The physical controls of snowmelt in the Pacific Northwest (PNW) are poorly
understood. While there have been numerous field and modeling investigations at the
plot and watershed scale, few studies have identified how the snow energy balance
(EB) components vary in importance both spatially and temporally. The identification
of how...
The age, or residence time of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways and source of water in a single integrated measure. While there has been tremendous recent interest in residence time to characterize catchments, there are few studies that quantify residence...
The arthropod community in a Douglas-fir forest near Blue River, Lane County, Oregon was investigated from March through August 1973. Five stands of Douglas-fir were sampled: two clearcuttings, a young-growth
(20 years old), a midgrowth (125 years old), and an old-growth (450 years old) plot. A pole pruner was used...
Montane meadows in the western Cascades of Oregon occupy approximately 5% of the landscape, but contribute greatly to the region's biodiversity. Western Cascades meadows are dynamic parts of the landscape and have contracted by over 50% in the past two hundred years in the HJ Andrews Experimental Forest (hereafter Andrews...
Nineteen l/4-hectare reference stands have been established in the central western Cascade Mountains of Oregon to represent widespread and important portions of the vegetation continuum. Their species diversity, cover, and structure are described here. The stands provide points of reference for visiting scientists and researchers who wish to design experiments...
Bioassays using red alder and snowbrush plants grown in soils collected
from a clearcut, a young Douglas-fir plantation, and an old-growth stand were
conducted. Sites are located at the Andrews Experimental Forest, Oregon. In
the first bioassays, more alder than snowbrush plants survived and nodulated.
Of the plants that survived,...
Ectomycorrhizal fungi (EmF) form symbioses with trees. These symbioses profoundly influence forest ecology. Certain EmF form specialized profusions of hyphae, known as ectomycorrhizal fungal mats (mats) which are visible to the naked eye, alter forest soil biogeochemistry, substantially contribute to soil microbial biomass/respiration and support unique microbial communities. Piloderma and...
A biological inventory of the butterflies of the H. J. Andrews Experimental Forest [HJA] in Linn/Lane County, Oregon was conducted during 1994 and 1995. It was the first comprehensive survey of HJA butterflies for the site and serves as a baseline for future butterfly research. A detailed ecological account is...
In recent years considerable interest has been shown in the diversity of ammonia-oxidizing bacteria in soil communities. The majority of the research has been carried out in Northern Europe where soils have received high atmospheric inputs of nitrogen over the past two centuries. In contrast, although much work has been...
Windthrow has been studied extensively as a cause of mortality and as a landscape
disturbance agent in temperate forests throughout the United States. The effects of
windthrow mortality on stand species composition and structure, forest regeneration and
seral development have been well described at the site (e.g. single gap) and...
The links between forests, streamflow, and climate are poorly understood. Despite hundreds of studies over the past 60 years, fundamental questions of forests' effects on the hydrologic cycle remain unanswered. The hydrological cycle involves mutually-dependent biological and physical processes that operate at multiple scales of time and space, and this...
This study investigated carbon dynamics in the hyporheic zone of a steep, forested catchment in the Cascade Mountains of western Oregon, USA. Water samples were collected monthly from a headwater stream and well network during baseflow conditions from July to December 2013 and again in March 2014. We also sampled...
For management purposes, it would be useful to be able to predict streamflow response to forest practices in small, unmonitored basins. The primary objective of this study is to investigate the influence of early successional vegetation on summer streamflow levels. The long-term data records from watershed 1 at the H.J....
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing downstream reaches with important constituents such as sediment and woody debris. Small headwater streams are particularly susceptible to...
Soil dissolved organic carbon (DOC) is a small but crucial part of the forest carbon cycle. Characterizing the relationship between detrital inputs and soil DOC chemistry is crucial to understanding the ultimate fate of root carbon, fallen wood and needles. Chemical differences in the DOC pool may help to explain...
Despite advances in the understanding of rain-on-snow storms and their resulting peak flows, little is understood about the response of snowmelt to precipitation and the relative timing of the two at multiple temporal scales within such events. To address this issue, climate, snowmelt, and streamflow data were analyzed for 26...
Montane meadows in the Cascade Range of Oregon have been declining due to tree establishment since records began. Montane meadow complexes in the H.J. Andrews Experimental Forest shrank by 60 to 75% from 1949 to 2005, but fine scale temporal and spatial processes of tree establishment in these meadows are...
The link between aboveground net primary productivity (ANPP) and resource gradients generated by complex terrain (solar radiation, nutrients, and moisture) has been established in the literature. Belowground ecosystem stocks and functions, such as soil organic carbon (SOC), dissolved organic carbon (DOC), and belowground productivity have also been related to the...