
Sökresultat:
262 Uppsatser om Diameter - Sida 8 av 18
Förtolkat digitalt data till skogsägarplan
The purpose of this study is to investigate how to use remote sensing data when making a forest management plan. The main focus of the study is to compare different methods to identify forest stands of a forest property, and by manual measures and estimates try to evaluate the quality of interpreting data.
This report is based on survey questions sent to five different organizations working with remote sensing data. Only two of these where willing to participate in this investigation. The organizations where asked to analyze the same forest property and divide into compartments and make estimations of volume, basal area etc. in every stand.
Granproduktion på tallmarker! : är produktionen hållbar?
The aim of this report was to investigate the hypothesis that Norway spruce (Picea abies L. Karst), planted on poor ?Scots pine? stands will not have sustained growth during the whole rotation, due to water deficit in the closed stands. In order to investigate this hypothesis, data from 10 Norway spruce stands in southern-eastern Sweden were collected. In 10 plots in each stand, Diameter and breast heights were measured on every tree.
Uttag av energisortiment vid gallring av contorta, ett komplement till konventionell gallring? :
A recommendation for stand treatment of lodgepole pine (Pinus contorta) is, in a scientific point of view, lacking when it comes to harvesting for biomass energy. Within the next decades it is expected that 280 000 hectares of lodgepole pine will have reached thinning age on the domains of Svenska Cellulosa Aktiebolaget (SCA). Due to this the interest has grown rapidly for studying the possibilities of harvesting biofuel assortments already in the first thinning.
In this study the distribution of the biomass within lodgepole pine trees has been studied and taken into account for estimating the proportions of harvested assortments when using different methods of thinning. The methods studied were conventional biofuel-harvesting (with delimbed branches gathered separately from the round wood) and thinning with cutting of round wood and long tops (incl.
Skogsbränsleuttag vid förstagallring och dess påverkan på beståndsutveckling : simulering i Heureka med olika skötselprogram
Stands where pre commercial thinning has been ignored or inadequate often tend to have high stem density and low average Diameter when they reach heights of thinning. In such stands, it can often be expensive to do a conventional pulpwood harvest as a first thinning. This study investigates the development of the stands and the economic outcome of forest fuel extraction, or a combined harvest as alternatives to the ordinary pulpwood harvest. Simulations in Heureka StandWise were performed for two thin and dense stands, which were constructed by data from the Swedish National Forest Inventory. The simulations show that the extraction of forest fuel in first thinning at an early stage can provide higher net revenue compared to conventional pulpwood harvest at the same time or later.
Utvärdering av svensk vindkraft : Skillnaden mellan skogs- och traditionella placeringar
During the last years commercial Wind Power Turbines (WPT) has become larger regardingto the generator sizes and hub heights. Available hub heights around 100 meters is nowcommon, which has led to profitability for WPT located in forests where there normally are tolow wind speeds. The current knowledgement regarding turbulence and the variation in thewind profile for the outcome of the power production for the WPT in forests is limited.In this Master of Science thesis an investigation concerning forest located wind power plantshas been made. The purpose has been to investigate if plants located in forest perform lesscompared to wind power turbines located at more common locations.The analyses are based on statically material for determining the availability,production/generator size, production/hub height, production/swept area and how thetopography affect the production results.The analyses show that the variation in production result for WPT located in forest comparedto turbines located at other locations is small. The availability is high and the productionresults are good..
Mortalitet och skottskjutningsförmåga hos ek (Quercus robur) efter brand :
In this study I analysed how burning affects sprouting ability and survival of oak (Quercus robur) during the first season after a burn in southern Sweden. The study
consisted of two separate field tests; in the first, two 300 m2- plots in western oak
dominated forest were burned to analyze the fire behavior and the immediate mortality of oak and beech seedlings defined as individuals (> 20cm of height). At the end of the season almost 50% of the oak seedlings had resprouted while the beech seedlings had 100% mortality. An attempt to investigate the effect of the burn of artificially sown acorns was totally ruined by wild boar grouting before any conclusive results could be seen.
In the second test the resprouting ability of oaks of varying Diameters (average BHD 7-9 cm, range 2-42 cm) was examined one season after a prescribed burn in southeastern Sweden.
Stjälkröksvamp (Tulostoma brumale) : stora eller små individer?
The spatial population structure of the saprotrophic basidiomycete Tulostoma brumale was investigated at a site in south eastern Sweden. Sporocarps were mapped and collected, and somatic incompatibility tests between mycelial cultures cultivated from the sporocarps were used to identify genets. Calculations of the size and numbers of genets and their distribution were performed. The spatial distribution of the tested sporocarps and the identified genets are presented graphically in a grid. The total number of identified genets within the investigated area (1210 m2) was 27 based on 48 tested sporocarps.
Hur ska tall- och gran bestånd i Götaland gallras för att minska risken för vindskador?
With knowledge of how the southern Swedish forests have been affected by storms the past years, this study intended to find out which factors affect the storm firmness of a stand the most. The study was based on data from stands in the, by the storm Gudrun, affected area. The results of the analyses that tested the stand factors that influence the amount of storm damage to the greatest extent showed that the storm sensitivity of Norway spruce stands were largely due to previous management actions. The factors that could be controlled by thinning and had relevance of storm damage standpoint, according to the results were; the dominant height, volume, basal area weighted mean Diameter and stand age at last thinning. In this study, these results are not as clear for Scots pine.
