Philip G. Comeau

Philip G. Comeau
University of Alberta | UAlberta · Department of Renewable Resources

Ph.D.

About

150
Publications
31,123
Reads
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Citations
Introduction
Phil Comeau is an Emeritus Professor with the Department of Renewable Resources, University of Alberta. Phil conducts research in Silviculture and Forest Ecology. Studies include examination of succession following oilsands reclamation, silviculture options for boreal mixedwood stands, effects of vegetation management practices on plant community diversity and stand composition. Phil is also involved in the development and refinement of the Mixedwood Growth Model for use in estimating yield and structural characteristics of western Canadian boreal, montane, and subalpine forests.
Additional affiliations
April 2000 - present
University of Alberta
Position
  • Professor (Full)
January 1994 - March 2000
Ministry of Forests
Position
  • Research Leader - Forest Dynamics
February 1988 - December 1993
Ministry of Forests
Position
  • Technical Advisor - Forest Vegetation Management
Education
September 1981 - March 1986
University of British Columbia - Vancouver
Field of study
  • Ecosystem production ecology

Publications

Publications (150)
Presentation
Full-text available
This presentation provides a brief description of the Mixedwood Growth Model (MGM) and presents results from simulations examining: 1) yield implications of low densities of trembling aspen regeneration and of fill planting of white spruce in these stands; 2) effects of ranges of aspen and spruce on yield; and 3) effects of variable (mature tree) r...
Technical Report
Full-text available
This Mixedwood Growth Model (MGM) Best Practices document is intended to help users deploy MGM in common growth and yield contexts. It provides an overview of inputs required to initialize MGM and recommendations on their use in the model.
Article
Full-text available
Competitive exclusion can lead to a loss of species diversity within small forest gaps. Thus, it poses a potential concern for mixed species regeneration following strip-cut harvesting in the species rich interior moist forests of British Columbia. In this study, we compare nine tree species widely used in reforestation for their growth rates along...
Chapter
Full-text available
Monitoring of forest response to gradual environmental changes or abrupt disturbances provides insights into how forested ecosystems operate and allows for quantification of forest health. In this chapter, we provide an overview of Smartforests Canada, a national-scale research network consisting of regional investigators who support a wealth of ex...
Article
This study examines the effects of climate, site index and structural diversity on maximum size-density relationships (MSDRs) for Korean red pine (Pinus densiflora Siebold & Zucc.) and Mongolian oak (Quercus mongolica Fisch. ex Ledeb.) which are widely distributed and abundant across South Korea. We used data collected between 2006 and 2015 from th...
Article
While deployment of white spruce (Picea glauca (Moench) Voss) from seed orchards is increasing in Alberta, genetic gain is only considered in pure spruce stands due to uncertainties in measuring yields in mixedwood stands. To better understand the performance of improved spruce in mixedwood stands, we compared the effects of inter-specific competit...
Technical Report
Full-text available
This report presents results from validation of the Mixedwood Growth Model (MGM21 VS8.2.21.39/Rev6378) using the 2020 Provincial Growth and Yield Initiative (PGYI) dataset from Alberta, Canada.
Article
Full-text available
A few studies in young mixedwood stands demonstrate that precommercial thinning of aspen at early ages can improve the growth of spruce and increase stand resilience to drought. However, information on tree and stand responses to thinning in older mixedwood stands is lacking. To address this need, a study was initiated in 2008 in Alberta, Canada in...
Technical Report
Full-text available
This note summarizes results from a recent update of the height and diameter growth models for black spruce used in the Mixedwood Growth Model (MGM21).
Technical Report
Full-text available
This research note summarizes methods and results from the fitting of maximum density-size relationships for use in the Mixedwood Growth Model (MGM21). For this purpose quantile regression was used to develop a model based on data from 3652 permanent sample plots in Alberta, British Columbia, Yukon, Manitoba, Northwest Territories, Saskatchewan and...
