The influence of shelter and the hypothetical effect of fire severity on the postfire establishment of conifers from seed

1985 ◽  
Vol 15 (1) ◽  
pp. 148-155 ◽  
Author(s):  
P. A. Thomas ◽  
Ross W. Wein
Keyword(s):  
Organic Matter ◽  
Vegetation Cover ◽  
Black Spruce ◽  
Fire Severity ◽  
Balsam Fir ◽  
White Pine ◽  
Direct Sunlight ◽  
Conifer Species ◽  
Eastern Canada ◽  
Seedling Community

Surface-charred organic matter is a common but unfavourable postfire seedbed in eastern Canada. Slatted screens providing 0, 25, 50, and 75% cover were used to shelter 1-m2 charred plots from direct sunlight. Plots were sown with four conifer species. Jack pine (Pinnsbanksiana Lamb.) established abundantly on all plots and dominated on unsheltered areas. As shelter increased, eastern white pine (Pinusstrobus L.), and eventually balsam fir (Abiesbalsamea (L.) Mill.) and black spruce (Piceamariana (Mill.) B.S.P.) increased in number. Thus, the size and composition of the seedling community depended upon the amount of shelter given. To test whether postfire herbaceous and shrub vegetation could have a similar effect, seeds were sown on pairs of charred 1-m2 plots. Vegetation was removed weekly from one plot of each pair. Removal of vegetation decreased the establishment of balsam fir and black spruce but not red pine (Pinusresinosa Ait.). It was concluded that, during the first growing season, changes in vegetation cover produce changes in establishment similar to those found using slatted screens. Increasing fire severity (organic matter consumption) may reduce the postfire vegetation cover. A hypothetical model is presented, linking the establishment of the above five species to fire severity.

Influence of recent fire season and severity on black spruce regeneration in spruce–moss forests of Quebec, Canada1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1316-1327 ◽  
Author(s):  
Mélanie Veilleux-Nolin ◽  
Serge Payette
Keyword(s):  
Organic Matter ◽  
Organic Material ◽  
Black Spruce ◽  
Fire Severity ◽  
Mineral Soil ◽  
Thick Layer ◽  
Fire Season ◽  
Eastern Canada ◽  
Postfire Regeneration ◽  
Crown Forest

Postfire regeneration problems compromise the maintenance of closed-crown forests of eastern Canada, often shifting toward lichen woodlands. Compounded disturbances like successive fires or insect outbreaks followed by fire may be responsible for this shift. Leaving behind unfavourable seedbeds for the germination of black spruce ( Picea mariana (Mill.) B.S.P.) seeds, low-severity fires may also be involved in this transformation. The severity of recent fires and their impact on black spruce regeneration were evaluated using 13 stands burned in spring or summer within the closed-crown forest in Quebec during the last 20 years. Two ecological indicators were used to characterize fire severity: thickness of residual organic material and recovery of plant species. Regardless of the season, the ground of all burned stands was covered with a thick layer of residual organic matter. Blackened organic matter and ericaceous vegetation, indicating the passage of a low-severity fire, were widespread in all sites whereas acrocarpous mosses and bare mineral soil, indicating the passage of a severe fire, were uncommon. The preponderance of the thick layer of residual organic material blackened at the surface can explain the failure of regeneration in most studied sites. Low-severity fires are thus among factors probably involved in the expansion of lichen woodlands within the closed-crown forest.

Root-rotting fungi associated with mortality of conifer saplings in northern Ontario

1978 ◽  
Vol 8 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Roy D. Whitney ◽  
Donald T. Myren
Keyword(s):  
Boreal Forest ◽  
Cause Of Death ◽  
Root Rot ◽  
Black Spruce ◽  
Red Pine ◽  
Balsam Fir ◽  
White Pine ◽  
Conifer Species ◽  
Northern Ontario

The roots of 435 dead or dying saplings, averaging 10 years of age, of seven conifer species from the Boreal Forest of northern Ontario were examined for root rot. Only trees with no obvious cause of death or decline, other than root rot, were selected. Eighty-three percent of the trees had root rot. Cultures revealed that Armillariamellea (Vahl ex Fr.) Kummer was associated with root rot in 68% of all trees examined, including more than 45% of the trees in each species. Ten other root-rotting fungi were isolated from 1% or fewer of the trees, 7 of them from balsam fir (Abiesbalsamea [L.] Mill.) and 3 from black spruce (Piceamariana [Mill.] B.S.P.). Scytinostromagalactinum (Fr.) Donk was isolated from sapwood of roots and lower stems of red pine (Pinusresinosa Ait.), balsam fir, white pine (P. strobes L.), and black spruce and appeared to be parasitic on these species. Coniophoraputeana (Schum. ex Fr.) Karst. was apparently associated with the death of one balsam fir.

