scholarly journals Early vegetation control for the regeneration of a single-cohort, intimate mixture of white spruce and aspen on upland boreal sites – 10thyear update

2015 ◽  
Vol 91 (03) ◽  
pp. 238-251 ◽  
Author(s):  
Douglas G. Pitt ◽  
Philip G. Comeau ◽  
William C. Parker ◽  
Michael K. Hoepting ◽  
Daniel MacIsaac ◽  
...  
2010 ◽  
Vol 40 (3) ◽  
pp. 549-564 ◽  
Author(s):  
Douglas G. Pitt ◽  
Philip G. Comeau ◽  
William C. Parker ◽  
Daniel MacIsaac ◽  
Scott McPherson ◽  
...  

In Canada’s boreal forest region, there is increasing demand for practical regeneration strategies that will recreate mixed stands of white spruce ( Picea glauca (Moench) Voss) and trembling aspen ( Populus tremuloides Michx.). In 2002, we implemented an experiment in both west-central Alberta and northeastern Ontario to better understand the effects of herbaceous and woody vegetation control on crop tree survival and growth, within the context of prescription development for the regeneration of a single-cohort, intimate mixture of spruce and aspen. After five growing seasons, good spruce growth, health, and survival were observed with 2 m radial treatments consisting of herbaceous and woody (i.e., complete) vegetation control centred on trees planted at 5 m spacing. These spruce were 4%–64% taller and 68%–178% larger in stem diameter than untended trees, leading to 167%–1166% gains in stem volume, and were at least equivalent to the same stock grown at 2.5 m spacing and provided with complete, continuous relief from competition. Removing only the woody vegetation within treated radii stimulated herbaceous competition, resulting in reduced survival and growth of spruce and reduced height of surrounding aspen. Early results suggest that spot treatments that provide 2–4 years of relief from herbaceous and woody competition may offer a practical strategy for growing spruce with aspen.


1989 ◽  
Vol 19 (2) ◽  
pp. 262-269 ◽  
Author(s):  
Alan J. Thomson ◽  
Robert G. McMinn

Growth of white spruce (Piceaglauca (Moench) Voss) and lodgepole pine (Pinuscontorta Dougl.) seedlings was studied on six installations, each containing different stock types and site-preparation treatments. Stock types included styroplugs from different cavity sizes, bare-root stock, and transplant stock; site preparations included no treatment, scalping, inverting, and mixing. Fertilizer was also used in combination with some of these treatments on some installations. Site-preparation treatments that gave some degree of vegetation control generally led to higher growth rates, but there was considerable variability among and within installations. The slope of the linear relationship of height versus age up to 10 years gave an estimate of early growth which was suitable for comparing treatments, whereas average height increment in a later measurement period gave a better estimate of growth for projection purposes. A normal distribution of growth rates around a mean for a particular stock type and site-preparation method was used in conjunction with height–dbh and crown width–dbh relationships to project growth of trees to crown closure, assuming different densities. The age at crown closure depended on both growth rate and density, and average size at crown closure depended primarily on density.


2011 ◽  
Vol 41 (4) ◽  
pp. 793-809 ◽  
Author(s):  
Andrew Youngblood ◽  
Elizabeth Cole ◽  
Michael Newton

To identify suitable methods for reforestation, we evaluated the interacting effects of past disturbance, stock types, and site preparation treatments on white spruce (Picea glauca (Moench) Voss) seedling survival and growth across a range of sites in Alaska. Replicated experiments were established in five regions. At each site, two complete installations differed in time since disturbance: “new” units were harvested immediately before spring planting and “old” units were harvested at least 3 years before planting. We compared mechanical scarification before planting, broadcast herbicide application during the fall before planting, and no site preparation with 1-year-old container-grown seedlings from two sources, 2-year-old bare-root transplants from two sources, and 3-year-old bare-root transplants. Seedlings were followed for 11 years on most sites. Based on meta-analyses, seedling survival increased 10% with herbicide application and 15% with mechanical scarification compared with no site preparation. Scarification and herbicide application increased seedling height by about 28% and 35%, respectively, and increased seedling volume by about 86% and 195%, respectively, compared with no site preparation. Soil temperature did not differ among site preparation methods after the first 7 years. Results suggest that white spruce stands may be successfully restored through a combination of vegetation control and use of quality planting stock.


