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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.
21

If a Tree Falls in the Forest - Three Interventions in the Swedish Forest to Come

Chigot Eriksson, Nils, Thysell, Hampus January 2023 (has links)
Our thesis project consists of three architectural interventions: The Mushroom, The Gnat and The Snake, fitting into a vision of a Swedish forest managed in a more sustainable way. A future in which the practice of clear-felling has been abandoned in favor of alternative methods falling under the umbrella term Continuous Cover Forestry (CCF). As the biological aspects of forestry is not our area of expertise, we have investigated what this reorganization at large would mean for the Swedish landscape, economy and society. Where it becomes a question for architecture. When the timber industry looses its hegemony over the forest, the forest becomes available to different uses. For life and recreation, and for the production of forest goods other than timber, such as wild game meat, berries, and mushrooms. These activities are able to take place within the same space as forestry, thereby overcoming the spatial separation of functions we see today. Our interventions work by docking onto different points of today’s logistics flow, in order to later replace them. They take into account more of the different values and users of the forest which we have identified. The project follows the flow of goods from the forest as they make their way towards the larger markets. The Mushroom is an outpost in the middle of the productive forest which supplies the surrounding area with the necessary infrastructure in order to extract goods from it, doubling as a recreational dwelling. One of these can be placed every 30 km. The Gnat is a tower structure containing multiple different functions ranging from marking the pick-up spot for the harvested timber, functioning as a hunting tower, shelter and storage. Many of them are placed along forest roads. The Snake is a local processing plant managing small-scale refinement of the goods of the forest close to their site of harvest, thus channeling some of the economical flow back to the communities living of the forest. Together they form a complete series of infrastructure demonstrating how we could organize the future Swedish forest.
22

Effect of upper stem diameter and errors of measurement on the accuracy of volume equations

Ngong, Fonweban John 29 November 2012 (has links)
Measurements of DBH, upper diameters, merchantable height and total heights were made on 80 standing white oaks (<i>Quercus alba</i>) which were then felled for detailed measurements of the same parameters. The data obtained were used to evaluate the accuracy of standing tree measurements, to develop and compare volume equations that used upper diameter as one of the predictor variables and to examine the contributions of individual predictor variables to total volume prediction bias and precision. Relative bias ranged from 0.85% for DBH measurement errors to 2.88% for total height measurement errors. Relative standard deviation ranged from 1.52% to 10.13% for DBH and total height errors respectively. When both bias and precision ( standard deviation ) were considered jointly, the relative root mean squared error ranged from 1.75% to 10.48% for DBH and total height errors respectively. Upper diameter and merchantable height showed negative bias. A comparison of eight fitted models against the combined variable model revealed a gain in precision and a reduction in bias for models that used upper diameter as a third predictor variable. The improvement as based on the relative root mean squared error ranged from 28.8% to 71.3% for taped measurements. However, models that used upper diameter as a substitute for either DBH or merchantable height performed worse than the combined variable model. An analytic examination of the impact of measurement error on volume prediction bias showed that merchantable height errors accounted for most of the bias and that DBH and upper diameter errors contributed almost equal amounts(in absolute terms) to the volume bias. / Master of Science
23

Ecological effects of the feeding and construction activities of the Eurasian beaver (Castor fiber) in Scotland : implications for reintroduction

