نتایج جستجو برای: pine trees
تعداد نتایج: 104582 فیلتر نتایج به سال:
Longleaf pine has been classified as very shade intolerant but leaf physiological plasticity to light is not well understood, especially given longleaf pine’s persistent seedling grass stage. We examined leaf morphological and physiological responses to light in one-year-old grass-stage seedlings and young trees ranging in height from 4.6 m to 6.3 m to test the hypothesis that young longleaf pi...
We studied the infestation rate of Scots pine Pinus sylvestris by xylophagous insects in relation to distance from forest lakes in eastern Latvia, northern Europe. In summers of 2008 and 2009, we felled 72 pines of approximately 65 years age. Sections of the logs were incubated in insect emergence traps. The trees located near lakes were significantly less infested by xylophagous insects than t...
Survival and growth of longleaf pine seedlings depends upon a well-developed root system. Soil moisture is also critical for the seedling to emerge from the grass-stage. When longleaf pine seedlings emerge from the grass stage, they grow rapidly in height and diameter. Branches are often few in number and, if present, may have low photosynthesis rates. This growth pattern is seen on all longlea...
Extensive mortality of whitebark pine, beginning in the early to mid-2000s, occurred in the Greater Yellowstone Ecosystem (GYE) of the western USA, primarily from mountain pine beetle but also from other threats such as white pine blister rust. The climatic drivers of this recent mortality and the potential for future whitebark pine mortality from mountain pine beetle are not well understood, y...
While there is strong evidence for hydraulic redistribution (HR) of soil water by trees, it is not known if common mycorrhizal networks (CMN) can facilitate HR from mature trees to seedlings under field conditions. Ponderosa pine (Pinus ponderosa) seedlings were planted into root-excluding 61-microm mesh barrier chambers buried in an old-growth pine forest. After 2 yr, several mature trees were...
The spatial influences of host and nonhost trees and shrubs on the colonization patterns of white pine weevil Pissodes strobi (Peck) were studied within a stand of planted interior hybrid spruce [Picea glauca (Moench) Voss x Picea engelmannii (Parry) ex Engelm.]. Planted spruce accounted for one third of all trees within the stand, whereas the remaining two thirds were comprised of early-succes...
A portable, low-frequency acoustic system was used to detect termite infestations in urban trees. The likelihood of infestation was rated independently by a computer program and an experienced listener that distinguished insect sounds from background noises. Because soil is a good insulator, termite sounds could be detected easily underneath infested trees, despite the presence of high urban ba...
To identify effects of chronic internal and external radiation exposure for components of terrestrial ecosystems, a comprehensive study of Scots pine trees in the Chernobyl Exclusion Zone was performed. The experimental plan included over 1,100 young trees (up to 20 y old) selected from areas with varying levels of radioactive contamination. These pine trees were planted after the 1986 Chernoby...
Finding alternative uses for raw material from small-diameter trees is a critical problem throughout the United States. In western states, a lack of markets for small-diameter ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta) can contribute to problems associated with overstocking. To test the feasibility of producing structural composite lumber (SCL) beams from these two wes...
Mountain pine beetle, Dendroctonus ponderosae Hopkins, is the most significant mortality agent in pine forests of western North America. Silvicultural treatments that reduce the number of susceptible host trees, alter age and size class distributions, and diversify species composition are considered viable, long-term options for reducing stand susceptibility to mountain pine beetle-caused tree ...
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