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355 Uppsatser om Trees - Sida 6 av 24
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.
En jämförelse mellan två datorprogram för utbytesberäkningar :
This thesis is made on behalf of SCA's Forestry Division and is a comparison of two bucking simulation tools: Aptan (manufactured by Skogforsk) and Best/upr (from Berget Systemdesign). The data is based on 32 stands from SCA's forests in Norrbotten and Västerbotten. The objective is to compare the simulations created by the tools with the harvested volumes from those stands. Three variables are needed for the bucking simulation; these are the diameter distribution (at breast height), the relationship function between diameter and height, and the taper coefficients. The volumes of five different assortments from the stands are compared.
Naturvärden i en värmländsk bruksskog : en skogshistorisk studie av Åbengtshöjden/Bogranghöjden
In this study I have analysed the history of a forest belonging to Saxåhyttan in Värmland. The study area is 448 hectares and has been used by iron industry since the 16th century. A forest that has been used by man during at least 400 years should have few ecological values. This inventory however shows the opposite.
The aim of the study is to interpret the history of the forest in the area, i. e.
Svamparnas roller i svenska barrskogsekosystem : hur ser kunskapsläget ut hos några olika grupper människor?
Fungi are everywhere around us and recently, there has been
an increased interest in their role and importance in the forest.
The fungi have several strategies to acquire energy and nutrition; one example is a mutual symbiosis with Trees and plants - another being dissolving organic materials.
Attempts have been made to better understand the circulation of nutrition in coniferous forests, and how fungi cooperate.
Trees and plants have adapted with mycorrhizae and are now interdependent which is important to consider in forestry.
A great number of fungi depend on dead wood and old Trees to set fruiting bodies and spread further. These fungi also create environments for other species, such as birds and insects.
The vegetation of a forest is determined by a series of factors; tree species, how old the forest is, soil type, as well as the ability of the fungal spores to spread and establish. Furthermore, in determining vegetation, the fungi?s ability to compete in the soil matters. These factors are nearly unexplored.
Researching fungi knowledge and interest, a survey was distributed to five groups of people.
The groups included forest owners, high school teachers, high school students, senior citizens, and a fifth group - ?o he ? - consisting of people of mixed ages and backgrounds.
KLIMATTOLERANS HOS URBANA TR?D I G?TEBORG: Analys av klimatgr?nser och framtida klimathot
Urban Trees contribute significantly to our society. By providing ecosystem services and a habitat that other urban species and ecosystems depend on, both biodiversity and the people in the city benefit. Some characteristics that the Trees possess include functioning as biological filters for the atmosphere and water, as well as positively impacting people's mental health. However, urban Trees are challenged by stressors such as pollution and a drier environment, making them particularly sensitive to climate change. The goal of this study was to estimate the expected magnitude of climate change in Gothenburg and compare it with the current urban species' natural climate boundaries to understand the extent of the climate threat and which species appear to be most at risk.
Förröjning i förstagalling - vad kostar det och följer utförarna instruktionerna?
This report is a B.Sc. Forestry thesis work at the school for Forest Management, SLU.
The work was an assignment from the forest owners? association Mellanskog.
The aim of the work where to investigate the economical result of removing undergrowth Trees before first thinning, and a follow-up of the contractors and their compliance with Mellanskog standards.
This thesis work was divided in three parts: The first was to find a relation between the net volume from the first thinning and the cost of cleaning undergrowth Trees. Secondly there was a follow-up in the field, to investigate whether the contractors have done the undergrowth cleaning according to Mellanskog?s directives.
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.
Vedlevande lavar på döda grenar på levande träd i produktionsskog
Saproxylic lichens in managed forests have less substrate available than in unmanaged forests due to the shortage of dead wood. However, a suitable substrate for these lichens could be dead branches on living Trees. To this date, there has not been any systematically collected data about theabundance of dead branches on living Trees and the lichens growing on these branches in managed forests. The aim of this study was to see where dead branches were located on living Trees of Pinus sylvestris and Picea abies, how large the surface area of these branches was and what lichens grewof wood on these branches. The study was made in Finspång, Sweden, where 11 forest stands of P.sylvestris and P.
Föryngring i stormfälld rekreationsskog : en jämförelse mellan föryngring i produktions-, rekreation/produktion och rekreationsskog.
When the storm Gudrun hit Sweden on the 8th and 9th of January, many recreational forests in southern Sweden blew down. For this reason there is a demand for new regeneration methods as to how these storm-felled areas should be regenerated and with what species.
In this study the forest is divided into three areas: production, recreation/production and recreation. The first area is a forest with production as main goal and these kinds of forests are located a bit from the city. The second type ? recreation/production forest ? has two equal goals: production and recreation, and is located close to the city.
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.
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.
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).
Fruktkvalitet inom äppelodlingen : en studie av och för Äppelriket Österlen
The main purpose of this Master Thesis has been to investigate issues concerning apple fruit quality in orchards of Äppelriket Österlen. The goal has been to develop a document, for future benefit towards growers and company management in the production of high quality apples.In order to investigate main issues of fruit quality, focus has been on statistics concerning apple varieties, age of the apple Trees, new planting, orchard size and growers opinions. Nine growers have been interviewed to investigate opinions and contribution of different growing techniques to increased fruit quality.
The investigation showed high age of the Trees in production and low rate of planting of new Trees. Differences in fruit quality were highest between small orchards. Most growers were satisfied with their fruit quality and with their own measures made to improve it.
Stem injection of different nitrogen forms into young Norway spruce
This master thesis has been a pilot study preceding a forthcoming project of a larger scale with the long term objective to separate the direct effect of added nitrogen on soil processes from indirect effects via Trees. The aim of this study has been to investigate the allocation of nitrogen following direct injection of liquid solutions into the xylem of 40 year old Norway spruce. The field site is located at Flakaliden (64°07?N, 19°27?E), approximately 60 km northwest of Umeå, Sweden. A total of 18 Trees were selected for treatment, equally divided between three treatments, potassium nitrate, glutamine and water (control).
Minskad trädtillväxt under Lilla sitiden? : En dendroklimatologisk jämförelse mellan nutid och 1600-talet invid trädgränsen i norra Skandinavien
During the period called Little Ice Age (1400 ~ 1900) the climate of northern Europe was in an annual year-basis overall colder than it was before and after that period. The numbers of short, cold and rainy summers and long, bitter-cold winters where often repetitive under the approximately 500-years the period lasted. In Scandinavia, the coldest time during this period is estimated to have started around the end of the 16th century and lasted to the beginning of the 18th century. Trees growing at the tree-line are limited by temperature for their annual growth and hence showing differences of growth during changes in the climate, a method called dendroclimatology. The variations of growth can be read in the tree-rings either by analyze the width of the ring or by look into the density of the wood and is used to reconstruct past climates.