Biogeoclimatic ecosystem classification is a system of ecological classification widely used in British Columbia. The system has been expanded by the B.C. Forest Service from the pioneering work of V.J. Krajina and his students. The recognized units result from a synthesis of vegetation, climate, and soil data. The approach to classification is hierarchical with three interrelated levels of integration. The multiple-category, local and regional levels involve vegetation and site; a chronological level deals with vegetation dynamics. Taxa of any level and category can be integrated according to their interpretive value for management.Vegetation units are defined and arranged into a floristic hierarchy based on the plant association, using traditional Braun-Blanquet methods modified to suit regional conditions. Where possible, zonal (climatic climax) plant associations are identified, thus defining biogeoclimatic subzones, which are divided into variants and aggregated into zones, regions, and formations. Plant associations are transformed into site associations-environmentally characterized classes of ecosystems with similar biotic potential. Site associations are then subdivided into series and types, using biogeoclimatic and adaphic characteristics as differentiae. Examples of classification at local and regional levels are provided, as are examples of management applications.Biogeoclimatic ecosystem classification is a unique approach that draws on several of the European (including Russian) and North American schools of vegetation and land classification, and has similarities with the Cajander forest type, Barnes land type, Daubenmire habitat type, and Hills site type approaches. The classification provides a powerful integrative and predictive tool, with proven practical value for forest managers.
Activities that remove CO2 from the atmosphere and store it in forest and agricultural ecosystems can generate CO2-offset credits that can thus substitute for CO2 emissions reduction. Are biological CO2-uptake activities competitive with CO2 offsets from reduced fossil fuel use? In this paper, it is argued that transaction costs impose a formidable obstacle to direct substitution of carbon uptake offsets for emissions reduction in trading schemes, and that separate caps should be set for emissions reduction and sink-related activities. While a tax/subsidy scheme is preferred to emissions trading for incorporating biologically-generated CO2 offsets, contracts that focus on the activity and not the amount of carbon sequestered are most likely to lead to the lowest transaction costs.
Traditional residual conversion return methods of stumpage appraisal, although consistent with economic theory, are not appropriate for the forestry sector in Canada. Imperfect competition, dynamic residual values, and the forest tenure system pose complications which prevent such methods from adequately representing stumpage values. In developing new stumpage fee systems, decision makers will have to consider these complications and assess whether and how residual conversion return methods may be adjusted to adequately reflect the value of standing timber. Key words: stumpage, residual conversion return, wood values, economic rent
Sociology has made only minor contributions to forest management and policy in the past. Changes in the dominant paradigm of forest management have opened a window of opportunity for practical applications of sociology in a forestry context. Sociological analyses of stakeholder values, social movements, conflict and its resolution, poverty in forest-dependence regions, complex organizations, and global restructuring may provide insight and valuable data to forest managers and policy makers. Recent theoretical advances with respect to community stability may also have important policy implications. Key words: Community stability, social movements, public involvement, stakeholder values, rural poverty
This paper was presented as a keynote address at the conference on Forest Sustainability --- Beyond 2000 held in May 2000 in Thunder Bay, Canada. The conference brought together forest sector leaders and professionals from across Canada. This paper is an extension of earlier work on the sustainability of North American wood supplies (Nilsson et al., 2000). The present paper examines the efficiency of the current established criteria and indicators for sustainable development of the forest sector. The current system of criteria and indicators concentrates on the management aspects instead of the objectives setting. The current system is too complicated to be implemented and neglects the fact that sustainability cannot be achieved by a top-down approach but only by the people working on the ground at the local level. This paper presents a number of guidelines on the necessary steps to be taken in order to move towards A Forest Sector for Sustainable Development. iv About the Authors ...
In 1920 varying amounts of white spruce and jack pine seed were sown on a series of small plots located on a well prepared seedbed of mineral soil. In 1957 only a few scattered specimens of jack pine survived, but the spruce plots supported a dense and apparently thrifty stand.