Estimating branch production in trembling aspen, Douglas-fir, jack pine, black spruce, and balsam fir

2007 ◽  
Vol 37 (6) ◽  
pp. 1024-1033 ◽  
Author(s):  
P.Y. Bernier ◽  
M.B. Lavigne ◽  
E.H. Hogg ◽  
J.A. Trofymow
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Black Spruce ◽  
Jack Pine ◽  
Douglas Fir ◽  
Balsam Fir ◽  
Trembling Aspen ◽  
Wood Production ◽  
Conifer Species ◽  
Branch Wood

Measuring net primary productivity of trees requires the measurement of total wood production of branches. Recent work on balsam fir ( Abies balsamea ) has shown that branch-wood production can be estimated as a function of foliage production. We extend the analysis to four other species found in the Canadian forest: black spruce ( Picea mariana ), jack pine ( Pinus banksiana ), Douglas-fir ( Pseudotsuga menziesii ), and trembling aspen ( Populus tremuloides ). Results show that the ratio of annual branch-wood production to annual foliage production is about 1.0 for conifer species (between 0.86 and 1.12) and 0.56 for aspen during a nondrought year. An analysis using field measurements of litterfall and stem-diameter increment from selected forested sites shows that branch-wood production accounts for a smaller proportion of aboveground net primary productivity in trembling aspen (15%–20%) than in conifer species (25%). Also, litterfall capture of small branches (<1 cm diameter) accounts for only 33% of branch detritus production in conifers and 50% in trembling aspen. This study supports the use of an alternative method for estimating branch-wood production that reduces the potential bias in field estimates of net primary productivity.

Critical period of interspecific competition for four northern conifers: 10-year growth response and associated vegetation dynamics

2006 ◽  
Vol 36 (10) ◽  
pp. 2474-2485 ◽  
Author(s):  
Robert G Wagner ◽  
Andrew P Robinson
Keyword(s):  
Interspecific Competition ◽  
Critical Period ◽  
Black Spruce ◽  
Jack Pine ◽  
Red Pine ◽  
Growth Responses ◽  
White Pine ◽  
Conifer Species ◽  
Stand Volume ◽  
Vegetation Control

The influence of the timing and duration of interspecific competition on planted jack pine (Pinus banksiana Lamb.), red pine (Pinus resinosa Ait.), eastern white pine (Pinus strobus L.), and black spruce (Picea mariana (Mill.) BSP) was assessed using 10-year growth responses in a northern Ontario experiment. Stand volume was 117%, 208%, 224%, and 343% higher for jack pine, red pine, white pine, and black spruce, respectively, with 5 years of vegetation control than with no vegetation control. Stand volume increased linearly with number of years of vegetation control, and the slope of the relationship varied among conifer species. Change-point regression analysis was used to derive segmented weed-free and weed-infested curves, and to simultaneously estimate key critical-period parameters. Weed-free and weed-infested curves in the 10th year were similar to those derived in year 5, indicating that the patterns established during the first few years after planting were relatively robust for the first decade. The critical-period was 2 and 3 years after planting for jack pine and red pine, respectively, and occupied most of the 5-year period for white pine and black spruce. Principal components analysis of the vegetation community indicated that repeated herbicide applications caused differential shifts in the relative abundance of shrub, fern, and moss species through the 10th year. Species richness, however, was not substantially different between the untreated control and the most intensive treatments. Difference modeling was used to quantify how annual volume increment during the first decade varied with time, conifer species, cover of woody and herbaceous vegetation, and stage of development.

Black spruce decline triggered by spruce budworm at the southern limit of lichen woodland in eastern Canada

2001 ◽  
Vol 31 (12) ◽  
pp. 2160-2172 ◽  
Author(s):  
Martin Simard ◽  
Serge Payette
Keyword(s):  
Black Spruce ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Jack Pine ◽  
Growth Patterns ◽  
Balsam Fir ◽  
Eastern Canada ◽  
Southern Limit ◽  
Epiphytic Lichen ◽  
Spruce Decline

Black spruce (Picea mariana (Mill.) BSP) is the dominant tree species of the southernmost (48°N) lichen woodlands in eastern Canada. Most spruce trees in mature lichen woodlands appear to be declining, as shown by the massive invasion of the epiphytic lichen Bryoria on dead branches of dying trees. A dendroecological study was undertaken to identify the main causal factors of the decline. A decline index based on the abundance of Bryoria on spruce trees was used to distinguish healthy from damaged lichen–spruce woodlands and to select sampling sites for tree-ring measurements. Three conifer species (black spruce, balsam fir (Abies balsamea (L.) Mill.), and jack pine (Pinus banksiana Lamb.)) were sampled to compare their growth patterns in time and space. In the late 1970s and mid-1980s, black spruce and balsam fir experienced sharp and synchronous radial-growth reductions, a high frequency of incomplete and missing rings, and mass mortality likely caused by spruce budworm (Choristoneura fumiferana (Clem.)) defoliation. Jack pine, a non-host species, showed no such trend. Because black spruce layers were spared, lichen woodlands will eventually regenerate unless fire occurs in the following years. Black spruce decline can thus be considered as a normal stage in the natural dynamics of the southern lichen woodlands.

