Effects of intra- and inter-specific competition on root and shoot biomass of young Douglas-fir and red alder

1992 ◽  
Vol 22 (1) ◽  
pp. 101-110 ◽  
Author(s):  
L.J. Shainsky ◽  
M. Newton ◽  
S.R. Radosevich
Keyword(s):  
Douglas Fir ◽  
Response Surfaces ◽  
Volume Index ◽  
Stem Volume ◽  
Shoot Biomass ◽  
Total Biomass ◽  
Mixed Stands ◽  
Red Alder ◽  
Biomass Components ◽  
Root And Shoot Biomass

The effects of intra- and inter-specific competition on root and shoot biomass of 5-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) were studied in experimentally manipulated stands. The density of each species was varied systematically in a two-way density matrix composed of five monoculture densities and 25 mixtures of all possible pairwise combinations of monoculture densities. Roots and shoots were harvested after the fourth growing season. Response surfaces for root, shoot, and total biomass per tree were generated within the matrix. Regression analysis quantified the effect of each species' density on biomass components. Alder overtopped the Douglas-fir in all mixed stands. Alder density influenced the root and shoot biomass of both species more than Douglas-fir density. Douglas-fir density interacted with red alder density to influence all biomass components. While increasing the density of each species reduced root and shoot biomass per tree, allocation of biomass to roots and shoot was not affected by competition, nor were the allometric equations relating biomass to stem diameter and stem volume index.

Effects of competition on the foliar chemistry of young Douglas-fir in monoculture and mixed stands with young red alder

1995 ◽  
Vol 25 (12) ◽  
pp. 1969-1977 ◽  
Author(s):  
Lauri J. Shainsky ◽  
Cathy L. Rose
Keyword(s):  
Free Amino ◽  
Douglas Fir ◽  
Response Surfaces ◽  
Nonstructural Carbohydrates ◽  
Regression Analyses ◽  
Foliar Chemistry ◽  
Mixed Stands ◽  
Red Alder ◽  
Growth Physiology ◽  
Total Nonstructural Carbohydrates

The effects of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) densities on foliar chemistry of 4-year-old Douglas-fir were examined in experimentally manipulated stands. The density of each species was varied systematically in a two-way density matrix composed of five monoculture densities and 25 mixtures of all possible pairwise combinations of monoculture densities. Foliage was sampled in July of the second growing season and analysed for concentrations of nitrogen (N), phosphorus (P), starch, sugars, total nonstructural carbohydrates, and free amino acids. Response surfaces were generated, and regression analyses quantified the effects of each species' density on biochemistry. Increasing the overstory alder density resulted in increased N, free amino acid, and P concentrations in the Douglas-fir foliage, and reduced starch and total nonstructural carbohydrate concentrations. Effects of Douglas-fir density were variable and dependent on the red alder density. Trends in biochemistry correlated well with soil moisture, light, and growth rates. Conditions favoring growth were associated with reduced concentrations of N and P and elevated levels of starch and nonstructural carbohydrates. The results strongly suggest that examination of foliar chemistry should be coupled with growth, physiology, and resources if biochemical constituents are to be used for testing tree vigor.

Five-year growth responses of Douglas-fir, western hemlock, and western redcedar seedlings to manipulated levels of overstory and understory competition

2006 ◽  
Vol 36 (10) ◽  
pp. 2439-2453 ◽  
Author(s):  
Timothy B Harrington
Keyword(s):  
Growth Rate ◽  
Nitrogen Content ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Volume Index ◽  
Stem Volume ◽  
Western Redcedar ◽  
Foliar Nitrogen ◽  
Relative Growth ◽  
Vegetation Control

