Boreal mixedwood tree growth on contrasting soils and disturbance types

2006 ◽  
Vol 36 (4) ◽  
pp. 986-995 ◽  
Author(s):  
Jennifer L Martin ◽  
Stith T Gower

Mixedwood forests are an ecologically and economically important ecosystem in the boreal forest of northern Canada. The objectives of this study were to (i) compare the age–height relationships for dominant tree species growing on two contrasting soil types and originating from different disturbances (logging versus wildfire), and (ii) determine the influence of competition on tree growth. Eight stands were selected that encompassed two age-classes replicated on two soil types (clay loam and sand) in a split-plot design. Four of the eight stands originated from logging (21–26 years old), and <F"Times">the four others originated from wildfires (80 years old). Nonlinear age–height analyses were used to compare annual height and radial increment growth of black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). Species, soil type, and size class explained significant amounts of the measured variation in the age–height models. Aspen, black spruce, and jack pine were 16%, 27%, and 19% taller, respectively, on clay soils than on sandy soils at the burned stand. Tree heights did not differ significantly among species or between soil types in logged stands. Diameter growth decreased as competition increased for black spruce and jack pine in the burned stands. The results for these three important boreal tree species are discussed in the context of sustainable forestry for boreal mixedwood forests.

1998 ◽  
Vol 28 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Manuel Lamontagne ◽  
Hank Margolis ◽  
Francine Bigras

Light-saturated photosynthesis following artificial frosts was monitored for black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). None of the species exposed to -9°C in May or to -6 and -9°C in August recovered within the 23- and 14-day monitoring periods, respectively. Black spruce and jack pine treated at -6°C in May recovered within 5 and 23 days, respectively. Black spruce treated at -3°C in August recovered within 10 days. Frosts were applied to the upper and lower canopies of mature black spruce and jack pine in June and to mature trembling aspen in July. For black spruce, the lower canopy did not recover whereas the upper canopy partially recovered over the 10-day monitoring period. For jack pine and trembling aspen, there were no differences in recovery between canopy levels. Jack pine treated at -5.5°C recovered within the 10-day monitoring period whereas at -8.5°C, it only partially recovered. Although recovery period varied with species, phenological state, and frost temperature, gradual recovery of photosynthesis over 5-21 days seems a reasonable modelling algorithm for boreal tree species when growing season frosts lower than -3°C occur. However, cooling rates in our experiments were greater than those that normally occur in nature.


1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz

An experimental burn in conjunction with a seed-tree system was successful in regenerating jack pine (Pinus banksiana Lamb.) on a fresh to somewhat moist upland, loamy till, cutover site in central Saskatchewan. About 20 well-formed, uniformly spaced seed trees per hectare were left standing during timber harvest. The ignition of logging slash was carried out under preselected weather and fuel conditions so that favorable seedbeds and adequate seed dispersal from the seed trees were produced. Four growing seasons after burning, jack pine stocking by 4-m2 quadrats was 90% with 12 195 seedlings/ha. Aspen (Populus tremuloides Michx.), to a lesser degree black spruce (Picea mariana [Mill.] B.S.P.), and other companion tree species also regenerated with the pine. Various seedbed and regeneration characteristics as well as height growth rates are discussed. Key words: Pinus banksiana, slash burning, seed-tree system, forest regeneration, growth rates, central Saskatchewan.


2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.


2010 ◽  
Vol 40 (11) ◽  
pp. 2215-2222 ◽  
Author(s):  
Victor G. Smith

Yield tables are used to identify trends in growing space efficiency (GSE) and to relate GSE to self-tolerance and intraspecific competition. The method is useful when data specifically collected for this purpose are not available. Plonski’s normal yield tables for jack pine (Pinus banksiana Lamb.), paper birch (Betula papyrifera Marshall), trembling aspen (Populus tremuloides Michx.), and black spruce (Picea mariana (Mill.) B.S.P.) are used. An exponential volume–age function was partitioned into volume–area and area–age functions. The exponents of these two components form the B/D ratio, which is used to determine the mode of the stand at a given time, e.g., if B/D is <3/2, then the stand is in area occupation mode, and if B/D is >3/2, then the stand is in area exploitation mode. The dominant mode is the one most responsive to availability of growth resources, showing greater acceleration when resources are plentiful and more rapid deceleration when resources are scarce. Jack pine and paper birch are identified as area occupiers, whereas trembling aspen and black spruce are area exploiters and are therfore self-tolerant. Asymmetric competition was deemed to be present for paper birch throughout the life of the stand on site class I and for trembling aspen on all sites prior to senescence.


2006 ◽  
Vol 36 (8) ◽  
pp. 1943-1950 ◽  
Author(s):  
Kevin J Kemball ◽  
G. Geoff Wang ◽  
A Richard Westwood

We examined jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP), and white spruce (Picea glauca (Moench) Voss) seed germination and seedling recruitment in aspen (Populus tremuloides Michx.) and conifer mixedwood stands following the 1999 Black River fire in southeastern Manitoba, Canada. Three postfire seedbed types were tested: scorched (surface litter only partially consumed), lightly burned (surface litter consumed with little or no duff consumption), and severely burned (complete consumption of litter and duff exposing mineral soil). Seeds were sown in 1999, 2000, and 2001, and each cohort was monitored for 3 years. In 1999, severely burned seedbeds had poor germination, while scorched seedbeds had the highest germination. The reverse was true in 2001. After the first growing season, continued survival of seedlings was greater on severely burned seedbeds for all three cohorts. However, better survival on severely burned seedbeds was not sufficient to overcome poor germination in 1999 and 2000. When using artificial seeding to promote conifer regeneration, we recommend a delay of one full year after a severe spring fire for jack pine and two full years for black spruce and white spruce on boreal aspen and conifer mixedwood sites.


