scholarly journals Long-term effects of peatland black spruce regeneration treatments in northeastern Ontario

2005 ◽  
Vol 81 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Arthur Groot ◽  
Michael J Adams
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Stocking Density ◽  
Basal Area ◽  
Long Term Effects ◽  
Seeding Rate ◽  
Site Class ◽  
Advance Regeneration ◽  
Rate Effects

Studies of black spruce (Picea mariana (Mill.) BSP) broadcast seeding and of harvest methods for advance regeneration protection were remeasured 17 to 20 years after establishment on peatland sites in northeastern Ontario. The effects of seeding rate on black spruce stocking, density or basal area were apparent at two study locations 20 years after treatment, but high levels of advance regeneration masked seeding rate effects at two other study locations. The effects of different harvest methods on black spruce stocking, density and basal area, which were evident at earlier ages, were no longer statistically significant 17 to 19 years after treatment. Black spruce density increased moderately with time because of gradual recruitment of new seedlings. Density of black spruce stems taller than 1.3 m tall exceeded 4000 ha-1 for nearly all treatments, but these stems were spatially aggregated at the 4-m2 scale. The stand characteristics of these regenerated peatland stands are consistent with site class 2 stands in the Ontario normal yield tables. Key words: black spruce; Picea mariana; advance regeneration; direct seeding; regeneration; peatland; stand dynamics

Long-term effects of thinning on growth and yield of an upland black spruce stand

2012 ◽  
Vol 42 (9) ◽  
pp. 1669-1677 ◽  
Author(s):  
Michel Soucy ◽  
Jean-Martin Lussier ◽  
Luc Lavoie
Keyword(s):  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Basal Area ◽  
Growth And Yield ◽  
Long Term Effects ◽  
Partial Cutting ◽  
Spruce Stands ◽  
Cutting Experiment ◽  
Management Approaches

Knowledge of the long-term effects of silviculture treatments is crucial to forest management. The long-term effects of thinning, a common and widely used silviculture treatment, is little documented for upland black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) stands. We revisited a partial cutting experiment installed in 1961 in a 65-year-old unmanaged upland black spruce stand. The aim was to document the long-term effects of thinning on tree and stand growth and to complete previously published results of the first 15 years of response to thinning by determining its influence in terms of merchantable volume. Free thinning was applied following three intensities: 0%, 25%, and 50% of total basal area removal. The retrospective analysis of growth rings showed that the response over the first 15 years was less significant when determined in net merchantable volume instead of net total volume. Heavily thinned plots, nonetheless, showed a net stand merchantable volume increment 33% greater than that of the unthinned plots. In the longer term, a spruce budworm ( Choristoneura fumiferana Clemens) outbreak affected the site; nevertheless, the heavily thinned plots maintained a superior tree growth rate and did not show senescence mortality like the other plots, allowing stand volume to catch up to that of the unthinned plots after 33 years. Results suggested that thinning upland black spruce stands may be useful in mitigating reductions in volume production associated with growing stands to longer rotations as called for by certain ecosystem-based management approaches.

Long-Term Effects of Early Pruning and Thinning Treatments on Growth of Natural Longleaf Pine

1980 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Robert C. Sparks ◽  
Norwin E. Linnartz ◽  
Harold E. Harris
Keyword(s):  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Diameter Growth ◽  
Stocking Rate ◽  
Long Term Effects ◽  
Natural Stand ◽  
Stocking Rates ◽  
Pruning Intensity

Abstract Pruning and thinning a young natural stand of longleaf pine (Pinus palustris Mill.) in southwest Louisiana had little influence on height. However, diameter growth was reduced substantially as pruning intensity or stocking rate increased up to 25-percent live crown and 200 stems per acre, respectively. Improved diameter growth at lower stocking rates was not sufficient to equal the total basal area increment of 200 trees per acre.

