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132 Uppsatser om Precommercial thinning - Sida 1 av 9

En utredning om effekterna av Skogsstyrelsens röjningsrådgivning

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.

Användning av satellitdata för lokalisering av skogsområden där lövröjning bedöms angelägen : en analys av användbarheten med fjärranalys som hjälpmedel till röjningsrådgivning

This master thesis project is a part of a project called ?Järboprojektet? at the regional board of forestry, the district of Gästrikland. The project will give answers to questions regarding if an analysis of satellite images can be used to contact and inform landowners of the located areas where Precommercial thinning is useful. The whole project is a part of the National Board of Forestrys IT-stake where the analysis of satellite images will, at the latitudes possible, be adapted to each district in purpose to identify these areas in need of Precommercial thinning. This master thesis project is based on a field inventory of identified objects where Precommercial thinning is useful.

Skogsvård hos privata skogsägare : vilka åtgärder utförs och av vem?

Many participants in the Swedish timber market procure raw material from private forest owners. They often also offer forest services to ensure reforestation after final felling. Selling silviculture services can be a part of creating a long term relationship with the landowner for future timber purchases. The Swedish Forest Agency monitors forest rejuvenation results in the entire country. In the latest survey (2006 - 2008) the proportion of approved regeneration area was 78%.

Röjningsformen och stamantalets effekt på höjd- och diametertillväxt i toppröjda och konventionellt röjda tallbestånd.

Topping is a Precommercial thinning (PCT) method where secondary stems are cut higher above the ground compared to conventional PCT. The secondary stems continue to live for a period and are supposed to compete with the main stems and promote their quality.The objective of the study was to compare the effect of PCT on height and diameter growth between topping and conventional PCT. The study also analysed the relationship between height and diameter growth and the number of stems after PCT.Nine topped stands and six conventional precommercially thinned stands were visited between February 28th and March 5. One sample plot per hectare was laid out in the investigated stands. In every sample plot the number of stems was counted and five main stems were measured for height, height growth since PCT, diameter and diameter growth since PCT.The results showed significantly higher effect on height growth after topping as compared to conventional PCT but no significant difference in the effect of diameter growth between topping and conventional PCT.

Röjningsförbandets betydelse för avverkningsekonomin i södra Sverige :

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.

Underröjning i förstagallring :

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%. .

Skötsel av tätortsnära skogliga rekreationsområden : besökares upplevelser i norra och södra Sverige

The main purpose of this M. Sc. thesis is to increase the knowledge about managing urban forestry for recreational use. The analysis is focusing on differences between visitors? experiences in the north and south of Sweden, represented by Nydalasjön and by Härlanda tjärn.

Skogsbruksplanens betydelse för aktiviteten hos privata skogsägare i Älvdalen :

The purpose of Älvdalens besparingsskog is to develop the district and most of all the forestry in Älvdalen. It's owned by about 2 300 private forest owners who's landed properties are located in Älvdalen. Every year the besparingsskogen gives out a lot of its profit in form different types of subsidies for agriculture and forestry. The owners can apply for subsidies for several of the costs that occur in forestry. During the period 2000-2003 the owners are offered forest management plans and pcSKOG-gård at no cost for their private forest properties. The purpose of this master's thesis was to find out if the activity in the forestry changed when the forest owners got new forest management plans and the computer program pcSKOG-gård.

Mellanskogs medlemmars syn på röjning

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.

En jämförelse avseende beståndsgående-och stickvägsgående gallringsmaskiner

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..

Produktivitet och kvalitet vid stickvägs- respektive beståndsgående förstagallring :

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.

Vad orsakar skador på kvarstående träd vid mekaniserad gallring - en intervjustudie

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..

The thinning Quotient - a relevant description of thinning?

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.

Privata markägares reflektioner med hänseende till den minskade röjningsaktiviteten : så kan skogsvårdsstyrelsen anpassa sitt arbete

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.

Höggallring i praktiskt skogsbruk : beskrivning av en gallringsmodell för granskog som tillämpas på Trolleholms Gods

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.

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