R.J. Hall

R.J. Hall
Natural Resources Canada, Edmonton, Canada · Canadian Forest Service

Doctor of Philosophy

About

132
Publications
34,033
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7,082
Citations
Citations since 2017
11 Research Items
3074 Citations
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20172018201920202021202220230100200300400500

Publications

Publications (132)
Article
Full-text available
Satellite forest inventories are the only feasible way to map Canada’s vast, remote forest regions, such as those in the Northwest Territories (NWT). A method used to create such inventories is the k-nearest neighbour (k-NN) algorithm, which spatially extends information from forest inventory (FI) plots to the entire forest land base using wall-to-...
Article
Full-text available
Sustainable forest management requires information on the spatial distribution, composition, and structure of forests. However, jurisdictions with large tracts of noncommercial forest, such as the Northwest Territories (NWT) of Canada, often lack detailed forest information across their land base. The goal of the Multisource Vegetation Inventory (M...
Article
Full-text available
Determining burned area in Canada across fire management agencies is challenging because of different mapping scales and methods. The inconsistent removal of unburned islands and water features from within burned polygon perimeters further complicates the problem. To improve the determination of burned area, the Canada Centre for Mapping and Earth...
Article
Full-text available
Satellite-derived spectral indices such as the relativized burn ratio (RBR) allow fire severity maps to be produced in a relatively straightforward manner across multiple fires and broad spatial extents. These indices often have strong relationships with field-based measurements of fire severity, thereby justifying their widespread use in managemen...
Article
Full-text available
A methods framework is presented that utilizes field plots, airborne light detection and ranging (LiDAR), and spaceborne Geoscience Laser Altimeter System (GLAS) data to estimate forest attributes over a 20 Mha area in Northern Canada. The framework was implemented to scale up forest attribute models from field data to intersecting airborne LiDAR d...
Article
Full-text available
Burn severity (ecological impacts of fire on vegetation and soils) influences post-fire stand structure and species composition. The spatial pattern of burn severity may compound the ecological impacts of fire through distances to seed sources and availability of bud banks and seedbeds. Land managers require spatial burn severity data to manage pos...
Chapter
A question of particular interest is which software program should be used for processing of hemispherical photographs (HP) of forest canopies? While a few studies have attempted to address this question, varying approaches to comparing different HP software have not resulted in conclusive evidence as to which software is best. Our objective was to...
Chapter
Full-text available
The purpose of this chapter is to summarize the key messages from each chapter of the book and the rationale for using hemispherical photography (HP) in the discipline of forest ecology. The chapters describing the theory and methods presented the state of the science and the opportunities for developing applications to forestry and natural resourc...
Article
Full-text available
Wildfires are a dominant disturbance to boreal forests, and in North America, they typically cause widespread tree mortality. Forest fire burn severity is often measured at a plot scale using the Composite Burn Index (CBI), which was originally developed as a means of assigning severity levels to the Normalized Burn Ratio (NBR) computed from Landsa...
Book
This book presents practical information about hemispherical photography from the perspectives of field data acquisition, image processing and information retrieval methods. This book is organized into three sections. The first section describes what is hemispherical photography and what are the fundamental elements of forest structure and light i...
Article
Biotic disturbances (BD, including insects, pathogens and wildlife herbivory) can alter forest structure and the capability of forests to deliver ecosystem services. Impact assessments, however, are limited by the lack of reliable and timely disturbance data at large spatial scales. This review synthesizes empirical data on the magnitude and distri...
Article
Full-text available
Wildfires are burning increasingly extensive areas of forest in Canada, reducing their capacity as carbon sinks. Here we compare the answers that four independent land cover datasets, produced from different satellite images (SPOT, Landsat, and MODIS), provide for the question of what burned in Canada in recent years. We harmonized the different da...
Article
Full-text available
Tree species information is a fundamental component of forest inventories that is challenging to obtain in northern boreal forests as a result of inherently open stands with individual trees that may be clumped or widely distributed, and contain multiple tree species. These challenges result in a mixed pixel problem that was investigated using Mult...
Article
Outbreaks of insect pests periodically cause large losses of volume in Canada’s forests. Compounded with climate change, outbreaks create significant challenges for managing the sustainable delivery of ecosystem services. Current methods to monitor damage by these pests involve both field and aerial surveys. While relatively cost effective and time...
