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Highlights: [•] Evaluation of new HWP accounting method leads to significant GHG emission reduction for Canada. [•] Use of harvested wood for energy and of construction lead to largest GHG savings. [•] A cascade-use for wood and paper products is paramount for further GHG improvement. [•] The end-of-life effect of using recycled waste wood for energy is delayed due to longer carbon uptake. [•] Cradle-to-cradle utilization of wood waste has an underdeveloped reduction potential. [Copyright &y& Elsevier]

The opioid crisis is disproportionately impacting Indigenous communities in Canada. There is a need to evaluate practical approaches to recovery that include community-based opioid agonist treatment (OAT) and integration of cultural treatment models. Naandwe Miikan, translated as The Healing Path, is an OAT program that blends clinical and Indigenous healing concepts and providers in a community-based setting. Aside from OAT pharmaceutical treatment, clients work with Indigenous counsellors that integrate culture with treatment, such as land-based activities, that reconnect the community to Indigenous teachings and harvesting. In this paper, we present a case study showcasing community advocacy in creating innovative funding models and engaging with clinicians to provide a shared care OAT model with traditional Indigenous counselling, cultural programs, and data sovereignty. Policy needs are identified. [ABSTRACT FROM AUTHOR]

The modernization of forest harvesting operations has significantly increased the cost of machine ownership and has turned forest harvesting into a capital-intensive process. To increase productivity and profitability, some companies have acquired multi-task harvesting machines. While many previous papers focused on optimizing the harvest scheduling to reduce the costs of harvesting, the assignment of multi-task machines was not considered in their models. In this work, an optimization model is developed for the detailed scheduling of harvesting activities on multiple cut blocks using multi-task machines. This model is a continuation of previous work on detailed harvest scheduling. It prescribes the start time and the end time of operations of each machine at each cut block, the number of machines to be assigned for each harvesting activity at each cut block, the cut block that the machine should move to after completing its operation at a cut block, and the type of activity it should perform. It is applied to a case study of a forest company in Canada. According to the results, the total harvesting cost decreased by Can$ 25,000 when multi-task machines were used compared to exclusive machines, due to less machine movement and the need for fewer machines. [ABSTRACT FROM AUTHOR]

Using a trellis to plant vegetables and fruits can double or triple the yield per acre as well as reduce diseases/pests, ease harvesting and make cleaner produce. Cultivars such as cucumbers, grapes, kiwi, melons, peas, passion fruit, pole beans, pumpkins, strawberries, squash, and tomatoes are all grown with trellises. Many of these cultivars showed increased yield with partial shading with semi-transparent solar photovoltaic (PV) systems. To further increase the efficiency of trellis-based growing systems, this study investigates novel low-cost, open-source, sustainable, wood-based PV racking designs for agrivoltaic applications. Design calculations are made to ensure these racks exceed Canadian building code standards, which with snow loads surpass those of most of the world. A complete bill of materials, fabrication instructions, and proof-of-concept prototypes are provided for three system topographies (sloped, T-shaped and inverse Y) along with economic analysis. In addition, to being cost competitive, the designs can act as trellis supports and be used for irrigation/fertigation purposes. The results indicate that these racking structures have enormous promise both agriculturally and energetically. If employed on only grape farms inside Canada, 10 GW of PV potential is made available, which is more than twice the total current installed PV in Canada. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) cultivars developed for improved digestibility by conventional breeding or genetic modification have not been evaluated in eastern Canada. This study compared yield, nutritive value, and profitability of two reduced-lignin genetically modified (GM) cultivars, three conventionally selected for low lignin or high pectin, and one population with improved stem degradability, with two commercially adapted cultivars as controls. Alfalfa was harvested at the early bud (intensive management) or early flower (extensive management) stage of development during the first post-seeding year at three sites and the second post-seeding year at one site. All cultivars/populations had similar annual dry matter (DM) yields, except for the lower DM yield (−20%) of the improved stem degradability population. Conventionally selected cultivars for improved digestibility did not differ from control cultivars for in vitro DM digestibility (IVTD) and neutral detergent fiber digestibility (NDFd). Reduced-lignin GM cultivars, however, had a greater IVTD and NDFd (+10%) and less lignin (−10%) than control cultivars at the same stage of development. Reduced-lignin GM cultivars under extensive management had similar NDFd and greater annual DM yield (+1 to 2 Mg DM ha−1), but reduced total digestible nutrients (−41 to 44 g kg−1 DM), in comparison to control cultivars under intensive management. Using partial budget analysis, the comparison of more digestible GM cultivars to the control cultivars resulted in an increase in annual farm net profits ranging from CAD$7.40 to $79.60 cow−1 year−1 depending on stage of development at harvest. Further investigations are needed to quantify the performance of dairy cows fed cultivars with improved digestibility. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Common property arrangements govern the subsistence harvest of berries in the Gwich'in region of the Northwest Territories, Canada. Some of these arrangements, including rules for resource access, sharing information and harvest sharing, enable the Gwich'in to deal with ecological variability. The rules change in response to year-to-year variations in the abundance and distribution of the species, spatially and temporally across the region. This paper illustrates the interrelationships between ecosystem dynamics and local institutions, a neglected area of commons research. [ABSTRACT FROM AUTHOR]

Salmon are an essential component of the ecosystem in Tsleil-Waututh Nation's traditional, ancestral, and contemporary unceded territory, centred on present-day Burrard Inlet, BC, Canada, where Tsleil-Waututh people have been harvesting salmon, along with a wide variety of other fishes, for millennia. Tsleil-Waututh Nation is a Coast Salish community that has called the Inlet home since time immemorial. This research assesses the continuity and sustainability of the salmon fishery at təmtəmíxʷtən, an ancestral Tsleil-Waututh settlement in the Inlet, over thousands of years before European contact (1792 CE). We apply Zooarchaeology by Mass Spectrometry (ZooMS) analysis to 245 archaeological salmon vertebrae to identify the species that were harvested by the ancestral Tsleil-Waututh community that lived at təmtəmíxʷtən. The results demonstrate that Tsleil-Waututh communities consistently and preferentially fished for chum salmon (Oncorhynchus keta) over the period of almost 3,000 years. The consistent abundance indicates a sustainable chum salmon fishery over that time, and a strong salmon-to-people relationship through perhaps 100 generations. This research supports Tsleil-Waututh Nation's stewardship obligations under their ancestral legal principles to maintain conditions that uphold the Nation's way of life. [ABSTRACT FROM AUTHOR]

