Black Spruce Plantations Research Articles

Retaining the largest aspen stems during motor-manual release allows to control aspen suckering in young mixedwood stands

Mixedwood stands containing aspens (Populus tremuloides or P. grandidentata) often convert to hardwood-dominated stands after harvesting due to the rapid regeneration of aspen from root suckers, even when sites are promptly replanted with conifer seedlings. Without the use of herbicides, this problem is usually dealt with several passes of motor-manual (“manual”) release of overtopped seedlings. The aim of this study was to test a variation of thinning from below treatment (thinning; only 20% of the largest aspens are retained), and to compare it against two traditional release treatments: broadcast brushing (brushing; 100% removal of aspen) or crop tree release (CTR; removal of competing vegetation 60 to 90 cm around planted spruce) and an un-treated control. The thinning treatment left the 20% larger aspen stems in place, in order that they continue exerting apical dominance on smaller suckers and limit re-suckering of the treated plots. Aspen suckering and growth of planted black spruce seedlings (Picea mariana (Mill.) B.S.P) were measured two- and four-growing seasons following treatments. Results four years after release application showed that the thinning and CTR treatments reduced aspen density by 61% compared to the brushing treatment. In addition, aspen individual stem volume in the thinning treatment was almost 10 times larger than the brushing and twice that of the CTR treatments. Spruce height and ground collar diameter (GCD; 5 cm aboveground line) were both measured, and while height increment was similar in all treatments, diameter increment was greater in the thinning treatment (+42%) compared to the control, brushing and CTR treatments (+17%). Thinning yielded better short-term results than the brushing release in terms of aspen re-suckering and aspen sawlog potential, highlighting the need for adapted silvicultural treatments based on the species’ ecology.

Early influences of tamarack (Larix laricina) on black spruce (Picea mariana) and its immediate environment in plantations

Mixed plantations are garnering increased attention due to their potential to provide a broader array of benefits compared to monocultures. Although numerous studies have indicated promising complementarity between black spruce ( Picea mariana) and tamarack ( Larix laricina), few have delved into individual tree growth interactions to thoroughly assess early growth complementarity. We sampled 119 planted black spruce and their immediate environment to quantify and qualify any differences between two conditions in young plantations: mixed tamarack (“mixtures”) and black spruce monocultures (“monocultures”) within young plantations. We investigated the effect of neighbouring under four perspectives: tree competition, microenvironment, foliar nutrients, and soil nutrients. Our results showed increased values for black spruce foliar nitrogen total concentration, soil pH, and canopy closure in mixtures compared to monocultures. Furthermore, black spruce stem volume was increased by 38.1% in mixture compared to monoculture. Black spruce stem volume was negatively affected (86% decrease) by the combined effect of shrubs and non-crop trees under high competition pressure, despite the plantation being mechanically released in 2017. Collectively, our results suggest that black spruce growing in mixtures holds a greater growth potential than black spruce in monocultures.

Allometric Equations for Estimating Biomass and Carbon Stocks in Afforested Open Woodlands with Black Spruce and Jack Pine, in the Eastern Canadian Boreal Forest

Allometric equations use easily measurable biometric variables to determine the aboveground and belowground biomasses of trees. Equations produced for estimating the biomass within Canadian forests at a large scale have not yet been validated for eastern Canadian boreal open woodlands (OWs), where trees experience particular environmental conditions. In this study, we harvested 167 trees from seven boreal OWs in Quebec, Canada for biomass and allometric measurements. These data show that Canadian national equations accurately predict the whole aboveground biomass for both black spruce and jack pine trees, but underestimated branches biomass, possibly owing to a particular tree morphology in OWs relative to closed-canopy stands. We therefore developed ad hoc allometric equations based on three power models including diameter at breast height (DBH) alone or in combination with tree height (H) as allometric variables. Our results show that although the inclusion of H in the model yields better fits for most tree compartments in both species, the difference is minor and does not markedly affect biomass C stocks at the stand level. Using these newly developed equations, we found that carbon stocks in afforested OWs varied markedly among sites owing to differences in tree growth and species. Nine years after afforestation, jack pine plantations had accumulated about five times more carbon than black spruce plantations (0.14 vs. 0.80 t C·ha−1), highlighting the much larger potential of jack pine for OW afforestation projects in this environment.