The results of further progress in a poplar hybridization project initiated in 1935 with the aim of producing valuable hardy and disease resistant material of rapid growth for the production of wood of high quality for industrial purposes, and of value for shelterbelts in the Prairies are reported. It has been possible to cross the native aspens of Eastern and Western Canada with several exotic aspens and their hybrids with silver poplar, and to obtain hybrid material of great promise for these purposes. Some western balsam poplars have also been crossed with exotic species and have yielded hybrids of promise for shelterbelts. An attempt to cross an aspen with a cottonwood has so far yielded indifferent results. The cross of a basket willow with a cottonwood was not successful. Hardiness, disease resistance, and good propagability from stem or root cuttings are at present the most important characters used in evaluating the young hybrids.
In 1958 considerable injury occurred to trees growing in Manitoba and Saskatchewan as a result of unusual weather conditions which prevailed between October 1957 and June 1958. Unreasonably warm temperatures and strong winds during the winter months caused winter drying of conifers. A severe frost in late April, which had been preceded by temperatures of above 80°F, and lighter frosts that occurred periodically throughout May and June, caused extensive injury to buds and foliage of both coniferous and deciduous trees
Release of white spruce from aspen competition improved spruce diameter at breast height (dbh), height and volume growth in the 35-year period following aspen removal. Overall, release improved spruce periodic growth by 41% in diameter, 38% in height and 82% in volume over the control for sample trees ranging from 5 to 65 years of age.Responses varied with site and age classes. Improved periodic dbh and height growth occurred in trees released throughout three age classes on good sites and in trees released at 26 to 45 years of age on medium sites.
Sustainable forest management has replaced sustained yield as the new management strategy for most countries and forest companies. This concept has generated a lot of interest and discussion, and a great deal of effort is being made to modify current forestry practices to be sustainable. In this paper, we argue that the still somewhat vague concept of sustainable forest management calls for a substantial modification in our way of thinking about and practicing forestry. To move toward that goal, we recognize important social and economic challenges to sustainable management and suggest nine essential notions: 1) manage the forest ecosystem as a whole and not in parts nor only for the crop species; 2) conserve a significant proportion of the boreal forest (i.e., at least 12%); 3) practice intensive forestry on a small portion of the land to recover the fibre lost from notions 1 and 2; 4) strive for innovation in thinking and acting; 5) foster research and development to support notion 4; 6) balance regional needs with that of the global community; 7) encourage public participation; 8) consider the impact of substantial change in climate over the next 100 years (or next rotation); and 9) substitute regulations that are adaptive for those that are restrictive. An example of the kind of silviculture that could be used in ecosystem management for the black spruce forest is also discussed.
Li-Cor weather stations and thermistor/resistance soil cells were used during 1994 to monitor microclimate in young spruce plantations during the first growing season after the following replicated alternative conifer release treatments [brush saw, Silvana Selective, Release® (a.i., triclopyr) herbicide, Vision® (a,i., glyphosate) herbicide], and control (no treatment) were applied. Treatments were conducted in mid-August (herbicides) and late October and early November (cutting) 1993. In 1994, temperature, photosynthetically-active radiation (PAR), and relative humidity (RH) were monitored near (0.25 m) and above (2 m) the forest floor. Fiberglass thermistor/resistance soils cells were installed 15 and 30 cm deep, and soil moisture and temperature were read bimonthly. In relation to controls, PAR near and above the forest floor increased on all conifer release treatments. By July, PAR near the forest floor declined on both the cut and herbicide treatments. That decline occurred in early July for the brush saw treatment, but in late July for the Vision® treatment. PAR at 2 m was similar among conifer release alternatives and significantly greater than for controls throughout the growing season. Increased solar radiation resulted in significant soil warming following the conifer release treatments. During the growing season, duff(5 cm) and mineral (15 cm) soil temperatures were highest for the Vision® and Release® treatments, and lower on the brush saw and control treatments. November soil temperatures were slightly cooler in released than control plots. Frequent rains resulted in relatively high RH and soil moisture readings during the 1994 growing season. Relative humidity near the forest floor was lowest for the Vision®, intermediate for the brush saw, and highest for the control treatments. During the growing season after treatments, soil moisture levels were higher on treated than control plots.