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western redcedar (Thuja plicata Donn ex D. Don) seedlings were planted in March 2001 within three clearcut-harvested, shelterwood, or thinned stands of mature Douglas-fir near Olympia, Washington. From 2002 to 2005, areas of vegetation control of 0, 4.5, or 9 m2 were maintained with herbicides around a total 162 seedlings per species. Photosynthetically active radiation (PAR) was 34%, 62%, and 100% of full sunlight in thinned stands, shelterwoods, and clearcuts, respectively. Effects of overstory level and vegetation control on seedling growth and resource availability generally were additive. Seedling stem volume index in clearcuts averaged four to eight times that observed in thinned stands, and with vegetation control, it averaged two to four times that observed without it. In thinned stands, relative growth rate of seedling stem volume index had a positive linear relationship with PAR (R2 = 0.38). Foliar nitrogen content of Douglas-fir explained 71% of the variation in relative growth rate. Factors explaining the most variation in foliar nitrogen content differed between thinned stands (PAR, R2 = 0.34) and clearcuts or shelterwoods (midday water potential, R2 = 0.63), suggesting that light and root competition, respectively, were the primary growth-limiting factors for these overstory levels.

Spatial extent of impact of red alder on soil chemistry of adjacent conifer stands

1992 ◽  
Vol 22 (9) ◽  
pp. 1434-1437 ◽  
Author(s):  
Charles C. Rhoades ◽  
Dan Binkley
Keyword(s):  
Soil Ph ◽  
Soil Chemistry ◽  
Douglas Fir ◽  
Spatial Extent ◽  
N Availability ◽  
Soil N ◽  
Mixed Stands ◽  
Red Alder ◽  
Soil N Availability ◽  
River Site

We examined patterns in soil N availability and pH along transects extending from mixed stands of conifers (mostly Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco)) and red alder (Alnusrubra Bong.) to pure conifer stands at two locations. At the relatively infertile Wind River site, increased N availability was apparent for about 8–12 m downslope of the alder–conifer stand, but no effect was apparent upslope. At the fertile Cascade Head site, no trend was apparent in N availability across the stand boundaries, but soil pH in the conifer stand was depressed for about 5 m from the alder–conifer stand. Overall, the effects of alder on soil chemistry appeared limited to a distance of less than half the height of the trees.

Size of Douglas-fir trees in relation to distance from a mixed red alder–Douglas-fir stand

1993 ◽  
Vol 23 (11) ◽  
pp. 2413-2418 ◽  
Author(s):  
Richard E. Miller ◽  
Donald L. Reukema ◽  
Timothy A. Max
Keyword(s):  
Stand Density ◽  
Positive Influence ◽  
Poor Quality ◽  
Douglas Fir ◽  
Mixed Stand ◽  
Stem Volume ◽  
Nitrogen Fixing ◽  
Red Alder ◽  
Wide Strip ◽  
Southwest Washington

Variation in diameter, height, and stem volume of 57-year-old Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) was related to distance of these trees from a 27 m wide strip in the same Douglas-fir plantation that had been interplanted with red alder (Alnusrubra Bong.). Within the interplanted strip and despite its greater total stand density, bole volume of dominant and codominant Douglas-fir averaged 1.27 m3 compared with 0.55, 0.45, 0.46, or 0.49 m3 in trees 15, 30,45, or 60 m, respectively, from the edge of the mixed stand. Some positive influence of nitrogen-fixing red alder apparently extended about 15 m beyond the edge of the mixed stand at this poor quality site in southwest Washington. We infer that similar ribbonlike distributions of naturally regenerated red alder could be retained to improve growth of nearby conifers on nitrogen-deficient sites.

Development and growth of even-aged stands of Douglas-fir and grand fir

1986 ◽  
Vol 16 (2) ◽  
pp. 367-372 ◽  
Author(s):  
Bruce C. Larson
Keyword(s):  
Growth Rates ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Mixed Stands ◽  
Site Class ◽  
Development Patterns ◽  
Western Washington ◽  
Eastern Washington

Stand development patterns and growth rates of even-aged mixed stands of Douglas-fir (Pseudotsugamensiesii Mirb. Franco) and grand fir (Abiesgrandis Dougl. Lindl.) were investigated by stand reconstruction in eastern Washington. Although Douglas-fir dominated the stands early, grand fir of the same age eventually overtook the tallest Douglas-firs. Dominant trees of both species were found to have highly variable taper form (based on basal area to height ratios), although a linear relationship existed in other crown classes. Stem volume growth rates were determined by reconstructing past diameters and heights and were found comparable to site class IV Douglas-fir in western Washington. Intensive management, especially planting and thinning, could improve upon the observed mean annual increments of 800 board feet per acre at 80 years of age.

