Download or read book Soil Moisture and Season Effects on Nitrogen Transformation Rates in Seep Soils of Two Northern Hardwood Forests in Vermont written by Amninder Jit Kaur Kaur and published by . This book was released on 2009 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wet soils are generally assumed as nitrate sinks because of increased denitrification potential; however they may be acting as sources of nitrate. The complex nature of hydrology of a site could affect biological N cycling process in the soils. Soils in and around enriched groundwater seeps may be sources or sinks of nitrate, and this role may alternate with wetting and drying conditions.

Download or read book Temporal Patterns of Soil Nitrogen Transformation in Two Northern Hardwood Forest Ecosystems in Vermont written by Guinevere Fredriksen and published by . This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seasonal Patterns of Microbial Biomass and Nitrogen Mineralization in Northern Hardwood Forests written by William E. Holmes and published by . This book was released on 1993 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Causes and Consequences of Soil Resource Heterogeneity in a Transition Oak Northern Hardwood Forest written by Adrien Claude Finzi and published by . This book was released on 1996 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vermont Forestry Publications written by Vermont. Forest service and published by . This book was released on with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Nitrogen and Shosphorus Addition on Soil Respiration in Northern Hardwood Forests written by Shiyi Li and published by . This book was released on 2018 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil respiration - the CO2 efflux from the forest soil surface - is an important indicator of root and microbial activity and is sensitive to global changes such as climate warming, anthropogenic nitrogen deposition and elevated atmospheric CO2. I evaluated the response of total soil respiration (TSR) to changes in soil nutrient availability in temperate deciduous forests in New Hampshire. Low-level N (3 g/m2/year), P (1 g/m2/year) or N + P have been applied annually to thirteen northern hardwood stands of different age and site quality since 2011. My analysis of TSR for 2013, 2014, 2016, and 2017 confirmed the overall suppression effect of N addition across these stands (p

Download or read book The Effects of Excessive Moisture on Soil Carbon and Nitrogen Mineralization and Forest Productivity written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conifers of regenerating cedar-hemlock (CH) forests exhibit slow growth and nutrient deficiencies (N and P), which are not observed on adjacent cutovers of hemlock-amabilis fir (HA) forests. I test the theory that excessive moisture and resulting low oxygen availability in CH sites create the low N supply and poor growth in these ecosystems. A field experiment determined: 1) whether CH and HA forests differ in soil moisture and aeration, 2) whether decomposition rate and soil C stores differ in CH and HA forests, 3) whether composition of plant communities are related to soil moisture and aeration, and 4) the impact of harvesting CH and HA forests on moisture and aeration conditions. A laboratory experiment investigated the effects of moisture levels, from field capacity to saturation level, on C and N mineralization rates. Lastly, a field trial was carried out to assess drainage as a potential forest management solution in wetland forests by comparing C dynamics in drained and un-drained sites. As hypothesized, CH forests were wetter, less aerated, had shallower aerated depth and higher frequency of anaerobic conditions compared with HA forests. Composition of plant species was related to soil moisture and aeration, however plant diversity was not. Soil aeration was the most important factor, explaining 25% of the variability of species within plant communities. Compared with HA forests with well-aerated soils, soils in HA clearcuts were anaerobic, had slower decomposition rate and shallower rooting depth. Microbial biomass, C mineralization and the soluble inorganic N: soluble organic N (SIN:SON) ratio all declined under water-saturated conditions. Concentrations of SIN increased with increasing moisture in HA soils; whereas in CH humus and soil, the SIN pool was small and decreased with increasing moisture. The results indicate that the low N availability on CH sites results from synergistic effects of litter quality and greater frequency of waterlogging. Drainag.

Download or read book Impact of Winter Climate Change on Nutrient and Water Uptake in a Northern Forest Ecosystem written by Anne M. Socci and published by . This book was released on 2012 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Plants are significant drivers of ecosystem nutrient and water retention and loss, and plant responses to climate change could impact ecosystem function. Forests of the northeastern United States are projected to experience a shorter duration and a smaller depth of the winter snowpack over the next century, which is expected to lower soil temperatures and increase soil freezing. To determine the effects of a reduced snowpack and increased soil freezing on plant function, I conducted a two-year snow removal experiment at the Hubbard Brook Experimental Forest, New Hampshire. Prior to snow removal, to address challenges inherent to measuring fine root nutrient uptake and better understand seasonal uptake patterns, I measured rates of inorganic nitrogen uptake by fine roots of mature sugar maple ( Acer saccharum ) and red spruce (Picea rubens ) trees using two approaches. During each growing season following snow removal, I measured rates of nitrogen uptake and xylem sap flux density by mature sugar maple trees. Snow removal delayed the onset of a continuous snowpack and increased the depth and duration of soil frost, which persisted into the early growing season in both years. A smaller snowpack and increased soil frost reduced fine root nitrogen uptake by sugar maple during the early and mid-growing season, which overlapped with increased rates of soil nitrogen leaching in both years. Responses of sap flux density to snow removal were variable, and suggest that sugar maple trees may be able to compensate for impaired water uptake capacity during the early growing season such that there is little or no net effect on whole-season water uptake. Results of this dissertation provide direct evidence that reduced nitrogen uptake by plants is an important mechanism for reduced forest nitrogen retention following years of a reduced snowpack and increased soil frost. Impacts of winter climate change on water uptake by trees remain unclear. Results demonstrate that projected changes to winter climate in northern forests may impair the ability of plants to take up nitrogen and water, which could yield greater ecosystem nitrogen losses, an effect that is associated with nutrient imbalances in trees and acidification of streamwater.

