Shedding of ephemeral roots in gymnosperms

1982 ◽  
Vol 60 (11) ◽  
pp. 2295-2302 ◽  
Author(s):  
Joanna T. Tippett
Keyword(s):  
Lateral Roots ◽  
Abies Balsamea ◽  
Protective Layer ◽  
Pinus Strobus ◽  
Tsuga Canadensis ◽  
Balsam Fir ◽  
Tissue Formation ◽  
White Pine ◽  
Vascular Tissues ◽  
Periderm Formation

Periderm formation across the base of short lateral roots facilitated their shedding in balsam fir (Abies balsamea (L.) Mill.), white pine (Pinus strobus L.), and hemlock (Tsuga canadensis (L.) Carr.). The periderm originated either from the pericycle, in line with normal subendodermal development, or after dedifferentiation and redifferentiation of cells across existing vascular tissues near the base of senescent short roots. Consequently the short roots were either shed neatly along with the cortex of the parent roots or they were isolated by a new layer of periderm linking existing parent-root periderm, analogous to protective tissue formation beneath petiole abscission zones. Short roots were not always isolated by periderm prior to detachment, but periderm still formed at the base of the root stubs and eventually became the superficial protective layer of the root scars.

USE OF THE RELATIVE TURGIDITY TECHNIQUE FOR MEASUREMENT OF WATER STRESSES IN GYMNOSPERM LEAVES

1965 ◽  
Vol 43 (2) ◽  
pp. 305-316 ◽  
Author(s):  
J. J. Clausen ◽  
T. T. Kozlowski
Keyword(s):  
Abies Balsamea ◽  
Pinus Resinosa ◽  
Tsuga Canadensis ◽  
Red Pine ◽  
Eastern Hemlock ◽  
Balsam Fir ◽  
White Pine ◽  
Sampling Variation

Adaptations of Weatherley's relative turgidity technique (Weatherley 1950), fitting it for use with red pine (Pinus resinosa Ait.), white pine (P. strobus L.), balsam fir (Abies balsamea (L.) Mill.), and eastern hemlock (Tsuga canadensis (L.) Carr.) are described. Results of preliminary investigations of sampling variation between trees, whorls, and needle ages in red pine are presented.

scholarly journals Effect of seed predation, shade and soil organic matter on the early establishment of eastern white pine and balsam fir seedlings

2000 ◽  
Vol 76 (5) ◽  
pp. 759-763 ◽  
Author(s):  
Luc C. Duchesne ◽  
D. G. Herr ◽  
S. Wetzel ◽  
I. D. Thompson ◽  
R. Reader
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Seed Predation ◽  
Fire Ecology ◽  
Mineral Soil ◽  
Abies Balsamea ◽  
Pinus Strobus ◽  
Balsam Fir ◽  
White Pine ◽  
Eastern White Pine

Eastern white pine (Pinus strobus L.) does not regenerate well in the absence of fire, or without mechanical exposure of mineral soil, while balsam fir (Abies balsamea L. Mill.) is a common understory species on sites occupied by white pine. We conducted two experiments to explain the difference in regenerative success of these two species. First, the effect of shade and soil organic matter on the emergence of white pine and balsam fir were compared using soil monoliths from a regenerating white pine stand. Balsam fir germination was significantly lower than white pine germination at different shade levels and at different levels of soil organic matter. Second, seed predation was compared between balsam fir and white pine in a non-regenerating white pine stand. Predation of white pine seeds was 10 times greater than balsam fir predation even when seeds of white pine and balsam fir were left as a mixture on the forest floor. We speculate that seed predation is a critical factor in white pine succession and that seed predators favour balsam fir succession by selecting white pine seeds. Key words: seed predation, fire ecology, Pinus strobus, Abies balsamea, Peromyscus maniculatus, succession

Seasonal variations in the uptake of [32P]phosphate ions by excised ectomycorrhizae and lateral roots of Abies balsamea

