Long-term outcome of precommercial thinning in northwestern New Brunswick: growth and yield of balsam fir and red spruce

2008 ◽  
Vol 38 (3) ◽  
pp. 592-610 ◽  
Author(s):  
Doug Pitt ◽  
Len Lanteigne
Keyword(s):  
Block Design ◽  
Abies Balsamea ◽  
Red Spruce ◽  
Balsam Fir ◽  
Growth And Yield ◽  
Stem Volume ◽  
Long Term Outcome ◽  
Precommercial Thinning ◽  
Minimum Requirement

A study was established between 1959 and 1961 to study the long-term responses of balsam fir ( Abies balsamea (L.) Mill.) and red spruce ( Picea rubens Sarg.) to precommercial thinning. Three nominal spacings of 4 ft (1.2 m), 6 ft (1.8 m), and 8 ft (2.4 m) were compared with an unthinned control in a randomized complete block design with five replicates. At the time of thinning, natural regeneration averaged 16 years of age, 8 years after harvest. Although thinning had minimal effect on gross total volume production over a 42 to 44 year observation period, actual spacings between 2.1 and 2.5 m produced an average of 360 m3·ha–1gross merchantable volume (GMV), representing a 21% gain over unthinned stands. The same spacings produced quadratic mean diameters of 21 and 23 cm, respectively, compared with 18 cm in the unthinned stands. These size increases translated to individual stem volume gains of 33% and 62%, significantly reducing the age at which thinned stands would meet a specified minimum requirement for merchantability or habitat. The mean annual increment of GMV ranged from 6 m3·ha–1·year–1in unthinned stands, to more than 7 m3·ha·–1·year–1in the thinned stands, and had not yet culminated an average of 50 years postharvest.

Forty years of spruce–fir stand development following herbicide application and precommercial thinning in central Maine, USA

2012 ◽  
Vol 42 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Matthew G. Olson ◽  
Robert G. Wagner ◽  
John C. Brissette
Keyword(s):  
Abies Balsamea ◽  
Balsam Fir ◽  
Stand Development ◽  
Long Term Effects ◽  
Herbicide Application ◽  
Precommercial Thinning ◽  
Clearcut Harvesting ◽  
Herbicide Treatments ◽  
Mixedwood Stands

We examined the development of a 33-year experiment in spruce–fir stands that received nine herbicide treatments (applied aerially in 1977), with and without precommercial thinning (PCT) (applied in 1986). We tested two commonly held assumptions about the long-term effects of herbicide and PCT in mixedwood stands managed for softwoods: (i) herbicide release produces stands dominated by softwoods and (ii) PCT promotes both softwood dominance and merchantable volume. All herbicides were effective at releasing balsam fir ( Abies balsamea (L.) Mill.) and spruce ( Picea spp.) from overtopping shrubs and hardwoods that had naturally regenerated following clearcut harvesting in 1970. Glyphosate (Roundup), triclopyr amine (Garlon 3A), 2,4,5-T, and a mixture of 2,4,5-T and 2,4-D herbicide treatments were all effective at shifting long-term species composition to softwood dominance after 30 years, irrespective of the rates applied. Herbicide-treated stands that did not receive PCT were overstocked with softwoods for at least 24 years and produced less than half of the merchantable softwood volume by 40 years than herbicide-treated stands that received PCT. Intolerant hardwoods dominated untreated stands for all 33 years of the experiment. When unsprayed plots received PCT, however, they produced stands at 40 years that were compositionally and structurally indistinguishable from those that had received both herbicide and PCT treatments. Results from this experiment clearly demonstrated that early herbicide application, regardless of type and rate of herbicide, created softwood-dominated mixedwood stands over the long term and that PCT more than doubled merchantable softwood volume within 25 years of application.

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.