1979 ◽  
Vol 55 (3) ◽  
pp. 102-105 ◽  
Author(s):  
D. G. Blackmore ◽  
Wm. G. Corns

Perennial herbaceous vegetation, mainly marsh reed grass, (Calamagrostis canadensis (Michx) Beauv.), was sprayed with glyphosate on the day before planting one-year-old plugs of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss) on cutover forest land north of Edson, Alberta. Spraying at 4.5 kg ai/ha, included spot and strip applications in June 1976, compared with unsprayed scalps and controls. At the same time, all treatments were repeated plus a 9 g, 22-8-2 fertilizer tablet for each seedling. Another experiment at the same site, begun on August 1, 1976, compared scalp, unfertilized control and glyphosate strip treatments, followed by planting of pine seedlings the day after spraying 4.5 kg ai/ha glyphosate. An adjacent experiment, also commenced on August 1, included dosages of 1.1 to 5.6 kg ai/ha with planting of pine seedlings in 4.5 kg/ha and in control plots in May 1977. August application of 2.2 kg/ha provided excellent initial vegetation control, as effective as the larger amounts applied at that time, and was superior during the first 12 months to 4.5 kg/ha applied in June. Twenty-six months after the spring planting new shoot growth of fertilized pine in the glyphosate strips was statistically significantly greater than that for all other treatments and growth in fertilized scalps was also very good. At the same time leader growth of spruce in fertilized scalps was significantly greater than that for other treatments but growth in glyphosate strips did not exceed that of unfertilized controls. Contrary to results of spring planting, there was marked injury and mortality of pine planted in August in glyphosate plots which had been sprayed on the preceding day. Seedlings planted in glyphosate-treated strips nine months after the August spraying exceeded the growth of control plants but not until the year after they were planted.


2011 ◽  
Vol 41 (4) ◽  
pp. 728-739 ◽  
Author(s):  
Robert L. Fleming ◽  
Allister D. Smith

Many of the major questions regarding stand establishment practices involve implications for longer-term ecosystem development. We examined 41-year treatment effects on stand composition and dynamics using a white spruce ( Picea glauca (Moench) Voss) planting, mechanical site preparation (MSP) – herbicide (2,4-D plus 2,4,5-T) trial in a trembling aspen ( Populus tremuloides Michx.) dominated mixedwood. Both barrel and blade MSP with planting increased total and white spruce year 41 stand-level biomass over that in untreated areas. Year 2 herbicide application reduced year 41 trembling aspen biomass without substantially increasing that of white spruce, resulting in total yields similar to those in untreated areas. Barrel MSP increased year 41 trembling aspen biomass over that of untreated areas whereas blade MSP reduced it. Herbicide-related declines in trembling aspen biomass persisted or increased with time whereas white spruce response to herbicide varied with time and MSP. By accounting for inherent growth patterns, age shift calculations gave more balanced temporal depictions of planted white spruce response than effect size or percentage gain calculations. With barrel MSP, stand composition demonstrated a degree of mixedwood homeostasis whereas with blading, trembling aspen composition declined unilaterally from year 20 to 41.


1999 ◽  
Vol 29 (7) ◽  
pp. 1002-1014 ◽  
Author(s):  
Arthur Groot

Overstory manipulation and vegetation control treatments were applied at three experimental locations in northern Ontario, Canada, to examine shelter and competition effects on planted white spruce (Picea glauca (Moench) Voss). Overstories were nearly pure trembling aspen (Populus tremuloides Michx.) or aspen-conifer mixedwoods. Overstory treatments included clear-cutting, uniform shelterwood (40% canopy removal), strip shelterwood (widths from 0.5 to 1.0H, where H is the height of dominants), patch shelterwood (diameter about 1.0H), narrow strips (width 0.25H), and intact overstory. Vegetation-control treatments included herbicide and no-herbicide treatments. Second-year seedling growth was poorest under intact overstories and in 0.25H strips, and vegetation control had little effect on growth in this situation. Vegetation control in clearcuts increased seedling diameter but not height growth. In shelterwood treatments, however, vegetation control often increased both diameter and height growth. Greatest diameter tended to occur in clearcuts with vegetation control, whereas greatest height growth tended to occur in shelterwoods with vegetation control. These differing responses likely occur because diameter growth is influenced primarily by light availability, but height growth is additionally affected by other environmental factors. Combining early vegetation control along with shelterwood treatments appears to provide the optimum environment for establishing white spruce.


