scholarly journals Reproductive limitation mediates the response of white spruce (Picea glauca) to climate warming across the forest–tundra ecotone

2019 ◽  
Vol 5 (4) ◽  
pp. 167-184 ◽  
Author(s):  
Trevor C. Lantz ◽  
Nina D. Moffat ◽  
Robert H. Fraser ◽  
Xanthe Walker
Keyword(s):  
Picea Glauca ◽  
Seed Viability ◽  
Stand Density ◽  
White Spruce ◽  
Mapping Accuracy ◽  
Forest Expansion ◽  
Cold Temperatures ◽  
Cone Production ◽  
Forest Density ◽  
Forest Tundra

Shifts in the extent of the boreal forest during past warm intervals and correlations between climate and the position of the forest–tundra ecotone suggest that recent temperature increases will facilitate forest expansion into tundra ecosystems. In this study, we used a unique set of high-resolution repeat photographs to characterize white spruce (Picea glauca (Moench) Voss) populations in 1980 and 2015 at 52 sites across the forest–tundra transition in the Northwest Territories, Canada. We also conducted field inventories at eight sites to examine mapping accuracy, construct age distributions, and assess cone production and seed viability. Our analysis shows that stand density in the forest–tundra has increased significantly since 1980 but that the density of spruce at sites in the tundra has not changed. Age distributions constructed from field sampling also indicate that recent recruitment has occurred in the forest–tundra but not at tundra sites. The nonlinear relationship between summer temperature and seed viability suggests that recent warming has facilitated recruitment in the northern Subarctic but that cold temperatures still limit recruitment at higher latitude tundra sites. Additional research to determine the extent of changes in forest density across the northern Subarctic should be conducted to determine if similar changes are occurring across this ecotone.

Soil carbon sequestration with forest expansion in an arctic forest–tundra landscape

2004 ◽  
Vol 34 (7) ◽  
pp. 1538-1542 ◽  
Author(s):  
Heidi Steltzer
Keyword(s):  
Soil Carbon ◽  
Picea Glauca ◽  
White Spruce ◽  
Tree Age ◽  
Forest Expansion ◽  
Soil C ◽  
C Storage ◽  
C Pools ◽  
Sampling Locations

Soil carbon (C) and nitrogen (N) pools were measured under the canopy of 29 white spruce (Picea glauca (Moench) Voss) trees and in the surrounding tundra 3 and 6 m away from each tree at three sites of recent forest expansion along the Agashashok River in northwestern Alaska. The aim was to characterize the potential for forest expansion to lead to increased soil C pools across diverse tundra types. Soil C beneath the trees correlated positively with tree age, suggesting that tree establishment has led to C storage in the soils under their canopy at a rate of 18.5 ± 4.6 g C·m–2·year–1. Soil C in the surrounding tundra did not differ from those under the trees and showed no relationship to tree age. This characterization of the soil C pools at the 3-m scale strengthens the assertion that the pattern associated with the trees is an effect of the trees, because tree age cannot explain variation among tundra sampling locations at this scale. Potential mechanisms by which these white spruce trees could increase soil C pools include greater production and lower litter quality.

SOIL APPLICATION OF CARBOFURAN TO CONTROL SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), IN A MANAGED WHITE SPRUCE SEED PRODUCTION AREA

1981 ◽  
Vol 113 (10) ◽  
pp. 949-951 ◽  
Author(s):  
W. H. Fogal ◽  
D. A. Winston ◽  
S. M. Lopushanski ◽  
D. A. MacLeod ◽  
A. J. Willcocks
Keyword(s):  
Seed Production ◽  
Picea Glauca ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
White Spruce ◽  
Cone Production ◽  
Seed Supply ◽  
Current Outbreak ◽  
Production Area ◽  
Production Areas

