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544 Uppsatser om Tree mortality - Sida 7 av 37

Betesskador på lärkplantor

The purpose of this study was to show how the Hybrid Larch (Larix eurolepis x) are used by large herbivores in terms of grazing and fraying. More specifically I studied how impact on the seedlings was affected by forest stand area, tree height and stem density (stems/ha).The survey was done in Jönköpings county in southern Sweden. About 50 % of all stems that are measured are damaged by grazing and 5,8 % was damaged from fraying. The conclusion of the study is that the biggest influencing factor is the height of the seedlings. The size of the stands and number off seedlings per hectare have almost no impact on the injuries on the seedlings. Fraying are common on trees smaller than 3 meters, and doesn?t occur on trees above that height.

Rekreationsanpassad skötselplan för Skedalaskogen :

In this master thesis we suggest a recreational directed forest management plan for the Skedalaskogen. The forest is situated 10 kilometres east of the city of Halmstad and is owned by the municipality. We have in literature and in research investigated what people like and want in the forest, how to manage the forest for recreation according to for example tree species, mixtures and density. We tried to adapt the forestry methods more to recreational thinking. We have also looked at issues like what is rare and not rare in this part of the country according to nature and forest, where people live and which connection they have to the Skedalaskogen. The Skedalaskogen is a quite big area, totally 830 hectares. The area have about 100 000 visitors a year.

Hur kan man få ned dödligheten hos kalvarna i dikobesättningarna?

This work is a literature review along with interviews from nine suckler herds. How to reducecalf mortality in the cow herd is the focus of this paper. To get profitability of a herd, it isimportant that you get a live calf per cow and year. Good fertility of the cows thus is veryimportant. During the years 2007 - 2008, approximately 5.5% of all calves born by beef cowsdied and about 8.5% of the calves born by heifers died.

Management factors influencing sow productivity in successful Swedish and Danish herds

The number of weaned piglets per sow and year is a good measurement of sow productivity since it is affected by the number of piglets born alive, the pre weaning mortality (i.e. mortality of live born piglets between birth and weaning) and the number of litters per sow and year. This measure is also closely connected to the number of piglets produced per year, which partly determines the profitability of the piglet producer. During this study, eleven successful piglet-producing herds were visited. Eight of the producers were Swedish and three of the producers were Danish.

Bevarande av naturvärdesträd i enlighet med FSC och Holmen Skogs naturvårdspolicy :

In the end of 1998 the company Holmen Skog AB was certified accordint to the FSC system with an area of 1 036 000 hectare. After that Holmen Skog AB has been working actively with the nature conservation in the forestry. In order to control the quality of the company?s nature conservation in final fellings they started a yearly inventory which is called BAKRUS (Judgement of ecological and culture care in relations to policies for a persevering silviculture). After 1999 the control was expended to include all actions in the forest.

Hur påverkar bävern skogens värden?

The activities of beavers in forested landscapes affect both ecological and economical values. The creation of the dynamic wetland mosaic associated to beaver activities can even improve the quality of water and have been documented as an important landscape engineer affecting the environment for many species. The local office of Sveaskog in Skinnskatteberg is responsible for the management of large areas of the forests in the County of Västmanland. In this area one of several company?s goals are to create ten new wetlands in their own forests as a part of cooperation with the Swedish bird society and Swedish wetland association.

Predation som selektiv kraft bakom differentiering av populationer av sötvattensgråsugga, Asellus aquaticus

Predation is a strong dective force on invertebrate prey. Asellus aquaticus differs in pigmentation reed and submerged vegetation habitats in lakes. Light pigmented individuals al vegetation dominated by Chara sp. while dark pigmented individuals dominate in the reeds. These differences have been hypothesized to result from background matching.

Hur man spaljerar kärnfrukt från spö till spaljéträd - ett undervisningsmaterial med processkisser

Uppsats för avläggande av filosofie kandidatexamen i Kulturvård, Trädgårdens hantverk och design 21 hp, 2012.

