scholarly journals Site Preparation for Establishing Interior Spruce in British Columbia: Trials at Upper Coalmine and Mackenzie

2001 ◽  
Vol 16 (1) ◽  
pp. 9-17 ◽  
Author(s):  
R.F. Sutton ◽  
L. Bedford ◽  
Linda Stordeur ◽  
Marvin Grismer

Abstract Two trials (“Upper Coalmine” and “Mackenzie”) were begun in the 1980s in the Prince George Forest Region, B.C., to evaluate a total of 13 site preparation treatments for establishing interior spruce (Picea glauca × engelmannii) in the Engelmann Spruce-Subalpine Fir and Sub-Boreal Spruce biogeoclimatic zones. Treatments included mounding (with various thicknesses of mineral soil “capping”), patch scarification, blading, disk trenching, and herbiciding. In each trial, five blocks each contained one 48 or 80 tree plot/treatment. Trees were monitored for 10 yr at Mackenzie and 15 yr at Upper Coalmine. Large mounds have had consistent biological success. Tree seedling response to blading was site specific; blading at Mackenzie was not significantly inferior to the best (Ministry mound) treatment, but at Upper Coalmine was no better than the untreated control. West. J. Appl. For. 16(1):9–17.

1980 ◽  
Vol 56 (2) ◽  
pp. 55-57 ◽  
Author(s):  
L. J. Herring ◽  
R. G. McMinn

The mean height of Engelmann spruce (Picea engelmanni Parry) advance growth 21 years after release by overstorey harvesting and residual tree felling, was eight times that of natural regeneration established following brush blade scarification. Subalpine fir (Abies lasiocarpa (Hook.) Nutt.) advance growth was nine times taller than natural regeneration established on scarified soil. Mean current annual height increment of Engelmann spruce and subalpine fir advance growth was 39 and 34 cm, respectively, compared with only 7 cm for natural regeneration on scarified soil. The performance gap does not appear to be narrowing. The poor performance of natural regeneration on mineral soil exposed by blade scarification is attributed to removal of organic and top mineral soil horizons beyond the immediate reach of seedlings. These soil layers remained available to the advance growth. Consideration should be given to preserving advance growth when scarification may be inappropriate.


2000 ◽  
Vol 76 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Craig Farnden

A localized version of the Forest Vegetation Simulator (FVS) individual tree growth model was developed to simulate stand level impacts under a variety of uneven-aged management regimes in old-growth interior spruce-subalpine fir forests near Prince George British Columbia. Options for using uneven-aged management to satisfy a range of management objectives were simulated using different sets of BDq regulation parameters, and by varying species composition and rules for reserve trees. The greatest timber yields were attained by promoting the highest possible spruce component, using high q ratios, low to moderate maximum diameters and 20 to 25 year cutting cycles, and allowing no reserves. Using strategies to promote stand structures maintaining some old-growth attributes resulted in much lower timber yields. Key words: white spruce, Engelmann spruce, subalpine fir, uneven-aged management, BDq regulation, simulated yield


2007 ◽  
Vol 37 (12) ◽  
pp. 2663-2676 ◽  
Author(s):  
J. E. (Ted) Newbery ◽  
Kathy J. Lewis ◽  
Michael B. Walters

For wet sub-boreal spruce–fir forests (white spruce ( Picea glauca (Moench) Voss) × Engelmann spruce ( Picea engelmannii Parry ex Engelm.) – subalpine fir ( Abies lasiocarpa (Hook.) Nutt.)) in east-central British Columbia, we asked (i) do compositional and structural dynamics differ for unmanaged (UN) and partial-cut (PC) (50% removal 45 years before measurement) forests and (ii) how does Inonotus tomentosus Fr. (Teng) affect these dynamics? Inonotus tomentosus infected stands had 17% less spruce basal area (P = 0.059) than uninfected stands, but PC did not exacerbate I. tomentosus effects. PC and UN had similar live tree density, but UN had lower dead tree density. In all stands, snag longevity was typically <32 years, and ~40 years was required for dead wood to reach decay stage 3 or greater. UN was characterized by variable severity disturbances averaging ~8% of the canopy per decade. Management implications include the following: (i) harvest systems designed to emulate small-scale disturbance could remove trees at 8% of the canopy per decade, varied spatiotemporally, (ii) emulating dead wood abundance with partial cutting may be difficult given the impacts of partial cutting on dead wood abundance, and (iii) forests with moderate levels of I. tomentosus should not respond differently to harvesting than uninfected forests and thus require no special management.


