scholarly journals Patrones de distribución espacial del arbolado en un bosque de Pseudotsuga menziesii en Chihuahua, México

2021 ◽  
Vol 27 (3) ◽  
pp. e2732242
Author(s):  
Samuel Alberto García-García ◽  
Eduardo Alanís-Rodríguez ◽  
Ernesto Alonso Rubio-Camacho ◽  
Oscar Alberto Aguirre-Calderón ◽  
Eduardo Javier Treviño-Garza ◽  
...  
Keyword(s):  
Pseudotsuga Menziesii

El objetivo de este estudio fue caracterizar los patrones de distribución espacial de un bosque maduro en el estado de Chihuahua, México, donde coexisten coníferas de importancia para la conservación como Pseudotsuga, Picea y Abies. Se utilizó un análisis de patrón de puntos para evaluar mezcla de especies, diferenciación y dominancia dimensional. Los datos se obtuvieron de ocho sitios de muestreo de 1000 m2. Se analizaron de manera general 203 grupos estructurales, Pseudotsuga generó 84, Quercus 22 y Pinus 42, reflejando una distribución aleatoria de acuerdo con el índice de uniformidad de ángulos (Wi), mientras que el grado de mezcla (Mi) manifestó que la especie referencia cuenta con más de dos vecinos de diferente especie. No se registraron diámetros y alturas dominantes de manera general ya que (UDi) y (UHi) mostraron valores similares en cada uno de los grados de dominancia, la diferenciación dimensional (TDi), (THi) fue moderada, similar a estudios en bosques perturbados y bajo manejo. El conocimiento de la dinámica de bosques maduros es vital para una descripción precisa de las relaciones entre especies de manera más auténtica y puede ser base para la conservación o futuras restauraciones en áreas perturbadas.

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.

Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia reforestation sites

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Root Colonization ◽  
Linear Trend ◽  
Poor Performance ◽  
Douglas Fir ◽  
Root Infection ◽  
Significant Linear Trend ◽  
Conifer Seedlings ◽  
Cylindrocarpon Destructans

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.

Distribution of leaf orientations in six conifer species

2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Pinus Contorta ◽  
Goodness Of Fit ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
The Other ◽  
Thuja Plicata ◽  
Leaf Angle ◽  
Conifer Species ◽  
Abies Grandis

Leaf angle distributions are important in assessing both the flexibility of a plant's response to differing daily and seasonal sun angles and also the variability in the proportion of total leaf area visible in remotely sensed images. Leaf angle distributions are presented for six conifer species, Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn. ex D. Don, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.) Franco, Picea sitchensis (Bong.) Carr. and Pinus contorta Dougl. ex Loud. var. latifolia. The leaf angles were calculated by measuring four foliar quantities, and then the distributions of leaf angles are cast in three forms: distributions of (i) the angle of the long axis of the leaf from the vertical for the range 0–180°; (ii) the angle of the long axis of the leaf for the range 0–90°; and (iii) the angle of the plane of the leaf for the range 0–90°. Each of these are fit to the ellipsoidal distribution to test the hypothesis that leaf angles in conifers are sufficiently random to fit the ellipsoidal distribution. The fit was generally better for planar angles and for longitudinal angles between 0° and 90° than for longitudinal angles between 0° and 180°. The fit was also better for Tsuga heterophylla, Pseudotsuga menziesii, Picea sitchensis, and Pinus contorta than for Abies grandis and Thuja plicata. This is probably because Abies and Thuja are more shade tolerant than the other species, and so the leaves in Abies and Thuja are preferentially oriented near the horizontal and are much less random than for the other species. Comparisons of distributions on individual twigs, whole branches, entire trees, and groups of trees were done to test the hypothesis that angle distributions will depend on scale, and these comparisons indicated that the apparent randomness and goodness-of-fit increased on passing to each larger unit (twigs up to groups of trees).Key words: conifer, leaf angles, ellipsoidal distribution.

In vitro studies on the fine structure of epicuticular leaf wax from Pseudotsuga menziesii

1981 ◽  
Vol 59 (5) ◽  
pp. 640-648 ◽  
Author(s):  
G. R. Lister ◽  
B. W. Thair
Keyword(s):  
Fine Structure ◽  
Physical Properties ◽  
Pseudotsuga Menziesii ◽  
Chloroform Solution ◽  
Scale Construction ◽  
Leaf Wax ◽  
Wax Crystal ◽  
Wax Crystals

The epicuticular leaf wax of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was recrystallized from chloroform solution in vitro. The striated, tubular forms were reconstituted in sizes which included that observed in vivo, indicating that the final dimensions and morphology of the wax crystals are functions of physical properties of the component molecules, rather than an enzyme-dependent polymerization. Subsequent evaluation of all observations and data formed the basis for the scale construction of a model of the tubular wax crystal.

Contarinia pseudotsugae. [Distribution map].

2020 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
New Distribution ◽  
Distribution In Europe

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).

Phytophthora pseudotsugae. [Distribution map].

1988 ◽  
Author(s):  
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
New Distribution

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.

Rhabdocline pseudotsugae. [Distribution map].

1976 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
Irish Republic ◽  
New Distribution ◽  
Distribution In Europe

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.

Elatobium abietinum. [Distribution map].

1986 ◽  
Author(s):  
Keyword(s):  
North Carolina ◽  
New Zealand ◽  
Pseudotsuga Menziesii ◽  
Pacific Islands ◽  
District Of Columbia ◽  
West Germany ◽  
Distribution Map ◽  
Elatobium Abietinum ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Elatobium abietinum (Walker) [Hemiptera: Aphididae)] Spruce aphid. Attacks Picea spp., Pseudotsuga menziesii. Information is given on the geographical distribution in EUROPE, Austria, Czechoslovakia, Denmark, Faeroe Islands, Finland, France, East Germany, West Germany, Iceland, Italy, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom, USSR, Latvian SSR, AUSTRALASIA and PACIFIC ISLANDS, Australia, Tasmania, New Zealand, NORTH AMERICA, Canada, British Columbia, Ontario, Quebec, USA, California, District of Columbia, North Carolina, Oregon, Utah, Washington, SOUTH AMERICA, Chile.

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