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.

Effects of Long-Term Military Training Traffic on Forest Vegetation in Central Minnesota

1996 ◽  
Vol 13 (4) ◽  
pp. 157-163 ◽  
Author(s):  
Thomas A. Greene ◽  
Thomas J. Nichols
Keyword(s):  
Military Training ◽  
Canopy Cover ◽  
Basal Area ◽  
Fold Increase ◽  
Bare Soil ◽  
Stem Density ◽  
Quaking Aspen ◽  
Area Reduction ◽  
Soil Area

Abstract We studied vegetation on traveled and untraveled loamy sands on military training land in central Minnesota to identify traffic-induced differences in species composition, cover, diversity, growth rates, and tree condition. Long-term military traffic resulted in a 23% reduction in overstory basal area, a 14% reduction in canopy cover, a 43% reduction in overstory stem density, and a 20% reduction in overstory species diversity compared with adjacent untraveled areas. Most of the overstory basal area reduction was accounted for by a 78% reduction in quaking aspen basal area. Crown dieback was not significantly affected by traffic. Midstory tree and shrub density was 70% lower on traveled areas. Herbaceous vegetation was denser and more diverse in traveled areas. Traffic caused a six-fold increase in bare soil area on sloping soils, but had no effect on bare soil area on level sites. Our data suggest that moderate, long-term traffic on loamy sand soils results in a relatively stable system which can be thought of as in equilibrium between traffic, natural regenerative forces, and management activities. We caution managers that quaking aspen may decline under traffic, and remind them of the risk of erosion on traveled slopes. North. J. Appl. For. 13(4): 157-163.

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.

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.

scholarly journals Impact of logging intensity on stem density, basal area and biodiversity indices five years after logging in a Caspian hardwood forest

2017 ◽  
Vol 63 (No. 4) ◽  
pp. 167-172 ◽  
Author(s):  
Behjou Farshad Keivan ◽  
Mollabashi Omid Ghaffarzadeh
Keyword(s):  
Canopy Cover ◽  
Basal Area ◽  
Diversity Indices ◽  
Stem Density ◽  
Forest Biodiversity ◽  
Northern Iran ◽  
Positive Effects ◽  
Biodiversity Indices ◽  
Harvesting Intensity ◽  
Evenness Indices

The aim of the present study was to analyse the impacts of different logging intensities after five years from logging including non-logged, low (3.4 felled stems per hectare), medium (5.2 felled stems per hectare) and high (7.1 felled stems per hectare) treatments on stem density, basal area, canopy cover, and forest biodiversity indices. The study area was located in northern Iran. Data was collected on a set of 120 circular plots with 5 m radius from both non-logged and logging areas. Stem density, basal area, and percentage of canopy cover were measured. Biodiversity study was done by measuring two diversity indices including Simpson’s and Shannon-Wiener’s, two richness indices including Margalef’s and Menhinick’s and two evenness indices including Pielou’s and Hill’s indices. The results indicated that the treatment with the medium logging intensity was found to cause the highest amount of positive effects on stem density, basal area, and biodiversity indices. It is concluded that harvesting intensity should be limited to a medium level (approximately 5 felled trees per hectare) during each logging operation to improve forest biodiversity indices.

scholarly journals Contrasting Release Approaches for a Mixed Paper Birch (Betula papyrifera)–Quaking Aspen (Populus tremuloides) Stand

2008 ◽  
Vol 25 (3) ◽  
pp. 124-132 ◽  
Author(s):  
Eric K. Zenner ◽  
Klaus J. Puettmann
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Complete Removal ◽  
Quaking Aspen ◽  
Betula Papyrifera ◽  
Mixed Stands ◽  
Early Release ◽  
Paper Birch ◽  
Area And Volume

