In comparison to the southern pine beetle (SPB), (Dendroctonus frontalis Zimmermann), less is known about the three species of Ips bark beetles; the six-spined engraver, Ips calligraphus (Germar); the eastern five-spined engraver, Ips grandicollis (Eichhoff); and the small southern pine engraver, Ips avulses (Eichhoff). Ips commonly enter a stand following the first commercial thinning, feeding on slash and stressed individuals. However, the factors that influence Ips severity are poorly understood. Therefore, this project was designed to study the seasonal effects of first commercial thinning operations on Ips activity in north Mississippi loblolly pine stands. Treatments represented the most commonly used thinning practices in this area (i.e., a fifth row harvest with select, a third row harvest with select, and control). Treatments were duplicated three times per site and two sites were utilized to compare Ips movement to harvesting season.

The study examined the goal fulfillment in edge zones along rivers and lakes in precommercial thinning stands based on national targets which is the basis for Swedish forestry. Pre-commercial thinning has a major impact on the future forest, as it determines how the tree species distribution will turn out. The study was conducted as a field study in February 2018 based on 30 precommercial thinning sites, aged 5–15 years, in connection to rivers and / or lakes. Of these, 25 rivers and five lakes were surveyed. 22 of the surveyed stands were privately owned and 8 were company-owned forests. The edge zones had between 0–100% shadowing of the water surface. Few sites with soil damage were detected and also a varying amount of tree species and deadwood. The most common deadwood was standing and lying dead wood with a diameter of 10 cm for both company and privately-owned forests. The percentage of number of stems per ha of deciduous trees in the edge zones was 52%, Norway spruce 41% and Scots pine 7% respectively. Within the edge zones, the sample areas closest to rivers and lakes had 55% of number of stems per ha deciduous trees, 40% spruce and 6% pine. In the sample areas closest to the stand, the number of deciduous trees was 48%, spruce 44% and pine 9%. Company-owned forests had more spruce (59%) along the waterfront compared to privately owned forests, who had a significantly higher proportion of deciduous trees (61%). By actively working with the composition of the edge zones, creating deadwood, saving trees for shadow and by thinning dense areas, particularly spruce-dominated, increased biodiversity can be achieved. Dense, spruce-dominated areas are those areas where the goal fulfillment is insufficient in many places.

The purpose of this study was to examine how small-scale private forest owners make decisions regarding pre-commercial thinning. In 2015 it is ten years ago since the storm Gudrun hit the southern parts of Sweden and now large areas are in need of pre-commercial thinning. This study is built upon qualitative interviews with seven small-scale private forest owners with forest properties in the county Kronoberg. The respondents were chosen by the model SKOGSÄGARPROFILENTM (forest owner profile). The results of the interviews showed that five categories: ownership, the storm Gudrun´s impact, silviculture, forestry contacts and driving force was important. How will their purpose and aim affect the pre-commercial thinning? Personal interests, and expectations of the next generation to take over, are purposes this study has found. Furthermore, when pre-commercial thinning is not carried out or postponed, the silviculture has got lower priority, and other chores higher priority. Lack of knowledge might be one issue. If so, a contact with someone with this knowledge is important for starting up the pre-commercial thinning. Key words: Gudrun clearing, pre-commercial thinning, personal interest, net of contacts, private forest owners, change-of generation, “forest owner profile”.

Forest management practices which reduce southern pine beetle (SPB) risk benefit not only the landowners who perform them, but all those who draw benefits from southern pine forests in Virginia, especially other forest owners within the same region. One such management practice is pre-commercial thinning (PCT), which is particularly unattractive to non-industrial private forest (NIPF) landowners because of the substantial costs and delayed financial returns involved. Since the benefits to society generated by PCT are not fully realized by the individuals who might implement it, there may be a market externality in which PCT is underprovided across the landscape. The Pine Bark Beetle Prevention Program (PBBPP) has the potential to correct this externality by reimbursing a portion of the costs of PCT for landowners who qualify. However, cost share incentives have been criticized for being ineffectual on the basis that landowners substitute publicly funded reimbursement for private investment, without altering their management practices. To investigate the effect of the PBBPP cost share for PCT, a survey was sent to 1,200 NIPF landowners in seven counties across the Piedmont and Coastal Plain physiographic regions of Virginia, where southern pine is prevalent and SPB hazard is a relevant concern. To measure willingness to participate in the program, a referendum style question was used in which the offered cost share ranged from 20% to 90%. Results of discrete choice models estimated from survey data indicate that cost sharing has a significant, positive effect on willingness to participate overall, though increasing reimbursement above 60% is unlikely to affect participation. Some landowners are not responsive or are less responsive to cost sharing due to personal and property characteristics. / Master of Science

Röjningsinstruktioner och virkesinköpare anser att rönn, asp, sälg/salix och ek (RASE) ska sparas i ungskogsröjningar för att det ska finnas annat foder åt skogslevande vilt än produktionsskog. Dessutom är ett vanligt råd till skogsägare av virkesköparna att satsa på foderskapande åtgärder för att avleda hjortdjuren. Undersökningen av ungskogsröjning visar dock att teori och praktik inte går ihop, där få stammar av RASE sparas och det är troligare att björk sparas. Enstaka RASE kan sparas i lucka där de inte kan konkurrera med en huvudstam av det planterade trädslaget. En alternativ skogsskötsel, som Öster Malma-modellen, ser blandskog som en mer ekonomiskt stabilt skogsbestånd och det bidrar samtidigt med mer lövskog än traditionell skötsel som sköter bestånd utifrån monokulturer. Forskning har även visat att foderkonkurrens mellan hjortdjuren kan göra att älg betar mer tall än bärris. En kunskapsbaserad viltförvaltning som omfamnar fler arter än en skulle kunna vara en del av lösningen.

