scholarly journals Ten-Year Growth Response of Young Douglas-Fir to Variable Density Varnishleaf Ceanothus and Herb Competition

1999 ◽  
Vol 14 (4) ◽  
pp. 208-213 ◽  
Author(s):  
V. J. Monleon ◽  
M. Newton ◽  
C. Hooper ◽  
J. C. Tappeiner
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Variable Density ◽  
Douglas Fir ◽  
The Other ◽  
Plantation Establishment ◽  
Single Application ◽  
Herbaceous Vegetation ◽  
Vegetation Control ◽  
Tree Diameter

Abstract The effect of different densities of varnishleaf ceanothus (Ceanothus velutinus var. laevigatus) and herbaceous vegetation control on stem diameter, height, and volume of plantation Douglas-fir (Pseudotsuga menziesii vat. menziesii) seedlings was examined during the 10 yr following planting. Initial densities of ceanothus ranged between 0 and 15,000 seedlings/ha and were obtained by interplanting ceanothus germinants or chemical thinning after clearcutting and broadcast-burning. Herbaceous vegetation control was achieved by a single application of glyphosate following planting, with shrub seedlings covered. Ceanothus density in the range of 0 to 6,750 plants/ha did not have an effect on Douglas-fir diameter, height, or volume at age 10; however, Douglas-fir growth was significantly decreased when ceanothus densities reached 15,000 plants/ha. Ten years after planting, Douglas-fir volume in the treatments with 6,750 ceanothus/ha or less was 1.7 times greater than that in the 15,000 ceanothus/ha treatment. On the other hand, removal of herbaceous vegetation after planting significantly increased tree diameter, height, and volume, regardless of ceanothus density. Even 10 yr after the application of the treatment, trees without early herb competition grew faster and had mean dbh, height, and volume that were 1.02 cm, 0.55 m, and 12.98 dm³/tree greater respectively than those with herbs. Thus, a treatment at plantation establishment to control herbaceous vegetation and to reduce ceanothus density to less than 7,000 plants/ha will ensure an increase in growth and stocking for at least 10 yr. West. J. Appl. For. 14(4):208-213.

Using decision analysis for stand-level silvicultural decisions

1991 ◽  
Vol 67 (4) ◽  
pp. 384-388
Author(s):  
Peter Marshall
Keyword(s):  
Decision Analysis ◽  
Treatment Response ◽  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Douglas Fir ◽  
Perfect Information ◽  
Analytic Approach ◽  
Planting Density ◽  
Response Information ◽  
Value Of Perfect Information

A decision analytic approach to assessing stand-level silvicultural decisions is illustrated using planting density and spacing decisions for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Information from several stand projection procedures was combined into a single analysis. The value of "perfect information" was calculated as an indicator of the value of additional response information. The value of perfect information should not be used as the sole justification for gathering treatment response information because it fluctuated with the economic assumptions made and the alternatives evaluated. However, it provides a relative ranking of treatment response requirements and a means for quantifying the risk associated with silvicultural decisions. The decision analytic approach proved flexible as a means for combining growth response information from several sources into a compromise decision.

Growth Response to Fertilization in Young Douglas-Fir Stands

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Intermediate Region ◽  
Fertilizer Response ◽  
Breast Height ◽  
Inverse Effect

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.

The effect of tree dimension on the diversity of bark microhabitat structures and bark use in Douglas-fir (Pseudotsuga menziesii var. menziesii)

2011 ◽  
Vol 41 (2) ◽  
pp. 300-308 ◽  
Author(s):  
Alexa K. Michel ◽  
Susanne Winter ◽  
Andreas Linde
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Large Diameter ◽  
Structural Complexity ◽  
Douglas Fir ◽  
Forest Monitoring ◽  
Tree Bark ◽  
Bark Thickness ◽  
Tree Diameter ◽  
The Us

The focus of this study was to investigate the role of tree dimension and associated bark structures for high structural complexity and high natural biodiversity in forest ecosystems. Two-hundred and ninety-one Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirbel) Franco) trees in two regions of the US Pacific Northwest were investigated for the relationship between tree diameter and bark thickness (measured as bark fissure depth) and the relationships of both to bark microhabitats and signs of bark use. Our results emphasize the habitat function of tree bark of large-diameter Douglas-fir trees. Many bark microhabitat types and their total abundance significantly increased with increasing tree diameter and bark thickness. These were bark pockets with and without decaying substrate, bowls in the bark, and signs of bark use, e.g., small holes from woodpecker drillings and large insects, large bark excavations from woodpeckers, spider funnel webs, natural cavities at the stem base without decay, and the occurrence of herb vegetation at the tree base. In forest monitoring, tree diameter may be a good indicator of the number of bark microhabitats and of bark thickness because it is strongly related to both of these variables. However, because of the high variability of bark thickness in large-diameter trees, we suggest monitoring bark fissure depth if an ecological evaluation of Douglas-fir forests is needed.

