Response of young Douglas-fir to urea fertilizer applied on and off snow

1994 ◽  
Vol 70 (3) ◽  
pp. 294-298
Author(s):  
Valin G. Marshall ◽  
Hugh J. Barclay

The effects of 200 kg N ha−1 applied as urea fertilizer on 50 cm of snow or on bare ground were studied in an 11-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation on Vancouver Island. Analysis was done on all trees per plot and on 20 selected dominant trees per plot. Up to 2 years after fertilization, urea significantly increased absolute DBH increments over controls in all trees and the 20 selected trees per plot; response to fertilization on snow was equal to that on bare ground. Between the 3rd and 9th year following fertilization, mean DBH increments were not significantly different for any treatment. Four-year absolute volume increments were 63 and 87% greater than the controls for bare-ground and on-snow applications, respectively. A positive and quantitatively similar response is expected in wetter coastal Douglas-fir stands whether urea is applied on snow or under better conditions during other seasons. Key words: Forest fertilization, season of application, nitrogen, tree response, Pseudotsuga menziesii (Mirb.) Franco

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.


1961 ◽  
Vol 93 (11) ◽  
pp. 952-967 ◽  
Author(s):  
A. F. Hedlin

A midge, Contarinia oregonensis, is one of a number of species of insects which causc seed losses in Douglas fir, Pseudotsuga menziesii (Mirb.) Franco. In recent years it has been reported causing more damage than any other single species of Douglas-fir cone insect in western Washington (Johnson and Heikkkenen. 1958). This has been the situation on Vancouver Island also.The species bas described by Foote (1956) from specimens taken in Oregon in 1916.


Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis

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.


1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton

Poor performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations established in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-year-old container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural) Douglas-fir seedlings from seven affected plantations. Percentages of seedlings harboring Cylindrocarpon spp.and percent root colonization were significantly greater for planted seedlings compared with natural seedlings. A significant linear trend in Cylindrocarpon root colonization was observed for planted seedlings with colonization levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10cm from that region. This trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon destructans (Zins.) Scholten var. destructans and C.cylindroides Wollenw. var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percentage of seedlings harboring Fusarium spp.and percent Fusarium root colonization were less than for Cylindrocarpon. Recovery of Fusarium spp.from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.


Author(s):  

Abstract A new distribution map is provided for Contarinia pseudotsugae Condrashoff (Diptera: Cecidomyiidae). Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in Europe (Belgium, France, Germany and Netherlands) and North America (Canada, British Columbia, USA, California, Idaho, Michigan, Montana, Oregon, Pennsylvania and Washington).


Author(s):  

Abstract A new distribution map is provided for Phytophthora pseudotsugae Hamm & Hansen. Host: douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in NORTH AMERICA, USA, OR, WA.


Author(s):  

Abstract A new distribution map is provided for Rhabdocline pseudotsugae Syd. Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in EUROPE, Belgium, Britain, Czechoslovakia, Denmark, France, Germany, Irish Republic, Netherlands, Norway, Poland, Romania, Sweden, Switzerland, Yugoslavia, NORTH AMERICA, Canada (Alberta, British Columbia), USA.


Author(s):  

Abstract A new distribution map is provided for Dendroctonus pseudotsugae Hopkins Coleoptera: Scolytidae Hosts: Mainly Douglas fir (Pseudotsuga menziesii), also other Pseudotsuga spp. Information is given on the geographical distribution in NORTH AMERICA, Canada, Alberta, British Columbia, Mexico, USA, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Texas, Utah, Washington, Wyoming.


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