Bryophyte and lichen communities in mature to old-growth stands in eastern boreal forests of Canada

2002 ◽  
Vol 32 (6) ◽  
pp. 1080-1093 ◽  
Author(s):  
Catherine Boudreault ◽  
Yves Bergeron ◽  
Sylvie Gauthier ◽  
Pierre Drapeau
Keyword(s):  
Populus Tremuloides ◽  
Boreal Forests ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Structural Diversity ◽  
Tree Age ◽  
Pleurozium Schreberi ◽  
Old Growth ◽  
Site Characteristics ◽  
Successional Stages

We sampled 22 black spruce (Picea mariana) - feathermoss (Pleurozium schreberi) sites (80 to >200 years) to describe and assess the diversity of bryophyte and lichen communities as a function of time since fire and site characteristics. Old growth had no more species than younger forests. We think that this result might be explained by the phenomenon of paludification, which is a major process in this region. Axis 1 of a nonmetric multidimensional scaling ordination (NMS) of terricolous species was interpreted as a paludification gradient. Mature forests were characterized by Pleurozium schreberi, Ptilium crista-castrensis, Polytrichum commune, and Dicranum polysetum, and older sites by a greater abundance of Sphagnum. Axis 1 of epiphytic species ordination (NMS) was interpreted as a gradient of time since the last fire. Abundance of Tuckermannopsis americana, Hypogymnia physodes, and Bryoria furcellata was greater in mature forests. In contrast, Mycoblastus sanguinarius, Bryoria trichodes, and Usnea spp. were more abundant in older forests. The abundance of epiphytic lichens increased with tree age, whereas their richness was higher in sites where trembling aspen (Populus tremuloides) and jack pine (Pinus banksiana) were present. Since species composition varied with time since the last fire, it is important to preserve the diversity of successional stages at the landscape level and the structural diversity at the stand level to maintain the bryophyte and lichen communities.

The effect of pedogenetic processes on the distribution of phosphorus, calcium and magnesium in Gray Luvisols

1991 ◽  
Vol 71 (4) ◽  
pp. 397-410 ◽  
Author(s):  
X. J. Xiao ◽  
D. W. Anderson ◽  
J. R. Bettany
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Soil Formation ◽  
Podzolic Soils ◽  
Exchangeable Ca ◽  
Phosphorus Losses

Pedogenesis and its effect on calcium (Ca), magnesium (Mg) and phosphorus (P) was studied on a sequence of seven Gray Luvisol soils in central Saskatchewan. The soils were formed on calcareous glacial till under trembling aspen (Populus tremuloides Michx), mixedwood (aspen and white spruce) (Picea glauca (Moench) Voss)) and coniferous (black spruce and jack pine) (Picea mariana (Mill) BSP and Pinus banksiana Lamb) forests. Soils under aspen had the highest concentration of total and exchangeable Ca and Mg in litter layers and Ae horizons, and had Ae and Bt horizons that were least acidic. The most acidic Ae and Bt horizons and lowest amounts of Ca and Mg occurred under coniferous forests, whereas the soils under mixedwood stands were intermediate. The thickness of eluvial (Ae and AB) horizons increased along the aspen to coniferous sequence. All soils had about 40% less P in their A and B horizons than was calculated to have been present at the start of soil formation. The greatest decrease in P was observed in the thickest and most acidic soil under coniferous forest. The present litter layers and vegetation make up only a small proportion of the P removed from the mineral soil. Unusually large amounts of P appear to have been translocated from A and B horizons during development of Gray Luvisols, in comparison to Chernozemic or even Podzolic soils. Our hypothesis proposes that P is ineffectively retained in the solum as P-clay-humus, or iron-P complexes and that organic P moves along with the soil water, laterally and downslope through permeable Ae horizon over less permeable Bt horizons, or vertically through macropores. Key words: Boreal forest, nutrient cycling, phosphorus losses, weathering, soil formation

scholarly journals Jack Pine Regeneration Following Postcut Burning under Seed Trees in Central Saskatchewan

1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Pinus Banksiana ◽  
Forest Regeneration ◽  
Black Spruce ◽  
Timber Harvest ◽  
Jack Pine ◽  
Growing Seasons ◽  
Pine Regeneration ◽  
Slash Burning

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.