The production of fruit, vegetables, and other horticultural crops in Canada relies upon the embodied labour of migrant agricultural workers who plant, prune, and harvest these crops. Using a feminist geopolitical lens, I foreground the bodies of these workers as these bodies are situated at the intersection of everyday lived experiences and systems of capitalist production through, in this case, Canada's Seasonal Agricultural Worker Program (SAWP). Drawing on workers' experiences of their bodies in the context of the regulatory provisions of the SAWP, I highlight the contradictory disembodiment of agricultural workers at the same time that their bodies are necessary to provide the physical labour at the heart of fruit and vegetable production. The disembodiment of these workers is possible because of their status as racialized non-citizens: while Canadians can insist upon the recognition of their bodies, migrant agricultural workers cannot. The disjuncture between embodied labour and embodied subjectivities was exacerbated with the onset of the COVID-19 pandemic, which disproportionately affected on migrant agricultural workers - through their bodies - while in Canada. Given the relative safety afforded to those who held citizenship (and other permanent) status in Canada, I argue that the active disembodiment of migrant agricultural workers in Canada demonstrates the ways that embodiment is a privilege that is tightly bound to citizenship. [ABSTRACT FROM AUTHOR]

Macroalgae are a new food source in the Western world. The purpose of this study was to evaluate the impact of harvest months and food processing on cultivated Saccharina latissima (S. latissima) from Quebec. Seaweeds were harvested in May and June 2019 and processed by blanching, steaming, and drying with a frozen control condition. The chemical (lipids, proteins, ash, carbohydrates, fibers) and mineral (I, K, Na, Ca, Mg, Fe) compositions, the potential bioactive compounds (alginates, fucoidans, laminarans, carotenoids, polyphenols) and in vitro antioxidant potential were investigated. The results showed that May specimens were significantly the richest in proteins, ash, I, Fe, and carotenoids, while June macroalgae contained more carbohydrates. The antioxidant potential of water-soluble extracts (Oxygen Radical Absorbance Capacity [ORAC] analysis–625 µg/mL) showed the highest potential in June samples. Interactions between harvested months and processing were demonstrated. The drying process applied in May specimens appeared to preserve more S. latissima quality, whereas blanching and steaming resulted in a leaching of minerals. Losses of carotenoids and polyphenols were observed with heating treatments. Water-soluble extracts of dried May samples showed the highest antioxidant potential (ORAC analysis) compared to other methods. Thus, the drying process used to treat S. latissima harvested in May seems to be the best that should be selected. [ABSTRACT FROM AUTHOR]

Forest managers across the Canadian boreal require detailed fire pattern information to support disturbance-based management. However, there are no consistent classifications of post-fire patterns, and those that exist rely on field-data that is both expensive and lacking in spatial representation. As a result, across the managed boreal forest there is limited fire pattern information, no standardized protocols to derive the quantitative fire pattern information nor agreement on the most appropriate metrics needed to implement management planning based on emulating natural disturbances. In this paper we first derived three classes of tree mortality based on Landsat spectral data and aerially photo-interpreted (API) polygons. Next we used these derived classes to compute seven fire pattern metrics over 14 fires that occurred from 1984 to 2006 in the Canadian provinces of Alberta and Saskatchewan, Canada. We then compared the metrics derived from the Landsat data to those computed from the API coverage. Lastly, we assessed the influence of a suite of environmental and fire pattern variables on the Landsat-derived indices. Overall we found very close correspondence for the two event-scale indices: the total area affected by fire and the complexity of the perimeter. The more detailed within-fire event metrics presented more varied results and were somewhat less precise. For example, the total amount of residuals or the largest disturbed patch were accurately captured. Other indices such as the number of disturbed patches or total amount of island remnants presented moderate systematic biases, but still might be serviceable given that the biases were predictable in direction. Fire size and seasonal drought variables were the most correlated with the Landsat derived pattern indices and their inclusion as model variables is likely to increase overall prediction accuracy. A pan-boreal geospatial database of detailed fire pattern metrics would be an invaluable tool to support the implementation of disturbance-based management approaches. Here we demonstrate that a cost-effective Landsat methods produces comparable fire pattern information to conventional approaches based on manual interpretation of aerial photographs. Building upon the standardized methods proposed here hundreds of fires could be mapped, to potentially, create a comprehensive national fire pattern database. [ABSTRACT FROM AUTHOR]

Post‐harvest recovery of biodiversity is one of important goals in modern forestry. A variable retention (VR) approach has been of particular interest in North America because it promotes rapid faunal recovery, while minimizing negative lasting impacts of logging on the natural fauna. We studied responses of rove beetles (Coleoptera: Staphylinidae) to a broad range of retention harvests (2, 10, 20, 50 and 75% retention) in comparison to uncut controls as part of the Ecosystem Management Emulating Natural Disturbance (EMEND) experiment in the boreal mixedwood forest of western Canada. We sampled beetles using pitfall traps 1, 2, 11 and 16 years post‐harvest in replicated (n = 3) stands representing four cover types (deciduous‐dominated, deciduous with spruce understory, mixed and coniferous‐dominated). We collected 74 263 individuals distributed across 99 species (excluding Aleocharinae). Estimated species richness was highest in clear‐cuts until year 11, but by year 16 species richness was similar among treatments. Species composition initially varied strongly in relation to intensity of harvest treatments, but overall variation decreased with time, and by year 16, species composition overlapped among most treatment combinations. Assemblages recovered more quickly in early successional (deciduous‐dominated) than in late successional (mixed and conifer‐dominated) stands. Overall, our results show that rove beetle assemblages in stands harvested to all VR prescriptions converged more rapidly toward those in fire‐origin mature stands than did assemblages in clear‐cuts over the first 16 years post‐harvest. Thus, it demonstrates that even modest levels of forest retention can facilitate the recovery of staphylinid assemblages in managed landscapes. [ABSTRACT FROM AUTHOR]