1999 ◽  
Vol 29 (6) ◽  
pp. 761-767 ◽  
Author(s):  
J R Nault ◽  
J F Manville ◽  
T S Sahota

White spruce (Picea glauca (Moench) Voss) and Engelmann spruce (Picea engelmannii Parry) parent trees were selected that were rated as highly resistant or highly susceptible to white pine weevil (Pissodes strobi Peck) attack, based upon attack measurements on their open-pollinated progeny. For each parent, levels of terpenes or other volatiles in leaf and bark were highly correlated within ramets and highly variable within progeny. For the ramets, levels of individual terpenes could not be used to predict resistance class because of their large variability. A multivariate model developed using the terpenes showing the greatest differences between resistant classes was found to predict the resistance levels of the original ortets well, with 15 of 16 parent trees correctly predicted using either leaf or bark chemicals. These models failed to predict the resistance level of the open-pollinated progeny. Discriminant analysis was also attempted by dividing the ramet data into independent sets and using each set to predict the other. Again, prediction was no better than chance. We conclude that there is no merit in using terpenes as a selection tool to find resistant genotypes amongst white and Engelmann spruce populations.


2003 ◽  
Vol 33 (11) ◽  
pp. 2210-2220 ◽  
Author(s):  
Cindy E Prescott ◽  
Graeme D Hope ◽  
Leandra L Blevins

Possible mitigation of nitrate losses associated with clearcuts through harvesting smaller gaps was tested in a high-elevation forest of Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.). We measured concentrations of ammonium and nitrate after 6-week buried bag incubations of forest floor and mineral soil samples in replicated plots of uncut forest and gaps of 10, 1.0, and 0.1 ha and single-tree removal for 7 years after harvest. Nitrate concentrations in forest floor and mineral soil were elevated 3–7 years after harvesting in gaps of 0.1 ha and larger. Removal of the same proportion of trees as single trees did not result in increased nitrate concentrations, suggesting that nitrate losses could be reduced by harvesting single trees rather than creating gaps. Greater N availability was not associated with faster rates of decomposition of litter and forest floor, which were similar in gaps of all sizes (0–10 ha). Reciprocal transplant of forest floor and soil from the 10-ha gaps and the uncut forests indicated that changes in the nature of the forest floor or soil following harvest had a greater influence on nitrate concentrations than the changes in environmental conditions in the gaps.


1999 ◽  
Vol 29 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Jianwen Zhong ◽  
Bart J van der Kamp

Unstratified seed of Engelmann spruce (Picea engelmannii Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in nylon mesh bags was placed on various natural and disturbed forest floor seed beds in the Engelmann Spruce - Subalpine Fir Zone in the southern interior of British Columbia in September 1995 and recovered just before snow melt in June 1996. Fifty-two and 86% of the viable spruce and fir seed, respectively, had germinated before snowmelt. Germination under snow may be an adaptation of these high-elevation species to short cool growing seasons. Seed viability at recovery was significantly lower on undisturbed forest floor seed beds (spruce, 13%; fir, 12%) than on exposed mineral soil (spruce, 57%; fir, 42%). Viability of seed placed on nurse logs was 38 and 23% for spruce and fir, respectively. Isolation from ungerminated seed yielded a Rhizoctonia sp., an as yet unidentified black mold at high frequencies, and several other seed pathogens at low frequency. Multiple linear regression of the frequency of isolation of Rhizoctonia and black mold on seed viability was highly significant for both tree species. Seed pathogens appear to cause a major loss of seed and seedlings in these forests, and this may explain both the common occurrence of regeneration on nurse logs and the requirement of mineral soil seed beds for adequate regeneration.