1993 ◽  
Vol 69 (5) ◽  
pp. 554-560 ◽  
Author(s):  
J. E Wood ◽  
F. W. von Althen

Five-year results of a field experiment to evaluate the effects of vegetation control either before or after planting on the performance of planted white spruce (Piceaglauca [Moench] Voss) and black spruce (P. mariana [Mill.] B.S.P.) transplants and black spruce containerized seedlings are reported. Annual vegetation control with and without chemical site preparation significantly (P < 0.05) improved height growth, ground-level stem diameter, and health of the planted seedlings. Survival and seedling growth were significantly (P < 0.05) higher with chemical site preparation than with chemical release in August of the year after planting. From the beginning of June to the first half of August, soil temperatures were higher in the plots with no competing vegetation than in the control plots. The difference in temperature reached a maximum of 5 °C at 5 cm of depth and 4 °C at 12 cm of depth. Key words: black spruce, chemical site preparation, glyphosate, growth response, Picea glauca, Picea mariana, release, tending, vegetation management, weed control, white spruce


2005 ◽  
Vol 79 (1) ◽  
pp. 21-33 ◽  
Author(s):  
C. Lemieux ◽  
C. Delisle

Vegetation control is a critical factor in reforestation. On abandoned agricultural lands, an alternative to herbicide application is the use of cover crops to compete with the weeds and to improve survival and growth rates of transplanted species. A factorial experiment was carried out on four sites to test this hypothesis. The experiment included three factors. The first factor consisted of lime versus no lime application. The second factor included four cover crop combinations and a control. Cover crop combinations were winter barley (Hordeum vulgare) underseeded with either birdsfoot trefoil (Lotus corniculatus), Kentucky bluegrass (Poa pratensis), ladino clover (Trifolium repens), or a mixture of Kentucky bluegrass and ladino clover. The third factor consisted in planting either white (Piceaglauca) or black (Picea mariana) spruce seedlings. Winter barley did not establish as rapidly and vigorously as expected. Nevertheless, the cereal reduced weed populations in the establishment year. For broadleaf weeds, this reduction was not large enough to allow a carryover during subsequent years. In contrast, subsequent increase of the grassy weed populations was slowed down in the presence of cover crops. The establishment of the other cover crops was poor and highly variable from site to site. It is not clear whether this relative failure was due to growing conditions, poor establishment of the cereal cover crop, or to other factors. Liming and cover crops had little effect on spruce growth but black spruce seedlings grew taller than white spruce seedlings at two out of four sites, and basal diameter of white spruce reached larger values than did black spruce. For white spruce, this might constitute an advantage in old fields where seedlings are prone to lodging under weed pressure. Finally, it was noted that seedling survival was exceptionally high in all treatments.


1991 ◽  
Vol 67 (4) ◽  
pp. 403-410 ◽  
Author(s):  
D. M. Morris ◽  
G. B. MacDonald

A competition index was developed, and then used to examine the relationships between perennial competition and plantation performance. Species included were white spruce, black spruce, and jack pine for both over-wintered containers and bare root stock. A total of fifteen four-year-old plantations were used in this study representing a range of soil textures located on boreal mixedwood sites in northern Ontario.Effective canopy cover, derived from vertical hemispherical photographs taken at the base of seedling leaders, provided an accurate estimate of the perennial woody competition affecting seedling diameter growth. Initial seedling size, defined by the stem volume at time of planting, proved to be an important covariate in the analysis.Using the relationship between effective canopy cover and seedling root collar diameter, the following questions regarding vegetation control decision-making were addressed: 1) jack pine was more sensitive to increased levels of competition, 2) over-wintered container stock were more sensitive than their larger bare root counterparts, 3) minimal differences occurred in the pattern of growth response to competition across the range of soil textures studied, and 4) early tending treatments should be concentrated on jack pine plantations or on spruce plantations with an effective canopy cover in excess of 60. Key Words: competition index, hemispherical photographs, boreal plantations, white spruce, black spruce, jack pine, tending guidelines.


2011 ◽  
Vol 41 (1) ◽  
pp. 180-194 ◽  
Author(s):  
Francesco Cortini ◽  
Philip G. Comeau ◽  
Jacob O. Boateng ◽  
Lorne Bedford ◽  
John McClarnon ◽  
...  

Site preparation and vegetation control can be used to mitigate climate change effects on early plantation growth in boreal forests. In this study, we explored growth of lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and white spruce ( Picea glauca (Moench) Voss) in relation to climate and site preparation using 20 years of data collected from studies in British Columbia. Results indicate that up to 45% of the variation in spruce growth and up to 37% of the variation in pine growth over this 20-year period can be explained by selected climatic variables. Monthly climate variables showed a stronger relationship to conifer growth than seasonal and annual variables. Climate variables related to the preceding year accounted for more than half of the variables in the final equations, indicating a lagged response in conifer growth. Future projections indicated that height growth of young lodgepole pine plantations in the sub-boreal zone could benefit (in the short term) from longer growing seasons by up to 12% on untreated stands. Untreated young white spruce plantations in the boreal zone may suffer height growth decreases of up to 10% due to increased drought stress. Vegetation control and mechanical site preparation treatments appear to mitigate effects of climate change to some extent.


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