Sök:

Sökresultat:

371 Uppsatser om Deciduous trees - Sida 4 av 25

Betydelse av lövinslag, död ved och variation i träddiameter för artrikedomen hos småfåglar

Forest management contributes to the changes in forest structure by turning heterogenous forests of varied age into homogenous forests of similar age and thus affect bird species depending on different structures or habitats which are lost during forestry. In this report, a study was made to investigate how the amount of decidious trees, dead wood and variation in tree diameter affect bird diversity. The purpose of this study was to be able to give forest management guidelines to increase bird diversity. This study was conducted by investigating 65 transects in forests of different structure south of Linköping, Sweden. Along the 65 transects, birds were inventoried as well as the vegetation.

En inventering av säregna trädformer funna i Sverige

In Sweden and in Scandinavia the amount of tree species are rather few. However many different forms of trees arise due to mutations and gives rare appearances like cut-leaved and hanging forms. In some cases these trees are interesting as cultivars and a few of them have become popular garden trees. The knowledge of the original trees and early propagation is meagre.In this study a selected group of trees were found through search of literature. Eight tree forms were chosen and investigated in situ.

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.

Heterogenitet i skogsbestånd : faktorer av betydelse för artrikedom och förekomst av småfåglar

Denna studie undersökte hur heterogenitet i skogsbestånd samt omgivningsfaktorerna träddiameter, variation i träddiameter, död ved och lövinslag påverkar förekomsten av 18 skogsfågelarter i södra Sverige. Fågelinventeringen utfördes med hjälp av linjetaxering längs 100 meter långa transekter. Omgivningsfaktorerna mättes i varje transekt i fem provcirklar med diametern 10 meter. Analysen av träddiameter visade att det främst var diameter på barrträd, men inte på lövträd som inverkade på förekomsten av fåglarna. Sambanden mellan diameter på barrträd och totalt antal fågelarter var övervägande negativa vid 0-30 centimeter i diameter och övervägande positiva vid 30-80 centimeter i diameter.

Röjning på snö och röjning på barmark : effekter på produktivitet och kvarvarande bestånd

Approximately 4000-5000 hectares, of SCA´s forest land area in Västerbotten, are in need of pre-commercial thinning (PCT) every year. Within the management district, the areas annually treated with PCT must increase, in order to decrease the area with an urgent need for PCT. This can be done by employing more forest workers or entrepreneurs, by mechanized PCT or by an extended season for PCT. Positive experiences from a private forest owner, who started to carry out PCT when the first snow came and then continued for several months, gave an idea to investigate the possibilities to prolong the season of PCT. The purpose of this experiment was to compare PCT carried out when there was snow on the ground with PCT performed when there was no snow on the ground.

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.

Hur påverkar naturvårdsåtgärder mängden av vedlevande insekter : Manuellt dödade träd vs självdöda

Today?s forest managers implement a large number of methods to increase the amount of dead wood in Swedish forests. They use everything from high cutting of trees to girdling trees and burning forests. However, implementation of these measures without proper knowledge of their consequences is a common problem. This study has been performed to increase knowledge about two of these measures, girdling and high cutting, and how these actions affect the number of wood-living insects living on dead trees.

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.

När trädens rotsystem får bestämma : En intervjustudie med en grupp yrkesverksamma inom anläggning av hållbara gröna miljöer.

ABSTRACTThis pilot study examines the knowledge about tree root systems amongst five treeplanting professionals. The aim is to find out the professionals? collective knowledge ofthe nature of root systems of various trees used in green areas. Furthermore; to explorehow the professionals adapt landscaped green areas to the tree root properties in asustainable manner. Questions: Which tree species have special root properties toconsider and how do the professionals utilize this knowledge? And: How do theprofessionals in general adjust planting according to the root systems of trees in areas tocreate sustainable green environments?Interviews with the professionals were performed.

Inventering och klassificering av kvarlämnad virkesvolym vid slutavverkning :

This final thesis is performed on commission of Hargs Bruk Ltd. Hargs Bruk manages one of Sweden?s largest privately owned forests. A main part of the managed forest is situated in Roslagen in eastern Uppland. Since 1934 felling calculations have been performed within the estate every tenth year.

Produktivitet och lönsamhet vid skogsbränsleuttag längs skogsbilvägar :

With an increased demand for biomass based energy and with development of better technique harvest biomass, new possibilities open up. With the possibility to combine traditional cleaning of road?s right of way with biomass harvesting, the work of suppressing tree vegetation could become profitable or at least decrease the road maintenance cost. However, knowledge about productivity and profitability in mechanical biomass harvesting in roads? right of ways are still limited.

Hur ser lavars fördelning ut runt stammen på ek, och påverkas den av trädets storlek och dess närmiljö?

The aim of this study was to describe preferences of geographic direction of ten, oak-living epiphytic lichen species and how they responded to sun exposure, nearby bushes and trees, bark fissure depth and circumference. The frequency of every species was recorded in arcs of ten degrees around the tree at a height of 130 to 180 cm above the ground. An estimation of the amount of every species in every arc was also recorded. To analyse how the distribution of the lichen species responded to the different factors their concentration for every tree was plotted against the four factors. The distribution of Cliostomum corrugatum had a positive response to high sun exposure and a negative response to a thick layer of bushes and trees.

Lodgepole pine - stability after thinning

SCA has today almost 300 000 hectares of their forest land planted with lodgepole pine(Pinus contorta var. latifolia). Due to initial extensive planting in the 1970ies the area oflodgepole pine forests in the thinning age has grown rapidly from the end of the 1990ies.During the years 1996-2005 first commercial thinning of lodgepole pine at SCA took place.The goal of the hereby presented study was to investigate the growth and stability in thosefirstly-thinned lodgepole pine stands a few years after thinning. Furthermore, the objectivewas to investigate the relationship between stand stability and different stand parameters.Additionally, lodgepole pine stem quality was estimated.The study is mainly based on the data collected during an inventory project carried out atSCA in 2008. Altogether 91 lodgepole pine stands in northern Sweden were measured afterthe first thinning.

Eld som naturvårdare : Kärlväxtflora och vegetationsutveckling efter naturvårdsbränning i två småländska naturreservat

This study has taken place in two nature reserves in the municipality of Uppvidinge in the Kronoberg region in southern Sweden. These have been chosen by the County Administrative Board to be part of a bigger landscape of fire affected nature, and prescribed fire has been implemented in these. The areas are called Ösjöbol and Berga fly and have been burned 2012 and 2013 respectively. Non-burned areas have been inventoried as well. Vascular plants and mineral soil have been inventoried with the Hult-Sernander-Du Rietz scale of five levels. Issues emanate from the County Administrative Board?s goals for prescribed fire: how sticks and herbs were affected, how much soil was uncovered, how the structure and fire favoured species were affected, and how Deciduous trees and spruces (Picea abies) were affected. The study shows that the soil increased, as well as the fire favoured species.

Naturhänsyn på slutavverkade hyggen i Östergötlands län.

95% of the productive forest land in Sweden are now being exploited for forestry. The new Forestry Act of 1993 equate the goal of production and the environmental goal which means that the objective for forestry is a sustainable yield, while the biological diversity must be preserved. Recent years results from the inventories of the Board of Forestry show declining trends in how nature conservation aspects taken into consideration at the felling sites.The aim of this study is to investigate what happends with the nature consideration taken at felling sites in the long run. 20 final fellings in the county of Östergötland were re-inventoried 7-9 years after final felling. These felling sites had previously been inventoried before final felling (P0) and one year after final felling (P1) in the inventory Polytax by the Board of Forestry.

<- Föregående sida 4 Nästa sida ->