Article
Full-text available
This study examined branch diameter, number of whorls, and number of branches in the lower 2 m of the stems of white spruce growing in pure stands and in mixture with a range of densities of trembling aspen. Data were collected from two study sites located north of Big River Saskatchewan, which were regenerated following clearcutting in 1992 and th...
Technical Report
Full-text available
This note provides updated survival probability models for seven western boreal tree species. These survival functions, which include tree size (DBH), competition from larger deciduous, large spruce and larger pine, and Climate Moisture Index (CMI), were developed using PSP data from across western Canada and are used in MGM21.
Article
Full-text available
Drought stress associated is causing increased mortality and reduced growth of trees in drier portions of the boreal forests of western Canada with both warming and drought expected to increase over the coming decades. While thinning is often shown to reduce drought stress, there is little information on its effects in stands comprised of mixtures...
Article
In the face of anticipated climate change, growth models require modifications to effectively model likely future growth and survival of trees and stands. To support incorporation of climate effects in the Mixedwood Growth Model (MGM), we developed climate-sensitive mixed effects models for lodgepole pine (Pinus contorta Douglas ex Loudon), jack pi...
Article
The understory is an important reservoir of plant biodiversity and a driver of ecological processes in Canada's boreal forest, making its re-establishment following reclamation of oil sands mines crucial. This study examined understory plant community development with time using two cover soil types (forest floor mineral mix (FMM) and peat mineral...
Technical Report
Full-text available
While juvenile white spruce height and diameter growth equations in MGM18 include effects of deciduous and pine competition, they do not consider effects of competition from taller spruce. This has led to MGM overestimating growth of juvenile (<4 cm dbh) white spruce which is most notable following partial cutting treatments such as understory prot...
Technical Report
Full-text available
This note provides tabular summaries of site index values for western boreal and foothills ecosystem classification units (Site Series in BC and Ecosites in British Columbia, Alberta, Saskatchewan and Manitoba) for use in estimating site index for stands being modelled. These are based on information published in field guides for ecological site cl...
Article
Understanding interactions between competition and climate in relation to its effects on individual tree growth is crucial to the development of climate sensitive growth models required for modelling boreal forest succession in a changing climate. We used data from permanent growth and yield sample plots in western Canada and Alaska to investigate...
Article
Understanding the effects of reclamation treatments on plant community development is an important step in setting realistic indicators and targets for reclamation of upland oil sands sites to forest ecosystems. We examine trends in cover, richness, evenness and community composition for four cover soil types (clay over overburden, clay over tailin...
Article
Full-text available
Trembling aspen (Populus tremuloides Michx.) is experiencing increased drought stress resulting from climate change together with increases in damage by forest tent caterpillar and other defoliators. Coupled with effects of intraspecific and interspecific competition this could result in an overall decrease in survival and growth. In order to impro...
Technical Report
Full-text available
Site index is used as the primary estimator of potential productivity in the Mixedwood Growth Model (MGM) and in other models. Site index can be readily determined for stands where there are healthy top height trees close to reference age (50 years is widely used as the reference age in western Canada) for the species of interest. However, site ind...
Technical Report
Full-text available
Site index is difficult to determine when healthy top height trees are not present, and where estimates of site index are required for species not currently present in the stand. In addition, site index estimates can be unrealiable when trees are less than 7 m tall or are very old. Estimating site index of one species from that of another species h...
Presentation
Full-text available
Discussion on regeneration options for sustainable management of Alberta's boreal forests. This was a podcast that is part of the "Your Forests" series facilitated by Matt Kristoff. The full series of podcasts are available at: https://yourforestpodcast.com.
Article
A knowledge of how light varies within gaps is fundamental to understanding variation in survival and growth of regenerating trees. Simple indices based on a small number of instantaneous measurements by portable sensors or cameras are widely used for this purpose. But the effectiveness of these indices for estimating growing season transmittance i...
