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691 Uppsatser om Wood density - Sida 1 av 47

En jämförande studie av fem lastbilsmonterade flishuggar

The study was carried out as a time study of five wood chippers placed on trucks,so?called huggbilar. They are trucks with built?in wood chipper, chip bowl and crane pulling a chip trailer. The system is used for chipping wood fuel, transporting, and delivering the chips to heating plants.

Pelletering av tallspån : grundläggande studier

Wood pellets are an upgraded product of residuals from several wood processing industries, for example saw mills and pulp industries. The pellets are produced by pressing the milled and dried sawdust to cylindrical units with a higher density than the initial raw material. Pellets have great benefits compared to the raw material: high energy per volume, good transport and storage properties and homogeneity. Several parameters collaborate in the whole process, which makes it complex. Wood is a heterogeneous material, chemically and structurally dependent on wood parts, habitat and storage procedures.

Productivity of integrated harvesting of pulpwood and energy wood in first commercial thinnings

The aim of this study was to quantify the productivity and the costs of different harvesting systems (teams), containing harvesters equipped with accumulating harvester heads and forwarders, in first commercial thinnings were an integrated harvest of pulpwood and energy wood were performed. In the beginning the plan was to study and measure 20 sites before and after harvest. Due to storms during the summer of 2010, complete data could only be obtained from 8 of these 20 sites. Seven of these sites were privately owned and one was owned by UPM, all of the sites had been pre-commercially thinned. The mean stem density before harvest was 2578 stems per ha and the mean stem volume was 0.074 m3solid over bark.On average 1518 stems/ha was harvested.

Tree species traits response to different canopy cover for 34 tree species in an enrichment planted tropical secondary rain forest in Sabah, Malaysia

Tropical rain forests only cover around six percent of the world?s land area and contain around 70 % of the world´s animals and plants. Tropical rainforests have been, and still are, negatively affected by human activities. These activities lead to forest degradation which has negative impacts on production and biodiversity. Between 1970-1980 forests in Borneo, Sabah, Malaysia, was subjected to intense logging.

Deadwood in piles or distributed : does it make any difference to saproxylic beetles?

Piles of deadwood are often retained in forests after management to support the biodiversity ofsaproxylic organisms which depend on deadwood to survive. Any knowledge about the crucial role ofpiles as suitable habitat of saproxylic organisms compared to single distributed deadwood objects thatare around the piles would help conservation actors to motivate more forest owners to supportsaproxylic organisms during their management. Therefore to give facts to this the saproxylic fauna ofdifferent pile positions (up and low) was studied and compared to distributed deadwood samplesaround each pile. Our study was focused on saproxylic beetles. Some other parameters such asdiameter, deadwood volume, pile volume and decay stage were assessed to define any effect.

Inverkan av nederbörd, temperatur och frost på årsringens egenskaper hos boreal tall (Pinus sylvestris L.) :

The wide distribution range of our boreal pine (Pinus sylvestris L.) provides a great variation in growing conditions and climate/weather factors that influence the wood development of the trees. A great number of extensive studies have been conducted over the years in order to clarify growth trends of this and other species over more or less wide-ranging areas. In this thesis effects of weather factors were instead compared between different forest stands from the about same geographical location. The effects of precipitation, temperature and frost on the year ring characteristics of pine were studied in the research forest of Svartberget Vindeln, in northern Sweden. The stands differed in site index and silvicultural treatment; fertile ? high stem density, fertile ? low stem density, poor ? high stem density and poor ? low stem density.

Utveckling av gran, Douglasgran, bok och tall under skärm av hybridlärk :

?Development of Norway spruce, Douglas fir beech and Scots pine with a larch shelter wood? is a report written by Per-Olof Magnusson. The thesis is a compulsory part of forest engineer program at ?Skogsmästarskolan?, SLU, Skinnskatteberg, Sweden. The purpose of this report is to describe and evaluate an experiment with hybrid larch (Larix x eurolepis) as shelter wood, and different tree species growth and survival depending on the density of the shelter wood. The experiment is conducted by southern Swedish forest research centre, faculty of forestry, SLU in Alnarp. The hybrid larch ought to be an interesting alternative to birch (Betula sp.) as shelterwood on suitable sites in southern Sweden.

