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

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.

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Vegetation management and site preparation effects on 13C isotopic composition in planted white spruce

Canadian Journal of Forest Research ◽

10.1139/x01-023 ◽

2001 ◽

Vol 31 (6) ◽

pp. 1093-1097 ◽

Cited By ~ 4

Author(s):

Thomas E Staples ◽

Ken CJ Van Rees ◽

J Diane Knight ◽

C van Kessel

Keyword(s):

Soil Moisture ◽

Picea Glauca ◽

White Spruce ◽

Vegetation Management ◽

Site Preparation ◽

Native Vegetation ◽

Active Radiation ◽

Growing Seasons ◽

Initial Hypothesis ◽

And Control

Moisture availability is the factor that most commonly influences the discrimination against 13C fixation (Δ) by C3 plants. Therefore, by changing the availability of moisture by way of controlling competing vegetation, Δ in white spruce (Picea glauca (Moench) Voss) seedlings should be affected. The objective of this study was to determine the influence of manual brushing on Δ in white spruce seedlings planted in disc-trenched and control (i.e., no site preparation) microsites. The effects of site preparation and vegetation management on soil moisture, photosynthetically active radiation (PAR), and Δ in white spruce seedlings were evaluated over three growing seasons. Vegetation management increased the amount of PAR reaching seedlings in the control and disc-trenched treatments by removing the shading by native vegetation around each seedling. It appears that the increase in PAR reaching seedlings decreased Δ by increasing the photosynthetic consumption of CO2. Differences in soil available moisture (up to 22%) between control and disc-trenched treatments were not reflected in Δ values, contrary to our initial hypothesis. This may indicate that the site was not moisture limiting. Also, these results underline the complexity and difficulty of determining the controlling mechanisms by which Δ is affected.

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Lodgepole pine stem diseases and management of stand density in the British Columbia interior

The Forestry Chronicle ◽

10.5558/tfc70773-6 ◽

1994 ◽

Vol 70 (6) ◽

pp. 773-779 ◽

Cited By ~ 13

Author(s):

B. J. van der Kamp

Keyword(s):

Tree Mortality ◽

Lodgepole Pine ◽

Stand Density ◽

Climatic Conditions ◽

Permanent Sample Plots ◽

Blister Rust ◽

Low Incidence ◽

Stand Density Management ◽

Crown Closure ◽

And Control

The incidence of western gall rust, stalactiform blister rust, comandra blister rust and Atropellis canker was measured in 16 permanent sample plots in young lodgepole pine stands in the Interior of B.C. in 1980, shortly following juvenile spacing, and again in 1985 and 1992. The incidence (as percent of living trees with live rust infections) of the three rusts increased substantially between 1980 and 1985 in both treated and control plots, but declined from 1985 to 1992, partly because of infected tree mortality, but mostly because of a low rate of new infection and the death of all branch infections on many surviving trees. More than 85 percent of all stalactiform and comandra blister rust infections and 60 percent of all gall rust stem infections occurred within 2 m of the ground. The low incidence of new infection in these plots since 1985 is probably attributable to the loss of live branches due to crown closure and branch suppression in that 2 m zone as well as altered climatic conditions and reduced inoculum levels. Atropellis canker infection increased at each remeasurement, and in 1992, was less in spaced plots than in unthinned controls (3.4 and 8.9% of trees infected). A set of recommendations concerning allowances for disease mortality at the time of regeneration and juvenile spacing is presented. Key words: stand density management, Lodgepole pine, western gall rust, blister rust, Atropellis canker

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

Arctic Science ◽

10.1139/as-2018-0012 ◽

2019 ◽

Vol 5 (4) ◽

pp. 167-184 ◽

Cited By ~ 4

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.

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

REFORESTA ◽

10.21750/refor.10.02.85 ◽

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.

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Regeneration of White Spruce Under Aspen Canopies: Seeding, Planting, and Site Preparation

Western Journal of Applied Forestry ◽

10.1093/wjaf/15.4.177 ◽

2000 ◽

Vol 15 (4) ◽

pp. 177-182 ◽

Cited By ~ 9

Author(s):

James D. Stewart ◽

Simon M. Landhäusser ◽

Kenneth J. Stadt ◽

Victor J. Lieffers

Keyword(s):

Populus Tremuloides ◽

Picea Glauca ◽

Germination Rate ◽

White Spruce ◽

Seed Rain ◽

Growing Seasons ◽

Significant Difference ◽

Different Types ◽

And Control ◽

Northern Alberta

Abstract This study investigated the establishment and survival of naturally and artificially seeded white spruce (Picea glauca), as well as three sizes of planted white spruce stock, on different types of scarification beneath mature aspen (Populus tremuloides) in northern Alberta. White spruce seed rain, natural and hand-seeded regeneration establishment and survival, and understory vegetation response were monitored for 4 yr on scarified strips (light blading, heavy blading, and ridged) and on undisturbed controls. Despite a heavy seed rain in 1993, seedling establishment on control plots was almost nil. On scarified plots, the number of seeds required to produce a live seedling after 3 growing seasons ranged from 15 to 37 and up to 68 in one site. Most mortality occurred during the summer. Germination rate on the hand-seeded plots ranged from 19 to 28% on the scarified strips. There was no significant difference in survival from seed (15%) after three growing seasons among the three scarification treatments. Survival of planted stock was 98% on scarified strips and 96% on control strips. Diameter growth was least on control plots but was not significantly different among the scarified treatments. In contrast, height increment was greatest on the light blading treatment and differed little among the other two treatments and control. These results suggest that spruce regeneration in aspen forests can be promoted by scarification or underplanting. West. J. Appl. For. 15(4):177–182.