Effects of contrasting light and soil moisture availability on the growth and biomass allocation of Douglas-fir and red alder

2003 ◽  
Vol 33 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Samuel S Chan ◽  
Steven R Radosevich ◽  
Amy T Grotta
Keyword(s):  
Soil Moisture ◽  
Biomass Allocation ◽  
Competitive Ability ◽  
Field Capacity ◽  
Douglas Fir ◽  
Red Alder ◽  
Moisture Availability ◽  
Biomass Components ◽  
Soil Moisture Availability ◽  
Moisture Conditions

We examined growth and biomass allocation of individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.) seedlings grown for 3 years under contrasting combinations of light and water. Alder growth was always greater than Douglas-fir. Full sunlight and soil moisture at field capacity caused large differences in size between the two species. With limited light and water, differences were smaller. Under full light and limited water, Douglas-fir allocated a high portion of its biomass to roots, whereas red alder allocated a high percentage to aboveground biomass components. Under light and water resource-limiting situations, red alder allocated more mass to stem, whereas Douglas-fir allocated more to roots. Red alder growth responded negatively to water limitation, whereas Douglas-fir did not. Red alder exhibited greater foliage plasticity to light. Species differences in size and allocation in response to resource availability may determine pathways by which Douglas-fir and red alder interact in a mixed community. Our findings support the hypothesis that the potential of species to use growth-limiting resources is an indicator of competitive ability. We suggest that red alder and Douglas-fir can co-exist under conditions of full light and limiting soil moisture availability. Furthermore, when contrasted with red alder, Douglas-fir's relatively greater tolerances to low light allow it to better persist in the understory. Red alder's rapid early growth and competitive ability will be superior under full light and nonlimiting soil moisture conditions.

Competitive interactions of whiteleaf manzanita, herbs, Douglas-fir, and ponderosa pine in southwest Oregon

1989 ◽  
Vol 19 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Diane E. White ◽  
Michael Newton
Keyword(s):  
Leaf Area ◽  
Ponderosa Pine ◽  
Canopy Cover ◽  
Douglas Fir ◽  
Stem Volume ◽  
Density Level ◽  
Mixed Stands ◽  
Area Index ◽  
Basal Diameter ◽  
Canopy Volume

Whiteleaf manzanita (Arctostaphylosviscida Parry) was established on three sites at densities ranging from 0 to 27 000 seedlings/ha in 2-year-old mixed stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and ponderosa pine (Pinusponderosa Dougl. ex Laws.). Invading herbs were controlled by spraying all plots, except one at each site at the 13 500 manzanita/ha density level. Intraspecific manzanita competition reduced individual shrub basal diameter, leaf area, biomass, and canopy volume by the 3rd year of our study. In contrast, these variables increased at the highest density in the manzanita stand. Stem volume of 5-year-old conifers was reduced in relation to manzanita density, biomass, leaf area index, and canopy cover. The presence of herbaceous vegetation reduced both manzanita and conifer growth by the 3rd year.