1984 ◽  
Vol 14 (3) ◽  
pp. 412-415 ◽  
Author(s):  
C. G. Langlois ◽  
J. A. Fortin
Keyword(s):  
Nutrient Solution ◽  
Seasonal Variations ◽  
Lateral Roots ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Phosphate Ions ◽  
Bud Set ◽  
Absorption Potential ◽  
Different Types ◽  
Root Apices

The absorption of phosphate ions by long lateral nonmycorrhizal roots and by four of the most prevalent types of ectomycorrhizae of Abiesbalsamea was followed over one season of growth. For each experiment, the excised roots were bathed for 2.5 h in a buffered nutrient solution containing 100 μg•L−1 of KH2PO4 and 100 μCi•L−1 (1 Ci = 37 GBq) of KH232PO4. The results indicate that the rates of absorption of the different types of balsam fir root apices varied during the season and differed from one type to another. The surface of absorption appeared to have an effect on the amount of phosphate ions taken up from the solution. The rates of absorption measured invitro, seemed to reflect the seasonal absorption potential for phosphate ions by balsam fir roots invivo. It was clearly demonstrated that the most intensive rates of uptake occurred in mid-August immediately after bud set. The possibility that the absorption of phosphate ions is controlled by internal demand and is related to the translocation of carbohydrates is discussed.

Weather and Outbreaks of the Spruce Budworm in the Province of Quebec from 1939 to 1956

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
The Past ◽  
Forest Regions ◽  
Tree Component ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.

scholarly journals Mixed Regional Shifts in Conifer Productivity under 21st-Century Climate Projections in Canada’s Northeastern Boreal Forest

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 248
Author(s):  
Tyler Searls ◽  
James Steenberg ◽  
Xinbiao Zhu ◽  
Charles P.-A. Bourque ◽  
Fan-Rui Meng
Keyword(s):  
Climate Change ◽  
Model Validation ◽  
21St Century ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Acer Rubrum ◽  
Forest Growth ◽  
Balsam Fir ◽  
Growth And Yield ◽  
Climate Projections

Models of forest growth and yield (G&Y) are a key component in long-term strategic forest management plans. Models leveraging the industry-standard “empirical” approach to G&Y are frequently underpinned by an assumption of historical consistency in climatic growing conditions. This assumption is problematic as forest managers look to obtain reliable growth predictions under the changing climate of the 21st century. Consequently, there is a pressing need for G&Y modelling approaches that can be more robustly applied under the influence of climate change. In this study we utilized an established forest gap model (JABOWA-3) to simulate G&Y between 2020 and 2100 under Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5 in the Canadian province of Newfoundland and Labrador (NL). Simulations were completed using the province’s permanent sample plot data and surface-fitted climatic datasets. Through model validation, we found simulated basal area (BA) aligned with observed BA for the major conifer species components of NL’s forests, including black spruce [Picea mariana (Mill.) Britton et al.] and balsam fir [Abies balsamea (L.) Mill]. Model validation was not as robust for the less abundant species components of NL (e.g., Acer rubrum L. 1753, Populus tremuloides Michx., and Picea glauca (Moench) Voss). Our simulations generally indicate that projected climatic changes may modestly increase black spruce and balsam fir productivity in the more northerly growing environments within NL. In contrast, we found productivity of these same species to only be maintained, and in some instances even decline, toward NL’s southerly extents. These generalizations are moderated by species, RCP, and geographic parameters. Growth modifiers were also prepared to render empirical G&Y projections more robust for use under periods of climate change.

Prescribed Burning for Stand Conversion in Budworm-killed Balsam Fir: An Ontario Case History

1986 ◽  
Vol 62 (2) ◽  
pp. 96-100 ◽  
Author(s):  
D. J. McRae
Keyword(s):  
Fuel Consumption ◽  
Prescribed Burning ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Fire Spread ◽  
Fire Effects ◽  
Balsam Fir ◽  
Prescribed Burn ◽  
Stand Conversion

Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.

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