Feeding Sites of Aphids of the Genus Cinara Curtis (Homoptera: Aphididae) in Northwestern Ontario

1959 ◽  
Vol 91 (10) ◽  
pp. 670-671 ◽  
Author(s):  
G. A. Bradley
Keyword(s):  
Black Spruce ◽  
Jack Pine ◽  
Red Pine ◽  
Balsam Fir ◽  
White Pine ◽  
White Cedar ◽  
Feeding Sites ◽  
Red Lake ◽  
Northwestern Ontario ◽  
Common Juniper

While working at Cedar Lake in Northwestern Ontario in the summers of 1957 and 1958 the author was able to observe the feeding sites of various species of Cinara. Most of the observations were made within an area of a few square miles on either side of Highway 105, between Red Lake Road and Ear Falls, Ontario. This area is fairly typical of the Laurentian Shield, with numerous lakes, rocky ridges, sandy patches, and small bogs. The principal coniferous trees in this locality are black spruce, jack pine, and balsam fir. White spruce, white cedar, white pine, red pine, and common juniper are also present.

Forest productivity after careful logging and fire in black spruce stands of the Canadian Clay Belt

2016 ◽  
Vol 46 (6) ◽  
pp. 783-793 ◽  
Author(s):  
Cécile Leroy ◽  
Alain Leduc ◽  
Nelson Thiffault ◽  
Yves Bergeron
Keyword(s):  
Organic Matter ◽  
Sustainable Forest Management ◽  
Black Spruce ◽  
Growth Potential ◽  
Juvenile Growth ◽  
Eastern Canada ◽  
Lower Growth ◽  
Soil Thickness ◽  
Study Region ◽  
Stand Productivity

Some regenerating stands of the boreal forest exhibit low juvenile growth after major disturbances, which compromises sustainable forest management objectives. In black spruce – feather moss stands of eastern Canada subject to paludification, careful logging methods could decrease stand productivity with time by preventing a beneficial reduction in organic soil thickness. The aim of this project was to confirm decreases in juvenile growth between stands originating from careful logging and the former stands originating from old fires on the same sites. Stem analyses showed that stands originating from CPRS had significantly better juvenile height growth than the former stands but significantly lower growth than stands originating from recent fire in the study region. If organic matter thickness apparently played a role in the growth differences observed between fire and harvesting, it was not the only factor determining stand productivity. According to our results, cohort status, climatic regime, and quality of the residual organic matter are other factors that seem to drive productivity. Our results show that postharvest management approaches (e.g., site preparation) should be used to increase yields after harvest for the sites to express their full growth potential.

scholarly journals Driving factors of conifer regeneration dynamics in eastern Canadian boreal old-growth forests

2020 ◽  
Author(s):  
Maxence Martin ◽  
Miguel Montoro Girona ◽  
Hubert Morin
Keyword(s):  
Black Spruce ◽  
Spatial Scales ◽  
Tree Regeneration ◽  
Balsam Fir ◽  
Diameter Distribution ◽  
Eastern Canada ◽  
Old Growth ◽  
Regeneration Dynamics ◽  
Old Growth Forest ◽  
Old Growth Forests

AbstractOld-growth forests play a major role in conserving biodiversity, protecting water resources, sequestrating carbon, and these forests are indispensable resources for indigenous societies. To preserve the ecosystem services provided by these boreal ecosystems, it becomes necessary to develop novel silvicultural practices capable of emulating the natural dynamics and structural attributes of old-growth forests. The success of these forest management strategies depends on developing an accurate understanding of natural regeneration dynamics. Our goal was therefore to identify the main patterns and the drivers involved in the regeneration dynamics of old-growth forests, placing our focus on boreal stands dominated by black spruce (Picea mariana (L.) Mill.) and balsam fir (Balsam fir (L.) Mill.) in eastern Canada. We sampled 71 stands in a 2200 km2 study area located within Quebec’s boreal region. For each stand, we noted tree regeneration (seedlings and saplings), structural attributes (diameter distribution, deadwood volume, etc.), and abiotic (topography and soil) factors. We observed that secondary disturbance regimes and topographic constraints were the main drivers of balsam fir and black spruce regeneration. Furthermore, the regeneration dynamics of black spruce appeared more complex than those of balsam fir. We observed distinct phases of seedling production first developing within the understory, then seedling growth when gaps opened in the canopy, followed by progressive canopy closure. Seedling density, rather than the sapling density, had a major role in explaining the ability of black spruce to fill the canopy following a secondary disturbance. The density of balsam fir seedlings and saplings was also linked to the abundance of balsam fir trees at the stand level. This research helps explain the complexity of old-growth forest dynamics where many ecological factors interact at multiple temporal and spatial scales. This study also improves our understanding of ecological processes within native old-growth forests and identifies the key factors to consider when ensuring the sustainable management of old-growth boreal stands.

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