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.

scholarly journals Long-Term Effects of Fuels Treatments, Overstory Structure, and Wildfire on Tree Regeneration in Dry Forests of Central Washington

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 888
Author(s):  
Allison K. Rossman ◽  
Jonathan D. Bakker ◽  
David W. Peterson ◽  
Charles B. Halpern
Keyword(s):  
Prescribed Burning ◽  
Basal Area ◽  
Tree Regeneration ◽  
Dry Forest ◽  
Permanent Plots ◽  
Long Term Effects ◽  
Fuels Reduction ◽  
Forest Fuels ◽  
Fuels Treatments

The long-term effectiveness of dry-forest fuels treatments (restoration thinning and prescribed burning) depends, in part, on the pace at which trees regenerate and recruit into the overstory. Knowledge of the factors that shape post-treatment regeneration and growth is limited by the short timeframes and simple disturbance histories of past research. Here, we present results of a 15-year fuels-reduction experiment in central Washington, including responses to planned and unplanned disturbances. We explore the changing patterns of Douglas-fir regeneration in 72 permanent plots (0.1 ha) varying in overstory abundance (a function of density and basal area) and disturbance history—the latter including thinning, prescribed burning, and/or wildfire. Plots were measured before treatment (2000/2001), soon afterwards (2004/2005), and more than a decade later (2015). Thinning combined with burning enhanced sapling recruitment (ingrowth) into the overstory, although rates of ingrowth were consistently low and greatly exceeded by mortality. Relationships between seedling frequency (proportion of quadrats within a plot) and overstory abundance shifted from weakly negative before treatment to positive after thinning, to neutral in the longer term. However, these relationships were overshadowed by more recent, higher-severity prescribed fire and wildfire that stimulated seedling establishment while killing advanced regeneration and overstory trees. Our results highlight the dependence of regeneration responses on the history of, and time since, fuels treatment and subsequent disturbance. Managers must be aware of this spatial and temporal complexity and plan for future disturbances that are inevitable but unpredictable in timing and severity.

Short-term effects of cut-to-length versus full-tree harvesting on conifer regeneration in jack pine, mixedwood, and black spruce forests in Manitoba

2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Jack Pine ◽  
Tree Regeneration ◽  
Understorey Vegetation ◽  
Advance Regeneration ◽  
The Impact

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.

scholarly journals Savanna burning and the assessment of long-term fire experiments with particular reference to Zimbabwe

2008 ◽  
Vol 32 (6) ◽  
pp. 611-634 ◽  
Author(s):  
Peter A. Furley ◽  
Robert M. Rees ◽  
Casey M. Ryan ◽  
Gustavo Saiz
Keyword(s):  
Stocking Density ◽  
Basal Area ◽  
Research Station ◽  
Herbaceous Plant ◽  
Burned Areas ◽  
Vegetation Surveys ◽  
Savanna Burning ◽  
The Impact ◽  
Fire Experiments

Long-term fire experiments in savannnas are rare, given the difficulties and demands of operation. Controlled fire experiments date from colonial times in West Africa, although the largest and best-known is located in the Kruger National Park, South Africa. The achievements of these experiments are assessed from examples in Africa, South America and Australia. A less well-known experiment in Zimbabwe was sited at the Marondera Grassland Research Station and ran from 1953 to 1991. Some of the preliminary results on the impact of fire on vegetation are analysed and compared with further vegetation surveys in 2007. Studies on tree growth in this miombo savanna woodland indicate that the plots burned at three- and four-year intervals recovered to greater mean heights than the unburned control plots. There was no significant variation between treatments, suggesting that the few trees that did survive in the frequently burned plots were large specimens. Brachystegia and Julbernadia dominated the plots throughout and after the experiment. Basal area and stocking density were highest in the four-yearly burned plots but there was a high variability throughout the experiment, suggesting that many trees may have attained heights and bark thicknesses sufficient to protect from fire damage. Fire also affected the composition of the herbaceous plant community, but not the number of species. By the end of the experiment some grass and sedge species had flourished while others revealed greater susceptibility to fire, and fire-tolerant species predominated in the most frequently burned areas. The experimental design appeared to cope well with the variability between plots and indicated the soundness of the initial design and its implementation.

Selection of Piceamariana for growing space efficiency

1987 ◽  
Vol 17 (5) ◽  
pp. 421-427 ◽  
Author(s):  
Laird Van Damme ◽  
William H. Parker
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Selection Method ◽  
Stem Volume ◽  
Base Line ◽  
Short Term ◽  
Space Efficiency ◽  
Early Results ◽  
Light Interaction

