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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Retained Woody Structure In 1-Year-Old Loblolly Pine Plantations In Mississippi, Louisiana, And Arkansas

Neu, Justin 09 December 2011 (has links)
I evaluated effects of 4 common site preparation techniques on residual structure while comparing 2 techniques commonly used to estimate CWD volume in Southeast loblolly pine (Pinus taeda) commercial pine plantations in 2 ecoprovinces. The strip plot method (SPM) estimated greater volume than the line intercept method (LIM; 9.7 m3/ha and 11.4 m3/ha respectively). The SPM had lesser volume estimate variability and appears more appropriate for the Southeast. Mechanical sites had the greatest densities of green trees and fewest snag retention and overall were least decayed. Chemical preparation combinations had lesser green tree densities but greater snag densities. Piled CWD volumes were greatest in mechanical treatments and least in chemical plus burn treatments. The Outer Coastal Plain Mixed Forest Ecoprovince had 20% less volume than the Southeastern Mixed Forest Ecoprovince. Chemical plus burn site preparations had the least densities of remnant trees, snags, piled and individual CWD pieces.
12

Social and Ecological Aspects of Managing Wildlife in Fire-dependent Forested Ecosystems

Weiss, Shelby A. 26 October 2017 (has links)
No description available.
13

Metoder för att undersöka effekterna av naturvårdshänsynen i skogsbruket efter den nya skogsvårdslagen / Methods for studying effects of nature consideration in forest management after the new forestry act

Eneland, Anna January 2010 (has links)
<p>Detta arbete har undersökt skillnaderna mellan den nuvarande skogsvårdslagen och den föregående. Undersökningen har bestått av två delar, där ena delen är en litteraturstudie av lagarna och den andra är en fältstudie av metoder för att mäta naturhänsynsförändring. Som komplement till fältstudien har en litteraturstudie av undersökningsparametranas naturvårdsnytta. Litteraturstudien av lagarna gick till på följande sätt, inledningen av båda lagarna och hänsynsparagraferna har lästs och jämförts. Fältstudie har gjorts efter metoder som har arbetats fram och sedan testats i fält. De undersökningsområden som har testats är stående död ved med undergruppen konstgjorda högstubbar, grova träd, hänsynsytor, trädslagsfördelning och boträd. Testningen skedde i trakterna kring Orsa i Dalarnas län. Resultatet blev att hälften av undersökningsområdena skulle kunna användas i en större studie efter några modifikationer. Andra hälften av undersökningsområdena kan det inte på grund av att referensdata saknas. Lagstudien visade att den största skillnaden mellan de båda lagarna ligger i att i den nuvarande har man jämställt miljömålet med produktionsmålet. Det finns även en attitydförändring till en större öppenhet mot naturvård i den nya lagen.</p> / <p>This work has examined the difference between the new forestry actand the previous one. The research has been divided in two parts, one is a literature study of the law and the other is a field study of methods for measuring the change in consideration of nature. As compliment too the field study a literature study of the research parameters nature conservation benefits. The examine of the laws were done in this way, the introduction of the laws and the nature conservation paragraphs were read and compared. For the field study methods have been worked out and tested in the field. The research parameters that have been tested are standing dead wood with subgroup man made snags, thick trees, consideration of nature areas, distribution of tree species and nesting trees. The field testing were made in the neighboring forest of the city Orsa in the administrative province of Dalarna.The results of the field methods are that half of the methods have a possible use in a larger study with some modifications. The other half are missing references data to be useful.The biggest differences between the laws are that in new law the goals for production and environment care are equal. There is also an change in attitude towards greater consideration of nature.</p>
14

Examination of airborne discrete-return lidar in prediction and identification of unique forest attributes

