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912 Uppsatser om Tree species - Sida 4 av 61
Identifiering av lek- och övervintringsområden för lax (Salmo salar) och öring (Salmo trutta) i Klarälven
Old hollow trees of oak contain a large amount of wood mould. Unfortunately, these trees have in the last century been greatly reduced in numbers. It has resulted in that species that depend on these habitats, saproxylic species, have become at risk to decrease in numbers or die out regionally. Previous studies have shown that the volume of wood mould is an important factor for occurrence and population size of saproxylic organisms. The aim of the present study was to examine how the volume of wood mould varies among ash (Fraxinus excelsior), lime (Tilia sp.), maple (Acer platanoides), aspen (Populus tremula) and oak (Quercus robur).
Viltets inverkan på vegetationsutvecklingen i en Sydsvensk skogsföryngring :
Herbivore impact on the Swedish forest has under a long time been a common subject of
debate. There are many different opinions depending on what direction the forest owner has with his/her forest. Populations of moose and roe deer have increased significantly in Sweden during the last decades. The purpose of this study is to get a full picture of the herbivore impact on the regeneration areas. The field work was done once a year for seven years (1999?2005).
Jaktens betydelse för Södermanlands landskap : Hur viltvård kan påverka variationen av lövträd och buskar
The fragmentation and reduction of deciduous forests in Sweden is threatening many species. Particularity worrying is the loss of broad-leaf trees, since a diversity of species is often associated to them. Today many deciduous trees are situated along the border between forested and open areas, and these small fragments can be important for biodiversity.The aim of this study is to analyze if wildlife management can affect the variation of deciduous trees and bushes in the landscape. In brochures and literature Svenska Jägareförbundet (the Swedish Association for Hunting and Wildlife Management) recommend hunters and landowners to promote deciduous trees ? often broad-leaf trees ? as wildlife management measures, while the Swedish forestry laws can be sensed as unclear regarding the treatment of these trees.Five properties in Södermanland, Sweden, were chosen as study areas and inventoried in respect of trees and bushes in September 2013.
Datering av röta i hålekar :
I have chosen in this work to examine which factors are affecting the artificially creation of a tree cavity containing decomposed wood. The purpose of the work is to find out which factors are affecting the most when a tree cavity is created, and to apply these results when you artificially try to create a tree cavity. The need to create tree cavities comes from the situation where many tree cavity living beetles finds themselves today. When existing trees are to pass out there will be no suitable inheritors yet. The work was initially to focus on cavities created from cut branches.
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.
The effects of mother trees and site conditions on the distribution of natural regeneration establishment in a Bornean rainforest disturbed by logging and fire
In the tropics, logging and wild fire can result in degraded secondary forests with lower biodiversity than in the natural forest. One way to limit forest degradation is to rehabilitate the present large areas of secondary forests. However, there is a lack of knowledge concerning the ecology of tropical Tree species and further studies would be advantageous for future rehabilitation efforts of degraded rainforest. The objective of this study was to investigate how mother trees in secondary forest and different site factors affect the abundance and spatial distribution of natural regeneration of non-pioneer Tree species in a tropical rainforest in Sabah, Malaysia.
The study took place in the INIKEA Forest Rehabilitation Project area, which suffered from wild fire in 1983 and has been selectively logged over both before and after the fire. Natural regeneration and site variables were inventoried in plots, while mother trees were inventoried in the whole survey area.
Mätning av stamdiameter med markstående scanner :
Booth for operational planning of harvesting and for long term planning, data is today collected manually. Intensive objective field inventories are usually too expensive. To enhance optimisation of timber flow from forest to industry Moore efficient methods for measuring tree stems of standing trees are needed. The performance of terrestrial laser scanners have improved and these could possibly be used within forestry in the future. The objective of this study was to validate how a terrestrial laser scanner could be used to measure stem diameter, and to test how the errors depend on distance from the scanner and Tree species.