Article
This paper presents and assesses spatially explicit estimates of forest growing stock volume (GSV) of the northern hemisphere (north of 10°N) from hyper-temporal observations of Envisat Advanced Synthetic Aperture Radar (ASAR) backscattered intensity using the BIOMASAR algorithm. Approximately 70,000 ASAR images at a pixel size of 0.01° were used t...
Conference Paper
Full-text available
The analysis of multitemporal sequences of remote sensing imagery is becoming increasingly important as Earth Observation archives continue to grow. While new methods and algorithms are continuously being developed, both for Landsat and MODIS, work in the change-visualization front is scant. In particular, new methods are needed that provide a mean...
Presentation
Full-text available
Natural resource management requires land-cover and tree species identification to support decision making for sustainable resource development, as highlighted by initiatives such as the NWT Biomass Energy Strategy and Boreal Woodland Caribou Action Plan. Satellite remote sensing provides a cost-effective and time-efficient way to obtain this infor...
Article
Full-text available
Estimating carbon emissions from wildland fires is complicated by the large variation in both forest fuels and burning conditions across Canada's boreal forest. The potential for using spatial fuel maps to improve wildland fire carbon emission estimates in Canada's National Forest Carbon Monitoring, Accounting and Reporting System (NFCMARS) was eva...
Article
Full-text available
Disturbances such as fire and harvesting shape forest dynamics and must be accounted for when modelling forest properties. However, acquiring timely disturbance information for all of Canada's large forest area has always been challenging. Therefore, we developed an approach to detect annual forest change resulting from fire, harvesting, or floodin...
Presentation
Full-text available
Natural resource management requires land-cover and tree species identification to support decision making for sustainable resource development, as highlighted by initiatives such as the NWT Biomass Energy Strategy and Boreal Woodland Caribou Action Plan. Satellite remote sensing provides a cost-effective and time-efficient way to obtain this infor...
Article
Full-text available
This letter proposes relationships between boreal forest microwave transmissivity and four forest structural parameters: summer and winter Leaf Area Index (LAI) from MODIS, biomass $(hbox{t ha}^{-1})$, and total volume $(hbox{m}^{3} hbox{ha}^{-1})$ for northern Québec, Canada. These relationships were derived for summer AMSR-E data sets that took i...
Presentation
Full-text available
Natural resource management in northern forested areas requires land cover and tree species identification for improved decision making for sustainable resource development. For example, the Northwest Territories (NWT) Biomass Energy Strategy and Boreal Woodland Caribou Action Plan require detailed forest resources information, from which resource...
Article
Full-text available
Free and open access to the more than 40 years of data captured in the Landsat archive, combined with improvements in standardized image products and increasing computer processing and storage capabilities, have enabled the production of large-area, cloud-free, surface reflectance pixel-based image composites. Best-available-pixel (BAP) composites...
Article
Full-text available
Rapid urban expansion is a major contributor to environmental change in many parts of the world. This study investigated land cover changes that occurred between 1988 and 2010 in the Calgary–Edmonton corridor in Alberta, a region that has undergone considerable recent urban expansion. We used satellite imagery to develop land cover maps for four di...
Article
Dead tree tops, or top kill, is one manifestation of the damage that results from Jack Pine budworm (Choristoneura pinus pinus Freeman) defoliation. Methods are needed to monitor and evaluate its impact on the Jack Pine (Pinus banksiana Lamb.) timber resource. This study was designed to determine the extent to which two-date, LANDSAT Thematic Mappe...
Article
De concert avec d'autres organismes, le Centre de recherches forestières du Nord, au sein du Service canadien des forêts, contrôle les conditions relatives aux ravageurs des forêts. Dans le centre-ouest du Canada, la livrée des forêts (Malacosoma disstria Hubner) est considérée comme le plus important défoliateur du peuplier faux-tremble. La survei...
Article
Full-text available
High spatial resolution digital multispectral (DMS) images were acquired at a pixel resolution of 32 by 25 cm to determine the extent forest stand and vegetation detail could be derived from existing per-pixel and spatial feature-based image analysis methods. The image data were acquired from approximately 150 m above a mature forest ecosystem near...
