نتایج جستجو برای: pinus ponderosa

تعداد نتایج: 13623  

2005
JOHN J. STRANSKY JOHN H. ROESE

The fruit of woody plants is important as food for wildlife (Martin et al. 1951, Lay 1965). The relation of fruit production to southern forest stand conditions has been explored in only a few studies. Fruit production is greater in forest clearings than in closed forest stands (Lay 1966, Elalls and Alcaniz 1968). In Georgia slash pine (Pinus elliottii) plantations, fruit yields of shrubs are g...

Journal: :Ecological applications : a publication of the Ecological Society of America 2011
Tania Schoennagel Rosemary L Sherriff Thomas T Veblen

Forests experiencing moderate- or mixed-severity fire regimes are presumed to be widespread across the western United States, but few studies have characterized these complex disturbance regimes and their effects on contemporary forest structure. Restoration of pre-fire-suppression open-forest structure to reduce the risk of uncharacteristic stand-replacing fires is a guiding principle in fores...

2002
KATHERINE J. ELLIOTT ALAN S. WHITE

Competition between ponderosa pine seedlings and various grasses and forbs was studied on :I site in northern Arizona burned in 1982 by a wildfire. Two-yearold pine seedlings were planted in 3.05 x 3.05 m plots in April 1983, followed by the sowing of grass and forb seeds on the same plots in July 1983 after summer rains had begun. Predawn xylem water potential of the pine seedlings was measure...

Journal: :Journal of nematology 1992
J E Warren M J Linit

Pinewood nematode, Bursaphelenchus xylophilus (Steiner &Buhrer) Nickle, spatial dispersion was determined in Scots pine, Pinus sylvestris L., bolts infested with the pine sawyer beetle, Monochamus carolinensis (Olivier) and in bolts without M. carolinensis. According to Taylor's power law and Green's index of dispersion, nematode dispersion was aggregated in both sets of bolts. The degree of ag...

2017
Pertti Hari Tuomas Aakala Juho Aalto Jaana Bäck Jaakko Hollmén Kalev Jõgiste Kourosh Kabiri Koupaei Mika A. Kähkönen Mikko Korpela Liisa Kulmala Eero Nikinmaa Jukka Pumpanen Mirja Salkinoja-Salonen Pauliina Schiestl-Aalto Asko Simojoki Mikko Havimo

Isaac Newton's approach to developing theories in his book Principia Mathematica proceeds in four steps. First, he defines various concepts, second, he formulates axioms utilising the concepts, third, he mathematically analyses the behaviour of the system defined by the concepts and axioms obtaining predictions and fourth, he tests the predictions with measurements. In this study, we formulated...

2006
Dan Binkley Daniel M. Kashian Suzanne Boyden Margot W. Kaye John B. Bradford Mary A. Arthur Paula J. Fornwalt Michael G. Ryan

We used data from 142 stands in Colorado and Wyoming, USA, to test the expectations of a model of growth dominance and stand development. Growth dominance relates the distribution of growth rates of individual trees within a stand to tree sizes. Stands with large trees that account for a greater share of stand growth than of stand mass exhibit strong growth dominance. Stands with large trees th...

Journal: :Journal of nematology 1977
F D McElroy D J Brown B Boag

Paralongidorus maximus was tested as a vector for 20 viruses. Nine were recovered directly from P. maximus, an indication that they had ingested the virus, but there was no correlation between the ingestion and transmission of these viruses. Raspberry ringspot (English and Scottish strains), arabis mosaic, and strawberry latent ringspot viruses were recovered from the roots of bait plants grown...

Journal: :Science 1985
T G Whitham S Mopper

Pinyon pine, Pinus edulis (Engelm.), in Northern Arizona is exposed to recurring high levels of herbivory by the moth Dioryctria albovitella (Hust.). During a 3-year period, infested trees experienced on average a 30 percent reduction in annual shoot production. This herbivory affects tree architecture, growth rate, reproductive output, and sexual expression. Less infested trees produce 47 perc...

2012
Chris J. Peterson Sheryl L. Costello

Lodgepole and ponderosa pine trees were treated with a 2% carbaryl solution at recreational areas near Fort Collins, CO, in June 2010 as a prophylactic bole spray against the mountain pine beetle. Bark samples from treated and untreated trees were collected one day following application and at 4-month intervals for one year. The residual amount of carbaryl was determined, and bark samples were ...

2006
Christopher J. Fettig

The western pine beetle, Dendroctonus brevicomis LeConte, is a major cause of ponderosa pine, Pinus ponderosa Dougl. Ex Laws., mortality in the western USA and particularly in California. Under certain conditions, the beetle can aggressively attack and kill apparently healthy trees of all ages and size classes. The average loss is substantial, and has been estimated at 1 billion board feet annu...

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