Impact of precommercial thinning on tree growth, lumber recovery and lumber quality in Abies balsamea

2009 ◽  
Vol 24 (5) ◽  
pp. 425-433 ◽  
Author(s):  
Shuyin Zhang ◽  
Gilles Chauret ◽  
Queju Tong
Keyword(s):  
Tree Growth ◽  
Abies Balsamea ◽  
Precommercial Thinning

Erratum: Effects of precommercial thinning on tree growth and lumber quality in a jack pine stand in New Brunswick, Canada

2007 ◽  
Vol 37 (11) ◽  
pp. 2380
Author(s):  
S. Y. Zhang ◽  
Gilles Chauret ◽  
D. Edwin Swift ◽  
Isabelle Duchesne
Keyword(s):  
New Brunswick ◽  
Tree Growth ◽  
Jack Pine ◽  
Precommercial Thinning

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.

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.

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.

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.

Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 1 – Roundwood production and stumpage value

2013 ◽  
Vol 89 (04) ◽  
pp. 446-457 ◽  
Author(s):  
Doug G. Pitt ◽  
Len Lanteigne ◽  
Michael K. Hoepting ◽  
Jean Plamondon
Keyword(s):  
Value Chain ◽  
Abies Balsamea ◽  
Stand Age ◽  
Annual Increment ◽  
Data Set ◽  
Individual Tree ◽  
Green River ◽  
Precommercial Thinning ◽  
Permanent Sample Plots ◽  
Sequential Evaluation

The Green River precommercial thinning trials were established between 1959 and 1961 in naturally regenerating balsam fir (Abies balsamea [L.] Mill.)-dominated stands, an average of eight years after overstory removal. Three nominal 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 blocks. In the fall of 2008, following completion of the ninth sequential evaluation of the study’s 48 permanent sample plots, three of the six replicates were clearcut harvested and data were collected on roundwood product recovery and value. These data were used to construct treatment-invariant (p ≥ 0.18) functions predicting product volume from tree diameter, allowing the volume of studwood, sawlogs and pulpwood to be predicted for the full Green River data set (all 6 replicates) through time. Mean annual increment of gross merchantable volume culminated in all treatments around stand age 45. Thinning to a nominal spacing of 6 ft, resulting in 1600 merchantable stems per ha by stand age 30, offered the best balance of individual tree and stand growth, producing 20% more gross merchantable volume and 26% more sawlog volume than unthinned stands, potentially increasing landowner stumpage revenues by 22% (p < 0.01). The sawlog volume produced in unthinned stands could be realized up to 15 years sooner in thinned stands, suggesting that PCT may offer substantive flexibility in balancing forest-level wood supply objectives.

scholarly journals Leaf Area and Structural Changes after Thinning in Even-AgedPicea rubensandAbies balsameaStands in Maine, USA

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
R. Justin DeRose ◽  
Robert S. Seymour
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Structural Changes ◽  
Abies Balsamea ◽  
Picea Rubens ◽  
Area Index ◽  
Precommercial Thinning ◽  
Density Reduction

We tested the hypothesis that changes in leaf area index (LAI m2 m−2) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density in even-agedPicea rubensandAbies balsameastands with and without a precommercial thinning history in Maine, USA. Diameter ratios varied predictably by thinning type: low thinnings were <0.7, crown thinnings were >0.7 but <1.0, and dominant thinnings were >1.0 . LAI change was affected by type and intensity of thinning. On average, 33% density reduction removed <50% of LAI, whereas 50% density reduction removed >50% of LAI. Overall reduction of LAI was generally greatest in dominant thinnings (54%), intermediate in crown thinnings (46%), and lowest in low thinnings (35%). Upon closer examination by crown classes, the postthinning distribution of LAI between upper and lower crown classes varied by thinning history, thinning method, and amount of density reduction.

Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 2 – Efficiency gains in cut-to-length harvesting

2013 ◽  
Vol 89 (04) ◽  
pp. 458-463 ◽  
Author(s):  
Jean Plamondon ◽  
Doug G. Pitt
Keyword(s):  
Value Chain ◽  
Abies Balsamea ◽  
Green River ◽  
Precommercial Thinning ◽  
Permanent Sample Plots ◽  
Thinning Intensity ◽  
System Data ◽  
Sequential Evaluation ◽  
Harvesting Costs ◽  
Different Levels

The Green River precommercial thinning trials were established between 1959 and 1961 in naturally regenerating balsam fir (Abies balsamea [L.] Mill.)-dominated stands an average of eight years after overstory removal. Three nominal 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 blocks. In the fall of 2008, following completion of the ninth sequential evaluation of the study’s 48 permanent sample plots, three of the six replicates were clearcut harvested using a cut-to-length system; data were collected on harvesting, forwarding and loading efficiency. Largely due to increased average tree size, precommercially thinned stands were associated with improvements in both harvesting and forwarding productivity, proportional to thinning intensity. For example, the nominal 6-ft spacing yielded 30% to 35% gains in harvesting productivity, and 16% to 39% gains in forwarding productivity (p ≤ 0.04), these ranges spanning the different levels of operator expertise and block conditions observed. In total, estimated harvesting costs were $12.58/m3 in the unthinned stands, compared to $9.10/m3 in the 6-ft spaced stands (p = 0.02). Such a difference represents a $3.48/m3 savings, which translates into just over $1000 per ha, based on the gross merchantable volume produced in the 6-ft spaced stands.

Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 3 – Incidence of root and butt decay

2013 ◽  
Vol 89 (04) ◽  
pp. 464-473 ◽  
Author(s):  
Gary Warren ◽  
Patricia Baines ◽  
Jean Plamondon ◽  
Doug G. Pitt
Keyword(s):  
Forest Management ◽  
Value Chain ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Stand Age ◽  
Stem Form ◽  
Green River ◽  
Precommercial Thinning ◽  
Permanent Sample Plots ◽  
Butt Rot

The Green River precommercial thinning (PCT) trials were established between 1959 and 1961 in naturally regenerating balsam fir (Abies balsamea [L.] Mill.)-dominated stands an average of eight years after overstory removal. Three nominal 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 blocks. In the fall of 2008, following completion of the ninth sequential evaluation of the study’s 48 permanent sample plots, three of the six replicates were clearcut harvested; butt rot data were collected immediately afterwards. To date, forest management research and goals have focused on the benefits of PCT, such as increased tree size and merchantable volume, shorter rotation ages, and better stem form and uniformity. Comparatively little attention has been placed on negative aspects of PCT, such as the incidence and development of root and butt rots, and their impact on fibre yields and wood product values. Results from the Green River study provide evidence that PCT may increase the incidence of butt rot in balsam fir, with incidence proportional to thinning intensity (p < 0.01). We also observed incidence and volume of butt rot to increase with stem diameter (p ≤ 0.05). The experiment suggests that factors such as stand age at time of thinning, and age at the time of harvest are important considerations when it comes to mitigating the impacts of butt rot through forest management.

scholarly journals Long-term precommercial thinning effects on Larix occidentalis (western larch) tree and stand characteristics

2017 ◽  
Vol 47 (7) ◽  
pp. 861-874 ◽  
Author(s):  
Michael S. Schaedel ◽  
Andrew J. Larson ◽  
David L.R. Affleck ◽  
R. Travis Belote ◽  
John M. Goodburn ◽  
...  
Keyword(s):  
Tree Growth ◽  
Tree Level ◽  
Recent Measurement ◽  
Larix Occidentalis ◽  
Western Larch ◽  
Individual Tree ◽  
Precommercial Thinning ◽  
Linear Contrasts ◽  
Stand Yield

Precommercial thinning (PCT) is used to increase tree size and shorten harvest rotation time. Short-term results from PCT studies often show a trade-off between individual-tree growth and net stand yield, while longer-term effects of PCT on tree growth and stand yield are less well documented. We used a 54-year-old PCT study to test long-term effects of forest density and thinning schedules on stand yield and tree-level characteristics in even-aged western larch (Larix occidentalis Nutt.) stands. The study has three target densities (494, 890, and 1680 trees·ha−1) crossed with three thinning schedules (target density achieved through one, two, or four entries). Analysis of variance (ANOVA) and linear contrasts were used to test the effects of density and number of entries on tree- and stand-level attributes. Thinning before stand age 10 years leads to long-term constant yield (219.0–269.5 m3·ha−1; P > 0.05) across the tested densities. We also found constant volume growth across stand densities during the most recent measurement interval (5.42–6.41 m3·ha−1·year−1; P > 0.05). Number of entries did not affect any tree- or stand-level attribute. The primary effect of early PCT is to control whether wood volume and growth are concentrated on few large, stable trees or spread over many small, unstable trees.

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