Röjningsförbandets betydelse för avverkningsekonomin i södra Sverige :
The aim of this work is to demonstrate how the net present value (NPV) at the time of the first thinning depends on the spacing after pre-commercial thinning, and show how net value from first thinning in same stand is influenced.
This study is performed with models based on non-distant dependent growth models for single trees. Two different growth models have been used, one for cleaning (pre-commercial thinning) and one for thinning. The first one yields stem density distributed over Diameter classes. In the second one, (the thinning model), it is possible to choose when thinning should be done, the thinning method, thinning grade and numbers of thinning.
Maskinduglighet på planlaserskärare
Lars Höglund AB is one of Scandinavia?s most qualified manufacturers of sheet metal products and provides custom designed products of very detailed precision. One of the main methods of manufacturing is laser cutting. When Lars Höglund AB signed up a new customer, with high demands in tolerances for the products, Lars Höglund AB thought it would be necessary to know the capability of the laser cutting machine. Also the process of how to retrieve this capability was interesting. The capability will be researched for the following elements: Cutting right angles in squares with a corner radius of 1 mmCutting corners which are not right angleCutting of circles with constant radius Measurements were made on 150 pieces of sheet metal details, which had been cut out by the machine. The data from the measurements where later used to study the capability.
Effekter av Zeoliter i Biogasproduktion
Biogas är benämningen för metangas (CH4) som är producerad via anaerob (syrefri) rötning av biologiskt material. I Linköping finns en av Sveriges största biogasanläggningar. Anläggningen drivs av Svensk Biogas AB som ägs av Tekniska Verken i Linköping AB (publ.). I anläggningen rötas stora mängder proteinrikt substrat vilket leder till höga halter av ammoniak (NH3) och ammonium (NH4+) i rötkammaren. Ammoniak (NH3) är toxiskt för de metanbildare som i en välmående process står för den största delen av metangasproduktionen.
Utbytesprognoser av rotstående skog : en studie av ett datasystem för apteringssimulering samt prov att generera prognoser för tillämpning i produktionsplanering vid skogsförvaltning och sågverk
Inom den svenska sågverksindustrin pågår idag en omdaningsprocess, i syfte att öka graden
av kundorderstyrd produktion. Detta medför ökade krav på sågverkens förhandsinformation
om råvarans beskaffenhet, med avseende på tirorets fördelning i Diameter, längd och kvalitet.
Ett sätt att skaffa denna information kan vara att simulera apteringen för de planerade
avverkningama.
Syftet med denna studie har varit att belysa vilken inverkan styrparametrar och omfattning på
indata har för prognosresultatet vid simulerad aptering. Ett datasystem ,BASS-BEST!UPR,
användes vid apteringssimuleringen för att generera utbytesprognoser av rotstående skog.
Analys av individinriktad ekskogsskötsel i Blekinge : en metod för tillämpning i ett kontinuitetsskogsbruk?
Ett ökat brukande av skog enligt skötselprinciper som leder till skiktade beståndsstrukturer, en blandad trädslagssammansättning och kontinuerligt skogbeklädd mark har potential att öka den biologiska mångfalden och värdet för rekreation (Emborg m.fl. 2000, Berg m.fl. 1995, Mattsson & Li 1994, Holgen m.fl. 2000). I ljuset av detta, tillsammans med svårigheterna som finns att nå goda ekonomiska resultat vid skötsel av ädellövskog (Lindén & Ekö 2002), ses det idag som angeläget att uppmärksamma och studera alternativa skogsskötselmetoder (Cedergren 2008) .
I östra Blekinge har ett antal skogsägare under längre tid praktiserat en metod att sköta naturligt föryngrad ek i blandbestånd som går ut på att, mer eller mindre tidigt, frihugga ekhuvudstammar, och att dana kvalitet genom stamkvistning/beskärning.
Experimentell studie av det mekaniska beteendet hos upphängningskrokar för pulvermålning.
Törestorps Tråd AB är ett företag vars viktigaste produkt är engångskrokar för användning vid pulvermålning av olika detaljer t.ex. inom bilindustrin. För att öka kunskapen om hur olika parametrar påverkar krokarnas mekaniska beteende har dragtester utförts. Dessa tester har utförts med hjälp av en dragprovmaskin och en ugn.För att se vad som händer när konsumenterna avlägsnar färgen på krokarna som uppkommer vid pulvermålning, har krokarna utsatts för värmning i 450°C resp. 600°C, i båda fallen under tiderna 30 resp.
En studie av produktionen i praktiska poppelplanteringar i södra Sverige
Informationen om vad poppel producerar i praktiska planteringar i södra Sverige är begränsad. De data som finns kommer ofta från SLU och Skogforsks försöksytor. Försöksytor är mer omsorgsfullt skötta jämfört med praktiska planteringar. Finns alltså en risk för överdriven optimism om trädslagets produktion. Det behövs därför undersökningar som visar vad poppeln producerar i praktiska planteringar.
Motiven för att plantera poppel är flera, bland annat kort omloppstid, hög tillväxt och ökande priser på energived.