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912 Uppsatser om Tree species - Sida 13 av 61
Tillämpning av kNN-Sverige i Södra Skogs verksamhet : behovsinventering, databearbetning och förberedelse för praktisk implementering
The digital map product kNN-Sweden contains nationwide data of the country?s forest land. The estimated forest variables are mean age, mean tree height, volume per Tree species and total volume. Today Södra Skog?s assessments of timber potentials are mainly based on experience rate and subjective assumptions.
Brandrelaterade insekters lokala artrikedom i förhållande till olika miljövariabler : Fokus på betydelsen av konnektivitet på brandfält i boreal skog i Västerbottens län
The last century, forest fires have decreased in frequency due to efficient fire-suppression along with the growth of the industrial forestry. Since 1990, fire has been reintroduced under controlled forms to recreate burnt habitats. Many species that are dependent on, or benefits from, forest fires have increased since fire was reintroduced. The importance of connectivity is often addressed in ecological research. This is particularly important for species dependent on short-lived habitats such as burnt forests.
VILKEN STRANDVEGETATION BIDRAR TILL DET ORGANISKA MATERIALET I KUSTN?RA SEDIMENT? Kols?nkor/k?llor, nedbrytbarhet och eDNA sp?rning
Coastal sediments are important carbon sinks, storing organic matter and thereby helping to
reduce the amount of greenhouse gases in the atmosphere. However, they can also act as
carbon sources if the deposited organic matter decomposes rapidly, contributing to increased
greenhouse gas emissions and global warming. Rapid decomposition partly depends on the
degradability of the material itself. In this literature review, I examine which coastal plant
species dominate different locations along the Swedish coast, based on coverage data from the
ClimScape project (www.climscape.se). For the most dominant species, I investigated the
type of organic matter they may contribute to the sediments and based on those results I
qualitatively assessed which sites that may function as carbon sinks or sources.
Biologisk mångfald i små grönområden : Inventering av insekter och fåglar i bebyggda områden i Solna kommun
All over the world the urbanisation increases at the expense of green areas. Many plants and animals are endangered today because their habitats gets smaller or disappear. The green areas that are left in city centres and suburbs are often small and surrounded by roads and buildings. Despite this, several studies have shown that these small green areas may house large biological diversity.This project aims to study the biological diversity in small green patches in residential areas. The study has been carried out in Råsunda in Solna municipality (Stockholm county) during the period May?July 2006.Three equivalent areas (5000?10 000 m2) with quite many old oaks were chosen for the study and inventoried for birds and saproxylic insects.
Biologisk mångfald i små grönområden : Inventering av insekter och fåglar i bebyggda områden i Solna kommun
All over the world the urbanisation increases at the expense of green areas. Many plants and animals are endangered today because their habitats gets smaller or disappear. The green areas that are left in city centres and suburbs are often small and surrounded by roads and buildings. Despite this, several studies have shown that these small green areas may house large biological diversity.This project aims to study the biological diversity in small green patches in residential areas. The study has been carried out in Råsunda in Solna municipality (Stockholm county) during the period May?July 2006.Three equivalent areas (5000?10 000 m2) with quite many old oaks were chosen for the study and inventoried for birds and saproxylic insects.
En jämförelse mellan får- och nötkreatursbetade hagmarker med avseende på populationsstorlek samt artsammansättning hos dagfjärilar och örter
Many of Europe?s day-living butterflies have shown decreasing populations during the last decades and many species are threatened. Many butterflies are dependent on managed semi-natural grasslands because of their richness in nectar sources and host plants for the butterfly larva. Swedish pastures are mostly managed through grazing. The number of cattle in Sweden have been decreasing while the number of sheep in the country increased by 30%.
Survey of Fusarium species on yellow onion (Allium cepa) on Öland
It has been observed by both onion producers and a plant protection advisor on Öland (an island off the east coast of Sweden) that basal rot is the largest contributory factor to reduced onion quality and yield. Basal rot is mainly caused by species of Fusarium fungi. The aim of this study was to: a) investigate which species of Fusarium that can be found in onion produced on Öland, b) describe the symptoms caused by the different Fusarium fungi found and c) explore, through interviews with the onion producers on Öland, the mechanisms that may be involved in the observed increase in basal rot.Onion bulbs (Allium cepa) were sampled on two occasions. In total 181 onions from 11 different fields were analysed. In addition, eight onion producers were interviewed.
Grodsamhällen längs vattendrag på Borneo : En identifiering av habitatkaraktärer viktiga för diversitet och abundans av grodor i tropisk regnskog
The stretch from the riparian zone of a major river, through the mouth and upstream in tributaries forms a range of differing habitats. The aim of this study was to investigate the effect of these different habitats on the riparian frog community in primary rain forest in Borneo; i.e. examine whether any gradients could be demonstrated in terms of species composition, diversity and density of frogs, as well as which environmental characteristics that seem to be of most importance in forming habitats of high conservational value. A major river, Segama, and three of its tributaries were investigated. The surveys were carried out at night by searching for frogs visually and acoustically along the streams, from the shore of the Segama river and 400 metres upstream in the tributaries.