White spruce, Picea glauca (Moench) Voss, is a major commercial tree species used in reforestation programs throughout Canada, and seed requirements cannot be met in some years because of insect damage and the periodic nature of cone crops. The spruce budworm, Choristoneura fumiferana (Clem.), feeds on buds and cones of its hosts, causing a pronounced decrease in cone production (Schooley 1978). A current outbreak in northeastern Ontario poses a serious threat to white spruce seed supply from high value, managed seed production areas. Therefore, in 1979, we began an experiment to determine whether carbofuran, a systemic insecticide, could be used to protect buds and cones when applied to soil. We chose carbofuran because it has proved successful for control of some insects in seed orchards in the southeastern United States (DeBarr 1978)

Age and size effects on first cone production among white spruce trees

2020 ◽  
Vol 50 (5) ◽  
pp. 519-522
Author(s):  
Michael T. Bronson
Keyword(s):  
Picea Glauca ◽  
Tree Height ◽  
White Spruce ◽  
Tree Age ◽  
Population Changes ◽  
Growth Rings ◽  
Reproductive Maturity ◽  
Cone Production ◽  
Competition For Light ◽  
Effect Of Age

The onset of lifetime reproduction is central to processes of plant adaptation and population changes. The relative contributions of size and age to the onset of reproduction are important to predicting that key event in individuals. To estimate respective size and age effects on first reproduction in a conifer, I observed white spruce (Picea glauca (Moench) Voss) trees in forest stands in Alaska, United States, over ranges of cumulative growth rates. Age was estimated by counting annular growth rings, size was indicated by tree height, and reproductive status was indicated by seed cones. Multiple logistic regression showed the relative contributions of tree height and age, adjusted for each other, to statistical predictions of reproductive maturity. Trees selected for having little competition for light first produced cones at heights between 1 and 5 m with little additional effect of age. Tree height contributed approximately 50% to regression predictions of reproductive maturity. In contrast, tree age contributed ≤1.5% and bore little relation to reproductive maturity other than as a component of growth rate. This is among the first reports to partial the effect sizes of tree size and age on the commencement of lifetime reproduction in a conifer.

scholarly journals Variation of White Spruce Carbon Content with Age, Height, Social Classes and Silvicultural Management

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8015
Author(s):  
Cyriac S. Mvolo ◽  
James D. Stewart ◽  
Christopher Helmeste ◽  
Ahmed Koubaa
Keyword(s):  
Carbon Content ◽  
Picea Glauca ◽  
Stand Density ◽  
White Spruce ◽  
Carbon Accounting ◽  
Accuracy And Precision ◽  
Freeze Dried ◽  
Stand Density Management ◽  
And Control ◽  
Volatile Carbon

The accuracy and precision with which carbon amounts have been accounted for in forests have been questioned. As countries seek to comply with agreements to reduce global warming and industries seek to maximize bioenergy potential, this matter has increased international concern. White spruce (Picea glauca (Moench) Voss) stand density management trials in the Petawawa Research Forest, Ontario, Canada, were sampled to evaluate carbon concentration variation within trees and plots of differing stand density. Sample-drying methodologies were also tested to compare freeze-dried carbon (FDC) and oven-dried carbon (ODC) measurements. The average FDC was 51.80 ± 1.19%, and the corrected freeze-dried carbon content (FDCCOR) was 51.76 ± 1.33%. The average ODC was 49.10 ± 0.92%, and the average volatile carbon fraction (Cvol) was 2.67 ± 1.71%. FDC was higher than ODC (mean of the differences = 2.52) and generally more variable. ODC significantly decreased radially and longitudinally. FDC was significantly affected by thinning, where heavy treatments resulted in the highest FDC amounts compared to medium, light, and control treatments. In addition to reducing carbon content (CC), drying influences wood CC in many ways that are still to be elucidated. The results of this study suggest that ODC should continue to be used within the bioenergy industry, while FDC must become the preferred standard for carbon accounting protocols.