Mixed-species effect on tree aboveground carbon pools in the east-central boreal forests

2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Mixed Forest ◽  
Jack Pine ◽  
Carbon Gain ◽  
Trembling Aspen ◽  
Niche Complementarity ◽  
Aboveground Carbon

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.

Factors controlling epiphytic lichen biomass during postfire succession in black spruce boreal forests

2009 ◽  
Vol 39 (11) ◽  
pp. 2168-2179 ◽  
Author(s):  
Catherine Boudreault ◽  
Yves Bergeron ◽  
Darwyn Coxson
Keyword(s):  
Boreal Forests ◽  
Stand Structure ◽  
Black Spruce ◽  
Tree Age ◽  
Stand Age ◽  
Epiphytic Lichens ◽  
Dominant Group ◽  
Epiphytic Lichen ◽  
Structure Tree ◽  
Species Groups

Alectorioid lichens are the dominant group of epiphytic lichens in boreal forests. Epiphytic lichen richness and abundance generally increase with stand age and within-stand heterogeneity. The objective of this study was to evaluate the importance of time elapsed since the last fire, stand structure, tree size, tree age, and branch height for epiphytic lichen biomass of the boreal forest of western Quebec. We sampled 12 sites belonging to four forest age classes (from 50 to >200 years). We assessed epiphytic lichen biomass of three species groups ( Bryoria , Evernia , and Usnea ) on 12 trees in each site. Our results showed that biomass of Bryoria and Usnea was higher in intermediate stages (between 101 and 200 years) compared with younger (50–100 years) and older (>200 years) stages. Biomass of the three species groups was greater on larger diameter trees (>16 cm) compared with smaller ones (<16 cm). These results indicate that the protection of postfire stands aged between 101 and 200 year should be prioritized to maintain the functional role of epiphytic lichens in managed landscapes.

Windthrow hazard modelling in boreal forests of black spruce and jack pine

2005 ◽  
Vol 35 (11) ◽  
pp. 2655-2663 ◽  
Author(s):  
Jean-Gabriel Elie ◽  
Jean-Claude Ruel
Keyword(s):  
Boreal Forests ◽  
Pinus Banksiana ◽  
Forest Cover ◽  
Black Spruce ◽  
Jack Pine ◽  
Soil Conditions ◽  
Mechanical Resistance ◽  
Mixed Stands ◽  
Tree Stability ◽  
Tree Resistance

In this study we compare the mechanical resistance of black spruce (Picea mariana (Mill.) BSP) and jack pine (Pinus banksiana Lamb.) and quantify the effect of species, forest cover type, and soil conditions on tree stability. To measure tree resistance to an applied load, 85 trees were pulled over using a cable and winch system. Predictive equations for the maximum turning moment that a tree can withstand (Mc) were developed with stem mass, and the other factors were used as explanatory variables. The presence of jack pine within the stand negatively affected black spruce resistance. In mixed stands, Mc was significantly influenced by the interaction between tree species and soil type. Jack pine was the only species with significantly lower resistance when grown on shallow and stony soils, which are likely to restrict root development. Black spruce resistance was not affected by soil conditions. Preliminary calculations of critical wind speeds required to cause damage using an adaptation of the ForestGALES model were much lower than those previously published for black spruce.

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
Keyword(s):  
Populus Tremuloides ◽  
Tree Growth ◽  
Tree Species ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Jack Pine ◽  
Soil Types ◽  
Radial Increment ◽  
Mixedwood Forests ◽  
Increment Growth

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.

Adapting forestry practices to address old-growth concerns in the Great Lakes–St.Lawrence forests of Ontario

2003 ◽  
Vol 79 (3) ◽  
pp. 613-620 ◽  
Author(s):  
Fred Pinto
Keyword(s):  
Great Lakes ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Natural Disturbance ◽  
Red Pine ◽  
Forest Composition ◽  
White Birch ◽  
Site Factors ◽  
Old Growth ◽  
Old Growth Forests