Article
En foresterie, les photographies aériennes constituent la principale source de données de télédétection, mais la qualité de ces photographies est variable. Le contraste d'image, la sensibilité spectrale et la résolution spatiale sont considérés comme des facteurs importants au moment de la définition des paramètres à utiliser en photographie aérien...
Conference Paper
Full-text available
This study represents one of the first documented cases of tree species classification using medium spatial resolution satellite imagery in the northern boreal forests of North America. It also investigated the problem of including mixed spectra into the background component of image endmembers. Improvements in classification accuracy were obtained...
Article
Full-text available
We describe the creation of a GIS vector layer of land cover polygons for the entire province of Alberta, Canada, based upon preexisting, Landsat-derived, land cover raster datasets circa 2000 that were produced by the Canadian federal government. Our novel spatial and semantic generalization algorithm begins with a morphological segmentation of th...
Article
Full-text available
Canada's National Forest Inventory (NFI) sampling program is designed to support reporting on forests at the national scale. On the other hand, continuous maps of forest attributes are required to support strategic analyses of regional policy and management issues. We have therefore produced maps covering 4.03 x 10(6) km(2) of inventoried forest ar...
Presentation
Full-text available
Natural resource management in northern forested areas requires land cover and tree species identification for improved decision making for sustainable resource development. For example, the NWT Biomass Energy Strategy and Boreal Woodland Caribou Action Plan require detailed forest resources information, from which resource inventory and maps of wi...
Article
Full-text available
A study was undertaken to assess Envisat Advanced Synthetic Aperture Radar (ASAR) ScanSAR data for quantifying forest growing stock volume (GSV) across three boreal regions with varying forest types, composition, and structure (Sweden, Central Siberia, and Québec). Estimates of GSV were obtained using hyper-temporal observations of the radar backsc...
Presentation
Full-text available
Mapping the species composition of forested areas is an important component of government-based forest inventories as they are needed for a range of multi-sector stakeholders. While the interpretation of aerial photographs is the primary method for forest inventory, it is cost prohibitive over widely distributed forests such as in the Northwest Ter...
Presentation
Full-text available
Information regarding the spatial distribution of tree species is of high interest and relevance to government agencies that require decisions relevant to the sustainable development of its land and forest resources. Aerial photo-interpretation is a common approach to inventory forests, but it is cost prohibitive over large areas of remote forests...
Article
Full-text available
As airborne laser scanning (ALS) gains wider adoption to support forest operations in Canada, the consistency and quality of derivative products that support long-term monitoring and planning are becoming a key issues for managers. The Canadian Consortium for Lidar Environmental Applications Research (C-CLEAR) has supported almost 200 projects acro...
Article
Full-text available
Forest insects and pathogens are major disturbance agents that have affected millions of hectares in North America in recent decades, implying significant impacts to the carbon (C) cycle. Here, we review and synthesize published studies of the effects of biotic disturbances on forest C cycling in the United States and Canada. Primary productivity i...
Article
Full-text available
Drought-induced, regional-scale dieback of forests has emerged as a global concern that is expected to escalate under model projections of climate change. Since 2000, drought of unusual severity, extent, and duration has affected large areas of western North America, leading to regional-scale dieback of forests in the southwestern US. We report on...
Article
Crown shyness is the empty space between crowns in fully stocked stands that is not related to tree-fall gaps. The objectives of this study were to determine the stand and site factors that control crown shyness in lodgepole pine (Pinus contorta Dougl. ex Loud.) stands and to evaluate whether stands experiencing crown shyness compensate for leaf ar...
Article
The estimation of tree top-kill volumes is an important component of quantifying defoliation impact of severe budworm (Choristoneurapinus Freeman) defoliation on jack pine (Pinusbanksiana Lamb.) trees. Field survey is the only method by which this assessment is currently undertaken. This study evaluated an alternative methodology based on large-sca...
Article
The occurrence and spatial distribution of top kill 1 year following a jack pine budworm (Choristoneura pinus pinus Freeman) outbreak were examined for possible associations with forest stand characteristics derived from resource inventory maps. Associations were computed between top-kill severity and jack pine (Pinus banksiana Lamb.) maturity, sta...