Effekt på värdeutfallet av sågad vara vid övergång från 30 till 60 cm moduler : - en fallstudie av Moelven

The purpose of this study is to explain how the value of sawn wood changes when sawn wood are cut in 30 respective 60 cm lengths. The raw material into the saw mill will mainly be bucked in 30cm and 60 cm modules. There will also be two alternatives where the timber will be bucked special lengths, 370, 490 and 550 cm but also in 490 and 550 cm.The method used for the study is to simulate both cutting and sawing the woods. For cutting the simulator Timan is used and for sawing the simulator Timberopt is used. When data is generatedfrom the simulators, calculations of some key figures is done and also how much the revenue need to be increased for the sawn wood in order to cover for the increased costs of changing sawn woodfrom 30 cm to 60 cm modulesThe conclusion is that the single biggest reason, impacting the value of the sawn wood is the cutting at the saw mill.When going from 30 to 60 cm modules, the impact will be that the customers to the saw mill must pay more to increase the revenue by at least 10% for the sawn wood in order to justifice the changein production.It is also possible to increase the value of the products further by bucking the timber in three lengths, 370, 490 and 550 cm, in order to get 12 % increase of the share of longer sawn wood (>= 480 cm)..

Skogsbrandens påverkan på död ved :

Fire is an important ecological factor, but its consumption of coarse woody debris, CWD, has hardly received any attention. In this study, I investigate the consumption in relation to the time of initial flame exposure and propensity for continued combustion of standing CWD of pine (Pinus sylvestris). Two types of CWD were studied. Firstly, wood that had been dead for one to ten years. Secondly, wood that had been dead for several decades. In the burning experiments, logs of approx.

Trä som fasadmaterial ? behandling och beständighet

Since prehistoric time man has used wood to build their environment. The material?s availabilitycombined with its good mechanical properties has often made it the material of choice. Like allmaterials exposed to natures degradative processes the properties of wood decreases over time.Rot, UV radiation and attacks by insects and pests damage wood if not protected. Since we wantwhat we build to consist, optimizing our building materials durability is of great interest.Techniques and methods for increasing the endurance of wood have been developed in severaldifferent places and for a long time.

Epoxidised linseed oil as hydrophobic substance for wood protection : technology of treatment and properties of modified wood

Public concern about the release of toxic compounds from wood-based products drives legislation towards enforcing industries to find and use more sustainable solutions for wood treatment. Plant oils are good alternatives to treat wood, minimizing or even neutralizing the impact on the environment. Wood modification with epoxidised linseed oil (ELO) and acetic acid as catalyst has proven a suitable method to impregnate and protect wood. However, the mixture presents a serious inconvenience because of the quick polymerization of the ingredients that limits its practical application. Therefore, this study was designed to evaluate an alternative method using a two-step process which bypassed the problem above.

Visuell handelsortering av furu och gran

This essay concerns the visual trade grading of pine and spruce.In the 1800s developed rules for sorting of wood. The rules used to facilitate the export trade.The terms of the regulatory sorting systems developed in the 1900s. While it still used some of the older terms.The essay deals with how the grading rules affect the use of wood and how the rule work and how the terminology works.Some of the terms used for sorting are O/S, Kvinta, Utskott and A,B,C,D.You sorting by counting the numbers of knots, cracks and other characteristics of each piece of wood.The sawmills have much influence in how the rules developed.Today it is often already determined in the sawmills which uses each piece of wood most have..

Habitat preferences and reproductive success forthe threatened longhorn beetle Plagionotusdetritus

Plagionotus detritus is a threatend longhorn beetle that only exists at one site in Sweden. It is saproxylic and depending on recently dead coarse oak wood for its larval development. Trees at Djurgården, Stockholm that have been colonized by Plagionotus detritus has been studied to find out the habitat preferences of the species and to see what affects the density of beetles in a tree. The bark of some trees and wood from the breeding project at Nordens Ark has also been studied to find out what affects the species reproductive success. The reproductive success was measured in two ways, the larval mortality and the size of the hatching holes.

Betydelsen av skogsbruksplaner som verktyg vid anskaffning av virke

Forest management plans have been sold to private forest owners by wood supplying companies for a long time. These plans are considered to be effi-cient tools to identify measures and wood volumes, and are simply a starting point for discussions between private forest owners and round wood pur-chasers. However, large variations are observed between different purchas-ers, in their usage of the plans. The purpose of this report is to identify to what extent a forest management plan can promote an increase in the amount of wood which a round wood purchaser can obtain and to find differences in the way of using the plans between different wood purchasers. Furthermore, the purpose is also to ana-lyse if varying owner structures can be underlie variations in the selling of forest management plans. Qualitative interviews with nine of Stora Enso?s round wood purchasers were performed.

Stubbtransporter och bränslekvalitet hos stubbved :

Stump wood is a hot alternative when the heating plants demands more and more forest fuel. The aim with the study has bean to calculate the costs in four different systems for transportations of stump wood, examine if there are any differences in fuel quality for the stump wood in the different systems, analyse if the fuel quality in stump wood is affected with the time it lays by the road side and how much space the stump wood demands on the road side. To calculate the costs for the different systems a system analysis was carried out, where some of the costs were collected through field studies on Holmen Skog stump experiment and other costs were collected from literature and contacts. Data for the fuel quality study was collected from Eons heat plant in Norrköping. Data for the study of how much space stump wood takes along a roadside was collected from field studies.

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