Resilience of natural forests can jeopardize or enhance plantation productivity

The demand for wood products continues to increase globally. Productivity of forest plantations can be greater than that of naturally regenerated forests. Plantation forestry could thus be employed to meet up to 75% of global wood supply by 2050. The resilience of natural forests could jeopardize plantation productivity. If the plantation scenario is not oriented in the same direction as the natural successional trajectories that are driven by resilience, then naturally regenerating tree species could recover to the detriment of planted species. Unproductive plantations will likely generate sustainability issues, as they must provide ecosystem services (e.g., wood fiber production) while being economically viable for forest management to be sustainable. Our general objective of our study was to assess whether resilience of natural forests can jeopardized plantation productivity. We studied successional trajectories in recent, young and old black spruce plantations that are located within the balsam fir ecological region on balsam fir ecological site types. To compare with a plantation scenario that was more susceptible to aiming in the same direction as resilience-driven successional trajectories, we also studied successional trajectories in recent, young and old black spruce plantations that are not only located within the balsam fir ecological region, but on black spruce ecological site types. Successional trajectories on balsam fir ecological site types pointed towards recovery of balsam fir and white birch, to the detriment of black spruce. Successional trajectories on black spruce ecological site types pointed towards the recovery of black spruce. Thus, we showed that resilience of natural forests could jeopardize plantation productivity when the plantation scenario is not oriented in the same direction as resilience-driven successional trajectories. It also can enhance plantation productivity when the regime is oriented in the same direction as resilience-driven successional trajectories. To ensure that plantations are economically viable and promote sustainability, forest managers should thus favor plantation scenarios that point in the same direction as resilience-driven successional trajectories. Finally, we suggest adopting such scenarios, and stress that it would also be necessary to develop regimes that would promote sustainability in the context of alternative successional trajectories that will undoubtedly arise because of global changes.

Inside and outside bark volume models for jack pine (Pinus banksiana) and black spruce (Picea mariana) plantations in Ontario, Canada

Accurate estimates of tree stemwood volume are a fundamental requirement for sustainable forest management. As jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana Mill. BSP) are the p...

The impact of a black spruce (Picea mariana) plantation on carbon exchange in a cutover peatland in Western Canada

Northern peatlands are sinks for atmospheric carbon (C), but peat extraction converts these ecosystems to C sources. Due to a dry regional climate, undisturbed bog peatlands in western Canada often have a tree cover of Picea mariana (Mill.) B.S.P. Thus, a coniferous forest plantation may be an appropriate land use for cutover peatlands. This study determined the effect of a 7-year-old P. mariana plantation on C balance of a cutover peatland. We measured C stored in P. mariana biomass and carbon dioxide (CO2) and methane (CH4) fluxes from bare peat at each of four fertilizer doses. Carbon stored in biomass of Betula papyrifera (Marsh.) that had spontaneously colonized the postfertilized site was also determined. Given that the water table remained very deep and that the sphagnum moss – ericaceous shrub peat-accumulating vegetation was not present, the site remained a source of C when only the planted P. mariana trees were considered, primarily in the form of CO2 emissions by soil respiration. However, C accumulation in trees, including B. papyrifera biomass, resulted in a net C sink in fertilized plots. Results from this study indicate that tree plantations on cutover peatland may be a suitable land-management strategy on sites difficult to effectively rewet.

Fast-growing hybrids do not decrease understorey plant diversity compared to naturally regenerated forests and native plantations

Plantations of fast-growing hybrid trees, such as hybrid poplars and hybrid larch, are increasingly used for wood and timber production, but they are also believed to impair forest biodiversity. Most studies that have assessed how such plantations may alter the diversity and composition of understorey plants were established in agricultural landscapes or have compared tree plantations with old-growth natural forests. Moreover, many important aspects of biodiversity have been overlooked in previous studies, such as functional and beta-diversity. Here, we present results from a study that was aimed at quantifying alpha- and beta-diversity of understorey plant species and functional groups in hybrid poplar (9–10 years) and hybrid larch plantations (16 years) located within a forested landscape of Quebec, Canada. These hybrid plantations were compared to naturally regenerated secondary forests and to native plantations of black spruce of the same origin (clear cut) and similar age. Our results indicate that fast-growing hybrid plantations do not present lower taxonomic and functional alpha-biodiversity indices, but may harbour more diverse communities, in part through the introduction of plant species that are associated with open habitats. We provide further evidence that planted forests may be as heterogeneous as naturally regenerated forests in terms of understorey plant composition. Plant species and functional composition differed slightly between stand types (naturally regenerated forests, native and fast-growing hybrid plantations), with plantations offering a greater potential for colonisation by ruderal species, while being detrimental to species of closed forest habitats. Lastly, plantations of fast-growing hybrids do not induce greater changes in understorey vegetation relative to native plantations of black spruce, at least during the first stand rotation.