Two plots (one pine and one spruce) were used for this study.
Vattensork och åkersork - skadegörare i svensk fruktodling
There are two species of voles that cause damage in Swedish fruit production: the water vole (Arvicola terrestris) and the field vole (Microtus agrestis). Both species make the most damage during the winter season. The water vole makes subterranean burrows and cause serious damage by gnawing on the tree roots. The field vole seldom makes burrows and gnaws the bark at the base of the tree trunk. In recent years there have been several reports about increasing vole damage.
Identifiering av gallringsbehov med hjälp av flygburen laserskanning :
Thinning is one of the most important silvicultural activities in middle aged forests, partly to minimize damages and partly because it leads to earlier harvesting revenues and increases the value of the remaining trees. There are many different indices used to describe stand density and thereby the need of thinning in forests today. Studies have shown that forest variables can be estimated with high accuracy using airborne laser scanning and it is likely that the method could also be used to estimate forest density indices. In this study, the possibility of using the forest density index ?H² to determine and map priorities for thinning operations for a forest area was examined.
Samgång av olika arter på svenska djurparker
Zoos currently aim at keeping animals in as natural habitats as possible, since they havegone from displaying exotic animals to working with conservation of endangered species.It is therefore more common that zoos keep groups composed of two or more species in thesame enclosure. The aim of this report is to study why and how different species are held atzoos. Species in the wild can interact in different degrees depending on season andresources. When species are held together at zoos the space can be more effectively used,the animals increase their activity and the visitors increase their learning. Mixed speciesenclosures involve more work and risks of injury.
Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten
Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons.
Nyckeltal för älg och fodertillgång på tall Pinus sylvestris och rönn Sorbus aucuparia
It has been shown that moose can affect plant community composition and structure. Selective browsing with other damages of large herbivores on Tree species with different tolerance to disturbance could reshape the tree layer in both managed and natural forests. Rowan Sorbus aucuparia is widely distributed throughout Sweden and Europe. Research has shown that browsing by moose may prevent rowan from reaching browsing safe heights. The goal has been formulated that, where rowan is indigenous, it should have a good competition status and be able to reach tree level.
Tee Tree Oil - Ett effektivt behandlingspreparat i tandvården?
Tea Tree Oil eller TTO som det förkortas, är en olja som utvinns ur en australiensisk buske vid det latinska namnet Melaleuca alternifolia. Oljan har sedan många år använts som antiinflammatoriskt och bakteriedödande ämne. Denna litteraturstudie gjordes på 13 artiklar som svarade på tre sökningar i databasen PubMed. Artiklarna påvisar att TTO har en viss antibakteriell förmåga och kan fungera som antimykotiskt medel, men fler in vivo studer behövs för att säkerställa TTO:s effekt på olika parodontala åkommor..
Skogsbränsledrivare i klen förstagallring med contorta
The aim for the study was to examine a harwarder´s (combined harvester-forwarder) productivity when harvesting forest fuel in first thinning stands that contains Lodgepole pine and calculate the economy of the harvesting work and estimate the quality of the thinning . The field study area where located near Arvån, about 15 kilometres south ?east from the city of Lycksele. The field studies were taken place in three different stands. All tree stands had the same tree age, but the Tree species combination and the density varied.
Skillnader i mulmvolymer mellan fem trädslag i Östergötlands eklandskap
Old hollow trees of oak contain a large amount of wood mould. Unfortunately, these trees have in the last century been greatly reduced in numbers. It has resulted in that species that depend on these habitats, saproxylic species, have become at risk to decrease in numbers or die out regionally. Previous studies have shown that the volume of wood mould is an important factor for occurrence and population size of saproxylic organisms. The aim of the present study was to examine how the volume of wood mould varies among ash (Fraxinus excelsior), lime (Tilia sp.), maple (Acer platanoides), aspen (Populus tremula) and oak (Quercus robur).