1998 ◽  
Vol 78 (3) ◽  
pp. 467-475 ◽  
Author(s):  
H. Y. H. Chen ◽  
K. Klinka ◽  
J. Fons ◽  
P. V. Krestov

To determine whether field-identified soil nutrient regimes (SNRs) can be characterized and segregated by direct soil nutrient measures, we collected samples of forest floor and mineral soil (0 to 30 cm) from a wide range of forest sites throughout the Engelmann Spruce — Subalpine Fir (ESSF) zone of British Columbia. The samples were analyzed for acidity, total C, total N, mineralizable N, and extractable Ca, Mg, K, P, and SO4-S. The study sites were stratified according to an a priori field classification (SNRs) and an a posteriori classification derived from quantitative classification (groups) using all direct measures of nutrients as discriminating variables. The two classification methods had 72% agreement. Regardless of the classification, nitrogen-related variables (C:N ratio, total N, and mineralizable N) in the mineral soil segregated best among SNRs or groups indicating the presence of a steep, N-driven regional soil nutrient gradient. Multiple regression models using SNRs, groups, or direct measures of nutrients together with surrogates of climate (elevation, latitude, and/or longitude) as predictors had the similar accountability for the variation in subalpine fir and Engelmann spruce site index (0.41 ≤ R2 ≤ 0.65). The similarity in the accountability for site index justifies the use of the a priori classification in estimating site quality. Comparison of mineralizable-N values for field-identified SNRs between different climatic regions showed similarities between boreal climates and discrepancies between boreal and cool mesothermal climates. The study gave further evidence that indices of plant-available nitrogen in the upper mineral soil provide useful measures for field-identified SNRs, but indicated that it may be necessary to expand the existing five-class a priori classification to accommodate differences in regional soil nutrient gradients. Key words: Classification, Engelmann spruce, subalpine fir, nitrogen, site index, soil nutrient regime


2002 ◽  
Vol 32 (12) ◽  
pp. 2116-2127 ◽  
Author(s):  
Milosh Ivkovich ◽  
Gene Namkoong ◽  
Mathew Koshy

Quantitative genetic variation in growth, latewood percentage, and wood density was investigated for British Columbia's interior spruce (the common name for white spruce, Picea glauca (Moench) Voss; Engelmann spruce, Picea engelmanni Parry ex Engelm.; and their hybrids). The study included 160 half-sib families from the East Kootenay and Prince George regions. At the time of sampling, progeny tests for those two regions were 20 and 22 years old, respectively. Univariate and multivariate restricted maximum likelihood (REML) estimates of genetic parameters were obtained. Estimates of genetic variances and heritabilities differed greatly across planting sites for the examined traits, especially after transplantation between the regions. Significant negative genetic correlation between overall growth and wood density was found for the East Kootenay progenies, while negative but nonsignificant genetic correlation between these traits was found for the Prince George progenies. Generally, there was no significant decrease in heritability for ring width and latewood percentage in successive growth rings. A general age trend for genetic correlation between those traits was not apparent, except that the correlation remained negative during the observed period. Our results show that it is not possible to select certain families as superior based on 1-year results because of the family by growing season interactions. Nevertheless, genetic age–age correlations for cumulative increments were high, having a decreasing trend with increasing difference in age.


2006 ◽  
Vol 36 (2) ◽  
pp. 482-494 ◽  
Author(s):  
C BD Hawkins ◽  
Thomas W Steele ◽  
Tony Letchford

A trend in forestry is to move away from intensive stand establishment practices in favor of prescriptions that are lighter on the land. This study examined the condition and projected yields of nine different site preparation treatments on two high-elevation sites in central British Columbia. Treatments included the following: raw planting (i.e., no site preparation); scalping; mounding; chemical site preparation; chemical brushing; and combinations of mounding and chemical treatments. All treatments were manually planted with 2+1 bare-root interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) seedlings. By age 15, trees growing on prepared sites had significantly greater survival, larger stem diameters, and taller tree heights than did trees that were raw planted as seedlings. Moreover, site preparation generally led to earlier and less costly compliance with mandatory reforestation requirements. Growth and yield simulations predicted raw-planted timber volumes that were just 33%–51% of the volumes in the most productive treatments. Financial returns varied as well. Site preparation typically resulted in larger land expectation values than that resulting from raw planting; however, the results were sensitive to rotation length and discount rate. Collectively, these results suggest that moderate investments in site preparation may lead to a more profitable allocation of regeneration resources and a greater future timber supply.


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