Effects of shelter and competition on the early growth of planted white spruce (Picea glauca)

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.

2009 ◽  
Vol 85 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Alison D Lennie ◽  
Simon M Landhäusser ◽  
Victor J Lieffers ◽  
Derek Sidders

Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but protect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration was inversely related to the basal area of residual aspen; however, sucker height was inversely related to the basal area of the residual spruce. Although there were adequate numbers of suckers after partial harvest, their viability and contribution to the long-term productivity of these mixedwood stands is not clear. Key words: silvicultural systems, forest management, residual canopy, white spruce, Populus tremuloides, Picea glauca, traffic


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.


2002 ◽  
Vol 80 (4) ◽  
pp. 370-377 ◽  
Author(s):  
David F Greene ◽  
Christian Messier ◽  
Hugo Asselin ◽  
Marie-Josée Fortin

Mean annual seed production is assumed to be proportional to basal area for canopy trees, but it is not known if subcanopy trees produce fewer seeds than expected (given their size) because of low light availability. Ovulate cone production was examined for balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) in 1998 and for balsam fir in 2000 in western Quebec using subcanopy stems, near or far from forest edges, or (at one site) planted white spruce trees in fully open conditions. A very simple light model for transmission through mature trembling aspen (Populus tremuloides Michx.) crowns and through boles near forest edges was developed to account for the effect of light receipt on cone production. The enhanced light near forest edges (e.g., recent clearcuts) leads to about a doubling of cone production for subcanopy stems. The minimum subcanopy height for cone production far from an edge is about 10 m for balsam fir and 14 m for white spruce, with these minima decreasing near edges. By contrast, the minimum height for white spruce in a plantation (full light) is about 3 m. Accounting for light receipt leads to an increase in the explained variance.Key words: balsam fir, cone production, light model, regressions, subcanopy stems, white spruce.


2011 ◽  
Vol 26 (2) ◽  
pp. 82-90 ◽  
Author(s):  
Richard D. Kabzems ◽  
George Harper ◽  
Peter Fielder

Abstract Managing boreal mixed stands of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca [Moench] Voss) is more likely to sustain a diversity of values and has the potential to increase productivity at both the site and landscape levels compared with pure broadleaf or conifer management. In this study, we examine growth of white spruce and aspen after 11 growing seasons over a range of aspen densities created by spot and broadcast treatment of broadleaves using manual and chemical means, aspen spacing, and an untreated control. Results indicate that survival and growth of both spruce and aspen were similar across the range of treatments. Spruce groundline diameter was greater, and height to groundline diameter ratio was lower, for the treatments in which aspen was chemically controlled or uniformly spaced compared with the control. Light measurements at the individual tree level suggested that increased light availability improved white spruce diameter growth. Spruce height growth did not vary by treatment. The status of these experimental mixedwoods was compared with current conifer and mixedwood regeneration evaluations, as well as the preharvest composition of the original stand. After 11 growing seasons, growth of aspen and white spruce indicated that opportunities exist to further modify aspen density to enhance treatment longevity and effectiveness to produce a greater range of boreal mixedwood stand types.


2007 ◽  
Vol 121 (2) ◽  
pp. 191 ◽  
Author(s):  
Sophan Chhin ◽  
G. Geoff Wang

The influence of microenvironmental conditions on the growth performance (i.e., diameter and height growth) of White Spruce [Picea glauca (Moench) Voss] seedlings was examined within three contrasting habitats: White Spruce tree islands, open prairies and Trembling Aspen (Populus tremuloides Michx.) groves. These habitats exist within a disjunct occurrence of White Spruce at its southern limit of distribution in three mixed-grass prairie preserves in the Spruce Woods Provincial Park within the forest-prairie ecotone of southwestern Manitoba. Microenvironmental measurements (i.e., light, temperature, relative humidity, soil moisture) were obtained on 10 sites in each of the three habitats and growth characteristics of 60 White Spruce seedlings were measured in each of three habitats. Higher light and soil temperature conditions occurred within the open prairie. In contrast, lower light and soil temperature conditions occurred under the tree canopy of aspen groves and the northern aspect of spruce islands, which moderated the effect of the dry regional climate. Height growth did not vary significantly among the three habitats. The greater diameter growth and decreased slenderness of White Spruce seedlings in the open versus the shaded habitats appears to be a result of increased photosynthesis at higher light intensity and may also represent a morphological adaptation to withstand the effect of increased wind exposure. The increased slenderness of White Spruce in the shaded habitats appears to be a morphological adaptation of increasing carbon allocation towards height growth and thus maximizing effective competition for light.


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.


1978 ◽  
Vol 54 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Roy F. Sutton

Environmentally safe, yet potent in controlling herbs, grasses, and woody species, with possibilities for selective use, glyphosate (Roundup®) has great potential usefulness in forestry.In the small study reported here, twelve.01 ha plots were established in August, 1973 in dense 6-year-old shrub and hardwood post-fire regrowth near Chapleau, Ontario. In each plot, 16 rising 3 + 0 white spruce (Picea glauca [Moench] Voss) were planted centrally at.9 m ×.9 m spacing. Six treatments with two replications were applied at random the next day: 1, control; 2, all woody vegetation cut off at ground level; 3, all woody vegetation cut off in central planted area of plot; 4, sprayed with 60 mL glyphosate in 1.892 L of water; 5, sprayed with double strength glyphosate; 6, sprayed with sextuple strength glyphosate. Eight trees in each plot were shielded during the spraying. Browsing affected 16% of the spruce after 2 weeks, 96% by spring. Half of each plot was replanted with eight white spruce (four of them caged against browsing) in May, 1974.The objectives were to observe the effect of glyphosate on hardwood and shrub competition, to assay this effect by white spruce outplantings, and to evaluate the resistance to glyphosate of newly planted white spruce. Glyphosate was highly effective in killing trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), and beaked hazel (Corylus cornuta Marsh.): pin cherry (Prunus pensylvanica L. f.) resprouted with moderate vigor. White spruce responded significantly (P.01) to first-year non-herbicide (i.e., immediate) weed control, but second-year height increment was significantly (P.001) less than that of the first year: second-year height increment in the glyphosate treatments was significantly (P.001) greater than in the non-herbicide treatments. Growth and survival were both affected by non-treatment disturbances, but shielding during spraying improved second-year survival significantly (P.001).


2007 ◽  
Vol 24 (4) ◽  
pp. 296-300 ◽  
Author(s):  
Yuhui Weng ◽  
Kathy Tosh ◽  
Yill Sung Park ◽  
Michele S. Fullarton

Abstract Polycross-pollinated white spruce (Picea glauca [Moench] Voss) families were evaluated in field and retrospective nursery tests in 1989, 1991, and 1992, respectively. Height growth was measured at age 10 for the field tests and at ages 1 to 6 for the retrospective nursery tests. Except for a few cases, the family mean correlations between nursery and field heights were significant for the 1989 and 1992 series, and their corresponding genetic correlations ranged from low to medium (from 0.37 to 0.74). Because of heavy noncrop competition, height growth in the 1991 nursery series showed consistently lower heritabilities and correlations with field performance compared with those of the other two series. Early nursery selection by theoretical prediction was generally efficient for the 1989 and 1992 series. Rank classification analysis indicated that application of early nursery selection should be used with caution for identifying elite families but could be used to cull inferior families or clones, apply multiple-stage selection, or perform positive assortative mating.


2007 ◽  
Vol 22 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Ryan J. Klos ◽  
G. Geoff Wang ◽  
Qing-Lai Dang ◽  
Ed W. East

Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.


Sign in / Sign up

Export Citation Format

Share Document