2003 ◽  
Vol 33 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Marc-André Parisien ◽  
Luc Sirois

This study examines how forest structure and composition change with spatial variations in the fire cycle across a shore-hinterland gradient. Twenty-one well-drained sites were sampled at different distances from James Bay to describe the forest stands. To quantify the role of fire in tree species distribution, a spatial analysis of fire polygons from 1930 to 1998 was undertaken in a 43 228 km2 study area adjacent to James Bay. Results from this analysis reveal an important decrease in the fire cycle, from 3142 to 115 years, from the shore to the hinterland. In forests bordering James Bay, white spruce (Picea glauca (Moench) Voss) is found in pure stands. It is gradually replaced by black spruce (Picea mariana (Mill.) BSP) at 0.5 km from the shore. Jack pine (Pinus banksiana Lamb.) abruptly appears at 22 km from the shore. There is a positive correlation between the frequency of white spruce and the fire cycle (R = 0.893), whereas this correlation is negative for black spruce (R = –0.753) and jack pine (R = –0.807) (Spearman correlations). Jack pine is confined to regions having a short fire cycle, while black spruce can seemingly maintain itself with or without fire. The exclusion of white spruce hinterland seems to be mainly due to a short fire cycle; however, other factors, such as soil development and species abundance, presumably have a marked influence on the distribution of this species.


2013 ◽  
Vol 43 (3) ◽  
pp. 266-277 ◽  
Author(s):  
E. Duchateau ◽  
F. Longuetaud ◽  
F. Mothe ◽  
C. Ung ◽  
D. Auty ◽  
...  

Existing models for describing knot morphology are typically based on polynomial functions with parameters that are often not biologically interpretable. Hence, they are difficult to integrate into tree growth simulators due to the limited possibilities for linking knot shape to external branch and tree characteristics. X-ray computed tomography (CT) images taken along the stems of 16 jack pine (Pinus banksiana Lamb.) trees and 32 black spruce (Picea mariana (Mill.) B.S.P.) trees were used to extract the three-dimensional shape of 3450 and 11 276 knots from each species, respectively. Using a nonlinear approach, we firstly fitted a model of knot geometry adapted from a Weibull function. Separate equations were used to describe both the curvature and the diameter of the knot along its pith. Combining these two equations gave an accurate representation of knot shape using only five parameters. Secondly, to facilitate the integration of the resulting model into a tree growth simulator, we extracted the parameters obtained for each knot and modelled them as functions of external branch and tree characteristics (e.g., branch diameter, insertion angle, position in the stem, tree height, and stem diameter). When fitted to a separate data set, the model residuals of the black spruce knot curvature equation were less than 2.9 mm in any part of the knot profile for 75% of the observations. The corresponding value from the diameter equation was 2.8 mm. In jack pine, these statistics increased to 5.4 mm and 3.2 mm, respectively. Overall, the ability to predict knot attributes from external tree- and branch-level variables has the potential to improve the simulation of internal stem properties.


2010 ◽  
Vol 40 (4) ◽  
pp. 822-826 ◽  
Author(s):  
Kevin J. Kemball ◽  
A. Richard Westwood ◽  
G. Geoff Wang

Mineral soils exposed by fire are often covered by a layer of ash due to complete consumption of the forest floor (litter and duff). To assess the possible effects of ash on seed germination and viability of jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.), white spruce ( Picea glauca (Moench) Voss), and balsam fir ( Abies balsamea (L.) Mill.), a laboratory experiment was conducted using ash derived from three types of forest floor samples. The samples represented areas of high conifer concentration, high aspen concentration, and mixed aspen and conifer and were collected from five mature aspen ( Populus tremuloides Michx.) – conifer mixedwood stands in southeastern Manitoba. Ash derived from each forest floor type neither prohibited nor delayed conifer germination, except that of balsam fir. Balsam fir had significantly less germination on ash derived from forest floor samples with high aspen concentration. When corrected for seed viability, balsam fir had significantly less germination on all three ash types compared with jack pine, black spruce, and white spruce. However, the impact of ash on balsam fir is unlikely to have meaningful ecological implications, as balsam fir is a climax species and will establish in undisturbed mature forests.


1987 ◽  
Vol 63 (6) ◽  
pp. 446-450 ◽  
Author(s):  
James E. Wood ◽  
Richard Raper

In the alternate strip clearcutting system, first-cut strips are regenerated by seed produced by black spruce (Picea mariana [Mill.] B.S.P.) in the forested leave strips. However, after the second cut, such a seed source is not available for regenerating the leave strips. Therefore, the forest manager must consider a number of alternative regeneration options. The selection of the most appropriate regeneration option is dependent upon several economic and biological criteria. These include future costs of delivered wood, site productivity, post-harvest site condition, future alternative sources of supply, and future demand for industrial wood. Regeneration options such as preservation of advance growth and direct seeding are recommended for sites on which the manager is concerned primarily with regenerating first cut strips and is willing to accept a lower level of stocking in leave strips. Planting, the most intensive option discussed, should be reserved for sites offering the highest potential return or greatest future cost savings. Direct seeding of jack pine (Pinus banksiana Lamb.) should be considered on the upland portions of this patterned site type. Mixing jack pine and black spruce is a suggested regeneration option if the site contains both upland and lowland topographic positions. Other seeding options include the use of semi-transparent plastic seed shelters. The manager might consider combining two or more of these options to meet management objectives.


2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.


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