The profitability of wild blueberry (Vaccinium angustifolium) production using two alternative mechanical harvesters was evaluated under three different harvester ownership/service arrangements commonly used by farmers. Production data for the economic analysis were obtained from on-farm trials conducted in Nova Scotia, Canada. Net returns were CAD$323 ha−1 using a semi-automatic bin handling system compared with CAD$281 ha−1 for a small box handling system with outright harvester purchase. By comparison, net returns were CAD$90 ha−1 using the semi-automatic bin handling system and CAD$63 ha−1 using the small box system using rental harvesting services. The results are more sensitive to changes in yield than price. [ABSTRACT FROM AUTHOR]

Waterfowl management is more effective when based on detailed information on population connectivity between breeding, wintering, and stopover sites. For the American black duck (Anas rubripes), a species of conservation concern, estimates for the fall age ratio at harvest differed depending on whether harvest data were derived from Canada or the United States, suggesting regional differences. Within Canada, hunters in Atlantic Canada were more likely to harvest black ducks from nearby breeding locations compared to hunters in southern Ontario and Quebec, Canada, who were more likely to harvest individuals from the Boreal Softwood and Taiga Shield of eastern Canada. Black ducks harvested in the United States are thought to originate predominantly from northern portions of the breeding range, leading to the flyover hypothesis, which postulates that black ducks produced in the Boreal Softwood and Taiga Shield region are less susceptible to harvest by hunters in Atlantic Canada and northeastern United States. To test the flyover hypothesis, we examined regional and temporal differences in the origins of harvested black ducks using feathers from wings (n = 664) submitted by hunters to the species composition and parts collection surveys across 3 hunting seasons (2017–2018, 2018–2019, 2019–2020). We used a likelihood‐based assignment method that relied on feather stable‐hydrogen isotopes (δ2H) and stable‐carbon isotopes (δ13C) to determine the natal or molt origin of individuals harvested within eastern Canada and the United States. We also used a spatial clustering technique to group harvested individuals by area of origin without a priori knowledge of such regions. Adult female black ducks originated farther south compared to males and juveniles. All sexes and ages of black ducks harvested in Atlantic Canada showed predominantly southern origins, while those harvested in the United States and other Canadian provinces primarily originated farther north within the boreal, supporting the flyover hypothesis. By contrast, we found no relationship between timing of harvest or peaks of migration and individual origin. After combining band returns and stable isotopes, we inferred 2 distinct stocks: the Mississippi flyway stock and the Atlantic flyway stock. We recommend that regional demographic parameters, particularly for Atlantic Canada, be directly measured to promote more effective conservation of black ducks and optimize harvest opportunities in the United States and Canada. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: A decision support system (DSS) for improved management decision making and to reduce impacts of forest insect outbreaks was developed and implemented for two defoliators, hemlock looper (Lambdina fiscellaria fiscellaria Guen.) and balsam fir sawfly (Neodiprion abietis Harris), in District 15, a 336,805ha forest managed by Corner Brook Pulp and Paper Ltd. in western Newfoundland, Canada. Over the past 15years, 56% and 12% of the landbase were defoliated by balsam fir sawfly and hemlock looper, which had major effects on forest growth and yield. Relationships between reduced growth and survival and cumulative defoliation were quantified for each insect, to permit calculation of relative impact per forest stand as a function of defoliation, stand age, and species composition. These were integrated into a forest estate model to project effects on timber supply for 25years. Defoliation during 1996–2008 was estimated to reduce total operable softwood growing stock and softwood harvest level by 26% and 31%, respectively, for balsam fir sawfly, and by 2–3% for the smaller-scale hemlock looper outbreaks. Given the long-term influence on forest structure, effects of defoliation on yield were projected to continue for up to 60years after defoliation ceased. Sensitivity analysis using different defoliation scenarios suggested that maximum reductions in harvest levels could be reduced from 40% to 17% by protecting the most susceptible 25% of the landbase using biological insecticides, and minimized further to 9% by re-optimization of harvest schedules to reduce losses. This DSS provides a tool to help forest managers decide when and where to use biological insecticides, and how to use rescheduling of harvest, forest restructuring or planned salvage to reduce future losses. [Copyright &y& Elsevier]

Abstract: Interest in the use of bioenergy is increasing because of the need to mitigate climate change, the increasing costs and finite supply of fossil fuels, and the declining price of lumber and paper. Sound bioenergy policies must be informed by accurate estimates of potential feedstock production, rights to the production, social values and economics. Two of the main sources of bioenergy feedstock from forests are (i) harvesting residue and (ii) dead wood resulting from natural disturbances (i.e. standing dead timber). We modeled the production of bioenergy feedstock from these two sources from 2005 to 2020 for Canada''s managed forest south of 60° N so that this information can be used in provincial and national strategic planning. Published estimates of harvesting residue vary widely, and our objective was to provide more precise estimates based on new forest inventory data and regional modeling. Natural disturbances result in very large quantities of dead wood on the landscape, but estimates of future stocks and annual production have not previously been made. Our estimates included a 50% discount factor to net-down theoretically available quantities to a more realistic estimate of potential ecologically sustainable bioenergy feedstock. The total future annual production averaged 51±17Tgyear−1 from natural disturbances and 20±0.6Tgyear−1 from clearcut harvesting residues. Harvesting residue for the area logged varied spatially from a low of 1.0±0.77kgm−2 year−1 to a high of 6.7±0.1kgm−2 year−1. Dead wood production due to insects was forecast to peak in the Montane Cordillera of British Columbia (BC) at 16.7Tgyear−1 due to the current mountain pine beetle outbreak. Total dead wood production due to fire was highest in the western portion of the boreal forest (3.6Tgyear−1 in the Boreal Shield of Saskatchewan), in part due to the high frequency of fires in these ecosystems and the large area of western boreal forest, but the highest density production was in BC: >9kgm−2 year−1 in the burned area. Our results showed that the dead wood stocks of 331Tg oven-dry matter potentially available for bioenergy in 2020 are much smaller than the 3100±84Tg of dead wood stocks estimated based on ecosystem dynamics. While bioenergy use will accelerate the release of greenhouse gases compared to on-site decay, the energy is renewable and can be used as a substitute for fossil fuels. The net benefit to the atmosphere of forest bioenergy use is affected by many factors, and future research should further assess which sustainable wood-based bioenergy strategies yield the greatest net greenhouse gas benefits over the different time scales needed for post-disturbance forest recovery. [Copyright &y& Elsevier]

