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544 Uppsatser om Tree mortality - Sida 10 av 37
Allanblackia stuhlmannii ? a tree under current domestication: what are the soil requirements?
Allanblackia is a genus of trees that grows in the rainforests of West, Central and Eastern Africa. Its big fruits contain seeds very rich in oil which has been used by
local communities for cooking and making soaps. The native stands are threatened by overexploitation and the demand for the oil is much greater than the supply.
Domestication programs, aiming at introducing the trees to small holder agroforestry systems, have been started for some of the species. The main aim of this study was to investigate the soil requirements of Allanblackia
stuhlmannii in terms of chemical and physical parameters, as revealed by the soil conditions in native stands. Another aim was to see if these varied along an altitudinal transect.
Hållbar Textil Produktutveckling : med växtfärgning
Författarna har haft ett samarbete med Panduro Hobby i samband med deras årliga miljökampanj. Syftet med examensarbetet har varit att med hjälp av befintliga produktutvecklingsprocesser och livscykelanalyser (LCA) ta fram en hållbar textil produkt med växtfärgning. Tanken var att konsumenter sedan själva skall kunna ta fram och växtfärga denna hållbara textilprodukt. Miljömedvetenhet och hållbarhet inom textilindustrin är ett aktuellt ämne. Trots det saknar dagens konsumenter förståelse för textilindustrins påverkan på miljön och har bristande kunskap om textila material för att kunna göra miljövänliga val ute i handeln.
Utveckling av en diameterklassmodell för grandominerade bestånd i Sverige :
Growth models are very useful tools for forestry to predict growth and yield. With growth models and optimising tools you can manage forest stands in a way that maximize benefit and income. There are three major types of growth models. Stand models; stage structured models and single-tree models. The most advanced models give the most accurate forecasts.
Förekomst & kostnad av kapsprickor i stormaskadad skog
The aim for this study where to investigate the frequency of cutting cracks in saw timber harvested in the storm-damaged forests in regions where the storms Hilde and Ivar hit. The idea for this work came from one of the region?s biggest actors, SCA Skog and Jämtlands district. The purpose where to find out how big proportion of the saw timber that contains cutting cracks, their financial cost in lost wood value and also give advice and suggestions on how to work against the frequency of cutting cracks.
For the field-study some guidelines where used to make sure that the samples were taken under the same conditions, they were:
? The field-study must be performed under harvesting of storm-felled forest, which are horizontal/inclined trunks.
? The averaged sized tree will make it possible to harvest saw timber.
? The trunks can?t be root cut.
A methodology called in Swedish ?Trissmetoden? was used because it is the most frequent used methodology in earlier performed studies and the only one that can be used I field.
Under the field-study data were collected from 570 saw timber logs, 30 logs from each one of the tested harvesters.
Flygburen laserskanning kopplat till skördarmätning för datainsamling till operativ planering :
The requirements for operative planning activities are increasing. The forest industry wants to gain better control over wood flow. A felling that is more market adjusted is desirable. However, this causes problems in the operative planning process because of the data collection methods used today. Data about timber assortments and data about the distribution of the tree diameter, etc., are often lacking.
Airborne laser scanning is used to a greater extent than before for estimation of forest variables and should perhaps be used to the same extent in operative planning activities as well.
Metoder för att undersöka effekterna av naturvårdshänsynen i skogsbruket efter den nya skogsvårdslagen
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.
Har antalet naturvärdesträd i Sverige förändrats mellan 1999-2009?
Forestry and forest products are vital components of the Swedish economy but the forest is also important for recreation, hunting, out-door life and conserving biodiversity. The Swedish Forest Act has two equally important objectives, production and environmental protection. Polytax is the Swedish Forest Agency´s inventory programme which monitors progress toward the two objectives in connection with regeneration fellings. It includes data on environmental protection measures taken in connection with regeneration fellings. 30 § of the Swedish Forestry Act and related regulations specify the demands for conserva-tion of nature.
Vedrötor i stadsträd : biologi, detektionsmetoder och förebyggande åtgärder
Urban trees have very little in common with trees on natural sites, such as forests or pastures. Trees in urban environments are often planted in packed soil and in small volumes. This can lead to decreased availability of water and oxygen, as well as deteriorated ability for the soil to store nutritional elements. Also above ground the tree usually have limited space in cities. Regulations on free height over roads and cycle tracks demands high stems at an early stage of their development.