Assessing Soil-Related Black Spruce and White Spruce Plantation Productivity

This article focuses on modelling and mapping the productivity of black (Picea mariana) and white spruce (Picea glauca) plantations across the Black Brook forest management area in northwestern New Brunswick, Canada, encompassing about 200,000 ha. This effort involved establishing 3500 50 m2 survey plots, each informing about: plantation age (15 to 43 years), planted species type, stem count, tree height, basal area, and wood volume. All of this was supplemented with location-specific productivity predictors, i.e., xy location and specifications pertaining to soil type, soil drainage (established through digital elevation modelling by way of the depth-to-water index DTW), and years since thinning (pre-commercial and commercial), and. The DTW index, as it emulates the elevation rise away from open water features such as streams, rivers and lakes, allowed the re-mapping of existing soil borders by topographic position and drainage association. Non-linear regression analysis revealed that plantation height, basal area and volume all increased with plantation age, as to be expected. Pre-commercial thinning in plantations <30 years old had a positive while the more recent commercial thinning still had the negative effect on standing wood volume and mean annual volume increment (MAI). White spruce MAI generally exceeded black spruce (MAI) by a factor of 1.25. Poor and excessive soil drainage reduced MAI. Best growth performances occurred on plantations established on well-drained calcareous soils. The best-fitted results so obtained allowed for generating black and white spruce MAI maps across the forest management area by ridge-to-valley soil and DTW location at 10 m resolution. These maps were subsequently used for site-by-site silvicultural evaluation and ranking purposes.

Simulating the Potential Effects of a Changing Climate on Black Spruce and Jack Pine Plantation Productivity by Site Quality and Locale through Model Adaptation

Modifying the stand dynamic functional determinates of structural stand density management models (SSDMMs) through the incorporation of site-specific biophysical height-age equations enabled the simulation of the effects of increasing mean temperature and precipitation during the growing season on black spruce (Picea mariana (Mill.) BSP) and jack pine (Pinus banksiana Lamb.) plantation productivity. The analytical approach consisted of calculating future values of growing season mean temperature and precipitation rates under three emissions scenarios (no change (NC); B1; and A2), spanning three continuous commitment periods (2011–2040; 2041–2070; and 2071–2100), for three geographically separated sites throughout the central portion of the Canadian Boreal Forest Region (north-eastern (Kirkland Lake); north-central (Thunder Bay); and north-western (Dryden) Ontario, Canada), using the Canadian Coupled Global Climate Model (CGCM3) in conjunction with a geographic-referencing climatic surface model. These estimates were entered into the embedded biophysical equations in the SSDMMs in order to forecast emission-scenario-specific developmental patterns of plantations managed under a conventional density management regime by species and site quality (poor-to-medium and good-to-excellent) at each locale; from which stand development rates and associated productivity metrics over 75 year-long rotations were estimated and compared (e.g., mean sizes, volumetric, biomass and carbon yields, end-products, economic worth, stand stability, wood quality indices, and operability status). Simulation results indicated that black spruce plantations situated on both site qualities at the north-western location and on the lower site quality at the north-eastern location were negatively affected from the predicted increased warming and rainfall as evidenced from consequential declines in stand development rates and resultant decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth (A2 &gt; B1). Conversely, black spruce plantations situated on both site qualities at the north-central location and on the higher site quality at the north-eastern location were minimally and positively affected under the A2 and B1 scenarios, respectively. Jack pine plantations situated on both site qualities at all three locations were negatively affected as evident by the reductions in stand development rates and rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth (A2 &gt; B1). Collectively, these response patterns suggest that stand-level productivity under a changing climate will vary by species, site quality, geographic locale, and emission scenario, potentially resulting in a landscape-level mosaic of both negative and positive productivity impacts in the case of black spruce, and mostly negative impacts in the case of jack pine. As demonstrated, modelling stand-level responses to projected increases in thermal and moisture regimes through the modification of existing stand-level forecasting models, and accounting for divergent effects due to species, site quality, and geographic locale differences, is a viable and efficient alternative approach for projecting productivity outcomes arising from anthropogenic-induced changes in growing conditions.