Almost 36 million tonnes (t) of cereal grains are harvested annually on more than 16 million hectares (ha) on the Canadian prairies. The net straw production varies year by year depending upon weather patterns, crop fertility, soil conservation measures, harvest method, and plant variety. The net yield of straw, after discountinng for soil conservation, averages approximately 2.5 dry (d)t ha-1. Efficient equipment is needed to collect and package the material as a feedstock for industrial applications. This paper investigates the costs, energy input, and emissions from power equipment used for harvesting straw. Five scenarios were investigated: (1) large square bales, (2) round bales, (3) large compacted stacks (loafs), (4) dried chops, and (5) wet chops. The baled or loafed biomass is stacked next to the farm. Dry chop is collected in a large pile and wet chop is ensiled. The baling and stacking cost was $21.47 dt-1 (dry tonne), with little difference between round and large square baling. Loafing was the cheapest option at $17.08 dt-1. Dry chop and piling was $23.90 dt-1 and wet chop followed by ensiling was $59.75 dt-1. A significant portion of the wet chop cost was in ensiling. Energy input and emissions were proportional to the costs for each system, except for loafing, which required more energy input than the baling systems. As a fraction of the energy content of biomass (roughly 16 GJ dt-1), the energy input ranged from 1.2% for baling to 3.2% for ensiling. Emissions from the power equipment ranged from 20.3 kg CO2e dt-1 to more than 40 kg CO2e dt-1. A sensitivity analysis on the effect of yield on collection costs showed that a 33% increase in yield reduced the cost by 20%. Similarly a sensitivity analysis on weather conditions showed that a 10°C cooler climate extended the harvest period by 5-10 days whereas a 10°C warmer climate shortened the harvest period by 2-3 days. [ABSTRACT FROM AUTHOR]

Canada's Fisheries Act was revised in 2019 to include new Fish Stocks provisions. Updated science guidelines to support the Sustainable Fisheries Framework policies, in particular the Fishery Decision-Making Framework Incorporating the Precautionary Approach (PA Policy), and legal and regulatory requirements are also under development. To inform the development of science guidelines, we reviewed the technical specifications of reference points and harvest control rules for a subset of key harvested stocks, focusing primarily on those domestically managed and subject to the PA Policy. The adoption of default guidance values of the limit reference point (LRP) and upper stock reference (USR) provided in the PA Policy (0.4 and 0.8 BMSY) is not required, but these values appear to have been widely embraced (43% and 65% of cases, respectively). The USR by definition serves a number of functions, including an operational control point (trigger for management action) to control the risk of approaching the LRP, Healthy-Cautious zone boundary, and target. Science guidelines can provide support for identifying alternative USRs by noting proxies for BMSY (enabling use of proxies for 0.8 BMSY) and by addressing various functions attributed to the USR separately. Removal References (RRs), like USRs, may serve multiple purposes across the stocks in this review. We found that RR values are consistent with indicating whether harvests are at "approved [target] levels" in a wide range of stocks, and sometimes with limits to be either avoided or with which to characterize acceptable stock status in terms of overfishing on the fishing mortality (F)-axis of the PA Policy. Science guidelines could provide support for identifying RRs by highlighting FMSY proxies and characterization of stock states on the F-axis. Four broad types of harvest control rules (HCRs) appear to be implemented in Canada: feedback status-based rules, mixed feedback/feed-forward risk-based rules, "constant" rules with no operational control points and feedforward-only objective-based "rules." The provisional HCR suggested in the PA Policy guidance is not often used although three-part rules with control points at the LRP and USR are common (38% of HCRs). Rules varied widely, although the vast majority are targeted toward informing quantitative output controls (catch limits). To support the new provisions, the development of updated science guidelines should aim to support easier identification of PA components and more consistent use of terminology for key aspects of the PA Policy, including reference points, operational control points for HCRs, and measurable objectives. The HCR types and other measures will vary widely for fisheries that represent a spectrum of data and assessment model availability for key harvested stocks. As science support may be requested for developing and evaluating a wide range of HCRs, science guidelines will need to address both prospective and retrospective evaluation for an array of possible rules that reflect input and output controls and interact with other management measures. [ABSTRACT FROM AUTHOR]

• Multiple succession pathways possible following harvesting in Acadian Forest Region. • Early succession pathways were driven by numerous succession mechanisms. • Landscape-level climate variability had strongest influence on early stand succession. • Pre- and post-harvest overstorey composition strongly influenced stand succession. • Climate change will influence forest regeneration by inhibiting cold adapted species. • Forest managers must consider climate change in future management planning. Predicting forest succession is not a trivial pursuit and has remained a central challenge for scientists and foresters for well over a century. While thousands of papers have been published on the topic, contributing to a plethora of concepts and terminologies, there remains confusion over causal mechanisms, inhibiting our ability to adopt many lessons learned to sustainable forest management. Based on an emerging conceptual model of forest succession, presented here as the "Succession Triangle", we sought to explore the relative importance of mechanisms hypothesized to drive succession following commercial harvesting across a wide landscape in the Acadian Forest Region of eastern Canada. Using machine learning techniques and repeatedly measured forest stand inventory data, including 19,332 forest stands measured over a ≈30 year period, we uncovered dominant early succession pathways and investigated key mechanisms driving these pathways. Overall, our results show stands may follow multiple succession pathways following harvesting, including early dominance by so-called "late-succession" species (e.g., black spruce and sugar maple), depending on causal mechanisms. More specifically, mechanisms related to the state of the environment (primarily climate) and differential species availability (mainly pre- and post-harvest overstorey composition) had the strongest control over early succession. The strong influence of pre-harvest composition on early succession supports the 'direct regeneration' hypothesis; while the importance of post-harvest overstorey composition suggests the use of partial-cutting as a means of regenerating shade-tolerant species (e.g., sugar maple and red spruce). Site conditions (i.e., slope and drainage) influenced the direction of succession, but landscape-level variation in climate had the overall strongest effect, with colder, more moist climates promoting regeneration of balsam fir, while warmer, dryer climates encouraged shade-intolerant, broadleaf species (birches, red maple and poplars), especially following clear-cutting. Given the strong influence of climate, we used our fitted model to predict the impact of late 21st century climate change on early succession using the "business-as-usual" RCP 8.5 radiative forcing scenario. Our results indicate climate change is likely to increase the regeneration of shade-intolerant, broadleaf tree species (e.g., red maple and poplars) across the landscape at the loss of cold-adapted balsam fir, supporting the hypothesis that young, post-harvest stands are vulnerable to climate-driven shifts in composition as postulated by 'resilience theory', and corroborating previous simulation studies that predict rapid 21st century climate warming will lead to 'deborealization' of Canada's Acadian Forest Region. [ABSTRACT FROM AUTHOR]

