نتایج جستجو برای: pine trees

تعداد نتایج: 104582  

Journal: :The Journal of animal ecology 2006
Kailen A Mooney Yan B Linhart

1. Intraguild predation occurs when top predators feed upon both intermediate predators and herbivores. Intraguild predators may thus have little net impact on herbivore abundance. Variation among communities in the strength of trophic cascades (the indirect effects of predators on plants) may be due to differing frequencies of intraguild predation. Less is known about the influence of variatio...

2010
T. A. Sazonova A. V. Olchev

The response of two dominant coniferous species (Picea obovata Ledeb. and Pinus sylvestris L.) of eastEuropean taiga to industrial pollution in the impact zone of the Severonickel metallurgical combine (Murmansk Region, Kola Peninsula) was investigated. The water deficit of the needles and shoots described by shoot water potential ( ) was used as indicator of the pollution level in the area. Th...

Journal: :Environmental entomology 2010
Matthew D Klingenberg Niklas Björklund Brian H Aukema

Hylobius warreni Wood, also known as the Warren root collar weevil, is a flightless insect that feeds on conifers throughout the boreal forests of Canada. Mature trees typically can withstand feeding, but larval feeding around the root collar may cause mortality to young trees. Recently, a large outbreak of mountain pine beetle (Dendroctonus ponderosae Hopkins) has killed a high proportion of m...

2003
Mats Warensjö

Warensjö, M. 2003. Compression wood in Scots pine and Norway spruce-Distribution in relation to external geometry and the impact on dimensional stability in sawn wood. With the aid of compression wood the conifer trees are able to maintain their predetermined growth form. Compression wood is formed as soon as the tree is displaced from its normal vertical position. Trees with expressed curvatur...

2004
Annie Plourde Cornelia Krause

In Quebec, the law requires forestry companies to look after the regeneration of the forests they exploit. The natural cycle of jack pine (Pinus banksiana Lamb.) is related to fire, which allows opening of the cones and dispersal of the seeds. But after harvesting, the exploited sectors are normally replanted. It has been shown that the current methods of seedling production and planting cause ...

2005
Dale G. Brockway Everett E. Johnson

32.1 Southern forest environment .......................................................................................... ..50 2 32.2 Longleaf pine ecology.. ..................................................................................................... .502 32.2.1 Longleaf pine ecosystems .................................................................................. ..50 2 32.2.2 E...

Journal: :Tree physiology 2009
Heljä-Sisko Helmisaari Ivika Ostonen Krista Lõhmus John Derome Antti-Jussi Lindroos Päivi Merilä Pekka Nöjd

Variations in ectomycorrhizal (EcM) short root tips of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) in 16 stands throughout Finland were studied, and their relationships with latitude, organic layer C:N ratio, temperature sum and foliage biomass were determined. There were no significant differences in EcM root tip frequency (number per milligram of fine roots) o...

Journal: :Journal of nematology 1987
R I Bolla K Fitzsimmons R E Winter

Pines responded to inoculation with Bursaphelenchus xylophilus by changes in reducing and nonreducing carbohydrate concentrations dependent on the pine species and the pathotype of B. xylophilus with which the trees were inoculated. Carbohydrate concentrations, in compatible pine-nematode pathotype combinations, decreased initially after inoculation and then increased slightly before decreasing...

Journal: :Environmental science. Processes & impacts 2014
Kristin M Mikkelson Lindsay A Bearup Alexis K Navarre-Sitchler John E McCray Jonathan O Sharp

Recent large-scale beetle infestations have caused extensive mortality to conifer forests resulting in alterations to dissolved organic carbon (DOC) cycling, which in turn can impact metal mobility through complexation. This study analyzed soil-water samples beneath impacted trees in concert with laboratory flow-through soil column experiments to explore possible impacts of the bark beetle infe...

2004
B. J. Bentz

Spatial accuracy in the detection and monitoring of mountain pine beetle populations is an important aspect of both forest research and management. Using ground-collected data, classification models to predict mountain pine beetle-caused lodgepole pine mortality were developed for Landsat TM, ETM+, and IKONOS imagery. Our results suggest that low-resolution imagery such as Landsat TM (30 m) is ...

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