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8 Uppsatser om Taper - Sida 1 av 1

Röjningsformen och stamantalets effekt på höjd- och diametertillväxt i toppröjda och konventionellt röjda tallbestånd.

Topping is a precommercial thinning (PCT) method where secondary stems are cut higher above the ground compared to conventional PCT. The secondary stems continue to live for a period and are supposed to compete with the main stems and promote their quality.The objective of the study was to compare the effect of PCT on height and diameter growth between topping and conventional PCT. The study also analysed the relationship between height and diameter growth and the number of stems after PCT.Nine topped stands and six conventional precommercially thinned stands were visited between February 28th and March 5. One sample plot per hectare was laid out in the investigated stands. In every sample plot the number of stems was counted and five main stems were measured for height, height growth since PCT, diameter and diameter growth since PCT.The results showed significantly higher effect on height growth after topping as compared to conventional PCT but no significant difference in the effect of diameter growth between topping and conventional PCT.

Volume and taper equations for Sitka spruce (Picea sitchensis (Bong.) Carr.), Norway spruce (Picea abies (L.) Karst.) and White spruce (Picea glauca (Moench) Voss) in Iceland

The aim of this study was to evaluate different types of volume and Taper equations that can be used to predict single-tree stem volume and stem diameter at any given height along the tree stem for plantation grown Sitka spruce (Picea sitchensis (Bong.) Carr.), Norway spruce (Picea abies (L.) Karst) and White spruce (Picea glauca (Mounch) Voss) in Iceland. A number of published tree volume equations were tested and modified to predict the total stem volumes over bark but three logarithmic equations were taken for more in-depth analysis. Three Taper equations were tested. Two variable-exponent equations (Kozak 1997, Kozak 2004) and one exponential equation described by Biging (1984). Data from a total of 617 sample trees were used in this study, collected from stands in various parts of the country and present different types of stands growing in different soil types and cover most of the site conditions suitable for forestry in Iceland.

En jämförelse mellan två datorprogram för utbytesberäkningar :

This thesis is made on behalf of SCA's Forestry Division and is a comparison of two bucking simulation tools: Aptan (manufactured by Skogforsk) and Best/upr (from Berget Systemdesign). The data is based on 32 stands from SCA's forests in Norrbotten and Västerbotten. The objective is to compare the simulations created by the tools with the harvested volumes from those stands. Three variables are needed for the bucking simulation; these are the diameter distribution (at breast height), the relationship function between diameter and height, and the Taper coefficients. The volumes of five different assortments from the stands are compared.

Planteringsförbandets betydelse för kvalitetsegenskaper i Contortatall (Pinus contorta var. latifolia)

In Sweden, large scale planting of Lodgepole pine (Pinus contorta var. latifolia) started in the beginning of the 1970?s. At first, the aim was production of pulpwood, but later, also production of timber became considered realistic. Today, Sweden has more than 520 000 ha of Lodgepole pine.

Prislisteoptimering för ett sågverk - Jarlträ AB :

This report is a thesis work for a B.Sc. in Forestry at the School for Forest Engineers, SLU. The work was an assignment from Jarlträ AB which is a privately owned sawmill located in southern Småland. The aim of the work was to investigate the economical result of different pricelists and how to adjust different parameters such as length correction to give an optimal result. The pricelists was examined through a computer program (SilviA). The pricelists was made in the program and after that a simulation was preformed with a selection of random sampled trees gathered from the area nearby the sawmill.

Kvalitetsprocesser och mätning av pinnfräsar : ? Empirisk studie av produktionsmätutrustning vid frästillverkning

This master thesis investigates quality procedures and measuring of solid carbide end mills, with the main focus on measuring equipment. The thesis has been written in collaboration with a special production department for solid carbide end mills at Sandvik Coromant in Gimo. The department?s needs and constraints have been the foundation of the project and the main research question is: how to measure end mills in order to ensure good quality of the produced end mills. The project has contained both a theoretical study consisting of a literature review and practical studies in the workshop with the objective to identify an end mill?s main parameters and the relationship between an end mill?s geometry and the manufacturing processes.

Förbättrat råvaruutnyttjande vid kvalitets-sortering av timmer : utvärdering av analysprogrammet Stockholmen för automatiserad timmersortering i dimensions- och kvalitetsklasser hos BARO WOOD AB

The aim of this thesis was to analyse BARO WOOD AB:s timber measuring and quality sorting and to evaluate the analyse program Stockholmen. The purpose was to get a better understanding for the quality sorting made at BARO WOOD AB today, analyse differences in center board quality from logs with a good quality and logs with a bad quality, suggest new sorting criterias developed from analyses made with Stockholmen and to evaluate the program Stockholmen. All analyses are based on data gathered in a test sawing made at BARO WOOD AB in June and July 2002. The test sawing was made on four different diameter classes and every diameter class consisted out of A or M-grade logs, with a better quality, and B-grade logs with a lesser quality. The logs where sorted out with BARO WOOD AB:s existing quality criterias.

Timmersorteringens inverkan på sågverksekonomin :

Modern sawmills are using the raw-material and the production-capacity more efficiently today, due to rising raw-material prices and higher production costs. Log sweepness has a negative effect on the sawn yield, for sawmills with straight-sawing. It is desirable that these logs could be sorted based on more criteria, if it increases value-yield and consequently the utilization of raw-material. Bow-heights over 1 cm have a negative effect on sawn yield, since the surface of the mantle cuts down in the sawn pattern. Some of these small bow-heights reduce the logs yield of value which affects the production planning negatively. Nearly half of all the Swedish logs have a bow-height over 1 cm.