The global offtake of wild animals is valued at US$400 billion annually and supports the livelihoods of 15% of the global population. Wetlands are amongst the most important ecosystems globally, but offtake may represent a substantial pressure. This study assessed the availability of information and evaluated the offtake of wild animals from wetlands by focussing on fish and waterbirds. A literature search identified 2726 studies on wetland offtake. Scoping of these resulted in 82 studies that contained quantitative information on fish or waterbird offtake. Fishing offtake statistics for inland waters are collated nationally by some governments, but other sources of information are few. Reporting of fish offtake for species or across scales was constrained by insufficient detail, even in relatively well-documented countries such as Bangladesh. Although government hunting statistics from Europe and North America were available, there was little waterbird data from less economically developed countries. The case of Canada indicated that the species richness and composition of waterbirds taken varied between indigenous subsistence and recreational hunting communities. Hidden (unquantified) offtake, of both fish and waterbirds, hinders obtaining precise data for offtake, which may threaten the conservation of species and the sustainability of wetland ecosystems. [ABSTRACT FROM AUTHOR]

Managing competing vegetation is crucial in stand establishment strategies; forecasting the abundance, composition, and impact of competing vegetation after harvesting is needed to optimize silviculture scenarios and maintain long-term site productivity. Our main objective was to identify factors influencing the short-term abundance and composition of competing vegetation over a large area of the Canadian boreal forest. Our second objective was to better understand the mid-term evolution of the regeneration/competing vegetation complex in cases of marginal regeneration conditions. We used operational regeneration surveys of 4471 transects sampled ≈5 years after harvesting that contained data on regeneration, competing vegetation, elevation, ecological classification, soil attributes, and pre-harvest forest stands. We performed a redundancy analysis to identify the relationships between competing vegetation, harvesting and biophysical variables. We then estimated the probability of observing a given competing species cover based on these variables. In 2015, we re-sampled a portion of the sites, where conifer regeneration was marginal early after harvesting, to assess the temporal impact of different competing levels and species groups on the free-to-grow stocking, vigour and basal area of softwood regeneration. Results from the first inventory showed that, after careful logging around advance growth, ericaceous shrubs and hardwoods were not associated with the same sets of site attributes. Ericaceous shrubs were mainly found on low fertility sites associated with black spruce (Picea mariana (Mill.) BSP) or jack pine (Pinus banksiana Lamb.). The distinction between suitable environments for commercial shade-intolerant hardwoods and non-commercial hardwoods was less clear, as they responded similarly to many variables. Analysis of data from the second inventory showed a significant improvement in conifer free-to-grow stocking when commercial shade-intolerant hardwood competing levels were low (stocking 0%–40%) and when ericaceous shrubs competing levels were moderate (percent cover 26%–75%). In these conditions of marginal regeneration, the different types and intensities of competition did not affect the vigour or basal area of softwood regeneration, 9–14 years after harvesting. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Arctic is a global hotspot of climate change, which is impacting the livelihoods of remote Inuit communities. We conduct a longitudinal assessment of climate change vulnerability drawing upon fieldwork conducted in 2004 and 2015 in Ikpiarjuk (Arctic Bay), Nunavut, and focusing on risks associated with subsistence harvesting activities. Specifically, we employ the same conceptual and methodological approach to identify and characterize who is vulnerable, to what stresses, and why, assessing how this has changed over time, including re-interviewing individuals involved in the original study. We find similarities between the two periods, with many of the observed environmental changes documented in 2004 having accelerated over the last decade, exacerbating risks of land use: changing sea ice regimes and wind patterns are the most widely documented at both times, with new observations reporting more frequent sighting of polar bear and orca. Socio-economic and technological changes have altered the context in climate change impacts are being experienced and responded to, both exacerbating and moderating vulnerabilities compared to 2004. The adoption of new technology, including GPS and widespread use of the internet, has helped land users manage changing conditions while sharing networks remain strong, despite concern noted in the 2004 study that they were weakening. Challenges around access to financial resources and concern over the incomplete transmission of some environmental knowledge and land skills to younger generations continue to increase sensitivity and limit adaptive capacity to changing climatic conditions. [ABSTRACT FROM AUTHOR]

Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well studied in temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests., We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our objectives were to quantify vegetation responses at edges of all types and to compare the strength and extent of edge influence among different types of edges and forests., Research was conducted using the same general sampling design in Alberta, Ontario and Quebec in Canada, and in Sweden and Finland. We conducted a meta-analysis for a variety of response variables including forest structure, deadwood abundance, regeneration, understorey abundance and diversity, and non-vascular plant cover. We also determined the magnitude and distance of edge influence (DEI) using randomization tests., Some edge responses (lower tree basal area, tree canopy and bryophyte cover; more logs; higher regeneration) were significant overall across studies. Edge influence on ground vegetation in boreal forests was generally weak, not very extensive (DEI usually < 20 m) and decreased with time. We found more extensive edge influence at natural edges, at younger edges and in broadleaf forests. The comparison among regions revealed weaker edge influence in Fennoscandian forests., Synthesis. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The 'Natural Disturbance Paradigm' for forest management seeks to meet conservation goals by modeling industrial harvest in fire-driven forest systems on patterns associated with wildfire. Fire suppression and increased forest harvesting may have detrimental effects on biodiversity, and therefore prescribed burning is suggested to retain legacies of wildfire not emulated under natural disturbance based approaches. The merits of this approach are being tested in the EMEND experiment in the Canadian boreal mixedwood forest. We compared responses of ground-dwelling spiders between sites subjected to prescribed post-harvest burning and retention harvest during three seasons during the first 7 years after disturbance. Overall, 38,661 adult spiders representing 190 species were collected. Estimated species richness was highest in undisturbed sites in all 3 years. Burning had the strongest negative effect on species richness 1-2 years after treatment; however, richness was higher in burns than in harvested sites 5-6 years post-disturbance. Species turnover was highest within controls but tended to increase over time between burned and harvested plots. Lower turnover in burned and harvested sites may reflect habitat homogenization by disturbance, suggesting a management and conservation challenge in relation to naturally disturbed and undisturbed areas. Species were grouped into disturbance-specialists, disturbance-tolerant, disturbance-generalists and generalists; 22 species were significant indicators for untreated sites, 18 for the burn and three for the harvest treatments. No major differences were observed in the spider fauna between harvested and burned areas within the first 6-7 years post-disturbance, and little evidence of recovery toward the pre-harvest fauna was evidenced. However, long term experiments may improve understanding of natural disturbance processes and improve management of boreal forests. [ABSTRACT FROM AUTHOR]