Download or read book Bibliography of Agriculture written by and published by . This book was released on 1998 with total page 1960 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil Moisture Regime and Soil Water Balance Under Upland Hardwood Forest During a Period of Subnormal Precipitation written by Richard L. Harlan and published by . This book was released on 1967 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil Moisture Storage as Affected by Varying Intensities of Cutting in a Northern Hardwood Forest of the Adirondacks written by Edward Sisk Corbett and published by . This book was released on 1960 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plant and Microbial Mechanisms of Nitrogen Retention in Northern Hardwood Forests Receiving Atmospheric NO3 Deposition written by William C. Eddy and published by . This book was released on 2006 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Season and Site Conversion on Mineral Soil Nutrient Content in a Northern Hardwood Forest Ecosystem written by Kevin B. Fox and published by . This book was released on 1991 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Long term Forest Growth and Decadal Soil Chemistry Change Across the White Mountain National Forest written by and published by . This book was released on 2019 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This dissertation integrated forest ecology, soil science, and remote sensing methods to investigate the spatiotemporal relationships between forest growth and soil properties"--Page 14. The objectives of this dissertation were to 1) automate the delineation of bedrock outcrops and associated shallow soil; 2) investigate the relationship between topographic metrics as proxies for site quality with the predicted asymptote of stand relative density and biomass; and 3) quantify rates of soil chemistry change in northern hardwood forests across the White Mountain National Forest in New Hampshire and adjacent western Maine"--Page 26.

Download or read book Direct and Indirect Effects of Tree Species on Forest Nitrogen Retention in the Catskill Mountains New York written by Pamela Heather Templer and published by . This book was released on 2001 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this research was to understand the influence of tree species on nitrogen (N) retention and cycling within forests of the Catskill Mountains, NY. These forests receive some of the highest rates of N deposition in the northeastern United States and many watersheds are beginning to show signs of N saturation. However, watersheds vary in the amount of N export even though they receive approximately uniform amounts of N deposition. I hypothesized that tree species of the Catskill Mountains vary in their influence on forest N retention and loss. Results from a laboratory study (Chapter 1) show that while tree species influence soil microbial biomass and organic soil C:N, the variation in these two properties cannot explain differences in potential net mineralization, net nitrification, or microbial uptake of 15N. Therefore, properties other than microbial biomass and soil C:N need to be examined to understand the factors controlling microbial N transformations and potential retention in these forest soils. A greenhouse experiment (Chapter 2) shows that sugar maple and hemlock seedlings take up more NH4 + than NO3-, while beech seedlings take up more NO3- than NH4 +. Results from a 300-day field 15N experiment (Chapter 3) show that most of the N deposited onto forests is retained within the forest floor, but the magnitude of N retention varies among tree species. Sugar maple stands retain the least N, while red oak stands retain the most. The fertilized treatment shows that red oak stands are most likely to have the greatest decrease in N retention if availability increases in the future. These results suggest that sugar maple stands currently export significantly more N than the other forested stands and this can be explained by a combination of soil and plant processes. Sugar maples are not able to take up a significant amount of NO 3- the form of N that is produced in the largest amount in their stands and is most susceptible to leaching losses. Results from this study suggest that tree species composition can be a strong regulator of forest N retention, and differences among species may change depending upon N inputs.

Download or read book Understory Composition Seedling Growth and Snag Frequency Across a Water Limited Forest Landscape written by Tanvir Ahmed Shovon and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global change is expected to increase drought intensity and make precipitation more uncertain. These changes can affect forest plant communities directly by altering demographic rates, and indirectly through interspecific interactions. Impacts can vary among forest strata. Here, I asked how different forest strata respond to topographic variation in soil moisture and other resources across a water-limited landscape. The objective of the second chapter was to compare responses of understory plant communities to soil moisture, nitrogen, and light, and to understand whether responses to soil moisture depend on the latter two. I measured functional traits (individual-level plant characteristics) of understory vascular plants and modeled the composition and diversity of understory plant communities as functions of soil moisture, nitrogen, and light availability. I found that understory plant communities on nitrogen-poor soils were more sensitive to soil moisture changes than communities on nitrogen-rich soil. The effect of soil moisture did not depend on light availability, however. In my third chapter, I conducted a competition removal experiment on white spruce seedlings to examine how competition intensity varies with both above and below-ground resource availability. I found that local competition and resource availability both affect the growth of white spruce seedlings, especially during a dry summer, when competition had an additive effect on seedling growth and mortality. The objective of my fourth chapter was to determine how snag (standing dead tree) distribution is affected by individual- and stand-level biotic and abiotic variables. I used an unmanned aerial vehicle to collect images of forest canopies and determine the position and characteristics of individual live and dead trees. I found that individual-level competition and stand-level biotic and abiotic factors affect three northern tree species in different ways, but that topographic variation in soil moisture had little direct effect on the frequency of snags. Resource availability affects every forest stratum. The intensity and direction of the effects depend on the biotic and abiotic environments, including soil conditions, individual plant traits, and competition from neighbours. Environmental variation in competition needs to be considered when predicting changes to plant communities under climate change.

Download or read book Annual Meetings Abstracts written by American Society of Agronomy and published by . This book was released on 1999 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: