نتایج جستجو برای: trees and shrubs canopy

تعداد نتایج: 16840862  

Journal: :Tree physiology 2008
Jon Lloyd Michael I Bird Lins Vellen Antonio Carlos Miranda Elmar M Veenendaal Gloria Djagbletey Heloisa S Miranda Garry Cook Graham D Farquhar

To estimate the relative contributions of woody and herbaceous vegetation to savanna productivity, we measured the 13C/12C isotopic ratios of leaves from trees, shrubs, grasses and the surface soil carbon pool for 22 savannas in Australia, Brazil and Ghana covering the full savanna spectrum ranging from almost pure grassland to closed woodlands on all three continents. All trees and shrubs samp...

2011
Chelcy R. Ford Katherine J. Elliott Barton D. Clinton Brian D. Kloeppel James M. Vose

Understanding changes in community composition caused by invasive species is critical for predicting effects on ecosystem function, particularly when the invasive threatens a foundation species. Here we focus on dynamics of forest structure, composition and microclimate, and how these interact in southern Appalachian riparian forests following invasion by hemlock woolly adelgid, HWA, Adelges ts...

Journal: :journal of rangeland science 2013
tahereh sadeghi shahrakht mohammad jankju mansour mesdaghi

in arid and semi-arid ecosystems, shrubs may act as fertility islands but theireffect may vary depending on their morphology and ecological impacts. this research wasaimed to study effect of three shrubs scariola orientalis, astragalus heratensis, and rosapersica on soil properties and on the microclimate conditions (temperature, luminance, andsoil moisture) of their understory in the steppe ra...

Spiny and aromatic species in rangelands can play important role in the conservation of plant species in rangelands; however, few studies  have been done on the role of these plants under different levels of livestock grazing. In this research, the facilitation effects of spiny (Astragalus chrysostachys Boiss) and aromatic (Artemisia kopetdaghensis (Poljakov) Y.R.Ling) shrubs were studied on sp...

Oak decline as one of the most important environmental problems of Zagros forests, requires proper management to decrease trees dieback and mitigate its effects. This study aimed to find the best sampling method for estimating density and crown canopy of declined oak trees in Zagros Forests. All declined trees in an area of 100 ha of Dinarkooh protected forest were surveyed and trees density, g...

Ehsan Zandi Esfahan Mohammad Taghi Zare Naser Baghestani Maybodi,

 Knowledge of the Saxaul dimensions used in sand dunes stabilization is considered essential for designing live windbreak in desert regions. This research aimed to collect and analysis data and was performed on the pruned and control shrubs of Haloxylon aphyllum L. in Yazd province, Iran in the last two decades. Our review clearly showed the superiority of shrubs pruned at the height of 35 cm i...

Mansour Mesdaghi, Mohammad Jankju Tahereh Sadeghi Shahrakht

In arid and semi-arid ecosystems, shrubs may act as fertility islands but theireffect may vary depending on their morphology and ecological impacts. This research wasaimed to study effect of three shrubs Scariola orientalis, Astragalus heratensis, and Rosapersica on soil properties and on the microclimate conditions (temperature, luminance, andsoil moisture) of their understory in the steppe ra...

2001
José M. Gómez José A. Hódar Regino Zamora Jorge Castro Daniel García

The spatial structure of plant communities as well as the quality and abundance of neighbours can strongly influence the intensity of herbivory suffered by a plant. In this paper, we study the effect of the association with shrubs on the ungulate herbivory suffered by Scots pine (Pinus sylvestris var. nevadensis Christ., Pinaceae) saplings in two isolated, fragmented populations in southeastern...

2002
P. D. PRATT R. ROSETTA B. A. CROFT

The predatory mite Neoseiulus fallacis (Garman) was evaluated as a biological control agent of herbivorous mites on outdoor-grown ornamental landscape plants. To elucidate factors that may affect predator efÞciency, replicated tests were conducted on 30 ornamental plant cultivars that varied in relationship to their generalized morphology (e.g., conifers, shade trees, evergreen shrubs, deciduou...

2007
G. A. Roth W. G. Whitford Y. Steinberger

This study addressed the question: can herbivory by a medium size herbivore, black-tail jackrabbits (Lepus californicus), change dominance in desertified ecosystems dominated by two species of shrubs. Shrubs that were pruned by jackrabbits in plant communities dominated by creosotebush (Larrea tridentata) and tarbush (Flourensia cernua) were compared to shrubs not browsed by the rabbits. In the...

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