(s):  
J M Pankuch ◽  
P V Blenis ◽  
V J Lieffers ◽  
K I Mallett
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pathogenic Fungi ◽  
White Spruce ◽  
Site Preparation ◽  
Fungal Colonization ◽  
Preparation Technique ◽  
Mechanical Site Preparation ◽  
Armillaria Ostoyae ◽  
Root Tissues

Fungal colonization of aspen (Populus tremuloides Michx.) roots was examined in boreal mixedwood sites that were mechanically site prepared 8–10 years earlier for white spruce (Picea glauca (Moench) Voss) regeneration using disc trenchers or ripper plows. A survey of root wounds determined that Armillaria sinapina Bérubé & Dessureault and Armillaria ostoyae (Romagn.) Herink were both wound pathogens of aspen; however, A. sinapina was more frequently associated with wounds than was A. ostoyae. Armillaria ostoyae was more common on unwounded root tissues. Sixty percent of wounds infected by A. sinapina were not compartmentalized and the likelihood of an A. sinapina infection did not increase with increasing wound size. Pathogenic fungi other than Armillaria were rarely associated with root wounds. Sever wounds were associated with furrows; scrape wounds were located both along and between furrows irrespective of the site-preparation technique (ripper plow vs. disk trencher).

Primary Stability of Short Implants Inserted Using Piezoelectric or Drilling Systems: An In Vitro Comparison

2019 ◽  
Vol 45 (4) ◽  
pp. 259-266
Author(s):  
Claudio Stacchi ◽  
Matteo De Biasi ◽  
Lucio Torelli ◽  
Massimo Robiony ◽  
Roberto Di Lenarda ◽  
...  
Keyword(s):  
Cancellous Bone ◽  
Operative Time ◽  
Primary Stability ◽  
Site Preparation ◽  
Preparation Technique ◽  
Implant Stability ◽  
Implant Stability Quotient ◽  
Custom Made ◽  
Implant Site Preparation

The primary objective of the present in vitro study was to evaluate the influence of implant site preparation technique (drills vs ultrasonic instrumentation) on the primary stability of short dental implants with two different designs inserted in simulated low-quality cancellous bone. Eighty implant sites were prepared in custom-made solid rigid polyurethane blocks with two different low cancellous bone densities (5 or 15 pounds per cubic foot [PCF]), equally distributed between piezoelectric (Surgysonic Moto, Esacrom, Italy) and conventional drilling techniques. Two short implant systems (Prama and Syra, Sweden & Martina) were tested by inserting 40 fixtures of each system (both 6.0 mm length and 5.0 mm diameter), divided in the four subgroups (drills/5 PCF density; drills/15 PCF density; piezo/5 PCF density; piezo/15 PCF density). Insertion torque (Ncm), implant stability quotient values, removal torque (Ncm), and surgical time were recorded. Data were analyzed by 3-way ANOVA and Scheffé's test (α = 0.05). With slight variations among the considered dependent variables, overall high primary implant stability was observed across all subgroups. Piezoelectric instrumentation allowed for comparable or slightly superior primary stability in comparison with the drilling procedures in both implant systems. The Prama implants group showed the highest mean reverse torque and Syra implants the highest implant stability quotient values. Piezoelectric implant site preparation took prolonged operative time compared to conventional preparation with drills; among the drilling procedures, Syra system required fewer surgical steps and shorter operative time.

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 Stand density biases the estimation of the site index especially on dry sites

2020 ◽  
Author(s):  
Astor Toraño Caicoya ◽  
Hans Pretzsch
Keyword(s):  
Norway Spruce ◽  
Stand Structure ◽  
Local Density ◽  
Generalized Additive Models ◽  
Stand Density ◽  
Moisture Stress ◽  
Site Index ◽  
Additive Models ◽  
Climate Conditions ◽  
Density Control

The Site Index (SI) has been widely used in forest management and silviculture. It relies on the assumption that the height of dominant trees in a stand is independent from the local density. However, research on climate change suggests that under certain moisture stress conditions, this may not hold. Here, based on 29 plots from 5 long-term research experiments, we have tested the effect of local stand density on the SI of Norway spruce (Picea abies (L.) H. Karst). With generalized additive models (GAMM), we analyzed the effect of stand structure and climate predictors on SI. The two evaluated models revealed that local stand density and age had a significant effect on SI (p≤0.001 ), showing a clear negative trend especially significant on sites with poor and dry soils, which may reduce the site index by a maximum of approximately 4 m for an increase in density between 400 and 600 trees/ha. We stress that the physiological characteristics of Norway spruce, flat-rooting system and xeromorphism, especially when growing in pure stands, may explain these effects. Thus, density control and growth in mixtures may help to reduce the water stress and losses in height growth under future climate conditions.

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?

scholarly journals A Landscape Approach to Aspen Restoration: Understanding the Role of Biophysical Setting in Aspen Community Dynamics

2002 ◽  
Vol 26 ◽  
pp. 97-102
Author(s):  
Kathryn Brown ◽  
Andrew Hansen ◽  
Robert Keane ◽  
Lisa Graumlich
Keyword(s):  
Populus Tremuloides ◽  
Community Dynamics ◽  
Rocky Mountain ◽  
Small Sample ◽  
Quaking Aspen ◽  
Climatic Fluctuations ◽  
Conifer Encroachment ◽  
Considerable Debate ◽  
Fire Exclusion

Considerable debate surrounds the persistence of quaking aspen (Populus tremuloides) communities in western North America. Loss of aspen cover has been documented in several studies in various Rocky Mountain ecosystems (Loope and Gruel 1973; Romme et al. 1995; Renkin and Despain 1996; Wirth et al. 1996; Baker et al. 1997; Kay 1997; Bartos and Campbell 1998; White et al. 1998; Gallant et al. 2003). Explanations for loss of aspen include conifer encroachment, fire exclusion, herbivory, and climatic fluctuations (Loope and Gruell 1973; Mueggler 1985; Bartos et al. 1994; Romme et al. 1995; Kay 1997; White et al. 1998). However, many studies documenting aspen decline have been geographically limited or based on a small sample of subjectively chosen stands (Barnett and Stohlgren 2001; Hessl 2002; Kaye et al. 2003).

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