scholarly journals Assessing Differences in Competitive Effects Among Tree Species in Central British Columbia, Canada

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 167
Author(s):  
Stella Britwum Acquah ◽  
Peter L. Marshall
Keyword(s):  
Tree Species ◽  
Lodgepole Pine ◽  
Basal Area ◽  
Douglas Fir ◽  
Competitive Effects ◽  
Basal Area Growth ◽  
Interior Spruce ◽  
Area Growth ◽  
Different Levels ◽  
Over Time

Research Highlights: We investigated the competitive interactions among three tree species (interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca [Moench] Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.)) in multi-aged stands in central British Columbia, Canada. Background and Objectives: Understanding competitive interactions among tree species in mixed-species stands is fundamental to supporting silvicultural decision-making in such stands. Using the periodic annual basal area increment for single trees as our dependent variable, we investigated whether neighboring trees competed with subject trees independently of species identity. We also examined the differences in single-tree basal area growth among the three conifer species over time under different levels of competition. Materials and Methods: We developed several spatially explicit, single-tree basal area growth models for interior Douglas-fir, interior spruce, and lodgepole pine using data from 16 plots in two blocks of a long-term study (five measurements over a 21-year period) on the response to pre-commercial thinning. We compared these equations to assess whether intraspecific or interspecific competition predominated. We also examined the differences in basal area growth among the three conifer species over time under different levels of competition. Results: We found asymmetrical relationships between the conifer trees and their neighbors for all species, indicating that the main driver limiting growth in these stands is aboveground competition for light. There was evidence of higher intraspecific competition for small (<10.0 cm DBH) interior Douglas-fir in one block. However, there was no general pattern among larger subject trees with respect to the identity of neighborhood competitive effects and the equivalence of neighbors. We observed a higher level of basal area growth over time for interior Douglas-fir than for lodgepole pine and interior spruce, irrespective of the competition intensity and, not surprisingly, the growth rate declined with increasing competition levels for the three species. Conclusions: Our results provide an understanding of how interior Douglas-fir stands will develop over time and information on species interactions that could help forest managers explore different silvicultural options and their effects on individual tree growth in these complex stands.

Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon

2002 ◽  
Vol 32 (7) ◽  
pp. 1232-1243 ◽  
Author(s):  
Nathan J Poage ◽  
John C Tappeiner, II
Keyword(s):  
Large Diameter ◽  
Basal Area ◽  
Douglas Fir ◽  
Slope Aspect ◽  
Site Factors ◽  
Old Growth ◽  
Site Class ◽  
Basal Area Growth ◽  
Area Growth ◽  
Age Range

Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100–300 years. The diameters of the trees at ages 100–300 years (D100–D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments (PAIBA) of all trees increased for the first 30–40 years and then plateaued, remaining relatively high and constant from age 50 to 300 years. Average PAIBA of the largest trees at ages 100–300 years were significantly greater by age 20 years than were those of smaller trees at ages 100–300 years. The site factors province, site class, slope, aspect, elevation, and establishment year accounted for little of the variation observed in basal area growth at age 50 years and D100–D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations.

Growth of aspen and white spruce on naturally saline sites in northern Alberta: Implications for development of boreal forest vegetation on reclaimed saline soils

2012 ◽  
Vol 92 (1) ◽  
pp. 213-227 ◽  
Author(s):  
E.B. Lilles ◽  
B.G. Purdy ◽  
S.E. Macdonald ◽  
S.X. Chang
Keyword(s):  
Electrical Conductivity ◽  
Boreal Forest ◽  
Basal Area ◽  
White Spruce ◽  
Forest Vegetation ◽  
Saline Soils ◽  
Basal Area Growth ◽  
Area Growth ◽  
Northern Alberta ◽  
Over Time

Lilles, E. B., Purdy, B. G., Macdonald, S. E. and Chang, S. X. 2012. Growth of aspen and white spruce on naturally saline sites in northern Alberta: Implications for development of boreal forest vegetation on reclaimed saline soils. Can. J. Soil Sci. 92: 213–227. We examined height and basal area growth over time for trembling aspen and white spruce in plots along a salinity gradient at six naturally saline sites in northern Alberta, as a benchmark for forest productivity on reclaimed saline sites. We measured root distributions and analyzed foliage for ions, nutrients and carbon and nitrogen stable isotope ratios. Both species grew on soil conditions previously considered unsuitable for forest vegetation [pH>8.5; electrical conductivity>10 dS m−1, sodium adsorption ratio>13 at depth (50–100 cm)] yet there was little evidence of nutritional toxicities or deficiencies. Aspen basal area growth decreased 50% as salinity increased, but aspen was commercially productive (site index=22) on soils with electrical conductivity of 7.8 dS m−1at 50–100 cm depth. Growth of white spruce seemed to be unaffected by salinity level differences, but 78% of white spruce site indexes were less than 13 and would be considered non-productive. Both species showed growth declines over time, compared with non-saline reference growth curves, and rooted primarily in the forest floor and top 20 cm of soil. This suggests that rooting limitations may constrain longer-term productivity of forests established on sites with salinity at depth.

scholarly journals Distance-independent tree basal area growth models for Norway spruce, Douglas-fir and Japanese larch in Southern Belgium

2016 ◽  
Vol 136 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Jérôme Perin ◽  
Hugues Claessens ◽  
Philippe Lejeune ◽  
Yves Brostaux ◽  
Jacques Hébert
Keyword(s):  
Norway Spruce ◽  
Growth Models ◽  
Basal Area ◽  
Douglas Fir ◽  
Japanese Larch ◽  
Basal Area Growth ◽  
Area Growth