The Kyoto Accord on climate change requires developed countries to achieve CO2-emissions reduction targets, but permits them to charge uptake of carbon (C) in terrestrial (primarily forest) ecosystems against emissions. Countries such as Canada hope to employ massive afforestation programs to achieve Kyoto targets. One reason is that foresters have identified large areas that can be afforested. In this paper, we examine this forestry option, focusing on the economics of afforestation in western Canada. In particular, we develop marginal C uptake curves and show that much less land is available for afforestation than would be the case if economics is ignored. We conclude that, while afforestation is a feasible weapon in the greenhouse policy arsenal, it might not be as effective on an economic basis as many forest-sector analysts make out.
A 1980 study compared wood volume production from 10-19 year-old naturally regenerated aspens growing on a loamy sand with the growth of 10-17 year-old hybrid poplars planted as one-year old rooted cuttings in a loamy soil in the Morgan Arboretum, Macdonald College, Quebec.Average volume per aspen sucker was 0.083 m³ versus 0.357 m³ for the hybrid poplars. The hybrids, on a better site but two years younger in age produced four times the volume growth of the natural stand regenerated following a strip clear cut in 1961. Both stands were thinned prior to the yields reported. The growth increment differences between stands was significant at the 0.01 level of probability.In spite of the better yields produced by the hybrids, the authors suggest that the potential for economic short rotation forest management from natural coppice hardwoods should be investigated more fully.
The rate of canker growth, caused by HYPOXYLON PRUINATUM (Klotzsch) Cke. (H. MAMMATUM (Wahl.) Miller) and the intensification of the disease were investigated on trembling aspen, POPULUS TREMULOIDES Michx. in Elk Island National Park, Alberta. In 1963, 45.1 per cent of the trees on a 1/3-acre plot were either killed or infected. This number increased to 49.0 per cent during the following three years. All stem cankers were located below the 9 foot level and 75.0 per cent were facing north or northeast. The disease was not confined to a particular crown class. Infected, trees were killed in 4 to 8 years. Fifteen cankers were sectioned to study the nature of canker growth. The rate of girdling was not related to either the diameter or dominance of the tree. The cankers grew at a faster rate on dominant and co-dominant trees during the initial year of infection than on intermediate and overtopped trees. The disease did not cause increment loss during the infection period.
Stem growth data from breast height were collected from about 2000 trees on 192 sample transects (plots) located adjacent to seismic lines. Sampled stands represented the most important forest cover types between 10 and 100 years of age over a range of site conditions in the foothills of western Albetra from Rocky Mountain House to Grande Prairie. Line clearing stimulated breast height radial increment fairly consistently in the 20% range of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) trees. This improvement expressed in terms of stand growth, however, fell far short of that required to make up for the loss of wood production over these lines if the cut trees are not utilized. The lack of significant stimulation from line clearing in aspen (Populus tremuloides Michx.) stands indicates a complete loss of production due to the lines.
Between 1980 and 1990, poplar (mainly trembling aspen, Populus tremuloides Michx.) harvested on Crown and private lands in Alberta increased from 2.4 to 24.7% of the total harvest. In 1987-90, three oriented strandboard mills used more than 40% of the 1.4 million m³ of annual harvest of poplar from Crown and private lands. By the year 2000, the poplar harvest of five pulp and paper mills to be built between 1990 and 2000 is expected to reach about 8.5 million m³. By then, the pulp and paper industry will use about four-fifths of all poplar cut in Alberta. -Author
In northeastern Alberta, the current biomass and periodic annual biomass increment (PAI) was measured in 29 stands of maturing aspen (Populus tremuloides)-white spruce (Picea glauca), aged 48 to 105 years. Plots in pure aspen were paired with nearby plots of aspen growing on a similar landform but with a spruce understory. Biomass was estimated by diameter at breast height and allometric equations. Totalled over both species, there was 10.5 % greater PAI and 10.0 % greater biomass in the mixed plots than in the pure aspen plots. Pure aspen plots, however, had 12.9% greater aspen biomass and 25.2% greater aspen PAI than the aspen component of mixed plots. The apparent decline in productivity of aspen in the mixed stands, however, could not be related to the variation in spruce abundance in these mixed stands.