Vad styr förekomsten av sälg och asp? : en studie av olika beståndstyper inom Hamra kronopark, Dalarna

Aspen (Populus tremula L.) and goat willow (Salix caprea L.) are two important tree species in the aspect of nature conservation. Due to the elimination of forest fires, a former negative attitude towards deciduous trees in forestry and a strong herbivore pressure, these tree species have been negatively affected during the last fifty years. The aim of this study was to investigate whether the occurrence of aspen and goat willow could be related to either human impact or to site properties, such as ground moisture and vegetation type. A side study included an inventory of a number of cyanobacterial tree lichens on aspen and goat willow in order to try to relate the occurrence of these lichens species to stand history and stand properties. The study was performed in Hamra State Forest in northern Dalarna. Nature reserves were compared with stands in managed areas.

Produktivitet och lönsamhet vid skogsbränsleuttag i klena gallringar : en tidsstudie av Vimek 608 BioCombi i contortabestånd

The annual demands for forest fuels increases in Sweden. At present, large unutilized biomass resources is found in young, dense forests from which about five million oven-dry tonnes (ODt) (23 TWh) could annually be extracted as forest fuel. But harvesting small trees give high logging costs and new cost-efficient harvesting techniques are therefore required. The aim was to study the productivity of Vimek 608 BioCombi in forest fuel thinning of Lodgepole pine and to calculate the economy of the harvesting and estimate the thinning quality. The time study was performed in Åmarken in the county of Västerbotten.

Evaluation of an ectomycorrhizal macrofungi as an indicator species of high conservation value pine-heath forests in northern Sweden

Since the 1950s, the development of modern rotation forestry in boreal Fennoscandia has resulted in a severe reduction of older forests, and a high degree of fragmentation among the small patches that remains of old forest. In Sweden, when performing conservation value assessments in order to identify and preserve the remaining forest habitats, the government authorities use to a significant extent a set of indicator species that indicate habitats of high biological conservation value. One species considered to indicate high conservation values in pine-heath forests is the red-listed ectomycorrhizal (EM) macrofungi Sarcodon scabrosus (Fr.) P. Karst. In the present study, the validity of using S.

Artificiella EkosystemSom Artificiell Intelligens I Actionrollspel : En jämförelse av algoritmer och deras anpassning till realtids-spel

Artificiella ekosystem är en tillämpning av artificiell intelligens som har funnits länge. Användningsområden för artificiella ekosystem innefattar främst biologiska simulationer men även andra typer av simulationer förekommer. Genom att simulera individuella djur blir den artificiella intelligensens uppgift att styra djurens beslut utifrån dess individuella förutsättningar och kamp för överlevnad. Detta arbete behandlar frågeställningen vilken beslutsalgoritm som är bäst lämpad att för att använda till ett artificiellt ekosystem i ett spel. Två beslutsalgoritmer jämförs, en dynamisk som bygger på maskin inlärning och en statisk som inte är kapabel att lära eller minnas.

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.

Vetlandas gatuträd : analys av trädens upplevelsekvalitéer

Street trees have had a prominent role in Vetlandas history from the turn of the century up to present day. Many trees have unfortunately been taken away through the ages, but most of them luckily remains and most of the streets in central Vetlanda are still tree lined. The comprehensive inventory that has been made shows that lime is the dominant species in Vetlanda with no less than 62 %. The age division is quite even with one peak at the turn of the century, one during the ?60s and another during the ?90s.

Influence of prescribed burning and/or mechanical site preparation on stand stem density and growth of Scots pine stands above the Arctic Circle : results 9-19 years after stand establishment

Prescribed burning was commonly used for site preparation in Sweden to establish new forests until the 1960?s, when mechanical scarification was introduced. During recent decades the interest in prescribed burnings has increased again, mainly due to certifications of forestry stating that 5% of the regeneration areas should be burned on dry and mesic soils. The objective of the study was to evaluate actual influence of prescribed burning compared to other site preparation on stand stem density, growth parameters and tree damages for Scots pine (Pinus sylvestris L.) after direct seeding and planting. The study also attempts to simulate growth until first thinning.

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