The aim of this work is to demonstrate how the net present value (NPV) at the time of the first Thinning depends on the spacing after pre-commercial Thinning, and show how net value from first Thinning in same stand is influenced. This study is performed with models based on non-distant dependent growth models for single trees. Two different growth models have been used, one for cleaning (pre-commercial Thinning) and one for Thinning. The first one yields stem density distributed over diameter classes. In the second one, (the Thinning model), it is possible to choose when Thinning should be done, the Thinning method, Thinning grade and numbers of Thinning.

This report is a thesis work for a B.Sc. in Forestry exam at the School for Forest Engineers, SLU. The work was an assignment from Sydved and the aim of the work was to investigate the economical output of removing understorey trees before first Thinning. Four treatments were studied. - no cleaning before Thinning - cleaning of all trees less than DBH 5 cm before Thinning - cleaning of all trees less than DBH 7 cm before Thinning - cleaning of all trees less then DBH 9 cm before Thinning The result shows a decrease of the cost per m3 for the harvester with about 38% if all trees less than DBH 9 cm was cleaned before Thinning compared with the un-cleaned area. At the same time the total net revenue increases with about 22%. .

The main purpose of this study is to investigate the needs of pre-commercial Thinning on private owned forest properties, which is considered to be increasing. The reason is believed to be the high cost of labor that pre-commercial Thinning brings. Furthermore Thinning is costly, the revenue created through pre-commercial Thinning are post-poned until the first Thinning. The study was made through a survey among members of Mellanskog forest owners association. The survey was distributed by e-mail. The time to answer was set to two weeks. The answers indicate that the most common reason why the pre-commercial Thinning is delayed, or not done at all, is the forest owner?s lack of time.

The purpose of this report is to investigate and compare the difference between stand-Thinning machines and strip-road Thinning machines, and how they affect the stand on behalf of future growth, theoretical economic result, wind impact, snow pressure and density of stand. The investigation is regarding the first commercial Thinning of pine stands, after pre-commercial Thinning that was well conducted. The investigation area was located near Katrineholm, Sweden. The measurements that were measured were strength of Thinning and amounts of wind throws, snow-breaks and hauling damages. The results that emerged, was that Thinning with strip-road machines had a significantly higher strength of Thinning over all, as compared with the stand- Thinning machines (45 percent versus 30 percent). Comparisons between wind-throws, snow-breaks and hauling damages of the stand could not establish any significant differences between the two methods that were investigated. Conclusions, over all, were that if forest owners want to have more timber volume left for second Thinning and final cut of the stand, the forest owners should choose the method with stand-Thinning machines. From the point of view of gentle treatment of the stand and ground damages the choice should be the same. However, the method with strip-road Thinning machines is the most common and accessible method in Sweden. Most likely it is the most economical way to manage the stand for forest owners in present time. If the method with stand-Thinning machines is becoming more common in Sweden, it is suggested for forest owners to consider the stand-Thinning method as a candidate for treatment due to economic aspects..

Nowadays the majority of the Thinnings made in Swedish forests are done by machines, harvesters and forwarders. The most common model in Thinning with a harvester is strip-road operated Thinning and stand-operated Thinning with one intermediate passage between the strip-roads. This study is a time study with some quality follow ups on a strip-road operated Thinning model, a stand-operated Thinning model with one intermediate passage between the strip-roads and a stand-operated Thinning model with two intermediate passages between the strip-roads. The machines in the study were a small harvester (Forestline MPM C90) and a medium sized forwarder (Timberjack 1110). The study was made in Litsnäset outside the city of Östersund in Sweden and was made during the autumn 2007. In a lodgepole pine stand six study units (0,6 ha) were thinned with the three different models, two study units per model.

This thesis includes a review of scientific studies of tree injuries following mechanized Thinning. Interviews have been made with drivers of single grip harvesters and forwarders in forest Thinning and a number of essential factors have been identified as the most important to take into account in order to minimize and/orprevent injuries to stems and roots of remaining trees..

Det finns en rad satt att beskriva gallringsformen. Ofta används begreppet gallringskvot i dessa sammanhang utan att närmare ange vilken metod eller definition som använts for att beräkna den. Detta kan lätt leda till att missuppfattningar uppstår. Denna studie belyser olika definitioners känslighet for bland annat beståndsstruktur, gallringsform och stickvägsavstånd. Studien innehåller dessutom en jämforelse mellan olika metoder att mäta och uppskatta gallringskvoten i ett bestånd.