Article
Full-text available
To investigate the feasibility of a spatially explicit, radiation-based regeneration model for the boreal forest, we tested the predictions of a three-dimensional simulator of photosynthetically active radiation transmission (%PAR), MIXLIGHT, and the growth response of understory Abies balsamea (L.) Mill. (balsam fir) and Picea glauca (Moench) Voss...
Article
Full-text available
Insects and pathogens are forest disturbance agents that have affected millions of hectares in North America in recent decades. The extensive area of outbreaks and large number of trees affected suggest significant impacts to the carbon (C) cycle in the form of reduced tree growth and tree mortality. Here we present a review of biotic forest distur...
Conference Paper
Full-text available
Knowledge of forest biomass is necessary for reporting on the state of Canada's forests. It is also an indicator of carbon that enables insights on the interaction between forests and the atmosphere. Forest biomass information has largely been aspatial and derived using plot estimates from Canada's National Forest Inventory. Provincial and territor...
Article
The amount and spatial distribution of aboveground forest biomass (AGB) are required inputs to forest carbon budgets and ecosystem productivity models. Satellite remote sensing offers distinct advantages for large area and multi-temporal applications, however, conventional empirical methods for estimating forest canopy structure and AGB can be diff...
Article
Full-text available
Disturbances are important ecosystem processes that greatly affect carbon cycling. In forests, disturbances contribute to modifications to carbon stocks and fluxes by increasing the amount of decomposing dead organic matter and decreasing the amount of carbon taken up by the ecosystem through photosynthesis. The net effect immediately following a d...
Article
Pixel windows are often used to average the image spectral response values that represent the area over which field measurements are collected to estimate biophysical parameters such as forest stand structure, aboveground biomass, and leaf area index. Averaging spectral values within a pixel window ensures the resulting spectral response is represe...
Article
Researchers and managers undertaking wildlife habitat assessments commonly require spatially explicit environmental map layers such as those derived from forest inventory and remote sensing. However, end users of geospatial products must often make choices regarding the source and level of detail required for characterizing habitat elements, with f...
Article
Remote estimation of canopy structure is important in forestry and a variety of environmental applications. Multiple Forward Mode (MFM) look-tip table (LUT) inversion Of canopy reflectance models is one approach for obtaining forest canopy biophysical-structural information (BSI). MFM provides inversion results from models that are not invertible d...
Article
Full-text available
The present study undertook a hierarchical analysis of the variability within and among some individual fire events in the boreal ecozones of Canada and Alaska. When stratified by ecozone, differences in the spatial and temporal distribution of wildfires were observed in the Canadian Large Fire Data Base that reflect climatic, terrain and land-use...
Article
Full-text available
Capture of land cover information is a key requirement for supporting forest monitoring and management. In Canada, provincial and territorial forest stewards use land cover information to aid in management and planning activities. At the federal level, land cover information is required to aid in meeting national and international reporting obligat...
Article
Determining the feasibility of a large-scale afforestation program is one approach being investigated by the Government of Canada to increase Canada's potential to sequester carbon from the atmosphere. Large-scale afforestation, however, requires knowledge of where it is suitable to establish and grow trees. Spatial models based on Boolean logic an...
Article
An evaluation of the use of airborne lidar for multi-temporal forest height growth assessment in a temperate mature red pine (Pinus resinosa Ait.) plantation over a five-year period is presented. The objective was to evaluate the level of uncertainty in lidar-based growth estimates through time so that the optimal repeat interval necessary for stat...
Article
Full-text available
Aboveground tree biomass and volume are required inputs to models that estimate carbon budgets and ecosystem productivity. Generalized equations are often used to estimate biomass and volume when local equations are unavailable. This study determined whether there was a concomitant increase in prediction error from increasing levels of equation gen...
Article
An evaluation of the use of airborne lidar for multi-temporal forest height growth assessment in a temperate mature red pine (Pinus resinosa Ait.) plantation over a five-year period is presented. The objective was to evaluate the level of uncertainty in lidar-based growth estimates through time so that the optimal repeat interval necessary for stat...
Article
Full-text available
In most forestry remote sensing applications in steep terrain, simple photometric and empirical (