The need for brushing before the first thinning has increased during the last few years. This brushing involves taking away small trees and bushes making it able for the harvester operator to see better and choose the correct trees to be harvested. In today’s silviculture the brushing is often neglected which means that the undergrowth becomes dense and leads to less efficiency for harvesters and a rise in costs. A well brushed first thinning will make the harvesting costs low and time efficient.   In brushing before the 1st thinning all stems below 9 cm d bh are traditionally taken down. This has a tendency to become stereotyped; i.e. brushes are also taken away in areas where  stronger nature conservation should be applied, as in wetlands, edge zones, etc. The harvester operator then gets stuck in these zones which threaten the biodiversity.    This study aims at examining two different types of brushing methods before the thinning, the traditional one and another (new) method where environmental and nature protection aspects were taken into account to a greater degree; i.e. where more stems and undergrowth have been left over and edge zones were not brushed. The study results show that the latter one is to prefer as the more cost efficient one. It also protects the harvester to drive out into the edge zones. This method is also beneficial for the wildlife.   Most harvester operators were positive to a new brushing manual.

I Sverige finns ca 1,2 miljoner hektar skog som bedöms ha omedelbart röjningsbehov. Skog där röjningen uteblir eller är svag kan komma att klassas som konfliktbestånd. I konfliktbestånd är stammarna många och diameterspridningen stor och dessa kan då behövas underröjas innan gallring. I denna studie jämfördes produktionen, kostnaderna och intäkterna från fyra olika underröjningsbehandlingar, oröjd, siktröjt, röjt allt upp till 5 cm i brösthöjd och röjt allt upp till 7 cm i brösthöjd. Behandlingen oröjd gav det bästa nettot och sämst hade upp till 5 cm efter gallring och uttransport av virke. En anpassad eller svag röjning gav lägre totalkostnader jämfört med ingen eller hårdare röjning. / In Sweden there are about 1,2 million hectares of forest with immediate need of pre-commercial thinning. Stands, where conducted pre-commercial thinning are light or even absent, become tight with thin stems. In such stands pre-commercial thinning before first thinning may be required, due to operational advantages such as increased visibility. This study compared production, cost and revenues from four different pre-commercial thinning treatments: no pre-commercial thinning, sight pre-commercial thinning, cleared everything up to 5 cm diameter at breast height and cleared everything up to 7 cm diameter at breast height. The treatments whit no pre-commercial thinning had best net value and worst had up to 5 cm. A custom or weak pre-commercial thinning give a lower total cost compared to no or harder pre-commercial thinning.