Flower stimulation in young miniaturized seed orchards of Douglas-fir (Pseudotsuga menziesii)

2007 ◽  
Vol 37 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Marilyn L Cherry ◽  
Thimmappa S Anekonda ◽  
Michael J Albrecht ◽  
Glenn T Howe

We studied flower stimulation in two young miniaturized seed orchards of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) in Oregon. In experiment 1, female and male flowering were substantially enhanced when the trees were treated 2–4 years after grafting with stem girdling plus stem-injected gibberellin A4/7 (GA 0.25× rate = ProCone(tm) at 0.084 µL·mm–2 scion cross-sectional area). Comparable results were obtained the following year when the same trees were retreated with 1× GA. In experiment 2, female and male flowering were significantly enhanced when 3-year-old trees were treated with girdling plus either 1× GA, 1.5× GA, or 2× GA. Some treatments had higher mortality and less height growth than the control in the year of cone development. We recommend using a combination of girdling and 1× GA biennially once trees are large enough to produce large per-hectare seed yields and withstand the stress of flower stimulation. At the study orchards, this seems to be about 5 years postgrafting, just before the sixth growing season. Yields were estimated to be 272 963 seeds·ha–1 at age 4 years, or 143 095 seeds·ha–1 annually with stimulation occurring every 2 years. Yields should increase as orchards age, with full stocking, and with higher planting densities.

1986 ◽  
Vol 1 (4) ◽  
pp. 108-111 ◽  
Author(s):  
Chao-Hsiung Tung ◽  
Jim Batdorff ◽  
David R. DeYoe

Abstract Two vegetation management methods, paper mulching and spot-spraying with glyphosate, were combined with a root-dipping treatment, Terra Sorb®, to test effects on seedling survival and height growth on a harsh site in Oregon. Survival of Douglas-fir (Pseudotsuga menziesii) seedlings was significantly higher after the third growing season when competing vegetation had been controlled with mulch or glyphosate during the first two growing seasons. Seedlings retreated with paper mulch and glyphosate before the second growing season had 36 and 25% higher survival than those that were not retreated. None of the seedlings was retreated before the third season; after this season, survival of seedlings treated twice with glyphosate was 26, 23, and 21% higher than seedlings receiving one glyphosate treatment and one or two mulch applications, respectively. There were no differences in seedling height growth among treatments. Rootdipping with Terra Sorb® did not influence survival or growth. West. J. Appl. For. 1:108-111 Oct. 86.


IAWA Journal ◽  
2006 ◽  
Vol 27 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Heidi J. Renninger ◽  
Barbara L. Gartner ◽  
Amy T. Grotta

The width of earlywood and latewood in conifer xylem may have a profound effect on water transport and storage, vulnerability to embolism, and wood strength, yet the controls over the timing of latewood formation are unclear. Tracheids differentiating in the cambial zone are influenced by IAA, indole-3 acetic acid, the radial concentration gradient of which appears to either increase cell expansion (earlywood) or increase cell wall deposition (latewood). There are suggestive data that latewood begins to form when the growth of the leader stops, but definitive results are lacking. Height growth was measured in 14 Douglas-fir (Pseudotsuga menziesii) saplings at 10 dates between May and August, from the beginning of the growing season until after height growth had ceased. The cambium was also pinned six times between June and July, to induce xylem scarring at known dates. After height growth ceased, saplings were harvested and transverse sections of the wood were made at the pin insertion points. The date at which 95% of the height growth had occurred and the date at which latewood formation had begun were estimated. Analysis showed no correlation of these data, suggesting that the two phenomena may occur around the same time, but that one is not causal of the other.


Author(s):  
David Carter ◽  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato

The invasive shrub Scotch broom (Cytisus scoparius (L.) Link) is a pervasive threat to regenerating Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stands in the Pacific Northwest, USA. Field observations indicate that the susceptibility of areas to Scotch broom invasion and dominance can vary by site. We selected ten sites throughout the western Pacific Northwest that spanned a gradient of soil textures and other factors to test the site-specific susceptibility of Douglas-fir to overtopping by Scotch broom. We expected to find that the ability of Scotch broom to dominate a site was mediated by site-level factors, particularly those influencing soil water – the most limiting factor to growth in the region. We found Scotch broom and Douglas-fir were inversely affected by site-level factors. In general, Douglas-fir absolute height growth rates were more competitive with those of Scotch broom on fine-textured soils than on more coarsely textured soils. We also found Douglas-fir to have a more dramatic response to increasing down woody material than Scotch broom. Scotch broom height growth approached an asymptote at 3 m. Sites with fast-growing Douglas-fir were able to surpass this height six to seven years after planting and appear likely to avoid suppression by Scotch broom.