LONG TERM STUDY OF THE EFFECTIVENESS OF AERIAL APPLICATION OF BACILLUS THURINGIENSIS – ACEPHATE COMBINATIONS AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Population Densities ◽  
Long Term Study

AbstractBacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

scholarly journals Stand Structure and Composition 32 Years after Precommercial Thinning Treatments in a Mixed Northern Conifer Stand in Central Maine

2011 ◽  
Vol 28 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Laura S. Kenefic ◽  
Rongxia Li ◽  
John Brissette
Keyword(s):  
Stand Structure ◽  
Abies Balsamea ◽  
Basal Area ◽  
Long Term Effects ◽  
Mixed Species ◽  
Precommercial Thinning ◽  
Large Trees ◽  
Stand Attributes ◽  
And Control

Abstract The effects of four precommercial thinning (PCT) treatments on an even-aged northern conifer stand in Maine were investigated by examining stand structure and composition 32 years after treatment. Replicated treatments applied in 1976 included: (1) control (no PCT), (2) row thinning (rowthin; 5-ft-wide row removal with 3-ft-wide residual strips), (3) row thinning with crop tree release (rowthin+CTR; 5-ft-wide row removal with crop tree release at 8-ft intervals in 3-ft-wide residual strips), and (4) crop tree release (CTR; release of selected crop trees at 8×8-ft intervals). PCT plots had more large trees and fewer small trees than the control in 2008. There were no other significant differences between the rowthin and control. The rowthin+CTR and CTR treatments had lower total and hardwood basal area (BA) and higher merchantable conifer BA than the control. CTR also resulted in more red spruce (Picea rubens [Sarg.]) and less balsam fir (Abies balsamea [L.]) than the other treatments. Although stand structures for rowthin+CTR and CTR were similar, the percentage of spruce in CTR was greater. Although the less-intensive rowthin+CTR treatment may provide many of the same benefits as CTR, the latter would be the preferred treatment if increasing the spruce component of a stand is an objective. Overall, early thinning treatments were found to have long-term effects on key stand attributes, even more than 30 years after treatment in areas with mixed species composition and moderate site potential.

Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 4 – Lumber production, quality and value

2013 ◽  
Vol 89 (04) ◽  
pp. 474-489 ◽  
Author(s):  
Isabelle Duchesne ◽  
Doug G. Pitt ◽  
Francis Tanguay
Keyword(s):  
Value Chain ◽  
Positive Impact ◽  
Abies Balsamea ◽  
Basic Density ◽  
Production Quality ◽  
Balsam Fir ◽  
Appreciable Effect ◽  
Precommercial Thinning ◽  
Product Value ◽  
Negative Effect

Forty-eight years after application, three nominal precommercial thinning (PCT) spacings of 4 ft (1.2 m), 6 ft (1.8 m) and 8 ft (2.4 m) were compared to an unthinned control in six replicate, balsam fir (Abies balsamea [L.] Mill.)-dominated stands. Within three of these replicates chosen for clearcut harvest in 2008, a total of 150 trees were bucked into 479 sawlogs that produced 10 829 board feet of lumber. PCT had a positive impact on Premium lumber grade recovery per tree, increasing it from an average of 9 foot board measure (fbm) in the unthinned control plots, to 22 fbm in plots nominally spaced to 8 ft (p = 0.02). No. 2 & Better grade yields increased from 42 to 76 fbm/tree in these same sets of plots (p < 0.01). PCT to 6 ft and 8 ft increased the production of 2×4 and 2×6 lumber over the control (p ≤ 0.04). Stand-level gross total product value increased between 11% and 23% in thinned stands (estimated at +$3000 to +$6600 per ha, p < 0.01). PCT had no appreciable effect on sawn lumber wood density (p ≥ 0.26) or lumber stiffness (MOE; ≤-6.2%, p ≥ 0.11), but had a negative effect on lumber strength (MOR; ≤ -13.4%, p ≤ 0.03) and wood basic density at stump height (≤- 7%; p < 0.01). MDF panel properties were generally good, regardless of spacing. We recommend thinning young balsam fir stands to a maximum nominal spacing of 6 ft (1.2 m) to maintain satisfactory lumber mechanical properties and maximize product value per hectare.