Effects of cold temperatures on breakage of lodgepole pine and white spruce twigs

2001 ◽  
Vol 31 (9) ◽  
pp. 1650-1653 ◽  
Author(s):  
Sarah M Lieffers ◽  
Victor J Lieffers ◽  
U Silins ◽  
L Bach
Keyword(s):  
Picea Glauca ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Bending Test ◽  
Bending Angle ◽  
Cold Temperatures ◽  
The Relationship ◽  
Compression Damage

Twigs from lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss) trees were bent at a range of temperatures below 0°C using a two-point bending test. This was done to determine how cold temperatures might affect twig breakage and potential shoot and foliage loss in maturing conifer stands. The bending angle necessary to cause 50% twig breakage decreased linearly with decreasing temperatures for both species. No difference in the relationship between temperature and twig breakage was evident among species. Below –13°C, all breakage was on the tension side; at warmer temperatures there was compression damage to many twigs.

VIABILITY OF WHITE SPRUCE SEED FROM SQUIRREL-CUT CONES

1964 ◽  
Vol 40 (1) ◽  
pp. 98-110 ◽  
Author(s):  
J. W. Bruce Wagg
Keyword(s):  
Picea Glauca ◽  
Seed Viability ◽  
White Spruce ◽  
Mature Seed ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Red Squirrels

A study was made of the viability of white spruce, Picea glauca, seed obtained from seven cone caches of red squirrels, Tamiasciurus hudsonicus. Habits of the red squirrel, relation of seed viability to cone-caching activities and the relation of viability of seed obtained from the cached cones to the cones on the trees are described.Viability of see from cached cones does not vary between the time squirrels began to cache cones in quantity and the time the last cones are cached. Seed from the cached cones showed a higher percentage of viability than seed of cones collected from trees, because some of the mature seed had fallen from the partially open cones on the trees resulting in an increase in the percentage of undeveloped seed in progressive cone collections.

The effect of light availability and basal area on cone production in Abies balsamea and Picea glauca

2002 ◽  
Vol 80 (4) ◽  
pp. 370-377 ◽  
Author(s):  
David F Greene ◽  
Christian Messier ◽  
Hugo Asselin ◽  
Marie-Josée Fortin
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Light Availability ◽  
Abies Balsamea ◽  
Basal Area ◽  
White Spruce ◽  
Balsam Fir ◽  
Forest Edges ◽  
Cone Production ◽  
Effect Of Light

Mean annual seed production is assumed to be proportional to basal area for canopy trees, but it is not known if subcanopy trees produce fewer seeds than expected (given their size) because of low light availability. Ovulate cone production was examined for balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) in 1998 and for balsam fir in 2000 in western Quebec using subcanopy stems, near or far from forest edges, or (at one site) planted white spruce trees in fully open conditions. A very simple light model for transmission through mature trembling aspen (Populus tremuloides Michx.) crowns and through boles near forest edges was developed to account for the effect of light receipt on cone production. The enhanced light near forest edges (e.g., recent clearcuts) leads to about a doubling of cone production for subcanopy stems. The minimum subcanopy height for cone production far from an edge is about 10 m for balsam fir and 14 m for white spruce, with these minima decreasing near edges. By contrast, the minimum height for white spruce in a plantation (full light) is about 3 m. Accounting for light receipt leads to an increase in the explained variance.Key words: balsam fir, cone production, light model, regressions, subcanopy stems, white spruce.

scholarly journals Exploring the potential of two-aged white spruce plantations for the production of sawlog volume with simulations using SORTIE-ND

REFORESTA ◽  
2020 ◽  
pp. 11-24
Author(s):  
Vincent St-Gelais ◽  
◽  
Martin Béland ◽  
Nelson Thiffault ◽  
◽  
...  
Keyword(s):  
Picea Glauca ◽  
Stand Density ◽  
White Spruce ◽  
Variable Density ◽  
Spatially Explicit ◽  
Single Tree ◽  
Management Objectives ◽  
Candidate Species ◽  
Shade Tolerant Species ◽  
Planted Tree