Quantifying size-dependent developmental trajectories of commercial-relevant fibre attributes within maturing black spruce plantations employing hierarchical linear models

The primary objective of this study was to quantitatively describe size-dependent developmental trajectories of commercially-relevant fibre attributes within maturing black spruce (Picea marina (Mill.) B.S.P.) plantations employing hierarchical linear models. A stratified random sample design was deployed within 5 density-stressed semi-mature plantations to obtain transverse breast-height radial xylem sequences from 47 trees representing 5 basal area size classes (quintiles). The cumulative annual ring-area-weighted moving average proceeding from the pith to the ith cambial age was calculated for density, microfibril angle, modulus of elasticity, fibre coarseness, tracheid wall thickness, tracheid dimensions (radial and tangential diameters) and specific surface area. Hierarchical linear regression models were used to quantify size-dependent effects on these developmental trajectories: (1) at the first hierarchical level, compound exponential models were specified following the assessment of a set of candidate functional forms; and (2) given (1), at the second hierarchical level, linear model specifications under fixed and random error structures were used to account for potential size-dependent effects on the first-level parameter estimates. In order to ensure statistically valid inferences regarding size-dependence by employing radial sequences devoid of serial correlation, and provide an independent data set for evaluating the parameterized models in terms of goodness-of-fit, lack-of-fit and predictive ability, the data set consisting of 1566 observations per attribute was systematically stratified into parameterization and valuation subsets. The results revealed that the parameters of the Hoerl-based compound exponential model varied by tree-size indicating the presence of significant (p⩽0.05) size-dependence in fibre attribute developmental trajectories. Statistical measures of model performance and associated graphical analysis of the final specifications indicated that the models performed well in terms of accounting for a relatively large proportion of variation (61–88%), unbiasedness and predictive ability (e.g., temporal invariant patterns in absolute and relative prediction errors). These results and related inferences demonstrated the utility of quantifying size-dependent fibre developmental trajectories employing hierarchical linear models.

Effects of initial planting density on tree and stand development of planted black spruce up to age 30

The effect of initial planting density on tree and stand development was investigated for a 30 year old black spruce plantation in northeastern Ontario. The data came from upland and transitional peatland sites where black spruce (Picea mariana (Mill.) B.S.P.) was planted at inter-tree spacings ranging between 1.25 and 4.00 m. A modified Chapman-Richards function was fit to observations of top height, total volume, basal area, quadratic mean diameter and cumulative stem mortality in relation to initial planting density, stand age and site quality. With the exception of mortality, the fitted models accounted for most of the variation in the response variables. Total volume and basal area increased strongly with initial planting density, whereas quadratic mean diameter decreased. The results quantify the tradeoff between stand volume and individual tree size to age 30, which will help forest managers make better decisions about initial planting density for black spruce plantations on similar sites.

Black spruce (Picea mariana) restoration in Kalmia heath by scarification and microsite mulching

Canopy removing disturbance such as clearcutting and fire in nutrient-poor boreal and temperate forests often create shrub-dominated vegetation causing significant delay in forest succession. Lack of favourable microsites for black spruce seedling establishment and growth has been identified as the primary cause for conifer regeneration failure in post-fire Kalmia heath in eastern Canada. The aim of this study was to compare the growth performance of black spruce planted in scarified plots and in microsites developed by a novel technique called micro-site mulching (MSM) in Kalmia heaths. We hypothesized that because of vegetation removal and exposure of mineral soil in scarified and MSM treatments, planted black spruce would suffer from frost heaving and animal browsing, but these treatments may offer better seedling growth by ameliorating the inhibitory effects of Kalmia organic matter and providing with favourable soil moisture, soil temperature, soil respiration and nutrient availability. We conducted this study in a 13year-old post-fire Kalmia heath in Triton Brook, Newfoundland, Canada (48°30′N, 50°00′W). We measured black spruce seedling survival and growth annually for three complete growing seasons and soil nutrient availability one year post-planting. In all three treatments black spruce seedling survival was >90%. About 20% of the seedlings in scarified and MSM treatments suffered herbivore damage and frost heaving with little damage in control plots. Black spruce in scarified and MSM plots were associated with significantly higher growth than control, with differences amplified each consecutive year since planting. Higher seedling growth in scarified and MSM plots was associated with higher soil moisture, lower organic matter content, and lower soil temperature. Soil nutrient differences in treatments had little effect on seedling growth. Since MSM treatment produced substantially less soil disturbance with similar or better seedling growth than scarification, we suggest MSM as a preferred site preparation technique in Kalmia heath in contexts where large-scale soil disturbance by standard mechanized scarification is undesirable. The novelty of his paper is the development of MSM as a potential alternative to scarification in creating suitable microsites for planted black spruce to restore forest cover in ericaceous heaths. However, an operationally suitable MSM tool must be developed and a longer-term (10years) monitoring is necessary before the method can be applied as a restoration tool.

