To gain a better foothold on the communication system of the
avifauna, calls and songs of the American Robin (Turdus migratorius)
were recorded and analyzed using the sound spectrograph. Ten different
calls were recognized as follows: three alarm calls, an excitement
call, challenge call, contact call, two flight calls and...
Controlling competing vegetation with the application of herbicides and increased seedling size at planting has been shown to increase seedling survival and growth. These two important reforestation tools have often been studied independently of each other, limiting comparisons that can be made between them. This study utilized a factorial treatment...
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RobinRose
Controlling competing vegetation with the application of herbicides and
Three studies were conducted to characterize and present early-seral
competition between Douglas-fir seedlings and the surrounding vegetation
communities during Pacific Northwest forest establishment. The first experiment
served as the foundation for this dissertation and was designed to quantify tradeoffs
associated with delaying forest establishment activities by introducing a fallow year...
A series of experiments were established to gain a better understanding of the extent to which Douglas-fir seeding root architecture may be manipulated and subsequent influences on seedling morphological and physiological development. The incorporation of amendments into nursery soils changed root architecture to some degree, but did not produce large...
Weed control in Pacific Northwest forests has been criticized for its potential impact on biodiversity. Changes were evaluated in conifer growth, diversity of vegetation in situ and of recruiting plants through different regeneration mechanisms after applying temporally-varied weed control by herbicide treatments based on the critical period concept. Conifer size...
Two-year-old ponderosa pine (Pinus ponderosa Laws.)
from two seed sources were grown at two nurseries. The
Fremont seed source was raised at Bend and Stone Nursery;
the Ochoco was grown at only the Bend Nursery. The
seedlings were fertilized in late September-early October
with nitrogen (N) or nitrogen plus potassium...
Two-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings of two seed sources raised in three nurseries in Oregon and Washington were tested for differences in frost hardiness from September 1985 to March 1986. The objective of the study was to determine whether nursery location had an influence on seedling acclimation, deacclimation...
Ammonia (NH₃) volatilization can result in a substantial amount of surface applied nitrogen (N) being lost into the atmosphere, making it an environmental pollutant as well as reducing plant-available N. However, N can also be easily lost from the soil through leaching,
and nitrous oxide (NO₂). Enhanced efficiency N fertilizers...