A portable delimber-debarker-chipper, designed for in-woods chipping operations, was used to produce waste bark and wood residue from winter-harvested tree-length trembling aspen logs. The residue was then utilized to create leachate, which was subsequently used to treat white spruce, lodgepole pine, paper birch, aspen and Calamagrostis canadensis seedlings grown in sand-filled pots. Treatment with the leachate significantly decreased height growth and shoot and root dry weights of all species relative to the control treatment. Root:shoot ratios of all tree species except lodgepole pine were increased significantly by application of leachate. The root:shoot ratios of treated C. canadensis were significantly increased during one season, but significantly reduced in the following season. The data indicated that leachate from aspen bark and wood residue contain allelochemical properties that could affect the regenerative capacity of aspen cutblocks harvested for in-woods chipping operations.
We model and compare the biological and financial constraints of four prescriptions that serve as alternatives to conventional clearcutting followed by planting in eastern and western boreal mixedwood stands. These alternative prescriptions for full or partial conifer stocking are (1) reliance on advance regeneration with or without augmentation by fill-planting; (2) understory scarification during a mast year; (3) direct seeding either aerially or with a scarifier-seeder; and (4) underplanting. Our main conclusions concerning the biological constraints are that (1) advance regeneration, mainly of balsam fir in the east and white spruce in the west, requires >26 000 and > 4000 trees/ha (because of different distributions), respectively, to achieve full conifer stocking; (2) reliance on a mast year requires at least 6 m2/ha of mature conifer basal area, but much less if some advance regeneration is present or only moderate stocking is desired; (3) aerial seeding with 35% scarification requires about a half-million seeds/ha to achieve full conifer stocking, while a scarifier-seeder would require only a third of this application rate; and (4) underplanting is constrained to aspen stands with >25% incident light at planting height. In all cases, alternative prescriptions become more feasible if only moderate or minimal stocking is the silvicultural objective. A costing exercise for the four prescriptions in comparison with a clearcut followed by planting shows that reliance on advance regeneration or understory planting are the cheapest alternatives to achieve full or partial conifer stocking. With the exception of full conifer stocking in situations where there is little advance regeneration (and where herbicides can be used), conventional plantations are never the cheapest approach. In such cases, fill planting and use of a scarifier-seeder become viable options. Aerial seeding and reliance on a mast year are the most expensive of the alternatives. We conclude, tentatively, that there is enough conifer basal area in most of the eastern boreal mixedwood of Canada to allow for the use of either or both a mast year and advance regeneration to achieve full or partial conifer stocking. By contrast, in the west conifer basal area will seldom be sufficient for natural seeding, and the density of advance regeneration is likewise often too low. Finally, because of light constraints, understory planting appears to have a much wider applicability in the west than in the east.
For many years silviculture and fire management have mostly been separate forestry disciplines with disparate objectives and activities. However, in order to accomplish complex and multiple management objectives related to forest structure, fuels, and fire disturbance, these two disciplines must be effectively integrated in science and practice. We have linked scientific and management tools to develop an analytical approach that allows resource managers to quantify and evaluate the effectiveness of alternative fuel treatments in dry interior forests of western North America. The principal tool is the Fire and Fuels Extension of the Forest Vegetation Simulator (FFE-FVS) for characterizing fuel succession and fire behaviour, and for quantifying and visualizing stand structure. FFE-FVS provides a user-friendly framework that facilitates rapid evaluation of thinning and surface fuel treatments intended to reduce crown fire potential and fireline intensity. This approach quantifies fire hazard at small and large spatial scales, assists with treatment priorities and schedules, and generates stand and landscape visualizations that facilitate decisions about appropriate fuel treatments.
Aspen poplar, although widely distributed over the northern half of North America, is greatly underutilized. However, because of its ease of reestablishment through vegetative reproduction, its short rotation management on appropriate sites and new technological development favouring such uses as chemimechanical pulp and waferboard, the forest industry will probably pay more attention to it in the future. Regional differences throughout its range are discussed for Ontario, the Prairie Provinces and the U.S. Lake States.
Three methods of seeding white spruce—in the humus layer, in moss, and on scalps—at the base of aspen were tested in dense young and open mature stands. Results indicated that scalps prepared at the base were more favourable for germination than either of the other two seedbeds tested, and for seedling survival more favourable than control scalps prepared between trees.