In an attempt to select black spruce (Piceamariana (Mill.) B.S.P.) based on growing space efficiency, 398 candidate black spruce trees from a 60-year-old upland stand were measured for various growth and crown parameters. The best 10 trees were selected by two base lines: basal area increment vs. crown area and stem volume vs. crown radius. For comparison 10 trees were also selected by a height vs. age base line and 10 were randomly chosen to serve as a control. Only one tree was selected by all three base lines, but four other trees were selected by two of the three methods. Although discriminant analysis correctly classified 85% of the trees into the four selection and control groups, the high levels of variation associated with the growing-space efficiency base line trees made it impossible to identify a generalized form (crop ideotype) that was associated with either method. Short-term and long-term progeny tests were established to determine the relative gains associated with the different base-line selection methods. A greenhouse test was conducted over one growing season and included light intensity as a treatment; the long-term test was planted in 1984 and included spacing as a treatment. Results of the short-term test demonstrated strong family differences and strong family × light interaction, but no selection method differences or selection method × light interaction. While the long-term test was not yet mature enough to test the effect of spacing, the 2-year height growth results demonstrated strong family differences and no selection method differences. Correlation between the results of the two tests was significant (r = 0.61, P < 0.01), indicating a fairly high level of reproducibility in the juvenile progeny results. A weak, but consistent, trend of slower growth by the progeny of selected parents relative to randomly selected controls was observed. These early results suggest that if black spruce trees selected for superior growing space efficiency have inherent advantages in lower light intensities or more densely spaced situations in mature stands, their open-pollinated progeny do not express these qualities after one or two season's growth.

Ten-year results of strip clear-cutting in Quebec black spruce stands

2000 ◽  
Vol 30 (1) ◽  
pp. 59-66 ◽  
Author(s):  
David Pothier
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Height Growth ◽  
Clear Cutting ◽  
Advance Regeneration ◽  
Spruce Stands ◽  
Harvesting Method ◽  
Cost Efficient ◽  
One Year ◽  
Cutting System

Regeneration of first-cut strips in a two-cut system of strip clear-cutting was compared to that of large clear-cutting in four different areas representative of the black spruce (Picea mariana (Mill.) BSP) stands of the boreal forest of Quebec. Seedlings were more evenly distributed in clearcut strips than in large clearcuts. Differences of about 10 000 black spruce seedlings per hectare and 20% of stocking were observed in favour of clearcut strips compared to large clearcuts. Black spruce stocking was about 14% larger on lowland than on upland sites but height growth was better on upland sites. A regeneration problem similar to that of large clearcuts was observed when the second strips were cut. One year after cutting these second strips, winter harvesting resulted in a 23% gain in black spruce stocking as compared to summer harvesting. Even if black spruce stocking marginally increased during the years following winter harvesting, the height advantage of the preserved advance growth justifies the application of this harvesting method. The strip clear-cutting system effectively improved the stocking of former black spruce stands but if the stocking level of advance growth is adequate, careful harvesting to preserve advance regeneration should be the preferred method since it would be more cost-efficient.

Long-term effects of thinning and fertilization on growth of red fir in northeastern California

2005 ◽  
Vol 35 (6) ◽  
pp. 1285-1293 ◽  
Author(s):  
Jianwei Zhang ◽  
William W Oliver ◽  
Robert F Powers
Keyword(s):  
Basal Area ◽  
Basal Area Increment ◽  
Stand Development ◽  
Long Term Effects ◽  
Annual Increment ◽  
Fourth Period ◽  
Abies Magnifica ◽  
The Impact ◽  
Second Period

To determine the impact of fertilization and thinning on growth and development of red fir (Abies magnifica A. Murr.) stands, we established an experiment in a 60-year-old stand using a 2 × 3 factorial design with nitrogen-fertilized and nonfertilized treatments and three stocking levels. Plots were established in 1976 and were measured every 5 years for 26 years. The periodic annual increment in basal area was 97%, 51%, 38%, and 33% greater in fertilized trees than in nonfertilized trees during the first, second, third, and fourth 5-year periods, respectively. After 20 years, annual basal area increment was greater in nonfertilized trees. The response of annual volume increment to fertilization was not statistically significant until the fourth period. Yet, volume increases of the fertilized plots were 25%–92% greater than those of the nonfertilized plots from 1976 to 1996. Similarly, basal area increment was greater in lightly thinned plots than in unthinned plots from the second period on, until heavy mortality during 1996–2002. Basal area increment was greater in the heavily thinned plots from the fourth period on. Results indicate that red fir can respond to fertilization and thinning quickly and that both treatments speed stand development. In addition, fertilization increases the stand's carrying capacity. Therefore, forest managers can use these silvicultural practices to improve stand growth, to reduce fire fuels, and to accelerate stand development.

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