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Foliar nutrient levels in Douglas-fir plantations 25 years after stump removal and fertilization to control Phellinus weirii
(2012-09-13)
Removal of stumps and fertilization after harvesting have been proposed to reduce root diseases in succeeding stands. Potential impacts such as compaction and loss of soil C or N could limit the use of this technique. This research examined forest soils and foliar nutrient levels in five Pacific Northwest stands 22-29 years ...
The Effects of Biogeoclimatic Properties on Water and Nitrogen Availability and Douglas-Fir Growth and Fertilizer Response in the Pacific Northwest
(2012-09-13)
Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is the predominant plantation species of the western Pacific Northwest, although soil and climate characteristics vary throughout the region. This study investigated the effects of water and nitrogen availability on Douglas-fir growth throughout the region. Sixty ...
Deep Soil: Quantification, Modeling, and Significance of Subsurface Carbon and Nitrogen
Soil is the primary sink for C in forest ecosystems, but is often overlooked in ecosystem C budgets. Efforts to quantify C pools often sample soils to a depth of 0.2 m despite observations that deep soil C is neither scarce nor entirely stable. This study examined the systematic sampling depth for ecosystem C analyses in the ...
Reservoir Sediment Carbon along the Elwha River after Dam Removal
Worldwide, numerous dams are aging and will either need to be replaced or removed within the next few decades. Little is understood about the fate of carbon stored in sediments that become soil when a reservoir is drained due to dam removal. This study assessed the pool of carbon in the sediments of former Lake Mills and ...
Canopy soils, litterfall and litter decomposition in a coastal old-growth temperate rainforest, Washington
(2013-11-14)
The canopy of trees has been an unreachable portion for scientific exploration until few decades ago, and the wonders and enigmas that the treetops enclose are increasingly unfolding. This study investigated the canopy environment and its epiphytes on the formation of canopy soil, transfers of biomass and N to the ground and ...
Soil Carbon and Nitrogen Stocks: Underestimation with Common Sampling Methods, and Effects of Thinning and Fertilization Treatments in a Coastal Pacific Northwest Forest
Soil contains substantially more carbon (C) than the atmosphere and vegetation combined. Consequently, the fate of soil organic C (SOC) in response to changes in climate, land use, and management is of great concern. The ability to accurately quantify and compare SOC stocks over time is an important part of understanding ...
The Response of Soil Organic Carbon to Climate Change and Potential to Increase Carbon Sequestration in Soils through Management
As the largest terrestrial carbon pool, changes in soil carbon pools in response to climate change or management practices have the potential to significantly impact atmospheric CO2 concentrations. This dissertation examines the effects of climate change and two management strategies on soil carbon pools in order to understand ...
Nutrient cycling and wood chemistry of sinuous Douglas-fir stands across different genetic gain levels in western Washington
Stem sinuosity is a deformation which occurs in Douglas-fir and other tree species, which can be thought of as the displacement of the stem from its original direction over the total length of displacement. Nutritional deficiencies, such as those of copper, zinc, boron and calcium have been positively associated with increased ...
The Effects of Forest Harvesting and Land-Use Change on Soil Carbon and Nutrient Cycling
The properties and processes of deep soil horizons remain an important gap in knowledge due to the long history of shallow soil sampling. The majority of soil carbon and nitrogen can be found beneath the A horizon in most soils, particularly those deeper than one meter to bedrock. Such soils are common in many parts of the ...
Greenhouse gas flux in canopy soils and forest floor soils in coastal old-growth bigleaf maples in temperate rainforests of Western Washington
As a whole, forest ecosystems sequester carbon from the atmosphere and serve as an enormous pool for carbon storage in their soils and vegetation. As climate change accelerates due to the buildup of greenhouse gases (GHGs) in our atmosphere, it is increasingly important to understand how these carbon pools exchange GHGs with ...