The two major disturbance types of boreal black spruce forest in north-central Quebec, Canada - natural disturbance by wildfire and anthropogenic disturbance by harvest - may affect processes of recovery differently and leave distinct post-disturbance soil and vegetation spatial patterns. We tested whether 1) spatial patterns of physico-chemical soil organic layer properties, black spruce diameter and density, and understory ericaceous shrub cover, differ between these two principal disturbance types; 2) operations associated with forest harvest result in distinct, regular spatial patterns of these same variables related to presence of machine trails; and 3) ericaceous shrub presence is a potential factor contributing to the legacy of spatial patterns after harvest. We explored these patterns on black spruce-feathermoss forest stands, including fire-origin stands (18 and 98 years) and stands originating from harvest (16 and 62 years) in central Quebec, Canada. We used two spatial analysis methods, spectral analysis and principal component analysis in the frequency domain, to characterize and relate spatial patterns of these soil and vegetation variables, measured along 50-m transects on each site. Spatial patterns of distribution of soil and vegetation variables were different on the burned and the harvested forest sites. Wildfire gave rise to spatial patterns in soil and vegetation variables at multiple scales, reflecting the complexity generated by variable burn intensity. Patterns following forest harvest were mainly related to the regular structure defined by trails created by logging operations. In contrast to burned sites, ericaceous shrub patterns on harvested sites were strongly associated with spatial arrangements of spruce diameter and density, promoting absence of canopy closure and persistence of trails. Moreover, different spatial signatures did not converge in the long-term (62-98 years) between the two disturbance types. The divergence in spatial structure between natural and anthropogenic disturbances has implications for ecosystem structure and function in the longer term. [ABSTRACT FROM AUTHOR]

Quantification of stand and forest C stocks in response to different disturbances is necessary to develop climate change mitigation strategies and to evaluate forest C accounting tools. Live tree, dead tree, woody debris (WD), stump, buried wood, and organic and mineral soil C stocks are described in chronosequences of black spruce (Picea mariana (Mill.) BSP) (harvest and fire origin) and balsam fir (Abies balsamea (L.) Mill.) (insect and harvest origin). The largest C stocks were found in mineral soil (≤179 Mg·ha-1), organic soil (≤123 Mg·ha-1), and live tree (≤93 Mg·ha-1) pools. Live tree C changed predictably with disturbance history and time since disturbance, increasing with forest age. Regeneration growth slowed under snags. Thinning accelerated production of larger trees but reduced site live tree C. Dead tree and WD C were temporally dynamic and strongly influenced by disturbance history and time since disturbance, but abundances in differently disturbed forests converged at low levels 40-60 years after disturbance. Only immediately following natural disturbances were there large amounts of snag C (26-30 Mg·ha-1). WD C was relatively abundant <3 years after harvesting (15-17 Mg·ha-1) and 31-36 years after natural disturbance (9 Mg·ha-1). Buried wood stocks were small, but comparable with WD stocks in some forests. Il est nécessaire de quantifier les stocks de C dans les peuplements et les forêts en réaction aux différentes perturbations pour élaborer des stratégies visant à atténuer les effets des changements climatiques et pour évaluer les outils qui servent à mesurer le C des forêts. Les stocks de C dans les arbres vivants, les arbres morts, les débris ligneux (DL), les souches, le bois enfoui, le sol organique et le sol minéral sont décrits dans des chronoséquences d'épinette noire (Picea mariana (Mill.) BSP), issues de coupes et de feux, et des chronoséquences de sapin baumier (Abies balsamea (L.) Mill.) issues de coupes et d'épidémies d'insectes. Le sol minéral (≤179 Mg·ha-1), le sol organique (≤123 Mg·ha-1) et les arbres vivants (≤93 Mg·ha-1) contenaient les plus grandes quantités de C. Le C des arbres vivants variait de façon prévisible en fonction de la nature des perturbations et du temps écoulé depuis qu'est survenue une perturbation et il augmentait avec l'âge de la forêt. La croissance de la régénération ralentissait sous les chicots. L'éclaircie accélérait la production de plus gros arbres mais réduisait le C chez les arbres vivants qui restaient. Le C des arbres morts et des DL était temporairement dynamique et fortement influencé par la nature des perturbations et le temps écoulé depuis qu'est survenue une perturbation, mais l'abondance dans des forêts ayant subi différentes perturbations convergeait vers un faible niveau 40-60 ans après la perturbation. La quantité de C dans les chicots (26-30 Mg·ha-1) était élevée mais seulement immédiatement après une perturbation. Le C était relativement abondant dans les DL moins de 3 ans après une coupe (15-17 Mg·ha-1) et 31-36 ans après une perturbation naturelle (9 Mg·ha-1). La quantité de C dans le bois enfoui était faible mais comparable à la quantité de C dans les DL dans certaines forêts. [ABSTRACT FROM AUTHOR]

