Relative competitiveness of nine early-successional boreal forest species associated with planted jack pine and black spruce seedlings

2000 ◽  
Vol 30 (5) ◽  
pp. 790-800 ◽  
Author(s):  
F Wayne Bell ◽  
Michael T Ter-Mikaelian ◽  
Robert G Wagner

Differences in yield-density models derived from an additive experimental design were used to compare the relative competitiveness of nine early-successional boreal forest plants (aster, grass, fireweed, fern, raspberry, willow, alder, birch, and aspen) on jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP). A randomized complete block split-split-plot design with three replications blocked on soil type was used. Initial density gradients were 0-4 plants/m2 for woody and 0-8 plants/m2 for herbaceous species. An a priori analytical approach that compared a full model (using linear regression analysis of 4th-year stem diameter of conifers under increasing cover and height of competitors) to various reduced models was used to assess competition. Increasing cover and (or) height of all competitors (except fern) significantly (P < 0.05) decreased conifer stem diameter. The final regression model (based on visual estimates of cover and differences in initial conifer size) accounted for 89% of the variation in stem diameter. During the years studied, both conifers responded similarly to competition, and herbaceous species were on average 28.9% more competitive than woody species. Under different growing conditions (e.g., a natural forest) the relative competitiveness of herbaceous and woody species may vary from these results.

2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.


2002 ◽  
Vol 32 (9) ◽  
pp. 1607-1615 ◽  
Author(s):  
I Charron ◽  
D F Greene

We studied the post-wildfire establishment of jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP), and white spruce (Picea glauca (Moench) Voss) in the southern mixedwood boreal forest of Saskatchewan, Canada. The major objective of the study was to determine the influence of post-wildfire seedbed types on the juvenile survivorship of trees. Through a combination of permanent plots and sowing experiments, we demonstrated that mineral soil, thin Polytrichum Hedw. moss, and humus are much more favorable than the organic fermentation (Of) and litter seedbeds. We also show that differences among seedbeds are significantly more important than differences among species. In addition, the first year of a cohort has the highest rate of mortality, about 85% on mineral and humus seedbeds and 98% on Of seedbeds; differences in age-specific survivorship between seedbeds become muted by the end of the second year, and survivorship rates approach 1 by the end of the third summer. Finally, age structures showed that germination rates of black spruce and jack pine were very low the initial summer of the fire; that there was a peak in recruitment in the first post-fire summer; and that by the fourth year the recruitment declined to nearly zero.


1984 ◽  
Vol 62 (12) ◽  
pp. 2650-2653 ◽  
Author(s):  
B. Pylypec ◽  
R. E. Redmann

Buffering capacity to acidity was defined as the microequivalents of H+ required to produce a 5 μeqiv. change of H+ concentration in a homogenate prepared from leaf tissue. The results for six species collected from the southern boreal forest of Saskatchewan, Canada, showed that trembling aspen (Populus trenudoides Michx.) and Labrador tea (Ledum groenlandicum Oeder.), had the highest buffering capacities (379 and 189 μeuiv. H+ ∙ g−1, respectively), while jack pine (Pinus banksiana Lamb.) had the lowest (33 μequiv. H+ ∙ g−1). Tamarack (Larix laricina (Du Roi) K. Koch), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) BSP) had intermediate values. Buffering capacity and pH of homogenates for all species showed seasonal fluctuations, with the lowest values occurring in the middle of the growing season. The results suggest that foliage of evergreen conifers, particularly jack pine, is less well buffered against acidic pollution than that of broad-leaved species such as trembling aspen.


1987 ◽  
Vol 63 (6) ◽  
pp. 446-450 ◽  
Author(s):  
James E. Wood ◽  
Richard Raper

In the alternate strip clearcutting system, first-cut strips are regenerated by seed produced by black spruce (Picea mariana [Mill.] B.S.P.) in the forested leave strips. However, after the second cut, such a seed source is not available for regenerating the leave strips. Therefore, the forest manager must consider a number of alternative regeneration options. The selection of the most appropriate regeneration option is dependent upon several economic and biological criteria. These include future costs of delivered wood, site productivity, post-harvest site condition, future alternative sources of supply, and future demand for industrial wood. Regeneration options such as preservation of advance growth and direct seeding are recommended for sites on which the manager is concerned primarily with regenerating first cut strips and is willing to accept a lower level of stocking in leave strips. Planting, the most intensive option discussed, should be reserved for sites offering the highest potential return or greatest future cost savings. Direct seeding of jack pine (Pinus banksiana Lamb.) should be considered on the upland portions of this patterned site type. Mixing jack pine and black spruce is a suggested regeneration option if the site contains both upland and lowland topographic positions. Other seeding options include the use of semi-transparent plastic seed shelters. The manager might consider combining two or more of these options to meet management objectives.


2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.


1998 ◽  
Vol 78 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Helmut Krause

The purpose of this study was to determine whether change of forest cover had an effect on the development of the organic surface horizons, particularly on those variables that influence nutrient cycling and forest productivity. Jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) plantations were selected from among the youngest to oldest (2–16 yr) within a 100 km2 area in southeastern New Brunswick. Natural forests were also included as benchmark sites. The forest floor and tree foliage was sampled and trees measured on 0.05-ha plots. The forest floor samples were used to determine organic mass, nutrient contents and pH. In pine plantations, organic matter accumulated rapidly during the period of exponential tree growth, but leveled off at about 45 Mg ha–1. This was within the range of benchmark sites with mixed conifer-hardwood cover. In spruce plantations, the forest floor mass ranged upward to 77 Mg ha–1. Development was strongly influenced by the nature of the previous forest. Spruce forest floors were on average more acid and had lower nutrient concentrations, particularly N and Ca. The observed differences suggest that nutrients are recycled more rapidly in the pine plantations, partly explaining the superior growth of the latter. Key words: Forest floor, Kalmia angustifolia L., Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., nutrient cycling, plantation forest


2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay

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.


1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz

An experimental burn in conjunction with a seed-tree system was successful in regenerating jack pine (Pinus banksiana Lamb.) on a fresh to somewhat moist upland, loamy till, cutover site in central Saskatchewan. About 20 well-formed, uniformly spaced seed trees per hectare were left standing during timber harvest. The ignition of logging slash was carried out under preselected weather and fuel conditions so that favorable seedbeds and adequate seed dispersal from the seed trees were produced. Four growing seasons after burning, jack pine stocking by 4-m2 quadrats was 90% with 12 195 seedlings/ha. Aspen (Populus tremuloides Michx.), to a lesser degree black spruce (Picea mariana [Mill.] B.S.P.), and other companion tree species also regenerated with the pine. Various seedbed and regeneration characteristics as well as height growth rates are discussed. Key words: Pinus banksiana, slash burning, seed-tree system, forest regeneration, growth rates, central Saskatchewan.


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