Article
The effects of competition and climate on the growth of black spruce (Picea mariana (Mill.) BSP.) were examined using long term measurement data collected across the western Canadian boreal forest. Non-linear mixed effect models were developed and used to examine tree growth responses to competition and climate across the range of upland forest typ...
Article
Canopy openings resulting from tree death provide opportunities for shade intolerant species such as aspen to establish and grow in the understory leading to development of aspen stands with multiple canopy layers and multiple cohorts. Stand structure is likely to influence survival probability since it will lead to differences in competition inten...
Article
Stockpiling of cover soil can influence vegetation development following reclamation. Cover soil, comprising the upper 15 to 30 cm of the surface material on sites scheduled for mining, is commonly salvaged prior to mining and used directly or stockpiled for various lengths of time until it is needed. Salvaging and stockpiling causes physical, chem...
Article
Advanced regeneration of black spruce and white spruce are common in lodgepole pine dominated stands of Alberta. These economically important species have the potential to replace lodgepole pine trees that are killed by mountain pine beetle (MPB). The growth responses of both species of spruce after overstory lodepole pine mortality were examined u...
Article
Mixtures of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) are a prominent component of the boreal forests of western Canada. Overyielding, indicating higher productivity in mixtures than in monocultures, has been observed in mature stands but has not been examined in young stands (<30 years old) in this...
Article
Red alder (Alnus rubra [Bong.]), is the most common broadleaf species in the Pacific Northwest, and is widely distributed as a component of mixed stands with conifers. It rapidly overtops associated juvenile conifers and is a strong competitor. However, red alder is also a symbiotic nitrogen fixer and can contribute to improvement in soil nitrogen,...
Article
Tree growth of boreal forest plays an important role on global carbon (C) cycle, while tree growth in the western Canadian boreal mixed forests has been predicted to be negatively affected by regional drought. Individual tree growth can be controlled by many factors, such as competition, climate, tree size and age. However, information about contri...
Article
Understanding how reclamation practices influence plant community assembly and succession is an important step in developing realistic indicators and targets for reclamation of oil sands mine sites to upland forest ecosystems. We currently have a poor understanding of factors affecting plant community assembly and succession in reclaimed oil sands...
Article
Full-text available
The purpose of this study was to evaluate the relationships between environmental factors and the site index (SI) of trembling aspen, lodgepole pine, and white spruce based on the sampling of temporary sample plots. LiDAR generated digital elevation models (DEM) and wet areas mapping (WAM) provided data at a 1 m resolution for the study area in Alb...
Article
Full-text available
Glyphosate herbicide is widely used to control bluejoint reedgrass (Calamagrostis canadensis (Michx.) Beauv.), trembling aspen (Populus tremuloides Michx.), and other competing species in regenerating white spruce (Picea glauca (Moench) Voss) plantations in Alberta, Canada. In 2004, we initiated a study to examine the effects of the aerial applicat...
Article
Maximum size-density relationships (MSDR) are examined in stands of trembling aspen (Populus tremuloides Michx.) in the boreal forest region of Alberta and Saskatchewan, Canada. Stochastic frontier function regression was used to develop the static self-thinning line, and a linear mixed-effects model was used to estimate the average dynamic self-th...
Article
Full-text available
Understanding the complex interactions of competition, climate warming-induced drought stress, and photosynthetic productivity on the radial growth of trees is central to linking climate change impacts on tree growth, stand structure and in general, forest productivity. Using a mixed modeling approach, a stand-level photosynthetic production model,...
Article
Full-text available
We developed individual tree deterministic growth and mortality models for jack pine (Pinus banksiana Lamb.) using data from permanent sample plots in Alberta, Saskatchewan and Manitoba, Canada. Height and diameter increment equations were fitted using nonlinear mixed effects models. Logistic mixed models were used to estimate jack pine survival pr...
Article
Insects, diseases, fire and drought and other disturbances associated with global climate change contribute to forest decline and mortality in many parts of the world. Forest decline and mortality related to drought or insect outbreaks have been observed in North American aspen forests. However, little research has been done to partition and estima...