Wing, Brian M. 08 June 2012 (has links)
Airborne discrete-return lidar is an active remote sensing technology capable of obtaining accurate, fine-resolution three-dimensional measurements over large areas. Discrete-return lidar data produce three-dimensional object characterizations in the form of point clouds defined by precise x, y and z coordinates. The data also provide intensity values for each point that help quantify the reflectance and surface properties of intersected objects. These data features have proven to be useful for the characterization of many important forest attributes, such as standing tree biomass, height, density, and canopy cover, with new applications for the data currently accelerating. This dissertation explores three new applications for airborne discrete-return lidar data. The first application uses lidar-derived metrics to predict understory vegetation cover, which has been a difficult metric to predict using traditional explanatory variables. A new airborne lidar-derived metric, understory lidar cover density, created by filtering understory lidar points using intensity values, increased the coefficient of variation (R²) from non-lidar understory vegetation cover estimation models from 0.2-0.45 to 0.7-0.8. The method presented in this chapter provides the ability to accurately quantify understory vegetation cover (± 22%) at fine spatial resolutions over entire landscapes within the interior ponderosa pine forest type. In the second application, a new method for quantifying and locating snags using airborne discrete-return lidar is presented. The importance of snags in forest ecosystems and the inherent difficulties associated with their quantification has been well documented. A new semi-automated method using both 2D and 3D local-area lidar point filters focused on individual point spatial location and intensity information is used to identify points associated with snags and eliminate points associated with live trees. The end result is a stem map of individual snags across the landscape with height estimates for each snag. The overall detection rate for snags DBH ≥ 38 cm was 70.6% (standard error: ± 2.7%), with low commission error rates. This information can be used to: analyze the spatial distribution of snags over entire landscapes, provide a better understanding of wildlife snag use dynamics, create accurate snag density estimates, and assess achievement and usefulness of snag stocking standard requirements. In the third application, live above-ground biomass prediction models are created using three separate sets of lidar-derived metrics. Models are then compared using both model selection statistics and cross-validation. The three sets of lidar-derived metrics used in the study were: 1) a 'traditional' set created using the entire plot point cloud, 2) a 'live-tree' set created using a plot point cloud where points associated with dead trees were removed, and 3) a 'vegetation-intensity' set created using a plot point cloud containing points meeting predetermined intensity value criteria. The models using live-tree lidar-derived metrics produced the best results, reducing prediction variability by 4.3% over the traditional set in plots containing filtered dead tree points. The methods developed and presented for all three applications displayed promise in prediction or identification of unique forest attributes, improving our ability to quantify and characterize understory vegetation cover, snags, and live above ground biomass. This information can be used to provide useful information for forest management decisions and improve our understanding of forest ecosystem dynamics. Intensity information was useful for filtering point clouds and identifying lidar points associated with unique forest attributes (e.g., understory components, live and dead trees). These intensity filtering methods provide an enhanced framework for analyzing airborne lidar data in forest ecosystem applications. / Graduation date: 2013
15

Metoder för att undersöka effekterna av naturvårdshänsynen i skogsbruket efter den nya skogsvårdslagen / Methods for studying effects of nature consideration in forest management after the new forestry act

Eneland, Anna January 2010 (has links)
Detta arbete har undersökt skillnaderna mellan den nuvarande skogsvårdslagen och den föregående. Undersökningen har bestått av två delar, där ena delen är en litteraturstudie av lagarna och den andra är en fältstudie av metoder för att mäta naturhänsynsförändring. Som komplement till fältstudien har en litteraturstudie av undersökningsparametranas naturvårdsnytta. Litteraturstudien av lagarna gick till på följande sätt, inledningen av båda lagarna och hänsynsparagraferna har lästs och jämförts. Fältstudie har gjorts efter metoder som har arbetats fram och sedan testats i fält. De undersökningsområden som har testats är stående död ved med undergruppen konstgjorda högstubbar, grova träd, hänsynsytor, trädslagsfördelning och boträd. Testningen skedde i trakterna kring Orsa i Dalarnas län. Resultatet blev att hälften av undersökningsområdena skulle kunna användas i en större studie efter några modifikationer. Andra hälften av undersökningsområdena kan det inte på grund av att referensdata saknas. Lagstudien visade att den största skillnaden mellan de båda lagarna ligger i att i den nuvarande har man jämställt miljömålet med produktionsmålet. Det finns även en attitydförändring till en större öppenhet mot naturvård i den nya lagen. / This work has examined the difference between the new forestry actand the previous one. The research has been divided in two parts, one is a literature study of the law and the other is a field study of methods for measuring the change in consideration of nature. As compliment too the field study a literature study of the research parameters nature conservation benefits. The examine of the laws were done in this way, the introduction of the laws and the nature conservation paragraphs were read and compared. For the field study methods have been worked out and tested in the field. The research parameters that have been tested are standing dead wood with subgroup man made snags, thick trees, consideration of nature areas, distribution of tree species and nesting trees. The field testing were made in the neighboring forest of the city Orsa in the administrative province of Dalarna.The results of the field methods are that half of the methods have a possible use in a larger study with some modifications. The other half are missing references data to be useful.The biggest differences between the laws are that in new law the goals for production and environment care are equal. There is also an change in attitude towards greater consideration of nature.
16

Cavity Presence in Snags Created Using Two Techniques in the Huron-Manistee National Forest

Nadler, Madison January 2020 (has links)
No description available.

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