Comparing growth patterns of jack pine and black spruce in mixed natural stands and plantations

This study examined changes in individual tree height and diameter at breast height and stand-level gross total volume over time, comparing plantation-grown jack pine (Pinus banksiana) and black spruce (Picea mariana) to wildfire-origin, mixed conifer stands. Mensurational data were collected from fixed-area plots in 32 plantations (15 jack pine; 17 black spruce; age 6–64 y) and 21 fire-origin conifer-dominated stands (jack pine/black spruce mixtures; age 4–91 y). Using a generalized three-parameter modified-Weibull function, we described relationships for individual tree and standlevel measures of growth and age for managed and natural origin stands, separately, and then compared the functions to assess growth pattern differences between managed and natural stands. Both the black spruce and jack pine plantations consistently outperformed the natural stands based on all measured individual and stand-level parameters, and significantly lowered the age to operability of the trees. For example, the modeled gross total volume at age 50 resulted in “improved” volumes over the natural stands of 35% and 50% for plantation-grown jack pine and black spruce, respectively. The results from this study suggest that establishing and maintaining desired species at moderate and relatively uniform densities on productive boreal sites can significantly increase yields and shorten the age to operability by nearly 15 y.

Growth and root development of black and white spruce planted after deep planting

The capacity of trees to produce new roots is essential for rapid early growth of planted seedlings. Black and white spruce trees (Picea mariana and Picea glauca) are widely planted in the eastern boreal forest of Canada and are known to develop substantial adventitious root systems. In this study, we compared root development and growth of 17-year-old trees that had been planted at two different depths (ground level vs 10–12cm) to see if partial stem burial would hasten adventitious root development, and in turn, growth. Root number (total and adventitious), root total area, rooting depth, year of root formation, tree height and basal diameter were measured in black and white spruce trees. Both species developed adventitious root systems, and adventitious roots size and area were greater for deeply planted trees than for trees planted at ground level. The number of adventitious roots and the speed of adventitious root development were greater for deeply planted black spruce but not for deeply planted white spruce, compared with trees planted at ground level. For the latter, site conditions could explain the absence of a planting depth response. Deep planting increased tree height and basal diameter of white spruce, but only height for black spruce trees. However, tree growth was related to total root cross-sectional area (not just adventitious roots), underscoring the importance of both types of roots for tree growth.

Epiphytic lichens in jack pine and black spruce plantations in northern Ontario, Canada: diversity and community patterns

This study was an investigation of epiphytic lichen communities in mid-rotation (45 to 55 years old) managed stands of jack pine (Pinus banksiana) and black spruce (Picea mariana) in northern Ontario. Lichen community structure was compared between pine and spruce stands, and relationships between community structure and environment (substrate, microclimate, and stand-level parameters) were explored. We also assessed habitat associations of lichens with differing growth forms and functional traits. Nonmetric multidimensional scaling was used to analyze community structure, and results showed that differences between pine and spruce stands were most strongly related to stand basal area and light levels, but were also associated with other factors such as branch diameter. In addition, distinct differences in occurrence patterns between functional groups were observed, with fruticose lichens more common in pine stands, and asexual foliose lichens more common in spruce stands. This study represents the first detailed examination of epiphytic lichen community composition in boreal plantation forests in North America. Our results suggest that the conifer species chosen to regenerate a harvested stand will influence epiphytic lichen communities, which may have further implications for ecosystem processes such as nutrient cycling, and for wildlife species dependent on lichens, such as woodland caribou (Rangifer tarandus caribou).