This project was a request of Norrbodal´s Forestry Board, Västra Götaland. It was performed as a qualitative interview analysis of private forest owner?s deficient motivation regarding pre-commercial Thinning. The purpose of the project is to investigate what the Forestry Board can do to motivate private forest owners to do more pre-commercial Thinning. The results build upon 16 qualitative phone interviews with forest owners that have their forest within the district of Norrbodal. The owners are divided into two groups, the one who have performed the pre-commercial Thinning and the one that has possible pre-commercial Thinning needs on their properties according to the pre-commercial Thinning analysis ,which is the result of a satellite analysis.

When Norway spruce is planted with large initial spacing and grows on highly productive sites in southern Sweden, a high proportion of the stems gets broad annual rings. The Thinning programme carried out at the estate of Trolleholm aims to extract stems with too broad ring width. The 3-4 first Thinnings are carried out as Thinning from above, where only the thickest trees are removed. The internal distance may not fall below 5-7 meters depending on the number of Thinning (short distance in young stands). The aim of this study was to examine the Thinning model that is carried out at the estate of Trolleholm. A volume table is calculated to describe the model, and data is collected on temporary plots.

With knowledge of how the southern Swedish forests have been affected by storms the past years, this study intended to find out which factors affect the storm firmness of a stand the most. The study was based on data from stands in the, by the storm Gudrun, affected area. The results of the analyses that tested the stand factors that influence the amount of storm damage to the greatest extent showed that the storm sensitivity of Norway spruce stands were largely due to previous management actions. The factors that could be controlled by Thinning and had relevance of storm damage standpoint, according to the results were; the dominant height, volume, basal area weighted mean diameter and stand age at last Thinning. In this study, these results are not as clear for Scots pine.

The purpose of this study was to analyze the two Thinning models: Bergvik Skog´s Thinning model, which is based on total stems and dominant height, And Swedish forest agency´s Thinning model which is based on basal area, habitat index, dominant height and recommended number of stems at final felling in Heureka´s StandWise and PlanWise. The data we chosen for our study were taken from the Swedish National Forest Inventory and we were creating a simulated stand based on a great number of sample plots in Region three from The Swedish National Forest Inventory. We had chosen to create one stand with low habitat index (T20) and one with high habitat index (T24). Our purpose were to come as close as possible to a natural stand in central Sweden. We performed the Thinning in StandWise and analyzed the data I Excel files. Our Thinning optimizing´s were performed and analyzed in PlanWise. There wasn´t any big differences between the Thinning on the lower habitat index.

This thesis is about the effects of fertilizing and Thinning on furniture timber from redwood. Interviews of furniture manufactures have been made and observing of timber from the Swedish fertilizing and Thinning trails. The result from the interviews showed which properties that is important for the furniture manufactures and then the result from the observation showed which type of management of the forest that gave the most timber that had those properties. .

The purpose of this study was to examine how small-scale private forest ownersmake decisions regarding pre-commercial Thinning. In 2015 it is ten years agosince the storm Gudrun hit the southern parts of Sweden and now large areas arein need of pre-commercial Thinning. This study is built upon qualitativeinterviews with seven small-scale private forest owners with forest properties inthe county Kronoberg. The respondents were chosen by the modelSKOGSÄGARPROFILENTM (forest owner profile).The results of the interviews showed that five categories: ownership, the stormGudrun´s impact, silviculture, forestry contacts and driving force was important.How will their purpose and aim affect the pre-commercial Thinning? Personalinterests, and expectations of the next generation to take over, are purposes thisstudy has found.

This is a study on the outcome of the Swedish Forest Agency´s mission to provide individual advice to private land owners about precommercial Thinning. The study was conducted in Sala municipality and included forest owners that had received private individual advice from a Swedish Forest Agency consultant as well as forest owners that had not received individual advice. One of the central issues was to make comparisons between these two groups. The survey was carried out by telephone interviews combined with a smaller field study. The questions were designed to provide information about to what degree the forest owners had been affected by the advice and if there had been a change in the way in which precommercial Thinning was performed. In terms of the amount of precommercial Thinning that had been carried out, no statistically significant differences were found between the two groups.

The purpose of this study is to compare the economic differences between withdraw of forest fuel and withdraw of pulpwood in first Thinning, to see which method gives the maximum profitability (income - cost). Another purpose is to investigate the economic impact of the thicket cleaning. The study compares four different methods: i) pulpwood output with thicket cleaning, ii) pulpwood output without thicket cleaning, iii) forest fuel output with thicket cleaning and iv) forest fuel output without thicket cleaning. The study was conducted in a 30-years old stand, dominated by spruce, outside Harg in Uppland. The method that generated the best economic net income was pulpwood without thicket cleaning. It generated a positive net of 1,383 SEK per hectare. Forest fuel output without thicket cleaning also generated a positive net in 720 kronor per hectare.