Abstract Early release from competitors can be used to influence the species composition, quality, and rate of development of young stands. Release strategies can vary in intensity, ranging from complete removal of competitors and infrequent future entries (early, heavy, infrequent [EHI]) to lighter entries that are repeated more frequently (early, light, often [ELO]). It is unclear, however, which strategy is more successful for producing high-quality birch sawtimber (Betula papyrifera Marsh.) in mixed stands with aspen (Populus tremuloides Michx.). We evaluated the effects of various release intensities on the growth and mortality of a 16–18-ft-tall natural aspen–paper birch stand in Minnesota following density reductions from 1,500–3,000 trees ac−1 (trees per acre [TPA]) to 750 (ELO750), 500 (EHI500), and 250 (EHI250) TPA. After 6 years, paper birch was overtopped by aspen and contributed only 14% of basal area in control plots, but it occupied all diameter classes and contributed 77–87% of basal area in release plots. The basal area and volume of all paper birch and of only paper birch crop trees (100 largest TPA) were highest in lightly released ELO750 and lowest in control plots. Growth of mean quadratic diameter, basal area, and volume of paper birch was 2–3 times higher in release plots but independent of release intensity. Early release is necessary to maintain paper birch dominance, but there is no short-term advantage among treatment intensities. Long-term growth simulations using the Forest Vegetation Simulator suggest that merchantable timber production was unaffected by release strategy but that the EHI250 strategy produced the most birch sawtimber (40 times as much as in ELO750).

Age Distribution and Reproduction of Intermountain Aspen Stands

1989 ◽  
Vol 4 (2) ◽  
pp. 41-45 ◽  
Author(s):  
Walter F. Mueggler
Keyword(s):  
Populus Tremuloides ◽  
Decision Model ◽  
Age Distribution ◽  
Older Age ◽  
Stand Age ◽  
Quaking Aspen ◽  
Mature Trees ◽  
Management Intervention ◽  
Mature Stands ◽  
Direct Management

Abstract Stand age and sucker reproduction was measured in 713 aspen-dominated forest plots on nine National Forests in Utah, southeastern Idaho, and western Wyoming. About 95% of the quaking aspen (Populus tremuloides Michx.) stands are dominated by mature or over-mature trees. Almost one-sixth are in the 120-year or older age class and can be expected to deteriorate rapidly. The oldest aspen measured was 222 years. Stands in central and southern Utah are generally older than those in southeastern Idaho and western Wyoming. A fourth of the stands had more than 2,000 suckers per acre; half had fewer than 800 per acre. Approximately a third of the essentially pure (i.e., not invaded by conifers), mature or over-mature stands may experience regeneration problems because they contain less than 500 suckers per acre. A decision model is presented that will assist managers in identifying stands that require direct management intervention to ensure their survival as aspen-dominated communities. West J. Appl. For. 4(2):41-45, April 1989.

Lichen chronosequences (postfire and postharvest) in lodgepole pine (Pinus contorta) forests of northern interior British Columbia

2001 ◽  
Vol 79 (12) ◽  
pp. 1449-1464 ◽  
Author(s):  
Darwyn S Coxson ◽  
Janet Marsh
Keyword(s):  
British Columbia ◽  
Forest Floor ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Canopy Cover ◽  
Basal Area ◽  
Stand Development ◽  
Area Index ◽  
Floor Surface ◽  
Fire Origin

Lichen community development was examined in a postfire chronosequence from lodgepole pine (Pinus contorta Dougl. ex Loud var. latifolia Engelm.) forests in the Omineca region of north-central British Columbia and in stands originating from logging in the early 1980s. Fire-origin stands showed dense regeneration of pine and widespread growth of acrocarpous mosses such as Polytrichum spp. As canopy thinning progressed, Cladonia spp. lichens initiated development at the forest floor surface. By 50–100 years after stand origin, Cladina mitis and Cladina rangiferina dominated at the forest floor surface, remaining at high cover values well into the second century of stand development. Late seral stages of stand development (approximately 150+ years) showed increasing basal area and canopy cover of lodgepole pine, with feathermoss mats (e.g., Pleurozium schreberi) replacing terrestrial lichens at the forest floor surface. Stand ordinations confirmed these groupings of species. Stand structural factors that correlate best with lichen mat development include tree density, basal area, and canopy cover. Changes in the leaf area index and associated litterfall loading appear to precipitate the replacement of terrestrial lichen mats in "old-growth" stands. Interestingly, this trend was reversed in mature stands where winter harvesting of trees removed canopy cover without disturbing the forest floor surface. Lichen cover in these sites, 15 years after harvest, exceeded that of comparably aged fire-origin stands. Summer harvesting (with a presumed greater disturbance of soils) did not trigger a similar rebound of lichen communities. Instead, vascular plants appeared to invade these sites, following a seral sequence different from that occurring in fire-origin stands.Key words: terrestrial lichens, pine woodlands, caribou habitat.