Presentation
Full-text available
Mixtures of trembling aspen and white spruce are an important component of Canada’s western boreal forests. Commonly used silviculture practices in the region can potentially lead to simplification of these forests to monocultures. In this presentation I explore several silviculture options for managing mixtures of trembling aspen and white spruce.
Article
Full-text available
Many studies have already addressed the existence of unstable and nonlinear relationships between radial growth of white spruce (Picea glauca) and climate variables in boreal forests along the high latitudes (>60° N). However, along the mid-latitudes, the climate-growth relationship is still poorly understood. In this study, we used a network of ri...
Article
Full-text available
Adequate and advance knowledge of the response of forest ecosystems to temperature-induced drought is critical for a comprehensive understanding of the impacts of global climate change on forest ecosystem structure and function. Recent massive decline in aspen-dominated forests and an increased aspen mortality in boreal forests have been associated...
Article
Carbon isotope ratio (δ¹³C) has been used as an indicator of water stress because plants discriminate less against¹³C when under stress. The depth-to-water (DTW) topographic index provides an estimation of soil moisture based on topographic position and other characteristics of a site. To evaluate whether DTW and carbon isotope discrimination were...
Article
Full-text available
The depth-to-water (DTW) index is defined as the cumulative slope along the least-cost pathway from any cell in the landscape to the nearest flow channel. The flow channel network is determined by the flow initiation area selected, allowing the representation of various geological and topographical attributes of the landscape. We used data from 125...
Article
Full-text available
Planting white spruce (Picea glauca (Moench) Voss) under established aspen (Populus tremuloides Michx.) stands has substantial potential for regenerating mixedwood ecosystems in the western Canadian boreal forest. The presence of an aspen overstory serves to ameliorate frost and winter injury problems and suppresses understory vegetation that may c...
Article
Full-text available
The relationships between white spruce radial increment and wood properties were investigated in relation to tree and stand attributes using data from mature white spruce stands in the boreal forest of western Canada that experienced a range of shelterwood treatments. The model with the highest predictive ability was radial increment (adj-R2 = 67%)...
Article
Full-text available
The western Canadian mixedwood boreal forests were projected to be significantly affected by regional drought. However, drought degrees were spatially different across elevations, longitudes and latitudes, which might cause inconsistent tree growth responses to climate change in different sub-regions within western Canada. In this way, regional cla...
Article
Full-text available
Intimate mixtures of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) are a key feature of western Canadian boreal forests. These mixtures have the potential to produce high yields of merchantable fibre and provide numerous ecological services. Achievement of this potential has been difficult, and often exp...
Article
Full-text available
We analyzed productivity, in terms of periodic annual increment (PAI) in volume, of pure and mixed unmanaged naturally regenerated boreal stands mainly comprised of Populus tremuloides Michx. (trembling aspen) and Picea glauca (Moench) Voss (white spruce) ranging from 25-260 years old, in Alberta, Canada. Measures of density, site occupancy (Reinek...
Article
White spruce (Picea glauca (Moench) Voss) and aspen (Populus tremuloides Michx.) from unmanaged stands in the boreal forest of Alberta, Canada, were examined for two of the main structural assumptions in the process-based model CROBAS: (i) a constant allometric relationship between foliage mass and crown length and (ii) a constant relationship betw...
Conference Paper
Full-text available
In the boreal forests of western Canada white spruce (Picea glauca [Moench] Voss) occurs primarily as a component of mixed stands with trembling aspen (Populus tremuloides Michx.). These mixedwood stands are the dominant forest type on productive uplands sites in the boreal plains and pure spruce stands are less common but do occur in later stages...
Conference Paper
Full-text available
Substantial temperature increases and associated increases in drought are forecast for the boreal forests of western Canada and these are expected to have significant impacts on the distribution of white spruce (Picea glauca (Moench) Voss). Since mixtures of aspen (Populus tremuloides Michx.) and white spruce are a common feature of upland sites, t...