Effects of diversity of tree species and size on forest basal area growth, recruitment, and mortality

2007 ◽  
Vol 243 (1) ◽  
pp. 116-127 ◽  
Author(s):  
Jingjing Liang ◽  
Joseph Buongiorno ◽  
Robert A. Monserud ◽  
Eric L. Kruger ◽  
Mo Zhou
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Basal Area Growth ◽  
Area Growth

Growth responses to commercial thinning in Douglas-fir stands with varying severity of Swiss needle cast in Oregon, USA

2005 ◽  
Vol 35 (10) ◽  
pp. 2394-2402 ◽  
Author(s):  
Douglas B Mainwaring ◽  
Douglas A Maguire ◽  
Alan Kanaskie ◽  
Jeff Brandt
Keyword(s):  
Basal Area ◽  
Douglas Fir ◽  
Growth Responses ◽  
Infection Level ◽  
Individual Tree ◽  
Needle Cast ◽  
Commercial Thinning ◽  
Basal Area Growth ◽  
Area Growth ◽  
Swiss Needle Cast

Concern has risen about the degree to which Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands with severe infections of Swiss needle cast (SNC) respond to thinning. A retrospective study was established in the fall of 2001 to assess the growth of Douglas-fir stands that were commercially thinned between 4 and 10 years ago. Current SNC infection levels in these stands ranged from severe to very light. Past volume and basal area growth declined with increasing severity of SNC, as measured by current foliage retention and crown length / sapwood ratio. As has been observed in many other studies, thinning to lower residual stock reduced stand level growth; however, individual tree growth increased with lower residual stand density. The ratio of growth in successive periods and analysis of annual basal area growth since thinning suggested that trees did respond to thinning, although less so as SNC increased. A positive response to thinning, regardless of infection level, was confirmed by an analysis of annual trends in basal area growth over the first 5 years after thinning.

scholarly journals Growth of Young Douglas-Fir Plantations Across a Gradient in Swiss Needle Cast Severity

2002 ◽  
Vol 17 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Douglas A. Maguire ◽  
Alan Kanaskie ◽  
William Voelker ◽  
Randy Johnson ◽  
Greg Johnson
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Height Growth ◽  
Douglas Fir ◽  
Site Quality ◽  
North Coast ◽  
Needle Cast ◽  
Basal Area Growth ◽  
Area Growth ◽  
Swiss Needle Cast

Abstract During the past decade, Swiss needle cast (SNC) damage has intensified in many Douglas-fir plantations in the Coast Range of Oregon, particularly along the immediate north coast. In plantations with severe symptoms, growth losses and reduced tree vigor are evident, but the magnitude of growth losses associated with varying intensities of damage is not known. A growth impact study was conducted in 1997 to quantify retrospectively the relationship between growth losses and visual symptoms in 10- to 30-yr-old Douglas-fir plantations in coastal northwestern Oregon, a population totaling 75,700 ha. A random sample of 70 Douglas-fir plantations was selected from the population and evaluated for Swiss needle cast severity. One 0.02 ha plot was destructively sampled in each plantation to reconstruct past height and basal area growth trends and to characterize foliage loss and distribution. The SNC “effect” was assessed by comparing growth of plantations with varying degrees of Swiss needle cast to growth of those that retained maximal amounts of foliage, after correcting for initial stand density, Douglas-fir growing stock, age, and site index. Of numerous possible SNC indices, mean needle retention (yr) explained the largest amount of variation in both basal area and top height growth. Prior to 1990, top height growth was similar across all plantations after correcting for site quality and plantation age; but, by 1992, top height growth losses appeared and were proportional to apparent foliage losses. In 1996, top height growth was reduced by up to 25% relative to plantations with little or no SNC. Basal area growth reductions began to appear around 1990, and in 1996 basal area growth of the most heavily damaged plantations was 35% less than the growth that would be expected in absence of SNC damage. The inferred volume growth loss for 1996 averaged 23% for the 75,700 ha target population, but this loss averaged as high as 52% for the most severely impacted plantations. West. J. Appl. For. 17(2):86ߝ95.

Four-year Basal Area Growth Response of a 25-year-old Douglas-fir Stand to Thinning and Urea Fertilization

1974 ◽  
Vol 4 (4) ◽  
pp. 568-571 ◽  
Author(s):  
Y. Jim Lee
Keyword(s):  
Nitrogen Fertilization ◽  
Growth Response ◽  
Basal Area ◽  
Douglas Fir ◽  
Site Quality ◽  
Growing Period ◽  
Basal Area Growth ◽  
Area Growth ◽  
Four Levels ◽  
Urea Fertilization

Four-year growth response to nitrogen fertilization and thinning is reported for an experiment established in a 25-year-old Douglas-fir stand of medium site quality. Four levels of nitrogen (0, 112, 224, and 336 kg N/ha), in the form of urea, were tested at two thinning levels in a randomized 4 × 2 × 2 factorial design replicated in 2 Blocks. Fertilizer was applied in spring or fall. Basal area growth per hectare in the thinned stand significantly surpassed that of the unthinned stand in the fourth growing period. Increased rate of nitrogen fertilization resulted in increased growth 1 year after fertilization. Urea applied in the fall resulted in greater growth response than that applied in the spring for the first growing period and over a 4-year period. Increased rate of fertilization increased mortality significantly in the fourth growing period, but had no prior effect. Thinning decreased mortality in all four growing periods.

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