Much has been learned of the ecology, management, and utilization of aspen and several comprehensive reviews are available. The development of forest ecosystem classifications as a framework for intensive management has occurred mainly in the past 10 years and such site classifications are now available for British Columbia, Alberta, Saskatchewan and Ontario in areas where aspen is important. The relevance of several such ecological site classifications to aspen management in Canada is discussed.
Seedlings of white pine, red pine, and white spruce which had germinated in a spot-seeding experiment, and which had been suppressed for 27 years under a mature aspen-pine stand were released in 1950. The development of a new dense stand of aspen suckers permitted conifer growth rates of about 0.3 m per year for the next 30 years (not as rapid as for open grown trees) yet limited white pine weevil damage. The stand was thinned in 1980 to remove the aspen and all but the best stem of the coniferous species at each seed spot.
A study was started in 1965 to quantify the effect of logging variables on initial sucker stand density and subsequent development of aspen (Populus tremuloides Michx.). The study found excellent stocking and density of sucker regeneration after both summer and winter logging of 70- to 80-year-old stands in east-central Saskatchewan. Logging slash on the ground reduced suckering but the density of regeneration even with heavy slash cover was similar to that found in fire-origin stands. Winter logging resulted in more uniform and less dense sucker regeneration. Large initial differences in stand density diminished to a 30% range or less by 5 years of age. This suggests that flexibility may be exercised in harvest scheduling and method of logging.
Ovendry mass of single trees of trembling aspen, largetooth aspen, and white birch in the Great Lakes — St. Lawrence and Boreal forest regions in Ontario was studied in relation to stem dimensions. Mass equations for tree components based on diameter at breast height outside bark and tree height were developed. Results were found more dependable for stem wood and the whole tree than for stem bark, live branches, and twigs plus leaves. Ovendry mass values were slightly higher than those reported for New York and northern Minnesota.
Sustaining forest productivity requires maintaining soil productivity and prompt establishment of adequate regeneration following harvest. We determined effects of commercial, winter-logging of aspen-dominated stands on soil disturbance and development of regeneration on three sites with clay soils. We established transects across each site, recorded pre-harvest stand information, post-harvest site disturbance, and first-year aspen sucker density and height. Use of large logging equipment produced heavy disturbance on 38% of a well-drained site; 45% of the area had no aspen suckers and 82% had less than the recommended minimum of 15 000 (15 k) suckers per ha (6 k ac-1). Mean height of dominant suckers was 45 cm (18 in). Hand felling and a small skidder caused heavy disturbance on 12% of a moderately well-drained site. Sucker density averaged 34 k ha-1(14 k ac-1) and height was 97 cm (38 in). Cut-to-length (CTL) equipment produced heavy disturbance on 11% of a somewhat poorly-drained site, mean sucker density of 24 k ha-1(9.6 k ac-1), and height Of 101 cm (40 in). These severely disturbed areas essentially are removed from the aspen-producing land base. Retaining the northern hardwood and conifer growing stock would result in less site disturbance and help maintain natural hydrologic and nutrient cycling processes.
A study of aspen sucker stands subjected to repeated harvesting at the Petawawa National Forestry Institute compared biomass production at rotations of 1, 2, 3, 5, 8,13, and 20 years. The shortest rotation at which sucker production can be physiologically sustained is unlikely to be less than 10 years. Biomass mean annual increment appeared to culminate at about 15 years. Declining yields at the shorter rotations were thought due mainly to starvation of rootstocks by the frequent removal of the photosynthesizing tops on which they depend for nourishment. High incidence of Armillaria infection in stump roots probably contributed to the diminished quantity and size of suckers, and may prove to be a serious factor in short-rotation systems for aspen. On the basis of foliar analysis there was no evidence of nutrient deficiency at any rotation.
This paper elaborates certain procedures briefly outlined in an earlier article. Although dry wood from dead trembling aspen has been found best suited to growth-ring analysis, in its absence use has been made of water-saturated wood from the underside of fallen trunks. A technique of wax impregnation, adaptable to wood in both early and advanced stages of decay, is described. Rapid impregnation with near-boiling wax is sufficient to facilitate transverse sectioning of relatively sound wood; advanced decays require a slower impregnation with cooler paraffin. Hot xylol is used to remove the wax and flatten the section. Successive, overlapped sections provide an extended series of measurements to establish the orientation in time of mortality. Incomplete rings for the years just prior to death are checked by measurement of the outer growth at additional points.