Habitat configuration has important implications for the persistence of faunal and floral populations at a variety of spatial scales. Forest harvesting alters habitat configurations. However, measuring and predicting such alterations remains challenging, in part because previously developed metrics of habitat configuration are often not statistically independent of habitat amount. Thus, their ability to measure independent effects of habitat configurations and habitat amount on ecosystem components such as wildlife populations has been limited. Here, we evaluate habitat configuration based on newly developed metrics that are independent of habitat amount but do not depend on regression residuals of abundance and configuration relationships on any population of landscapes. We use these new metrics to measure and predict changes in habitat configuration following forest harvesting in the boreal forest of Alberta, Canada. Our findings clearly demonstrate changes in habitat configuration resulting from forest harvesting can be predicted precisely with information about initial habitat patch structure and harvesting patterns. Because forest harvesting has significant implications for habitat configuration, accurately predicting these changes is critical for determining if forest harvesting strategies are sustainable for ecosystem components and processes. This study provides a set of novel, robust metrics for tracking landscape-scale changes in habitat configuration in harvested boreal forests. [ABSTRACT FROM AUTHOR]

Peat bog harvesting is an important industry in many countries, including Canada. To harvest peat, bogs are drained and drainage water is evacuated towards neighboring rivers, estuaries or coastal waters. High suspended sediment concentrations (SSC) were found in the drainage water at one particular site during the 2001–2002 spring seasons in New Brunswick (Canada). The main objective of this study was to verify this observation at other sites, compare SSC levels leaving harvested peat bogs with those leaving an unharvested bog, and to determine if high SSC events happen only in Spring or all year round. Suspended sediment concentrations were monitored downstream of three harvested peat bogs and an unharvested reference bog located in New Brunswick during the ice free seasons of 2003–2004. On average, SSC at the harvested sites exceeded 25 mg/l, which is the recommended daily maximum concentration, 72% of the time, while the same concentration was exceeded 30% of the time at the unharvested sites. SSC were found to be significantly higher at harvested sites than at the reference sites for all seasons. The highest SSC medians were recorded in the Fall but SSC was elevated in all seasons. High SSC levels in receiving waters may be caused by field ditching activities and insufficient sediment controls. Findings suggest the NB Peat Harvesting 25 mg/l SSC guideline should be reviewed. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Historical and future projected landscape patterns and changes caused by harvesting and silviculture were evaluated for a 189,000 ha, intensively managed forest in New Brunswick, Canada. We compared changes in species composition, age classes, and patch characteristics (area, size, density, edge, shape, and core area) between 1945, 2002, and projections to 2027 (based on the landowner's spatial forest management plan). In 1945, the landbase was 40% softwood, 37% mixed hardwood-softwood, 10% hardwood, and 9% softwood-cedar. From 1945 to 2002 and 2027, respectively, softwood forest area increased by 2 and 11%, mixedwood decreased by 19 and 20%, and hardwood area increased by 15 and 14%, and softwood-cedar increased by 6% and then decreased by 7%. In 1945, forest >70 years old comprised 85% of the landscape, but declined to 44% in 2002 and was projected to encompass 41% in 2027. Increased area harvested, decreasing harvest patch size, and protection against natural disturbances resulted in progressively smaller mean and less variable patch sizes from 1945 to 2002. Based upon the 25-year forest management plan, this trend was projected to continue, with the exception of nine patches >1000 ha created by 2027, eight of which were softwood plantations. Stand type successional dynamics were highly variable in both harvested and non-harvested areas, and in some cases were unexpected. Few of the 1945 stand types remained static by 2002, with 42 and 35% of mixedwood shifting to softwood as a result of harvesting, and to hardwood as a result of both harvesting and spruce budworm(Choristoneura fumiferana Clem.) outbreaks in the 1950s and 1970s. This study demonstrates the strong cumulative effect of forest management on landscape patterns, especially the socially mandated drive for smaller clearcuts resulting in the loss of large patches. [ABSTRACT FROM AUTHOR]

As timber harvest expands over a previously unharvested landbase, riparian buffers will make up an increasing proportion of old-growth forests. This study examined the impact of different criteria for the formulation of riparian buffers on the temporal supply of old-growth forests in western boreal Canada. Three common criteria were applied through computer simulation over an ∼313 000-ha timber merchantable landbase for a 200-year time horizon. Guideline criteria included: (1) broad prescriptive approach, i.e. few-sizes-fit-all; (2) special management of fish-bearing streams; and (3) two-zone, partial harvest buffers. While the numerical results are specific to this study area, they suggested five general results applicable to forest planning. (1) Regardless of the criteria for buffers, old growth accumulated over the first 40–60 years thereafter it dropped to 2–4 per cent of the total landbase after 100 years. (2) Guidelines recognizing fish-bearing water bodies retained more old growth, particularly conifer, because of their application to higher elevation and more intermittent stream types. Few-sizes-fit-all retained the most deciduous and mixed-wood old growth, i.e. low elevation forest types. Two-zone buffers exhibited less temporal variance but an overall lower amount of old growth. (3) Operational and field interpretations of the few-sizes-fit-all guidelines retained three times more riparian area and three to seven times more old growth than just the planning phase alone. (4) Old-growth mixed-wood forests virtually disappeared from both timber harvest and riparian landbases. (5) The primary location of old growth shifted from the harvest to the riparian landbase. [ABSTRACT FROM AUTHOR]