1989 ◽  
Vol 4 (3) ◽  
pp. 85-88
Author(s):  
James L. Vander Ploeg ◽  
James A. Moore

Abstract Stem analysis data from Douglas-fir (Pseudotsuga menziesii) collected throughout the inland Northwest were used for testing height growth and site index equations. The equations performed well in northern and central Idaho, northeast Oregon, and northeast Washington on vegetative types similar to those sampled in model development. However, if the equations were applied on drier sites outside the original geographic study area, overestimates of height growth and under-estimates of site index could result. Therefore, revised height growth and site index equations are presented for western Montana and central Washington. West. J. Appl. For. 4(3):85-88, July 1989.


1964 ◽  
Vol 40 (3) ◽  
pp. 298-307 ◽  
Author(s):  
K. J. Mitchell

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations on the east coast of Vancouver Island, British Columbia, were examined to determine the effect of animal feeding upon height growth.Length of internodes and evidence of past leader damage were recorded and cumulative average height-age growth curves compared for undamaged trees and for trees suffering various intensities of damage.The average reduction in tree height attributable to animal feeding in heavily browsed plantations varied from one-half to two feet over a period of 8 to 10 years. It is unlikely that either tree volume or quality at rotation age would be seriously affected.Exposed trees were browsed more heavily than those protected by vegetation or logging slash.


Author(s):  
Birte Pakull ◽  
Pascal Eusemann ◽  
Janine Wojacki ◽  
Diana Ahnert ◽  
Heike Liesebach

AbstractIn Germany, Douglas fir (Pseudotsuga menziesii Franco) is seen as a valuable species for future cultivation in times of climate change. Local seed production in seed stands and seed orchards may secure that local adaptation is transferred to the next generation, but small population sizes could lower genetic diversity and thus future adaptability. Here we analyse the transfer of genetic diversity from parent to offspring generation in four older German seed orchards. We detected low pollen contamination rates due to high levels of spatial isolation. Even with a relatively low number of 40 clones, seed orchard design with randomized and repeated planting of clones led to low selfing rates, and despite uneven parental contributions, the number of successful parents and the level of genetic intermixture were high enough to allow the transfer of an adequate part of the genetic diversity to the next generation. Larger numbers, however, might be needed to reliably conserve the entire genetic diversity over succeeding generations. Conclusions on the establishment of future seed orchards and regarding areas requiring further research are drawn at the end of the paper.


1994 ◽  
Vol 9 (1) ◽  
pp. 5-7 ◽  
Author(s):  
D. L. Copes ◽  
Mike Bordelon

Abstract Two treatments involving tree spacings (12 and 24 ft) within rows spaced 24 ft apart and height control (topped or not topped at 20 ft) were evaluated in 17- and 22-yr-old coast Douglas-fir (Pseudotsuga menziesii var. menziesii) seed orchards. Treatment differences for cone production were not significant because of the large tree-to-tree variation in cone production and, at one orchard, the confounding of location with treatment. Cone production in 1990 averaged slightly more than 2 bushels per tree (range 0 to 11.7 bushels). Average production per 96 linear ft of orchard row was 14.8 bushels. West. J. Appl. For. 9(1):5-7.


1999 ◽  
Vol 14 (4) ◽  
pp. 183-185
Author(s):  
Gladwin Joseph ◽  
Rick G. Kelsey

Abstract To test whether methanol or ethanol stimulated growth of coast Douglas-fir (Pseudotsuga menziesii vat. menziesii) or ponderosa pine (Pinus ponderosa) seedlings, we sprayed concentrations of 1 to 10% (v/v) on the foliage twice a week for 13 wk during the growing season. Foliar applications of methanol and ethanol neither significantly stimulated nor inhibited growth, and signs of damage at these concentrations were lacking. West. J. Appl. For. 14(4):183-185.


1996 ◽  
Vol 128 (6) ◽  
pp. 1065-1076 ◽  
Author(s):  
Suzie E. Blatt ◽  
John H. Borden

AbstractLeptoglossus occidentalis Heidemann (Hemiptera: Coreidae) is considered to be an important cone and seed pest in seed orchards in British Columbia; however, no impact studies have been done in Canada. Surveys to determine the distribution of L. occidentalis were conducted over a 3-year period in three coastal seed orchards of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and over a 2-year period in two seed orchards of lodgepole pine, Pinus contorta var. latifolia Engelmann. Leptoglossus occidentalis was found to distribute itself in patches, coinciding with a clonal preference. Seed losses were assessed for 2 years in the coastal Douglas-fir orchards and for 1 year in one lodgepole pine orchard. The percentages of partially filled seed that could have been caused by feeding of L. occidentalis or by a number of other factors were < 5% in coastal Douglas-fir for both 1992 and 1993 and ~14% in lodgepole pine in 1993. Apparently because populations of L. occidentalis were low, there was no correlation between the percentage of partially filled seed and number of insects per tree. Except in unusual circumstances, management measures in Canada are judged not to be necessary as populations of L. occidentalis are consistently below the calculated threshold levels required to cause ≥5% loss in seed production.


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