Winter selection of roost sites by ruffed grouse during daytime in mixed nordic-temperate forests, Quebec, Canada

2007 ◽  
Vol 85 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Pierre Blanchette ◽  
Jean-Claude Bourgeois ◽  
Sylvain St-Onge
Keyword(s):  
Canopy Cover ◽  
Basal Area ◽  
Stem Density ◽  
Ruffed Grouse ◽  
Multinomial Models ◽  
Stand Type ◽  
Logistic Regressions ◽  
Roosting Behavior ◽  
Selection Of ◽  
Habitat Variables

We determined the categories of roost sites used by ruffed grouse ( Bonasa umbellus (L., 1766)) during daytime in winter from 245 radiotelemetric locations of 26 adult females. We conducted our study in the Réserve faunique de Portneuf, located in a mixed nordic-temperate softwood–hardwood forest in Quebec, Canada. We evaluated the effects of weather, snow, and habitat variables on the incidence of snow burrowing, tree roosting, and on-snow roosting using mixed multinomial models, ANOVA, and logistic regressions. The best logistic regression model of snow burrowing probability was identified using the Akaike path. The incidence of each category of roost sites was 41.2% tree roosts, 36.3% snow burrows, and 22.4% on-snow roosts. Coniferous canopy closure and depth of fluffy snow were the variables that influenced roosting behavior the most. Probability of snow burrowing increased with compaction depth and decreased with coniferous cover. Probability of tree roosting increased with temperature. On-snow roosts had a denser lateral obstruction than snow burrows, whereas tree roosts had a greater coniferous basal area, stem density, and canopy cover than snow burrows. Stand type also influenced the incidence of each category of roost sites, snow burrows dominating in deciduous stands and tree roosts dominating in mixed and coniferous stands.

scholarly journals Successional dynamics in Neotropical forests are as uncertain as they are predictable

2015 ◽  
Vol 112 (26) ◽  
pp. 8013-8018 ◽  
Author(s):  
Natalia Norden ◽  
Héctor A. Angarita ◽  
Frans Bongers ◽  
Miguel Martínez-Ramos ◽  
Iñigo Granzow-de la Cerda ◽  
...  
Keyword(s):  
Land Use ◽  
Time Series ◽  
Forest Succession ◽  
Initial Conditions ◽  
Basal Area ◽  
Species Density ◽  
Stand Age ◽  
Stem Density ◽  
Neotropical Forests ◽  
Study Sites

Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes—stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration.

Building a dynamic growth model for trembling aspen in western Canada without age data

2013 ◽  
Vol 43 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Oscar García
Keyword(s):  
Populus Tremuloides ◽  
Site Occupancy ◽  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Site Quality ◽  
Diameter Distribution ◽  
Stand Age ◽  
Parameter Estimates ◽  
Trembling Aspen

A biologically inspired whole-stand growth and yield model was developed for even-aged thinned or unthinned stands dominated by trembling aspen (Populus tremuloides Michx.). The estimation used permanent sample plot data from British Columbia, Alberta, Saskatchewan, and Manitoba, supplemented by published site index and young stand information. An ingrowth imputation procedure was devised to facilitate the use of plot measurements where small trees are not measured. Two published site index models were closely approximated by a simple age-base invariant equation. Good parameter estimates for mortality and basal area growth were obtained without using age observations, which were unreliable or missing. Four differential equations describe the dynamics of top height, trees per hectare, basal area, and a site occupancy factor. Current values of these variables are used to estimate total and merchantable volumes up to any diameter limit and diameter distribution parameters. When an independent source of site quality estimates is available, the final model does not require stand age knowledge for making growth and yield predictions.

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