نتایج جستجو برای: foliage

تعداد نتایج: 3618  

2010
Y. S. Meng Y. H. Lee

In this paper, a large number of studies of the effect of the foliage on single or lines of trees on modern wireless communication systems are reviewed. The paper is focused on the experimental works mainly done for commercial applications such as cellular communication and high speed point-to-point fixed link at the microwave and millimeter wave frequencies. For this review study, the developm...

2005
VINCENT D’AMICO JOSEPH S. ELKINTON JOHN D. PODGWAITE GREG DWYER

1. Previous work has shown that transmission of some insect pathogens is a non-linear process. A number of hypotheses have been put forward as explanations for this phenomenon; however, none have proven wholly satisfactory. Here we test the effects on transmission of spatial distribution of an insect virus by testing whether or not experimental manipulations of pathogen clumping lead to differe...

Journal: :Plant physiology 2006
Cheng Bai Charles C Reilly Bruce W Wood

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Fol...

2001
G. B. BERGESON

Secondary microbial invasion of tomato plants inoculated with 6,000 Meloidogyne incognita larvae caused 75 and 48% weight reduction of foliage and roots, respectively. Under aseptic conditions the same number of larvae caused only 37% reduction of foliage and increased root weight by 50%.

2000
Kenneth J. Stadt Victor J. Lieffers

We describe the calibration and structure of a multi-species, two-scale light transmission model, and demonstrate its effectiveness for predicting instantaneous light availability at the stand scale across a wide range of forest stand compositions. The model, MIXLIGHT, calculates light transmission through the forest overstory at the stand or microsite scale using standard forest inventory data...

2012
Carl W. Wardhaugh Nigel E. Stork Will Edwards Peter S. Grimbacher

Estimates suggest that perhaps 40% of all invertebrate species are found in tropical rainforest canopies. Extrapolations of total diversity and food web analyses have been based almost exclusively on species inhabiting the foliage, under the assumption that foliage samples are representative of the entire canopy. We examined the validity of this assumption by comparing the density of invertebra...

Journal: :Tree physiology 2004
Robert C McGarvey Timothy A Martin Timothy L White

We examined photosynthetic characteristics of two fast- and two slow-growing half-sib families of both loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii var. elliottii Engelm.) on two sites in northern Florida to: (1) quantify variation in light-saturated net photosynthesis (Amax) associated with vertical crown position and foliage age; (2) quantify the amount and distribution of l...

Journal: :The Canadian Entomologist 1911

2012
Eric M. Wood Anna M. Pidgeon Volker C. Radeloff Nicholas S. Keuler

a r t i c l e i n f o Keywords: Band 4 Foliage-height diversity Horizontal vegetation structure Image texture Infrared air photo Landsat NDVI Wildlife habitat Ecologists commonly collect data on vegetation structure, which is an important attribute for characterizing habitat. However, measuring vegetation structure across large areas is logistically difficult. Our goal was to evaluate the degre...

2004
ROBERT G . MOORE

1. Neonate evergreen bagworms, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae), disperse by dropping on a strand of silk, termed silking, and ballooning on the wind. Larvae construct silken bags with fragments of plant foliage. This species is highly polyphagous, feeding on more than 125 species of woody plants of 45 families. The larvae commonly infests juniper (Juniperus spp....

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