The Great Lakes–St. Lawrence forest, particularly the eastern white (Pinus strobus L.) and red pine (P. resinosa Ait.) forests around Temagami and Sault Ste. Marie, was the centre of controversy regarding the treatment of old-growth forests in Ontario in the 1980s and 1990s. The controversy stemmed from changes in forest composition and structure occurring in the forest. For example, the Ontario public was concerned with the obvious reduction in numbers of large eastern white and red pine trees and their replacement with small, often poor quality, white birch (Betula papyrifera Marsh.), aspen (Populus tremuloides Michx.), and jack pine (Pinus banksiana Lamb.) trees. Over the past two decades, changes in legislation, forest planning and stand prescriptions have been made in Ontario and practices at the forest and stand levels have also changed significantly. The new practices are based on linking forest activities to a better understanding of ecological processes in the forest; in particular, linking harvest and regeneration activities to our current understanding of natural disturbances and plant adaptations. These practices attempt to match more closely the conditions found in forests with a heritage of natural disturbance and reproduction, i.e., old-growth forests. For example, stand-initiating disturbances result in some trees being killed, some being damaged, and some surviving. The new harvest practices consider tree adaptations and site factors when deciding whether a tree will be cut or not. This paper provides examples of how this ecosystem-based forestry is being applied in Ontario. Key words: old growth in Ontario, conservation of old growth, application of old growth conservation practices, stand practices for old growth, landscape practices for old growth

Trends in growing space efficiency of four boreal forest species based on yield table data

2010 ◽  
Vol 40 (11) ◽  
pp. 2215-2222 ◽  
Author(s):  
Victor G. Smith
Keyword(s):  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Jack Pine ◽  
Dominant Mode ◽  
Trembling Aspen ◽  
Site Class ◽  
Space Efficiency ◽  
Paper Birch ◽  
Table Data

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.

Are mineral soils exposed by severe wildfire better seedbeds for conifer regeneration?

2006 ◽  
Vol 36 (8) ◽  
pp. 1943-1950 ◽  
Author(s):  
Kevin J Kemball ◽  
G. Geoff Wang ◽  
A Richard Westwood
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Seedling Recruitment ◽  
Black Spruce ◽  
Mineral Soil ◽  
White Spruce ◽  
Jack Pine ◽  
Conifer Regeneration ◽  
Mineral Soils

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.

scholarly journals Breeding Bird Communities in Boreal Forest of Western Canada: Consequences of “Unmixing” the Mixedwoods

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 759-769 ◽  
Author(s):  
Keith A. Hobson ◽  
Erin Bayne
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Deciduous Forest ◽  
Black Spruce ◽  
Bird Species ◽  
White Spruce ◽  
Trembling Aspen ◽  
Vegetation Heterogeneity ◽  
Mixedwood Stands

Abstract Silvicultural practices following clearcutting in boreal forest may encourage the creation of monospecific, single-aged stands having less vegetation heterogeneity and diversity than original stands. We conducted point counts in central Saskatchewan, Canada, 1993–1995, in pure and mixedwood stands dominated by black spruce (Picea mariana), jackpine (Pinus banksiana), trembling aspen (Populus tremuloides), or white spruce (Picea glauca). Mixedwood stands supported more individuals and more species than pure stands. Higher abundance in mixedwood stands relative to pure stands was consistent among nesting guilds and migration strategies. Rarefaction revealed similar patterns, although pure trembling aspen stands were predicted to support more species than aspen-dominated mixedwood stands. Increased avian diversity in mixedwood stands was not solely the result of the mixing of bird species associated with coniferous or deciduous forest types. Chipping Sparrow (Spizella passerina), Pine Siskin (Carduelis pinus), White-winged Crossbill (Loxia leucoptera), Red-breasted Nuthatch (Sitta canadensis), Swainson's Thrush (Catharus ustulatus), and Tennessee Warbler (Vermivora peregrina) were more abundant in mixedwood stands than pure stands. Black-throated Green Warbler (Dendroica virens), Magnolia Warbler (D. magnolia), and Blackburnian Warbler (D. fusca) were abundant in stands dominated by white spruce but were absent from jackpine or black spruce. Other species such as American Redstart (Setophaga ruticilla) and Chestnut-sided Warbler (D. pensylvanica) relied exclusively on pure trembling aspen, particularly stands with dense shrub cover. Several bird species in the boreal forest will be adversely affected by forestry practices that target mature to old aspen and white spruce mixedwoods and promote reduction in mixedwood compositions of regenerating stands.

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