The special characteristics of the hemp (Cannabis sativa L.) plant make it one of the most challenging crops to handle. Several studies, both in the laboratory and the field, have been conducted at the University of Manitoba, Canada, on the engineering perspectives of hemp production, including the physical and mechanical properties of the hemp plant, hemp harvesting and processing. Physical properties of the hemp plant, such as plant height, seed-head length, stem diameter and stem specific mass, vary highly within a field and across fields. The force and energy required for cutting a hemp stem are much greater than those required for cutting maize stalk and forage crops. The two-windrow harvesting concept has been demonstrated to be feasible and can be implemented into a commercial windrower for harvesting dual-purpose hemp. Conditioned hemp dries significantly faster than unconditioned hemp. However, conditioning hemp requires more power than conditioning a forage crop. The basic machine functions required for hemp fibre processing are separating the fibre from the core and cleaning the fibre. A field-going processing unit can be formed by combining a modified forage harvester and a straw walker from a grain combine. However, the effectiveness of such a unit is limited, and the design of new separating and cleaning devices may be required for higher fibre yield and purity. [ABSTRACT FROM PUBLISHER]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of partial and clear-cut harvesting on forest floor physical, chemical, and biological properties, forest floor mesofauna, and nutrient cycling were investigated in conifer- and deciduous-dominated stands of Alberta's mixedwood boreal forest. Forest floor samples were collected 2.5 years after harvest from clearcuts, strip-cut corridors in a partial cut, green tree retention patches in a partial cut, and uncut control sites. Partial cuts showed intermediate decreases in annual litter input and NH[sub 4] -N between uncut and clear-cut sites of both the deciduous and conifer stands, as did microbial biomass, PO[sub 4] -P, mesofauna abundance (total, Acari, and Collembola), and fine root biomass in the conifer stands. In the deciduous stands, microbial biomass and fine root biomass in partial- and clear-cut treatments were not significantly different, but were significantly reduced compared with the uncut controls. Mesofauna abundance was reduced in the corridors of the partial-cut treatment compared with partial-cut patch, clear-cut, and uncut treatments. In both deciduous and conifer stands, NO[sub 3] -N was elevated in the partial-cut corridors and clearcuts compared with partial-cut patch and uncut treatments. Findings from this study show that negative impact to forest floor properties associated with clear-cut harvesting may be reduced in partial-cut harvesting systems.Les effets de la coupe à blanc et de la coupe partielle sur les propriétés physiques, chimiques et biologiques de la couverture morte, sur la mésofaune de la couverture morte et sur le recyclage des nutriments ont été étudiés dans des peuplements dominés soit par des conifères, soit par des feuillus, dans la forêt mixte boréale de l'Alberta. Des échantillons de la couverture morte ont été prélevés dans des sites coupés à blanc, dans les corridors de coupes partielles par bandes, dans les îlots de réserves de coupes partielles et dans des sites témoins non coupés deux ans et demi après la récolte. La coupe partielle a entraîné une diminution de l'apport annuel de litière et de N (NH[sub 4] ) intermédiaire entre les sites coupés à blanc et les sites non coupés dans les deux types de peuplements de même qu'une diminution de la biomasse microbienne, du P (PO[sub 4] ), de l'abondance de la mésofaune (totale, d'acariens et de collemboles) et de la biomasse des racines fines dans les peuplements résineux. Dans les peuplements feuillus, la biomasse microbienne et la biomasse de racines fines ne différaient pas significativement entre la coupe partielle et la coupe à blanc mais étaient significativement plus faibles que dans les sites témoins non coupés. L'abondance de la mésofaune dans les corridors de la coupe partielle était inférieure à celle observée dans la coupe partielle avec réserves, dans la coupe à blanc et dans les sites non coupés. Tant dans les peuplements résineux que feuillus, N (NO[sub 3] ) était plus élevé dans les corridors de la coupe partielle et dans la coupe à blanc que dans la coupe partielle avec réserves ou dans les sites non coupés. Les résultats de cette étude montrent que l'impact négatif de la coupe à blanc sur les propriétés de la couverture morte peut être minimisé avec des systèmes de coupe partielle.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Summary Disturbances by fire and harvesting are thought to regulate the carbon balance of the Canadian boreal forest over scales of several decades. However, there are few direct measurements of carbon fluxes following disturbances to provide data needed to refine mathematical models. The eddy covariance technique was used with paired towers to measure fluxes simultaneously at disturbed and undisturbed sites over periods of about one week during the growing season in 1998 and 1999. Comparisons were conducted at three sites: a 1-y-old burned jackpine stand subjected to an intense crown fire at the International Crown Fire Modelling Experiment site near Fort Providence, North-west Territories; a 1-y-old clearcut aspen area at the EMEND project near Peace River, Alberta; and a 10-y-old burned, mixed forest near Prince Albert National Park, Saskatchewan. Nearby mature forest stands of the same types were also measured as controls. The harvested site had lower net radiation (R n ), sensible (H ) and latent (LE ) heat fluxes, and greater ground heat fluxes (G ) than the mature forest. Daytime CO2 fluxes were much reduced, but night-time CO2 fluxes were identical to that of the mature aspen forest. It is hypothesized that the aspen roots remained alive following harvesting, and dominated soil respiration. The overall effect was that the harvested site was a carbon source of about 1.6 gC m-2 day-1 , while the mature site was a sink of about -3.8 gC m-2 day-1 . The one-year-old burn had lower R n , H and LE than the mature jackpine forest, and had a continuous CO2 efflux of about 0.8 gC m–2 day-1 compared to the mature forest sink of - 0.5 g C m-2 day-1 . The carbon source was likely caused by decomposition of fire-killed vegetation. The 10-y-old burned site had similar H , LE , and G to the mature mixed forest site.... [ABSTRACT FROM AUTHOR]

The Montane Alternative Silvicultural Systems (MASS) partnership wasformed in 1992 to test new approaches to harvesting high-elevation old-growth forests of Vancouver Island, British Columbia. Uniform Shelterwood (SW), Green Tree Retention (GT) and Patch Cuttings (PC) were tested as alternatives to Clearcutting (CC). All systems were compared to an Old Growth (OG) control. Harvesting was completed in 1993. This paper summarizes the conclusions from the operational aspects of the study and reviews some early results from studies of the biological impacts. Harvesting costs to roadside were about 12% greater for the PC and GT and 49% greater for the SW. Cumulative losses to windthrow after three years were 25% in the GT and 5% in the SW. Site disturbance, soil compaction and rates of organic matter decomposition were low across all harvested treatments. Rates of organic matter decomposition and N mineralization on SW, GT and PC were intermediate betweenCC and OG. Nutrient loss in soil solution was reduced with partial harvesting but lack of available nitrogen is limiting the early growthof coniferous regeneration among all systems. During spring and summer, SW and CC treatments were generally cooler than PC or GT. Damage to understory vegetation and advanced conifer regeneration was least in the SW, which also provided the greatest amounts of seedfall amongall harvested treatments. [ABSTRACT FROM AUTHOR]

Provides information on a study which characterized optimal harvesting policies for a renewable resource under stationary conditions in Canada. Notations and assumptions of the study; Optimal strategy types; Comparative dynamic properties of optimal continuous harvesting and abandonment policies.