Jones, Kevin Christopher January 2006 (has links)
Beavers have been described as a “keystone species” and “ecosystem engineers”, and in this dual role have great potential to physically modify their environment through tree-felling, foraging and construction activities. The resultant change in habitat heterogeneity can affect the flora and fauna that share the habitat with them. There has been recent interest in reintroducing the Eurasian beaver to the United Kingdom after an absence of over 400 years. To date, no research (aside from this thesis) has focussed on beaver ecology and behaviour in Scotland. This study has investigated the ecological effects of a small number of beavers in two enclosed but semi-natural Scottish sites at Bamff in Perthshire. The research conducted over a three-year period, with particular emphasis on the effects of tree-felling, foraging and construction activities. Trees were felled for both dietary and construction purposes, with felling rates being influenced by habitat availability, quality and the degree of habitat modification required. Highest rates were evident during the initial colonisation period of marginal sites (c. >300 trees / beaver / calendar year), and lowest rates in later years of occupation of more optimal sites (c. 55 – 70 trees / beaver / calendar year). Preferences were generally for willow and aspen trees, with conifers almost entirely avoided, and smaller trees preferred over larger ones. Proximity of trees to waterbodies was also an important factor, with nearer trees favoured, and generally most felling occurred within 50 m of water. Such behaviour followed the principles of optimal central place foraging. These preferences were less predictable however when intense construction activity was undertaken, with larger trees preferred and generic preferences for deciduous trees apparently invalid. In such cases, close proximity to the construction site was of prime importance. Increased cover of herbaceous plant species was observed in beaver-created canopy gaps in riparian woodland, whilst macrophyte diversity within waterbodies increased slightly in areas of herbaceous grazing. The diversity of terrestrial ground invertebrates was highest in areas of heavy tree-felling, and invertebrate richness and abundance was greatest in areas of herbaceous grazing under an intact tree-canopy. Furthermore, the abundance, diversity and richness of macroinvertebrate communities were increased by beaver-generated woody debris in ponds and streams. Overall, 30% of all macroinvertebrate species collected were found only in beaver-affected areas, due to the refugia and food supply provided by beaver dams, caches and lodges, as well as hydrological effects of these structures. These results are discussed with reference to future plans to return the beaver to Scotland. The habitat usage and modification of riparian ecosystems in northern Britain is likely to be similar to that found in this study, and the results are believed to be relevant, applicable and transferable to many areas of Scotland.
24

ANALYSIS OF OLDER FARMER WORK-RELATED FATALITIES IN INDIANA WITH APPLICATION OF FINDINGS TO INJURY PREVENTION EFFORTS

Sean A Tormoehlen (7441232) 17 October 2019 (has links)
<p><a>The primary goal of this research was to summarize the occupational farm-related fatalities of Indiana farmers 55 years and older and to recommend evidence-based intervention strategies targeting older farmers who perform activities that involve the cutting and trimming of trees. The primary activities consisted of (1) preparing a summary of occupational farm-related fatalities of farmers who were 55 years and older, (2) preparing a summary of occupational farm-related fatalities of older farmers who were performing activities in a woodlot setting or that included the occasional cutting and trimming of trees, and finally (3) the development of recommendations for evidence-based injury prevention strategies targeting older farmers who conduct occasional woodcutting activities. </a></p> <p>The summary of older Indiana farmer fatalities identified a total of 388 fatalities reported between 1988 and 2017 with an increase in the number of reported fatalities over the period of 2012-2017. Tractors were identified as the most common source of injury (40.5%) with tractor overturns involved in no fewer than 86 cases or 22.2% of all cases. Older farmer fatalities for occasional woodcutters accounted for 40 fatalities with the cutting and trimming of trees to be the most common cause of injury (67.5%). </p> <p>Core desired safety competencies were identified that were used to develop injury prevention strategies based upon the summary of injuries, areas of concerns reported in the review of literature and the results gathered from the summaries of Indiana older farmers killed while performing woodcutting activities. A pilot evidence-based intervention instructional presentation was developed with the assistance of a panel of experts to be used by Extension Educators to increase awareness of the target population of current safety practices relating to woodlot activities. </p>
25

Conservation and yield aspects of old European aspen Populus tremula L. in Swedish forestry /

Hazell, Per, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
26

Optimization of forest management decision making under conditions of risk /

Lu, Fadian, January 2004 (has links) (PDF)
Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
27

Long term changes in stand structure and biomass production in short rotation willow coppice /

Nordh, Nils-Erik, January 2005 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.
28