Growth and virulence of Ceratocystis rufipenni and three blue-stain fungi isolated from the Douglas-fir beetle

1998 ◽  
Vol 76 (10) ◽  
pp. 1763-1769 ◽  
Author(s):  
Halvor Solheim ◽  
Paal Krokene
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
The Other ◽  
Malt Agar ◽  
Low Oxygen ◽  
Dendroctonus Pseudotsugae ◽  
Dendroctonus Rufipennis ◽  
Spruce Beetle ◽  
Blue Stain Fungi ◽  
Blue Stain

Blue-stain fungi were isolated from the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, and from Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, colonized by the beetle. Growth of the three most commonly isolated blue-stain fungi (Leptographium abietinum (Peck) Wingfield, Ophiostoma europhioides (Wright & Cain) Solheim, Ophiostoma pseudotsugae (Rumbold) von Arx), and Ceratocystis rufipenni Wingfield, Harrington, & Solheim, an important associate of the spruce beetle, Dendroctonus rufipennis (Kirby), was studied in sapwood and phloem of live Douglas-fir trees, on malt agar, and on malt agar under oxygen-deficient conditions. The two Ophiostoma species grew better in the phloem and induced longer phloem necroses than the other fungi. Ceratocystis rufipenni and O. europhioides grew better in the sapwood and induced deeper sapwood occlusion. All fungi were relatively fast growing on malt agar, with O. pseudotsugae growing fastest and L. abietinum, slowest. Growth of C. rufipenni and O. europhioides was inhibited less by low oxygen levels than the other fungi, and this may explain why these two fungi were better able to colonize live sapwood.Key words: Ceratocystis rufipenni, Dendroctonus pseudotsugae, Douglas-fir, Leptographium abietinum, Ophiostoma europhioides, Ophiostoma pseudotsugae.

Soil and Douglas-fir (Pseudotsuga menziesii) foliar nitrogen responses to variable logging-debris retention and competing vegetation control in the Pacific Northwest

2010 ◽  
Vol 40 (2) ◽  
pp. 254-264 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Stephen H. Schoenholtz
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Soil N ◽  
Vegetation Control ◽  
Competing Vegetation ◽  
Total Soil ◽  
The Pacific ◽  
N Acquisition ◽  
Total Soil N

Experimental treatments of logging-debris retention (0%, 40%, or 80% surface coverage) and competing vegetation control (initial or annual applications) were installed at two sites in the Pacific Northwest following clearcutting Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stands to assess short-term effects on tree N acquisition, soil N supply, and total soil N. Vegetation control treatments began in the first year after harvest, and logging-debris manipulations were installed 2 years after harvest. Annual vegetation control increased foliar N concentration and content in most years at both sites, which was associated with higher available soil N and increased soil water content. Logging-debris retention treatments had no detectable effect on any of the foliar variables or soil available N at either site. There were no treatment effects on total soil N at the site with relatively high soil N, but total soil N increased with logging-debris retention when annual vegetation control was applied at the site with a low initial soil N pool. Competing vegetation control is an effective means to increase tree N acquisition in the initial years after planting while maintaining soil N pools critical to soil quality. The effect of logging-debris retention on tree N acquisition appears to be limited during early years of stand development, but increased soil N with heavy debris retention at certain sites may be beneficial to tree growth in later years.

Pit and pit aperture dimensions in plantation-grown Douglas fir as affected by local growth conditions and height in stem

IAWA Journal ◽  
2020 ◽  
Vol 41 (2) ◽  
pp. 131-140
Author(s):  
Andreas Christof ◽  
Anders Ræbild ◽  
Lisbeth G. Thygesen
Keyword(s):  
Environmental Factors ◽  
Soil Fertility ◽  
Pseudotsuga Menziesii ◽  
Allometric Scaling ◽  
Growth Conditions ◽  
Douglas Fir ◽  
Model Fit ◽  
The Other ◽  
Local Growth ◽  
Poor Soil

Abstract This study assessed whether allometric scaling applied to pit sizes in stems of Douglas fir. Pit and pit aperture diameters were measured in xylem from stems of four plantation-grown Douglas fir (Pseudotsuga menziesii) trees from each of two different sites in Denmark. One site had fertile soil, the other had poor soil fertility. Three different heights were accessed for each tree, and 40 pits were measured per height. Results showed that pit diameter varied between 17 and 24 μm and decreased significantly with increasing height above ground. Representing the position in the tree as a power function of distance from the top of the tree (L0.2) rather than the height above ground improved the model fit for pit diameter as expressed by the R2 value. However, the pit diameter relationship was found to be significantly affected by site, suggesting that anatomic dimensions relate not only to tree size but also to growth conditions. This would imply that even though pit size supposedly has a strong biophysical determination, some xylem plasticity may still be induced by environmental factors.

Equipment Trials for Uprooting Root-Rot-Infected Stumps

1988 ◽  
Vol 3 (3) ◽  
pp. 80-82 ◽  
Author(s):  
W. J. Bloomberg ◽  
G. Reynolds
Keyword(s):  
Pseudotsuga Menziesii ◽  
Root Rot ◽  
Douglas Fir ◽  
The Other ◽  
Root Volume ◽  
Root Extraction ◽  
Phellinus Weirii ◽  
Similar Site

Abstract Root residues were measured following stump-root extraction 1 year after harvesting a 55-year-old Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stand with 20% infestation of Phellinus weirii (Murr. Gilbertson) root rot. A D8 Cat, a 180-hp (large) backhoe, and a 115-hp (small) backhoe were each used to uproot stumps on 1.2-1.3 ha blocks. All treatments resulted in less than 10% of root volume remaining in the soil compared with pretreatment volumes calculated from dbh-root volume relationships on a similar site. Average numbers and lengths of root residues/m³ soil were significantly greater for the small backhoe than for the other treatments, and volume was greatest for the D8 Cat treatment. The large backhoe treatment resulted in smaller residual volumes than the other treatments. West. J. Appl. For. 3(3):80-82, July 1988.

scholarly journals Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
The United States ◽  
Douglas Fir ◽  
Tree Seedlings ◽  
Pythium Species ◽  
Forest Nursery ◽  
Damping Off ◽  
Greenhouse Study ◽  
Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

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