<p>Den här uppsatsen grundar sig på två fältstudier i nyutlagda demonstrationsförsök på Asa försökspark som ska användas i utbildningssyfte. Studie 1 bestod av försöksytor i ett 13 år gammalt bestånd som röjts till samma röjningsförband men med tre skilda metoder; motormanuell selektiv röjning, maskinell stråkröjning och som en kombination av bägge metoderna. Syftet var att beskriva det nuvarande tillståndet, simulera fram prognoser för beståndsutvecklingen och beräkna dess ekonomiska konsekvenser fram till och med första gallring och jämföra de olika metoderna med varandra. Studie 2 bestod av försöksytor i ett 23 år gammalt eftersatt bestånd där fyra olika åtgärder testades; ingen röjning innan gallring, underröjning i samband med gallring, sen röjning och skogsbränsleuttag. Syftet var även här att jämföra de olika metoderna med varandra genom beskrivning av det nuvarande tillståndet, göra prognoser för beståndsutvecklingen och beräkna dess ekonomiska konsekvenser vid första gallring och i den här studien även fram till och med den andra gallringen. De två nya metoderna, stråkröjningsmetoderna i studie 1 och skogsbränsleuttag i studie 2, hade stor potential gentemot de konventionella metoderna.</p> / <p>This thesis is based on two field studies in a recently started demonstration experiment by the Asa Experimental Forest, where it will be used for educational purposes. Study 1 consisted of experimental plots in a 13 years old stand which have been pre-commercial thinned to the same number of tree stems but with three different methods: motor-manual selective pre-commercial thinning by brush saw, mechanical pre-commercial line thinning and as a combination of the both methods. The purpose was to describe the present status, run simulations and produce forecasts for the development of the stand and calculate the economical aspects up to and including the first thinning and then compare the different methods with each other. Study 2 consists of experimental plots in a 23 years old stand with a pre-commercial thinning backlog, where four different treatments were tested; no pre-commercial thinning at all before the first thinning, low pre-commercial thinning in connection with the first thinning, late pre-commercial thinning and extraction of wood fuel. The purpose was also here to compare the different methods with each other through describing the present status, run simulations and produce forecasts for the development of the stand and calculate the economical aspects at the first thinning and in this study also up to and including the second thinning. The two new methods, mechanical pre-commercial line thinning in study 1 and wood fuel extraction in study 2, showed a great potential in comparison with the conventional methods.</p>

Den här uppsatsen grundar sig på två fältstudier i nyutlagda demonstrationsförsök på Asa försökspark som ska användas i utbildningssyfte. Studie 1 bestod av försöksytor i ett 13 år gammalt bestånd som röjts till samma röjningsförband men med tre skilda metoder; motormanuell selektiv röjning, maskinell stråkröjning och som en kombination av bägge metoderna. Syftet var att beskriva det nuvarande tillståndet, simulera fram prognoser för beståndsutvecklingen och beräkna dess ekonomiska konsekvenser fram till och med första gallring och jämföra de olika metoderna med varandra. Studie 2 bestod av försöksytor i ett 23 år gammalt eftersatt bestånd där fyra olika åtgärder testades; ingen röjning innan gallring, underröjning i samband med gallring, sen röjning och skogsbränsleuttag. Syftet var även här att jämföra de olika metoderna med varandra genom beskrivning av det nuvarande tillståndet, göra prognoser för beståndsutvecklingen och beräkna dess ekonomiska konsekvenser vid första gallring och i den här studien även fram till och med den andra gallringen. De två nya metoderna, stråkröjningsmetoderna i studie 1 och skogsbränsleuttag i studie 2, hade stor potential gentemot de konventionella metoderna. / This thesis is based on two field studies in a recently started demonstration experiment by the Asa Experimental Forest, where it will be used for educational purposes. Study 1 consisted of experimental plots in a 13 years old stand which have been pre-commercial thinned to the same number of tree stems but with three different methods: motor-manual selective pre-commercial thinning by brush saw, mechanical pre-commercial line thinning and as a combination of the both methods. The purpose was to describe the present status, run simulations and produce forecasts for the development of the stand and calculate the economical aspects up to and including the first thinning and then compare the different methods with each other. Study 2 consists of experimental plots in a 23 years old stand with a pre-commercial thinning backlog, where four different treatments were tested; no pre-commercial thinning at all before the first thinning, low pre-commercial thinning in connection with the first thinning, late pre-commercial thinning and extraction of wood fuel. The purpose was also here to compare the different methods with each other through describing the present status, run simulations and produce forecasts for the development of the stand and calculate the economical aspects at the first thinning and in this study also up to and including the second thinning. The two new methods, mechanical pre-commercial line thinning in study 1 and wood fuel extraction in study 2, showed a great potential in comparison with the conventional methods.

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.

Growing forests are extremely valuable for the climate, for our shift towards a non-fossil-based society as well as to our economy. In order to create a healthy and lucrative forest that can cope with increasing future demands and challenges, certain forestry actions are required in which pre-commercial thinning is the most important one. Studies show that pre-commercial thinning today suffers from an acute shortage of available workforce with necessary qualifications. This project investigates the possibilities of creating a forest machine that can perform pre-commercial thinning autonomously. This project resulted in a concept called CURO. CURO is a fully autonomous robot that carries out pre-commercial thinning in young forest stands. It is designed to be agile and compact to be able to move around easily in the forest. For an autonomous forest machine to be able to perform successfully in a difficult terrain, lots of data is needed. Information about the forest is gathered over time when different forestry actions are carried out in the area. This information is shared with CURO. It combines all the collected information with data perceived from its own sensors to make the best suitable decision for each individual forest stand.