Regeneration under shelterwood : control of environmental factors /

Erefur, Charlotta, January 2007 (has links) (PDF)
Lic.-avh. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2007. / Härtill 2 uppsatser.
29

Forest policy, continuous tree cover forest and uneven-aged forest management in Sweden's boreal forest /

Axelsson, Robert, January 2008 (has links) (PDF)
Lic.-avh. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 2 uppsatser.
30

The use of time study, method study and GPS tracking in improving operational harvest planning in terms of system productivity and costs

Odhiambo, Benedict O. 12 1900 (has links)
Thesis (MScFor (Dept. of Forest and Wood Science)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This study aims to quantify the benefits of implementing an operational harvesting plan in forest harvesting operations. This is to be achieved by comparing productivity and costs from unplanned and planned harvesting operations. The study was conducted on a Pinus radiata plantation owned by Mountain to Ocean Forestry Company (Pty) Ltd (MTO) located near the town of Grabouw in the Western Cape Province of South Africa. MTO conducts harvesting operations using semi-mechanised tree-length harvesting systems. A wheeled H67 Clark Ranger cable skidder is used to extract tree-lengths from infield to the landing. Data was obtained both manually (work study) and from GPS tracking. Choking and dechoking data was obtained through time and method studies. GPS tracking was used to measure travel loaded and travel empty times, as well as travel distances and travel speeds. The aim of using both manual techniques and GPS tracking was to obtain detailed and spatially accurate information about the operation. The operating costs were estimated using South African Harvesting and Transport Costing Model. Productivity of the newly introduced tagline system (45.97 m³/pmh) exceeded that of mainline system (37.85 m³/pmhh) by 26%. The unit production cost of using tagline system (R20.21/m³) was 10% lower than the unit production cost of using mainline system (R22.54/³3). There were no benefits to be gained from improving the level of skid trail construction by removal of logging residue or cutting down stumps to as near the ground level as possible. A combination of manual (time and method studies) data collection and GPS tracking provided more detailed and accurate information on the semi-mechanised harvesting system. / AFRKAANSE OPSOMMING: Hierdie studie beoog om die voordele van die uitvoering van 'n operasionele inoestingsplan te kwantifiseer. Dit word bereik deur produktiwiteit en kostes van beplande en onbeplande inoestingswerksaamhede te vergelyk. Die studie is gedoen in Pinus radiata opstande van Mountain to Ocean Forestry Company (Pty) Ltd (MTO) naby Grabouw in die Wes-Kaap provinsie van Suid Afrika. MTO gebruik semi-gemeganiseerde boomlengte inoestingstelsels in hul inoestingswerksaamhede. . H67 Clark Ranger wielsleeptrekker met kabel en wenas is gebruik om boomlengtes van die veld na die pad te sleep. Data is versamel deur van beide hand (werkstudie) en GPS-opsporing gebruik te maak. Afhaak en aanhaak data is verkry deur van tyd- en metodestudies gebruik te maak. Gelaaide en ongelaaide tyd, spoed en afstande is met behulp van die GPS gemeet. Deur van beide hand en GPS versamelingsmetodes gebruik te maak, kon omvattende sowel as ruimtelik akkurate inligting oor die werksaamhede verkry word. Die bedryfskostes is verkry van die South African Harvesting and Transport Costing Model. Produktiwiteit van die nuut ingestelde verbindingslynstelsel (45.97 m³/pmh) het die hooflynstelsel (37.85 m³/pmh) met 26% oorskry. Die eenheidsproduksiekoste van die verbindingslynstelsel (R20.21/m³) was 10% laer as die eenheidsproduksiekoste van die hooflynstelsel (R22.54/m³). Daar was geen voordeel in die verbetering van die sleeppad konstruksie deur afval te verwyder of stompe nader aan die grondvlak af te sny nie. 'n Kombinasie van hand (tyd- en metodestudies) dataversameling en GPS-opsporing het meer akkurate en omvattende inligting oor die semi-gemeganiseerde inoestingstelsel verskaf.

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