Aboveground modular component responses to intraspecific competition within density-stressed black spruce stands

1998 ◽  
Vol 28 (11) ◽  
pp. 1587-1610 ◽  
Author(s):  
P F Newton ◽  
P A Jolliffe

A broad range of measures of aboveground growth were used to assess whether competition occurs by processes of resource depletion or resource preemption within monospecific, even-aged, density-stressed, and spatially heterogeneous black spruce (Picea mariana (Mill.) BSP) stands. The assessments proceeded by evaluating the relationships between relative growth and partitioning indices of individual subject trees and directional-specific indices of cumulative competition. Significant directional-specific asymmetrical relationships between subject trees and their local competitors were found, indicating the occurrence of competition by resource preemption. All measures of growth, however, did not respond to directional-specific competition to the same degree. Larger responses, characterizing the response of black spruce trees to increasing competition from their larger neighbours, involved decreased branch production and changes in foliar morphology. Such adaptive, plastic responses in phenotype, combined with lesser responses of foliage production and nutrient concentrations, suggest a strategy used by black spruce to compete within density-stressed populations situated on nutrient-limiting sites: decreased allocation of resources to nonphotosynthetic components, maintenance of the photosynthetic apparatus through adjustments in foliage morphology, and nutrient conservation through foliage retention.

1993 ◽  
Vol 23 (9) ◽  
pp. 1917-1929 ◽  
Author(s):  
P.F. Newton ◽  
P.A. Jolliffe

Three density-stressed black spruce (Piceamariana (Mill.) B.S.P.) populations that naturally regenerated following harvesting in 1970 were selected for study within central insular Newfoundland. Employing historical tree and stand reconstruction techniques, bark, stem, branch, foliage, and total mass distributions were estimated by age-class. Regression analysis was used to assess the effect of density stress on distributional indices, and stepwise multivariate analysis of variance was used to investigate dry matter partitioning patterns. Bark and foliar mass proportions increased with increasing density stress, whereas stem and branch mass proportions declined. Among components, decreased stem proportions best expressed the effects of increasing density stress on dry matter partitioning. Asymmetry within the mass frequency distributions for bark, branch, and foliar components shifted from negative skewness at low relative densities to positive values at high relative densities. Inequality (mass concentration) within the stem mass frequency distributions remained constant, whereas inequality within the bark mass frequency distribution declined in direct proportion to increasing density stress. Inequality within both the branch and foliar mass distributions had curvilinear relationships with increasing density stress: inequality increased from low to intermediate levels of density stress, but declined thereafter. Specific leaf areas did not differ among trees of varying size, suggesting that competition for light may not have been of consequence within the sampled stands. The results are consistent with a resource depletion competitive process, implying that competition within the dense second-growth black spruce stands may have been principally for belowground resources.


1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.


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


1998 ◽  
Vol 15 (3) ◽  
pp. 135-140 ◽  
Author(s):  
David A. MacLean ◽  
Wayne E. MacKinnon

Abstract Data from the assessment of current defoliation levels on 172,000 individual shoots from 6890 midcrown branches sampled from balsam fir and spruce stands were used to define sampling protocols for assessing defoliation caused by spruce budworm. The method was based on sampling one midcrown branch from each of x host trees per stand, and assessing defoliation of y individual shoots per branch. Both the number of shoots per branch and the number of branches required per stand varied with host species (balsam fir, white spruce, or red-black spruce) and with average defoliation level. Sample sizes required to estimate mean defoliation with 90% confidence that the confidence interval is ±10% ranged from 7 to 24 branches per stand and from 17 to 58 shoots per branch, with the largest samples required at moderate (31-70%) defoliation levels. Estimated costs of shoot and branch sampling and processing ranged from $40-110/stand, based on a 90% confidence level salary rate of $12(Can.)/hr, and excluding travel costs. Results can be applied using a preliminary assessment to determine the general defoliation level, which along with species, determines the required sample size. North. J. Appl. For. 15(3):135-140.