Quaking aspen (Populus tremuloides Michx.) is a remarkable species that performs several significant ecological roles throughout its range while at the same time is facing ever-increasing harvesting pressure. Although its full product potential remains untapped, aspen utilization has increased noticeably in the past 15 years as it has become a desired species for engineered wood products such as oriented strand board, and a preferred hardwood in the production of high quality pulp and paper products. Concurrent with this increase in aspen utilization has been an increase in the importance of ecological concepts in forest management. Any new silvicultural concepts in aspen management designed to address these ecological concepts must be grounded in the silvics and life history traits of the species. Here we present three trends in aspen management; aspen retention, a renewed interest in aspen thinning, and the advent of cut-to-length (CTL) harvesters that allow forest managers to address these considerations by capitalizing on aspen's unique characteristics. Finally, we discuss traditional harvesting methods and these trends in the context of their genetic implications.
In many cases, complete clearcutting will ensure prompt restocking at a satisfactory level without the need for further treatment. However aspen has traditionally been underutilized, and this led to the development of decadent stands. Aspen has such a large range that regional adaptations may be necessary for consistent success. Clonal differences have been used to a small extent to improve natural stands through silvicultural manipulations, but the potential of such techniques is low, as opposed to the use of genetic variations to develop more productive hybrids. -from Author
Repeated harvesting of young aspen sucker stands at the Petawawa Forest Experiment Station indicated that biomass production cannot be sustained on rotations of up to ca. 10 years. Results for longer periods are not yet available but growth trends point to at least 15 years as the minimum rotation age.
The propagation of aspen cuttings of sucker origin is described. The suckers were stimulated on root-cuttings planted in the greenhouse. Abundant suckers were produced and rooted without difficulty in plastic tube containers. Suckering and rooting ability varied between and within species and hybrids.
Soil disturbance from forest practices ranges from barely perceptible to very obvious, and from positive to nil to negative effects on forest productivity and / or hydrologic function. Currently, most public and private land holders and various other interested parties have different approaches to describing this soil disturbance. More uniformity is needed to describe, monitor, and report soil disturbance from forest practices. We describe required elements for attaining: (1) more uniform terms for describing soil disturbance; (2) cost-effective techniques for monitoring or assessing soil disturbance; and (3) reliable methods to rate inherent soil susceptibility to compaction, rutting, mechanical topsoil displacement, and erosion. Visual disturbance categories are practical for describing soil disturbance. Soil disturbance categories for the Pacific Northwest are described in detail to illustrate essential elements for attaining Element One. A number of potential products are listed to meet the other elements. Completion of these will facilitate collecting comparable data and sharing research and training information. Coordinated efforts will also ensure a more seamless process for assessing and reporting for sustainability protocols, and responding to third-party certification protocols. Additionally, these products will improve operational relevance of research results.
Estimates of the location and extent of the red-attack stage of mountain pine beetle (Dendroctonus ponderosae Hopkins) infestations are critical for forest management. The degree of spatial and temporal precision required for these estimates varies according to the management objectives and the nature of the infestation. This paper outlines the range of information requirements associated with mountain pine beetle infestations, from the perspectives of forest inventory, planning, and modeling.Current methods used to detect and map red-attack damage form a hierarchy of increasingly detailed data sources. The capability of satellite-based remotely sensed data to integrate into this hierarchy and provide data that is complementary to existing survey methods is presented, with specific examples using medium (Landsat) and high (IKONOS) spatial resolution imagery. The importance of matching the information requirement to the appropriate data source is emphasized as a means to reduce the overhead associated with data collection and processing.