Conference Paper
Full-text available
The Western Boreal Growth and Yield Association (WESBOGY) is a regional association of industrial, federal, provincial and university foresters and researchers interested in evaluating the dynamics of boreal forest development and the yield implications of silviculture practices. The four western provinces and the Northwest Territories are represen...
Technical Report
Full-text available
Introduction The invariance of the slope and intercept of maximum size-density relationships (MSDRs) has been a subject of long standing concern. Since stand characteristics and other factors can influence self-thinning behavior, functions that represent how individual stands self-thin (dynamic thinning line) are desirable for stand density models...
Conference Paper
Full-text available
This presentation examines potential impacts of forest waste utilization on biodiversity and productivity of Alberta forests. Evaluation is based largely on a review of the literature. Utilizing woody slash that is at the roadside makes sense and is preferable to slash burning from a greenhouse gas perspective. Lifecycle analysis is needed to eval...
Article
Herbicide application in strips offers a cost-effective way to accelerate spruce growth in young mixedwood stands, while also retaining the mixedwood character of the stand. In June of 2006 data were collected to evaluate the effects of aerial strip spraying on subsequent growth of treated stands. These blocks had been planted in 1991 and treated i...
Article
We examine maximum size–density relationships (MSDR) of pure and mixed stands of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss.) in the Boreal Forest Natural Region of Alberta, Canada. Stochastic frontier function regression was used to estimate the MSDR species boundary or static line and mixed models we...
Article
Full-text available
We examined the effect of competition on stem growth of Picea glauca and Populus tremuloides in boreal mixedwood stands during the stem exclusion stage. We combined traditional approaches of collecting competition data with dendrochronology to provide retrospective measurements of stem diameter growth. Several competition indices including stand ba...
Article
Radial patterns of modulus of elasticity (MOE) were examined for white spruce ( Picea glauca [Moench] Voss) and trembling aspen ( Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to: (1) evaluate the relationship between pith-to-bark changes in MOE and...
Article
Full-text available
We evaluated the Mixedwood Growth Model (MGM) at a whole model scale for pure and mixed species stands of aspen and white spruce in the western boreal forest. MGM is an individual tree-based, distance-independent growth model, designed to evaluate growth and yield implications relating to the management of white spruce, black spruce, aspen, lodgepo...
Article
Full-text available
In the boreal plains of western Canada, white spruce (Picea glauca (Moench) Voss) height−age and site index (SI) curves have been developed and applied to assess site productivity for white spruce without fully considering the competition that usually occurs between the spruce and taller deciduous trees. In this study, we evaluated the effects of d...
Article
A quantitative understanding of the effects complex residual forest structure has on the understorey light environment is useful in guiding strategies that facilitate regeneration in irregular stands. In this study we evaluate several methods for estimating the understorey light environment in an uneven-aged mixed conifer forest in the Interior Dou...
Article
Full-text available
Statistical probability density functions are widely used to model tree diameter distributions and to describe stand structure. The objective of this study was to compare the performance of normal, logarithmic-normal and threeparameter Weibull distributions for fitting diameter data from Akashmoni (Acacia auriculiformis A. Cunn. ex Benth.) plantati...
Article
a b s t r a c t We investigated the combined effect of trembling aspen competition and climate on white spruce growth using data from a long term study with matching treatments spread across the boreal mixedwood forests of Alberta and Saskatchewan (Canada). Results indicate that competition (i.e., aspen basal area), initial size of the tree and mea...
Article
Full-text available
a b s t r a c t We investigated the effects of climate on the growth of red alder across a broad latitudinal gradient and over a wide range of growing conditions in the Pacific Northwest of North America (PNW). Data for this study came from a study established in 1988 that includes 31 research installations located between the Pacific Coast and the...
Article
Full-text available
Density manipulation of overstory aspen provides increased light levels to promote growth of understory spruce, while it may also impact the air and soil temperature. We monitored temperature for three growing seasons in young mixedwood stands of variable de