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Canopy and emergent white spruce in “pure” broadleaf stands: frequency, predictive models, and ecological importance

Canadian Journal of Forest Research ◽

10.1139/x09-094 ◽

2009 ◽

Vol 39 (10) ◽

pp. 1997-2004 ◽

Cited By ~ 3

Author(s):

Steve Cumming ◽

Mariana Trindade ◽

David Greene ◽

S. Ellen Macdonald

Keyword(s):

Picea Glauca ◽

Boreal Forests ◽

Stand Density ◽

White Spruce ◽

Stand Age ◽

Large White ◽

Forest Management Planning ◽

Mixedwood Forests ◽

Seed Sources ◽

Ecological Importance

In mixedwood boreal forests of western Canada, stands classified as “pure deciduous” by forest inventories sometimes contain a few large white spruce (Picea glauca (Moench) Voss) trees among or emerging from the canopy. These trees are important as regeneration seed sources and for habitat structure. Neither their abundance nor the characteristics of stands in which they occur have previously been quantified. Of 275 “pure aspen” stands in northeastern Alberta, 19.6% contained at least one such spruce detectable in an aerial photograph. These trees were found in stands across the range of sampled canopy heights, densities, age classes, and stand sizes and were often present in the interior of stands, not just on the perimeter. The frequency of 3 ha cells containing at least one spruce was related to (i) stand shape and size, (ii) amount of mature white spruce in adjacent forest, (iii) canopy height, (iv) stand age, and (v) stand density. We conclude that such trees are relatively abundant and widely distributed within the boreal mixedwood forests of Alberta. There is presently no provision to maintain this landscape element within managed forests. More information is needed to determine if or how they should be considered in forest management planning.

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Validation of ecoregion-based taper equations for white spruce in Alberta

The Forestry Chronicle ◽

10.5558/tfc75281-2 ◽

1999 ◽

Vol 75 (2) ◽

pp. 281-292 ◽

Cited By ~ 14

Author(s):

Shongming Huang ◽

Daryl Price ◽

Dave Morgan ◽

Stephen Titus

Keyword(s):

Model Validation ◽

Picea Glauca ◽

Mean Squared Error ◽

White Spruce ◽

Data Sets ◽

Accuracy And Precision ◽

Taper Function ◽

The Mean ◽

Predicted Values ◽

Taper Equations

Ecoregion-based variable-exponent taper equations for white spruce (Picea glauca (Moench) Voss) were validated on independent tree sectioning data sets. Criteria used for model validation were briefly reviewed, along with applicable interpretations. Examination of the validation plots and statistics indicated that the mean prediction biases were small and very close to zero (−0.0058 ≤ ē ≤ 0.0247; −0.03% ≤ ē% ≤ 0.20%), and the mean squared error of prediction was low. The agreement between observed and predicted values from the taper equations was strong and obvious, and was consistent across the size classes of the predicted values. Approximately 99% of the total variation in both the diameter inside bark predictions and volume predictions were explained by the application of the fitted taper equations. Key words: model validation, accuracy and precision, taper function, Picea glauca

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Prothrombin Time Standardization: Report of the Expert Panel on Oral Anticoagulant Control

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657004 ◽

1979 ◽

Vol 42 (04) ◽

pp. 1073-1114 ◽

Cited By ~ 31

Keyword(s):

Prothrombin Time ◽

Expert Panel ◽

The Other ◽

Rabbit Brain ◽

Calibration Constant ◽

Freeze Dried ◽

The Mean ◽

Point Of Intersection ◽

And Control ◽

Standardization Report

SummaryIn collaborative experiments in 199 laboratories, nine commercial thromboplastins, four thromboplastins held by the National Institute for Biological Standards and Control (NIBS & C), London and the British Comparative Thromboplastin were tested on fresh normal and coumarin plasmas, and on three series of freeze-dried plasmas. One of these was made from coumarin plasmas and the other two were prepared from normal plasmas; in each series, one plasma was normal and the other two represented different degrees of coumarin defect.Each thromboplastin was calibrated against NIBS&C rabbit brain 70/178, from the slope of the line joining the origin to the point of intersection of the mean ratios of coumarin/normal prothrombin times when the ratios obtained with the two thromboplastins on the same fresh plasmas were plotted against each other. From previous evidence, the slopes were calculated which would have been obtained against the NIBS&C “research standard” thromboplastin 67/40, and termed the “calibration constant” of each thromboplastin. Values obtained from the freeze-dried coumarin plasmas gave generally similar results to those from fresh plasmas for all thromboplastins, whereas values from the artificial plasmas agreed with those from fresh plasmas only when similar thromboplastins were being compared.Taking into account the slopes of the calibration lines and the variation between laboratories, precision in obtaining a patient’s prothrombin time was similar for all thromboplastins.

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