An experiment to limit damage by the white pine weevil (Pissodes strobi Peck), using strip-cuts aligned north-south to control the number of hours of direct sunlight falling on seedlings of white pine (Pinus strobus L.) planted on the strips, was carried out from 1964 to 1982 at the Petawawa National Forestry Institute. Strip widths (in relation to stand height) that would admit nominal values of 25, 50, 75, and 100% of daily full light were employed, and the experiment conducted in a pine-mixedwood and a mixed hardwood stand. Percentages of trees attacked by the weevil were clearly stratified by treatment in the mixed-wood stand, increasing from the narrow (25% light) to the open (100% light) strips. It was concluded that clear-cut strips in conifers or mixedwoods, where the ratio of strip width to stand height is in the range of 0.66 to 1.00 (admitting a nominal 50 to 75% of full light), will allow adequate numbers of white pine to reach a height of one log-length (5.2 m) free from weevil damage. However, rate of height growth will be diminished. This approach, which holds promise for natural regeneration of the pine or stand conversion by planting, is not effective in hardwood stands because leafless trees will not provide the necessary side shade when adult weevils are active in early spring.
This paper revisits 3 broad predictions about forestry’s future presented by the author in 1993: the growing importance of products that come from forests, forests increasingly valued for more than the sum of their products and uses, and better appreciation of forests as complex ecological systems controlled by forces larger than humans. These predictions have played out in more dramatic ways than initially envisioned, driven in part by 3 emergent forces: the energy crisis, the ascension of new economic superpowers, and climate change. Examples of these trends and relationships are examined from Canadian and United States contexts.
All species of bark beetles of economic importance prefer to attack freshly-killed host material. Logging slash, wind-throw, and fire-killed timber provide ideal breeding grounds for bark beetles. A few species, mostly in the Dendroctonus group, are able to kill living trees. When beetles in the group, raised in preferred host material, cannot find any or enough freshly-killed trees, logs, or slash to enter, they may attack living trees. In the interior of British Columbia, infestations of the Douglas fir beetle can often be traced to logging disturbance.
A 36-ha experiment was carried out to assess the possibility of naturally regenerating jack pine stands following harvesting on clay soils of northwestern Quebec. Although differences between treatments were not statistically significant, there was a trend toward a positive effect of one treatment combining on-site delimbing and scarification with the Silva Wadell(TM) cone scarifier on jack pine seedling density (up to 10 000/ha) and distribution (50% of 1 m2 plots with at least one seedling, corresponding to 94% with 4 m2 plots), two years after harvest. However, scarified microsites contained fewer seedlings than expected and undisturbed humus contained more seedlings than expected. This result, contrary to what is generally reported in the literature may be explained either by the fairly humid conditions, favourable to germination and seedling establishment, occurring on clay sites or by the scarifier spreading the cone-bearing slash outward. Seedling abundance and distribution improved substantially from the first year to the second year following treatment. Although the irregular branch distribution over the cutover area appears to have limited regeneration success, combining on-site delimbing with soil scarification could lead to relatively good stocking of jack pine regeneration that could be enhanced by some fill-planting. This regeneration method could constitute an alternative to planting jack pine on clay. However, vegetation control to remove aspen competition might be necessary.
An experiment was conducted to evaluate the effect of leaf smothering upon establishment of white spruce in Alaska. Treatment consisted of protecting seed-spots from leaf litter of an overstory paper birch stand with hardware cloth screens for varying periods. Protection significantly improved survival through the first four growing seasons following germination of the spruce seed. After the fourth growing season, most seedlings were large enough to avoid being smothered or crushed by fallen leaves; additional protection through the fifth growing season was not significantly beneficial. It appears unlikely that more than an occasional white spruce can become naturally established beneath birch stands in this region.
Terrestrial biodiversity is closely linked to forest ecosystems but anthropogenic reductions in forest cover and changes in forest structure and composition jeopardize their biodiversity. Several forest species are threatened because of reduced habitat quality and fragmentation or even habitat loss as a result of forest management activities. In response to this threat, integrated forest management (IFM) was developed in the early 1990s and has been applied over large spatial scales ever since. While IFM seeks to satisfy both human resource demands and ecosystem integrity, the whole forest matrix is affected and this may also have negative impacts on biodiversity. The concept of forest zoning (e.g., Triad) avoids these issues by physically separating land uses from each other. The zoning approach has been developed in the same period as IFM, but there are still very few examples of large-scale applications. This may be because its distinctiveness from IFM may not always seem clear and because forest zoning is not easily implemented. Here we explain these differences and show that IFM and the zoning approach are indeed different management paradigms. We advocate the use of high-yield plantations within the zoning paradigm as a means for biodiversity conservation and review the literature (with an emphasis on the northern hemisphere and on plantation forestry within a land-zoning approach) on impacts of forest management activities on biodiversity. Furthermore, we give advice on issues that require consideration when implementing forest zoning at both the stand and the landscape levels. We recommend several small changes in design and management of forest plantations as a means to significantly increase their biodiversity value. We conclude that while forest zoning seems an adequate strategy for the Canadian forestry sector, a shift in paradigm must carry over to policy-makers and legislation if this approach is to succeed.