Variation in protein precipitation and phenolic content within and among species across an elevational gradient in subarctic Sweden
This project investigated how elevation and vegetation type influences variation in plant litter phenolic content and protein precipitation capacity among and within common plant species for two different vegetation types, heath and meadow, in a subarctic ecosystem in the Abisko region of northern Sweden. As nutrient availability generally decreases with increasing elevation as a result of decreasing temperature, I hypothesised that phenolic content would increase with elevation and be higher on the heath than the meadow. To test this, the total phenolic content and protein precipitation capacity was estimated in leaf litter from 13 species in both heath and meadow vegetation across an elevational gradient ranging from 500 to 1000 meters above sea level (m.a.s.l.) in the study region. The results showed that elevation and vegetation type both had a strong impact on both variables. Total phenolic concentrations decreased with elevation for the meadow, and were greater for the heath than the meadow.
Kunskapsläge och attityder till vildsvin (Sus scrofa) och dess förvaltning i Sverige
The wild boar (Sus scrofa) is since its recent establishment and increasing density a controversial species in Sweden. But the attitudes towards the wild boar are poorly documented so far. To improve this knowledge, a questionnaire was sent out to chosen people (n=400) connected to the management and/or land use activities.
The study got 162 replies (reply frequency 40,5%) and the results show varying attitude trends among organizations and individuals, with some aspects coherent within groups and some not. Farmers and their organization showed the most negative attitudes towards wild boars, which was expected due to the practical and economic problems they suffer from this species. People involved with forestry were more positive to wild boars, probably because the species does not affect forest growth etc severely, and may even promote plant establishment by the rooting.
Resultat från tre klonförsök med fågelbär, Prunus avium L, i södra Sverige :
This study was based on measurements of growth and shape of 50 clones of wild cherry, Prunus avium L, in south Sweden and aimed at finding out wether or not any of these clones are useful for commercial propagation.
Initially, a short assembly of documented knowledge concerning wild cherry as a timber producing Tree species was put together. The study of the 50 clones includes information gathered during the fall of 2006 from four trials located in the counties of Blekinge, Småland and Västergöland. The oldest trial, founded in Tranemåla, Blekinge, in 1992, was focused on offspring and aimed at discerning differences between provenances and at developing an adapted plant material. The other experiments were both clone trials and founded in 2002. These are based on 50 individuals selected from the offspring trial in Tranemåla.
Fältinstruktion för skogsbruksplanering av inhemska skogar i Andinska Patagonien :
The thesis first objective was to develop field instructions for forest planning of native forests in Andean Patagonia, and the second objective was to test the plan on an actual property in the area. The thesis was limited to studies in the province of Rio Negro. Today, there are no official forest management plans for native forests in the Argentinean province of Rio Negro; thus, there is an obvious need for an official forest management plan with clear guidelines. To be granted permission to manage, i.e. through thinning, the native forests on a property it is required to have a forest management plan that is approved by the Forestry Board in the province in question (Thill, B.
Biologin hos svenska Lilioceris arter och åtgärder för att begränsa deras skadeverkningar :
Summary
The leaf beetles, Lilioceris lilii and L. merdigera have existed in Asia, Europe and in North Africa for a long time, but have become much more abundant the last twenty-five years. Even North America has been affected during the last years.
The purpose of this investigation of Lilioceris species in Sweden, is to give advice to gardeners, which type of control measures is the most effective in order to restrict their damage to lilies.
Lilioceris species overwinter normally as pupae in the soil under the host or close by.
Literature and contact with advisors have described the life cycle and spreading of Lilioceris. Under favourable conditions these leaf beetles have two generations/year in the south of Sweden. Both the adults and the larva eat the foliage, and by strong attacks even flowers can be eaten and only the stem is remaining.
My own observations include different treatments of both lily foliage and of the leaf beetle.
Skogseldens påverkan på epifytiska trädlavar på tall i relation till brandintensiteten :
Not much is today known about how epiphytic lichens are effected by fire. A considerable part of the fires in Sweden today are prescribed fires for the purpose of environmental conservation. How these fires affect lichens is largely unknown. The aim of this study is to find out how epiphytic fruticose and foliose lichens on Scots pine are affected by fire, and to elucidate the relationship between fire intensity and the survival of lichens and later re-colonization.
The study was performed at three locations just outside Umeå in Västerbotten that were burned 5-7 years earlier. In all locations there were larger groups of surviving Scots pines with varying amount of fire-damage in the crown, which enabled a reconstruction of fire intensity.
Timmerkvalitet hos björk i blandskog med gran
Birch is the dominant deciduous Tree species in Sweden but only 16 % is found in pure birch stands. The majority of the birch (51 %) is to be found in conifer dominated stands. Swedish forest land comprises approximately of 23 % mixed stands and one problem is that for mixed stands there are few management recommendations. The underlying aim of this thesis was to study the management of mixed forest stands of spruce and birch to achieve good timber quality of birch. The study was based on a literature study and measurement in a field experiment launched in 1998 by the Swedish University of Agricultural Sciences (SLU).