2017 ◽  
Vol 63 (No. 8) ◽  
pp. 344-354
Author(s):  
Novotný Radek ◽  
Lomský Bohumír ◽  
Šrámek Vít

For 17 Norway spruce stands located in the Krkonoše Mts. in the Czech Republic a long-term assessment of defoliation, height increment, foliage concentration of nutrients (N, P, Ca, K, Mg) and stress elements (S, F) was carried out. The results show a decrease of defoliation and a slight increase of height increment, which occur in accordance with the decreasing concentration of sulphur in spruce needles. However, neither sulphur concentration nor height increment trends are significant, suggesting that both the main pollution abatement and the growth resumption took place already in the 1990’s. During the late 1990’s the average spruce defoliation was greater than 35%, while since 2007 it has fluctuated between 18 and 25%, which corresponds with the figures for the forest stands located in the other regions of the Czech Republic. The evaluation of single nutrient concentrations detected occasional deficiencies of P and Mg at individual plots. The good N nutrition (&gt; 15 mg N·g<sup>–1</sup>) in combination with a significantly decreasing trend of P, K and Ca concentrations in Norway spruce needles may potentially constitute a problem in regard to both the future health and the stability of forest stands in the studied region.


2007 ◽  
Vol 37 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Martin Lavoie ◽  
David Paré ◽  
Yves Bergeron

The surface of the soil in recently harvested or burned lowland black spruce (Picea mariana (Mill.) BSP) sites is composed of a fine mosaic of different bryophytes (mostly Sphagnum spp. and feathermosses), disturbed organic material originating mostly from mosses at different stages of decay, and exposed mineral soil. Growth substrates were compared in lowland black spruce stands regenerating after either careful logging or wildfire. The 3-year annual increment for black spruce seedlings was greatest with substrates of feathermosses, mainly Pleurozium schreberi (Brid.) Mitt., fibric material of P. schreberi origin, and a mixture of fibric P. schreberi and humic materials; it was least with fibric Sphagnum spp., mineral soil, and decaying wood substrates. The most favourable substrates for growth were characterized by better black spruce N and P foliar status. Our results also suggest that categories of growth substrates in the rooting zone reflect nutritional quality better than categories of growth substrates on the soil surface. To maintain or increase black spruce growth following careful logging of sites prone to paludification, we recommend fill-planting of seedlings in substrates originating from P. schreberi; management techniques that favour P. schreberi over Sphagnum mosses should also be developed.


1954 ◽  
Vol 30 (4) ◽  
pp. 372-379 ◽  
Author(s):  
Henri LeBlanc

Lack of reproduction of black spruce, Picea mariana, in pure black spruce stands in old cut-over areas, has always been a great subject of discussion and one for intensive work among foresters. Many reasons such as the absence of an adequate seed supply stored on top of humus, or adverse germination conditions are said to be partly responsible.This study on the humus of this unregenerated cut-over area, indicates clear cutting of this stand will influence the normal concentration of definite micro-nutrients such as manganese and magnesium.The augmentation of manganese in the soil has a detrimental effect on the growth of plants when, its concentration is too high. The diminution of magnesium, which is an element necessary to stimulate the growth, must create abnormal nutritive conditions of the habitat. This visible lack of equilibrium might be the cause of the absence of seedlings of Picea mariana on certain parts of this cut-over area.


1996 ◽  
Vol 13 (2) ◽  
pp. 68-72 ◽  
Author(s):  
Joanie Burns ◽  
Klaus J. Puettmann ◽  
Don Perala

Abstract Two different thinning methods were applied to three 6- or 7-yr-old black spruce stands in northern Minnesota which were measured after 20 yr. Overall, thinning improved the growing conditions for crop trees. Strip thinning with a 0.6 m leave strip and three widths of cleared strips (1.5 m, 2.1 m, and 2.7 m), and spacing to 1.5 m, 2.1 m, and 2.7 m resulted in reduced numbers of crop trees, but with larger diameters and, in the spacing thinned plots, greater heights. Because of these contradicting trends, stand volume was unaffected by thinning. Crop tree growth was not affected by the width of the cleared strip, but the distances between the leave trees in the square spacing were positively related to the increased growth response after thinning. The study is still too young to evaluate the economic feasibility of both thinning treatments, but shorter rotations or substantially increased volume seem possible by early thinnings of black spruce. North. J. Appl. For. 13(2):68-72.


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