Objective measures of forest ecosystem condition are needed to gauge the effects of management activities and natural phenomena on sustainability. The Bioindicators of Forest Condition Project seeks to develop a Forest Condition Rating (FCR) system using a physiological, remote sensing approach. In particular, the goal of the project is to test whether hyperspectral remote sensing may be used to infer stand-level information about pigment concentration, chlorophyll fluorescence, and other physiological features of condition. The project spans a four-year period of intensive sampling in tolerant hardwood forests in Ontario using the Compact Airborne Spectrographic Imager (CASI). For each airborne campaign, concurrent ground-based sampling for leaf physiological features was performed. Controlled laboratory and greenhouse studies were also conducted to derive relationships between leaf-based spectral measurements and physiology in the presence of environmental stresses. The project has identified several promising bioindicators of strain that are discernible from hyperspectral images and related to ground-based physiology. The most promising remote indicator for semi-operational testing is estimation of chlorophyll content, which can be used to classify maple stands on a five-stage scale of health. Chlorophyll fluorescence has also been discerned from spectral signatures, but our studies indicate it may be confounded by chlorophyll content. The intent here is to update the forestry community on progress made, insights gained, and the practical implications of the research.
A challenge facing forest managers is providing habitats for wildlife associated with mature or old-growth forests. One approach is to use partial cutting which maintains forest cover while still allowing timber harvest. We compared small mammal (voles, mice and shrews) and bird abundance after two intensities of partial cutting (30% and 60% volume removal) to clearcuts and uncut natural stands in coast-interior transitional forests of British Columbia. The 30% removal resulted in no significant difference in the bird community compared to the uncut stands, while southern red-backed voles (Clethrionomys gapperi) increased in abundance. Bird and small mammal communities in the 60% removal treatment were closer to the uncut forest than to clearcuts, but also included species typical of clearcuts. At least one bird species, Yellow-rumped Warbler (Dendroica coronata), was most abundant in the 60% removal treatment. Several species such as the meadow vole (Microtus pennsylvanicus) and Dark-eyed Junco (Junco hyemalis) were most abundant in clearcuts, and Lincoln's Sparrow (Melospiza lincolnii) and Chipping Sparrow (Spizella passerina) were almost exclusively found in clearcuts. Scattered aspen and birch trees left in two of the clearcuts were used as cavity nest trees by Red-breasted Sapsuckers (Sphyrapicus ruber), Hairy Woodpeckers (Picoides villosus), and Tree Swallows (Tachycineta bicolor). We concluded that both of the partial cutting treatments provided habitat for small mammals and birds typical of mature forest, although the heavy removal began to show a shift towards species typical of clearcuts. Because no single treatment was optimal for all species, we recommend that partial cutting be part of a landscape strategy to provide a range of habitat conditions similar to those occurring under natural disturbance regimes.
Conservation of genetic resources of forest trees has become a major objective for the management of forests. Much theoretical work has been devoted to the subject, and implementation has already started at the local, national, or international scales. Poplars are probably the most representative and threatened forest tree species of old natural floodplain forests in the temperate zone. Gene conservation needs to be integrated with intensive breeding activities, habitat conservation and restoration. For Populus nigra, while research in genetics and ecology is reinforced, a combined conservation strategy is applied at the European scale; simultaneously, the conservation of riparian ecosystems is also a priority. Research and application benefit from each other. The question now is the evaluation of such an integrated strategy. Criteria and indicators for the follow-up of gene resource management are progressively developed, but still need to be tested on the operational scale.