Influence of young black spruce plantations on moose winter distribution

AbstractLogging in the boreal forest may benefit moose by increasing food availability. However, the influence of tree plantations on moose behavior, especially on moose spatial ecology, is poorly understood. We assessed the impacts of black spruce plantations on moose winter distribution at a landscape scale in the Bas‐Saint‐Laurent region (Québec, Canada). We used winter aerial surveys to examine relationships among plantation characteristics and other habitat variables known to affect moose distribution. The total area of plantations positively influenced moose abundance, but highly aggregated plantations resulted in fewer moose. Moose abundance was also positively associated with food availability and the density of edges between stands providing cover and stands offering high food availability, but moose abundance was negatively associated with road density. Although plantation characteristics were less influential than habitat variables related to foraging and predator avoidance, we demonstrate that the area of black spruce plantations and their configuration should be considered in moose management. We conclude that an integrated management strategy is needed to find a balance between overdeveloped road networks (needed to join homogeneously distributed plantations) and agglomerated plantations in order to mitigate impacts on moose winter distribution. © 2012 The Wildlife Society.

Yield Responses of Black Spruce to Forest Vegetation Management Treatments: Initial Responses and Rotational Projections

The objectives of this study were to (1) quantitatively summarize the early yield responses of black spruce (Picea mariana(Mill.) B.S.P.) to forest vegetation management (FVM) treatments through a meta-analytical review of the scientific literature, and (2) given (1), estimate the rotational consequences of these responses through model simulation. Based on a fixed-effects meta-analytic approach using 44 treated-control yield pairs derived from 12 experiments situated throughout the Great Lakes—St. Lawrence and Canadian Boreal Forest Regions, the resultant mean effect size (response ratio) and associated 95% confidence interval for basal diameter, total height, stem volume, and survival responses, were respectively: 54.7% (95% confidence limits (lower/upper): 34.8/77.6), 27.3% (15.7/40.0), 198.7% (70.3/423.5), and 2.9% (−5.5/11.8). The results also indicated that early and repeated treatments will yield the largest gains in terms of mean tree size and survival. Rotational simulations indicated that FVM treatments resulted in gains in stand-level operability (e.g., reductions of 9 and 5 yr for plantations established on poor-medium and good-excellent site qualities, resp.). The challenge of maintaining coniferous forest cover on recently disturbed sites, attaining statutory-defined free-to-grow status, and ensuring long-term productivity, suggest that FVM will continue to be an essential silvicultural treatment option when managing black spruce plantations.

Growth of planted black spruce seedlings following mechanical site preparation in boreal forested peatlands with variable organic layer thickness: 5-year results

Context Following forest harvest, mechanical site preparation (MSP) is commonly used to regenerate harvested sites. In boreal forested peatlands, however, the effectiveness of MSP to regenerate harvested sites is likely to be hampered by thick organic layers.

A Height Growth Model and Associated Growth Intercept Models for Estimating Site Index in Black Spruce (Picea mariana Mill. B.S.P.) Plantations in Northern Ontario, Canada

Abstract Site quality is a key component of growth and yield models because height growth rates are known to be influenced by available site resources. Accurate prediction of future growth and yield requires site quality information for both plantations and natural stands. The forest industry in northern Ontario relies on high-quality wood and fiber from black spruce (Picea mariana Mill. B.S.P.); therefore, these tools are essential to ensure sustainable forest management. Although there are site index (SI) models for natural-origin black spruce stands in northern Ontario, models for estimating site quality of young black spruce plantations have not been developed. We used stem analysis data collected from 62 plantations (&gt;40 years of age) of pure black spruce across northern Ontario to develop height growth, SI, and variable growth intercept models. The distinct height growth patterns we observed may be attributed to early silvicultural treatments (site preparation and herbicide) in plantations allowing black spruce trees to attain breast height (1.3 m) faster than in fire-origin stands in northern Ontario. Our models can be used to estimate site quality of black spruce plantations, a key consideration for silviculture and forest management planning. We also compare our managed stand SI model to one we developed from a comparable subset of data from black spruce growing in unmanaged stands and propose a method to assign an SI with a common base age to pure upland black spruce stands regardless of origin.

Growth and yield comparisons for red pine, white spruce and black spruce plantations in northwestern Ontario

Intensive forest management for wood production requires that we identify our most productive forest lands as well as the most productive and most commercially valuable tree species that should be managed on these lands. The Thunder Bay Spacing Trial established in 1950 provides growth and yield comparisons on a productive site for red pine, white spruce, and black spruce. Our analysis based on six remeasurements from 1983 to 2007 show that red pine has produced more than twice the volume of white spruce and about three times the volume of black spruce. The greater volume for red pine in comparison to the spruces is attributed to taller trees, larger average diameters and more basal area.