Klibbalens gödslingseffekt på volymproduktionen i ett blandbestånd av gran och klibbal : en simulering i Heureka
A secondary and a pioneer tree species can with advantage be included in a mixed stand to increase the use of sunlight. Nitrogen-fixing plants have been shown to increase the supply of nitrogen in the soil by, for example, litter fall. This deposition acts as a biological fertilization, which may be used by non-fixing plants. Alder is a nitrogen-fixing, pioneer tree species that loses its nitrogen-rich leaves late in the autumn. The aim of this study was to examine the effect on the total volume of production, when different proportions of nitrogen-fixing Alder were part of spruce stands.
Piglet mortality in commercial piglet production herds
Dödfödda grisar och smågrisdödlighet under diperioden leder till både produktionsförlust och innebär dessutom försämrad djurvälfärd. Förluster orsakade av dödfödslar, smågrisar som kläms ihjäl av suggan och som svälter ihjäl kan förebyggas genom god skötsel, bra djurstallar ochavelsurval. För att lyckas med detta krävs att riskfaktorer för smågrisdödlighet kan identifieras.Syftet med den här studien är att undersöka variationen i förekomsten av dödfödda smågrisar och dödligheten under digivningsperioden beroende på kullnummer, kullstorlek, säsong och besättning. Ett andra syfte är att fastställa om det finns någon upprepbarhet för suggor vad gällerförekomst av dödfödda smågrisar. Data erhölls från fyra kommersiella grisbesättningar, belägna i centrala Sverige, som använder sig av besättningsövervakningsprogrammet ?PigWin Sugg?.
Hundens parvovirus : patologi och riskfaktorer
Canine parvovirus is associated with two disorders: enteritis, which is common, and myocarditis, which is rare. Prominent clinical signs of parvovirus enteritis are vomiting, diarrhea and rapid dehydration. Canine parvovirus type 2 (CPV-2) is very contagious. When CPV-2 first emerged it had high rates of mortality, but later studies have shown that most infections are self-limiting and do not require veterinary care. Mortality rates vary greatly, and therefore it is important to determine risk factors for developing severe canine parvovirus enteritis.
Planteringsförbandets inverkan på bildningen av kärnved hos tall (Pinus sylvestris L.) : en modellsimulering av planteringsförbandets inverkan?
The current state of knowledge indicates that there is more than one factor that initiates heartwood transition. This study supports its hypothesis on the theory that heartwood is formed by a fixed fraction of the annual growthring, 0,5 to 0,8 rings. To calculate heartwood volume modelings were carried out in four different pine stands with different spacings, 0,75, 1,25, 1,5 and three meters. The model indicates heartwood diameter (HWD) and is based on four explanatory variables, height (H), crown ratio (CR%), diameter breast height (DBH) and tree height (TH). The shifting plant spacing results in varying growth rate in the juvenile stage.
Skötselmetoder för bestånd med produktions- och naturvårdsmål :
This study is made on assignment by the local board of forestry in Skåne,
Blekinge and Halland.
The change of the forest law 1994 brought a new type of management plan.
A more active planning was introduced in order to equate the environment goal
with the production goal. The purpose with this study is to give a better picture of
how planning for nature conservation in production forest is made and to develop
support for selection of silviculture methods for stands with combined goals. With
combined goals means production forestry with a reinforced consideration to both
nature and culture, called PF-classified stands. This was done by:
? Describing silviculture models from the literature that are possible to use
for stands with combined goals.
? Describing silviculture models that is used in practice in stands with
combined goals.
? Describing how the classification of stands with combined goals is used.
Which means, were in the terrain, with which frequency and in which type
of forest PF-classification is used.
? Comparing differences and similarities of theoretical and practical used
models.
The study was done partly as a literature study and partly as an interview study of
forest planners.
Avledning av öringsmolt (Salmo trutta) från turbinintag
Vattenkraftstationer, med dammar och turbiner, utgör hinder för nedströmsvandrande smolt. Syftet med denna studie var att undersöka turbindödligheten för öringsmolt (Salmo trutta) vid två kraftstationer, de befintliga ytlänsarnas avledningseffekt och om effekten kunde förstärkas genom mörkläggning i form av övertäckning av kraftkanalen med en presenning vid turbinintaget. Utöver detta var avsikten även att undersöka om det fanns något samband mellan smoltgrad och smoltens förmåga att förflytta sig mot havet. I Emån i Småland fångades 46 öringsmolt som radiomärktes och sattes ut vid två kraftstationer och pejlades dagligen i sex veckor. Det var en större dödlighet vid den övre stationen än vid den nedre.
Vad orsakar skador på kvarstående träd vid mekaniserad gallring - en intervjustudie
This thesis includes a review of scientific studies of tree injuries following mechanized thinning. Interviews have been made with drivers of single grip harvesters and forwarders in forest thinning and a number of essential factors have been identified as the most important to take into account in order to minimize and/orprevent injuries to stems and roots of remaining trees..