CONTACT AND RESIDUAL EFFECT OF LOW-VOLUME DOSAGES OF PHOSPHAMIDON TO CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE) ON TWO SPECIES OF CONIFERS

1972 ◽  
Vol 104 (7) ◽  
pp. 1051-1054
Author(s):  
J. F. Stewart ◽  
N. R. Brown
Keyword(s):  
Statistical Difference ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Residual Effect ◽  
Spruce Budworm ◽  
Picea Rubens ◽  
Fourth Instar ◽  
Red Spruce ◽  
Balsam Fir ◽  
Low Volume

AbstractA series of low-volume spray treatments were conducted to study the contact and residual effect of two concentrations of the insecticide phosphamidon to fourth instar spruce budworm, Choristoneura fumiferana (Clem.), on balsam fir, Abies balsamea (L.) Mill, and red spruce, Picea rubens Sarg. Treatment of sprayed larvae on sprayed trees, unsprayed larvae on sprayed trees, and sprayed larvae on unsprayed trees, resulted in two principal conclusions: (a) Higher concentrations of phosphamidon (1% versus 0.5% active) accelerated mortality in all instances and (b) no statistical difference (P = 0.1%) was found in the final mortalities between treatments in which only the foliage was treated and where both larvae and foliage were treated with phosphamidon.

Changes in root morphology after precommercial thinning in balsam fir stands

2003 ◽  
Vol 33 (12) ◽  
pp. 2452-2459 ◽  
Author(s):  
Jean-Claude Ruel ◽  
Catherine Larouche ◽  
Alexis Achim
Keyword(s):  
Radial Growth ◽  
Abies Balsamea ◽  
Stand Density ◽  
Balsam Fir ◽  
Cross Sectional ◽  
Beam Shape ◽  
Precommercial Thinning ◽  
Beneficial Effects ◽  
Density Control ◽  
Over Time

Precommercial thinning is often used to control stand density in naturally regenerated balsam fir (Abies balsamea (L.) Mill.) stands. Early stand density control could have beneficial effects on longer term stand stability through a modification of stem shape and root development. To assess the effect of precommercial thinning, two thinned and two unthinned stands were selected. Root sections were collected at 25 cm from the centre of the stem for all major roots (diameter greater than 2 cm). A disk was also cut at breast height level. From these disks, response in radial growth was determined. Detailed root measurements were taken on the sample disks to assess treatment effect on the following variables: asymmetry in root cross-sectional area (CSA) distribution, individual root shape, as well as changes in root shape over time. A quick and pronounced response in root growth occurred. This response was greater than that observed in the trunk. No asymmetry in root CSA distribution was observed at the stand level. Trees allocated more to radial growth above the biological centre of the root both in treated and control stands, but this trend was increased by thinning. Roots also tended to develop T-beam shapes over time, both in control and thinned stands. Most roots initially did not possess an I-beam shape and did not develop one during the course of the study. According to our results, trees respond quickly to the new growing conditions created by thinning by increasing biomass allocation to parts of the roots where mechanical stresses are greater.

Advantages of long-term measurement of fine root demographics with a minirhizotron at two balsam fir sites

2010 ◽  
Vol 40 (6) ◽  
pp. 1128-1135 ◽  
Author(s):  
M.J. Krasowski ◽  
M.B. Lavigne ◽  
J. Olesinski ◽  
P.Y. Bernier
Keyword(s):  
Fine Root ◽  
Abies Balsamea ◽  
Early Years ◽  
Balsam Fir ◽  
Annual Production ◽  
First Year ◽  
Green River ◽  
Root Demography ◽  
Annual Mortality

We used 15 site-years of minirhizotron observations (1998–2006 at one site; 1998–2000 and 2004–2006 at second site) from two mature balsam fir ( Abies balsamea (L.) Mill.) sites to quantify interannual variability in fine root demography and assess the accuracy of estimates from early years of observation. Annual production varied fourfold at Forêt Montmorency (FM) (5.8–26.5 roots·100 cm–2) and twofold at Green River (GR) (7.2–14.2 roots·100 cm–2). Annual mortality varied more than 30-fold at the two sites (FM: 0.7–23.2 roots·100 cm–2; GR: 0.3–10.9 roots·100 cm–2), year-end standing crops varied two- to eight-fold (FM: 3.6–28.4 roots·100 cm–2; GR 8.5–18.6 roots·100 cm–2), and median life-span of annual cohorts varied from 180 to 540 days at FM and from 350 to 577 days at GR. This variation illustrates that root demography estimates from short-term studies may differ widely from long-term means. Annual mortality and standing crops were lowest in the first year of observation and tended to increase for two or more years at both sites, whereas these trends were not observed for annual production. Our results indicate that minirhizotron tubes must be in place for more than 2 years to accurately estimate fine root demography at balsam fir sites.

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