The main objective for even-aged plantation (EAP) management of producing sawlog material has driven practices towards low initial planting densities and lower post thinning densities. For semi-shade tolerant species, the resulting stand density potentially leaves enough growing space for the introduction of a second cohort of trees in the understory, making it a two-aged plantation (TAP). TAP could have many silvicultural benefits, especially in sensitive areas where intensive treatments associated with EAP are incompatible with local management objectives. White spruce (Picea glauca) is a good candidate species for modeling TAP because it is the most widely planted tree species in Canada and has proven tolerance to understory planting. SORTIE-ND, a single-tree spatially explicit growth model was used to explore the yield of variable density and rotation length scenarios when each white spruce cohort is introduced mid rotation, compared to traditional even-aged management. All TAP scenarios tested produced more sawlog volume and more merchantable volume than equivalent densities of EAPs. The lowest density tested, 400 stems ha-1 planted every 35 years, had the highest sawlog yields (3.23 m3 ha-1 yr-1). Considering smaller size products changes the optimum TAP scenario but maintains the advantage over EAPs.

scholarly journals Seed Production in Grafted Clonal Orchards at Longlac, Ontario

1982 ◽  
Vol 58 (1) ◽  
pp. 31-34 ◽  
Author(s):  
J. A. McPherson ◽  
E. K. Morgenstern ◽  
B. S. P. Wang
Keyword(s):  
Seed Production ◽  
Picea Mariana ◽  
Picea Glauca ◽  
Black Spruce ◽  
White Spruce ◽  
Seed Orchard ◽  
Northern Ontario ◽  
Cone Production ◽  
Cone Development ◽  
Number Of Seeds

One seed orchard each of black spruce (Picea mariana) [Mill.] B.S.P.) and white spruce (Picea glauca) [Moench] Voss) was established in northern Ontario gradually during the 1958-78 period. Each species was represented by approximately 45 clones and 450 ramets. During the whole period, records were kept of cone production by individual ramets and of seed production by clones expressed as average number of seeds per cone extracted and germinated. Substantial cone production began 8 years after grafting in black spruce and after 10 years in white spruce. The figures indicated that a clonal orchard of black spruce planted at 5 × 5 m spacing (400 ramets) produces approximately 1 million sound seeds per ha per year; the white spruce equivalent is 900 000. Conditions of cone development and cone storage and damage by insects and fungi can reduce germination of the sound seed harvested by about 20%.

A visual index for estimating cone production for individual white spruce trees

2005 ◽  
Vol 35 (12) ◽  
pp. 3020-3026 ◽  
Author(s):  
Jalene M LaMontagne ◽  
Susan Peters ◽  
Stan Boutin
Keyword(s):  
Picea Glauca ◽  
Information Criterion ◽  
White Spruce ◽  
Small Sample ◽  
Validation Data ◽  
Data Set ◽  
Simple Method ◽  
Conversion Factors ◽  
Cone Production ◽  
Cone Index

The number of cones produced by coniferous trees is commonly estimated by visual counts from the ground of a portion of the tree multiplied by a simple conversion factor. Linear conversion factors have been used to estimate total cone production by white spruce (Picea glauca (Moench) Voss). However, these conversion factors originate from other coniferous species and were often based on assumptions of cone visibility within the crown and not on empirical data. We propose a simple method for estimating the total number of cones produced by individual white spruce. We counted visible cones (an index of cone production, or cone index) on a total of 60 trees located in Alberta and Yukon, Canada, that were then felled and all cones were counted. We found that log(actual total cones) = 0.073 + 1.189 × log(cone index) is more accurate for estimating total cone numbers for white spruce than are other conversion factors (ranging from total cones = 1.5 × cone index to total cones = 3.35 × cone index), as determined using Akaike's information criterion with small sample bias adjustment and a validation data set. The relationship between the index of cone production and actual total cones produced is nonlinear, which is contrary to that proposed for various Pinus species.

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