Influence of species proportion and timing of establishment on stem quality in mixed red alder – Douglas-fir plantations

2004 ◽  
Vol 34 (4) ◽  
pp. 863-873 ◽  
Author(s):  
Amy T Grotta ◽  
Barbara L Gartner ◽  
Steven R Radosevich
Keyword(s):  
Stand Structure ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Form ◽  
Mixed Stands ◽  
Red Alder ◽  
Stem Quality ◽  
Multiple Stems ◽  
Old Trees ◽  
Species Proportion

The relationships among stand structure, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) branch characteristics, and red alder (Alnus rubra (Bong.)) stem form attributes were explored for 10- to 15-year-old trees growing in mixed Douglas-fir – red alder plantations. Treatments included a range of species proportions, and red alder was either planted simultaneously with Douglas-fir or after 5 years. Both replacement effects (total stand density held constant) and additive effects (stand density doubled) of competition were considered. When the two species were planted simultaneously and red alder proportion was low, red alder trees had low crown bases and much stem defect (lean, sweep, and multiple stems). Douglas-fir grew slowly when the two species were planted simultaneously. When red alder planting was delayed, species proportion did not affect red alder stem form, and height to the base of the Douglas-fir live crown decreased with increasing red alder proportion. Doubling Douglas-fir density increased the height to the base of the Douglas-fir live crown; however, doubling stand density by adding red alder did not affect Douglas-fir crown height. Douglas-fir lumber coming from mixed stands may be inferior because of the changes in knot characteristics associated with these different patterns of crown recession. In stands with a low proportion of red alder, red alder product recovery may be compromised because of the stem defects described above.

Impact of Shrub Sprout Competition on Douglas-fir Seedling Development

1989 ◽  
Vol 4 (3) ◽  
pp. 89-92 ◽  
Author(s):  
Steven D. Tesch ◽  
Stephen D. Hobbs
Keyword(s):  
Dry Weight ◽  
Douglas Fir ◽  
Shoot Biomass ◽  
First Year ◽  
Summer Drought ◽  
Percentage Cover ◽  
Live Oak ◽  
Arctostaphylos Patula ◽  
A Site ◽  
Root And Shoot Biomass

Abstract In 1983, 1-0 container-grown Douglas-fir (Pseudotsuga menziesii) seedlings were planted on a site subject to summer drought under three levels of sprout competition from greenleaf manzanita (Arctostaphylos patula) and canyon live oak (Quercus chrysolepis). Seedlings were planted with 0.25-m-tall dead sprouts, mature shrubs slashed just before planting, or 1-m tall sprouts, which represent an increasing order of competition. After 3 years, Douglas-fir survival did not differ significantly among levels of competition. However, percentage cover of competing shrubs was negatively correlated with conifer root and shoot biomass. Under the least competition, root biomass increased 25 times and shoot biomass 103 times over dry weight at planting, but dry weights in other treatments increased <5 times. Douglas-fir seedling growth did not increase significantly following shrub removal when vigorous sprouting occurred during the first year. After 3 years, however, competitor cover in the minimum-competition plots was less than 15%, and conifer biomass had increased exponentially. West. J. Appl. For. 4(3):89-92, July 1989.

Aboveground biomass distribution within trees and stands in thinned and fertilized Douglas-fir

1986 ◽  
Vol 16 (3) ◽  
pp. 438-442 ◽  
Author(s):  
H. J. Barclay ◽  
P. C. Pang ◽  
D. F. W. Pollard
Keyword(s):  
Aboveground Biomass ◽  
Basal Area ◽  
Douglas Fir ◽  
Total Biomass ◽  
Regression Equations ◽  
Biomass Distribution ◽  
Biomass Components ◽  
Wood Bark

Nine years after thinning (removal of 2/3 of the basal area) and fertilization (at 448 kg N ha−1, applied as urea), 34-year-old Douglas-fir trees (Pseudotsugamenziesii (Mirb.) Franco) were destructively sampled. The dry weights of seven aboveground components were determined and regression equations from dbh were developed. Differences among treatments were shown for all biomass components and the proportions of the total biomass allocated to the various components. Specifically, thinning decreased the proportion of biomass allotted to wood, bark, and dead branches, while increasing the proportions in foliage and live branches; fertilization increased the proportion of biomass in branches, but had negligible effects on the proportions of other components.

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