Control of timber flows tailored to enstomer needs : influence of size of tract register and accuracy of log tally projection

För att kunna styra våra avverkningsoperationer i skogen är vi beroende av någon form av beslutsunderlag. En form beslutsunderlag är prognoser på utfall vid avverkning som ger en skattning av längd-, diameter- och kvalitetsfördelning i ett avverkningsobjekt Prognoser kan vara till hjälp vid styrning av timmerflöden från skog till såg. Denna uppsats har till syfte att besvara frågorna: Vilken prognosnoggrannhet kan erhållas med hjälp av SkogForsks apteringssimulator Aptan i praktisk drift? Hur påverkas möjligheterna att styra timmerflödet mot vad marknaden efterfrågar av hur stor traktbanken är? Arbetet har bestått i att jämföra stocknotor från prognos, skördare, inmätning och postning samt simuleringar av hur olika traktbanksstorlekar kan uppfylla skiftande efterfrågan. Skiftande efterfrågan har simulerats genom att skapa önskestocknotor ( detaljerad efterfrågan) för fyra olika efterfrågescenarier. Efterfrågescenarierna simulerar ökad efterfrågan på: gran, tall, specialdimensioner samt ingen förändrad efterfrågan. Allt material i studien kommer från AB Forssjö Bruk i Forssjö, nära Katrineholm. Studien av prognosens noggrannhet i termer av fördelningsgrad visade att det finns problem förenade med att göra objektsvisa prognoser på utfall vid avverkning. Fördelningsgraden anger, förenklat uttryckt, hur väl två stocknotor stämmer överens Vid jämförelse av fördelningen mellan ett virkesparti vid prognos och sedan vid inmätning och postning var fördelningsgraden i medeltal 48 % för tall och 53 % för gran. Fördelningsgraden mellan skördare och postning är för gran lika rättvisande som fördelningsgraden mellan inmätning och postning. Fördelningsgraden mellan inmätning och postning 88 %för tall och 80% för gran. I andra studier har fördelningsgrader på 90 % erhållits mellan prognos och inmätning. Studien visar att möjligheterna att kunna hantera en skiftande efterfrågan ökar med en större traktbank. En liten traktbank kan vara tillräckligt, men då ställs högre krav på förmåga att förutse efterfrågan samt ett noggrannare val av objekt till traktbanken. En stor traktbank ger större valfrihet och har således ett värde. Om inte önskestocknotan och traktbanken har en liknande trädslagssammansättning minskar möjligheterna att leverera en liten avvikelse för flera olika scenarier.In order to direct our harvesting operations, we need information about the forests that we are operating in. One way of getting information about our forests is to make computerized bucking simulations that will provide information of how the length, diameter and quality will be distributed in a stand. Computerized bucking simulations ma y therefore be a useful tool for directing the flo w of timber from the forests to the sawmill. The aim of the study was to answer the following questions: What is the accuracy of the prognosis that we can expect if using the computerized bucking simulation tool Aptan, designed by the Farestry Research Institute of Sweden, in practical use? How are the possibilities to direct our customer-oriented flow of timber from the forests to the sawmills affected by the size of the register of harvesting tracts? The study was conducted by camparing the conformity between log tallies from the prognosis, log tallies from the harvester, log tallies from the sawmilllog measurements and log tallies from the sawmill productian planning log measurements. The variation in customer demands was simulated by creating different demand log tallies for four different demand scenarios: increased demand of spruce timber, increased demand of pine timber, increased demand for special dimension timber and finally no change in demand. All data in the study originates from AB Forssjö Bruk in Forssjö, close to Katrineholm, central Sweden. The following conclusions were made: • There are problems associated with computerized bucking simulations on log tall y lev el. • The conformity between the prognosis log tall y and the sawmilllog tall y was in average 48 % for pine and 53 % for spruce. The conformity between harvester log tall y and sawmilllog tally was in average 81 %for pine and 82% for spruce. • The possibilities to meet a change in customer demand increases with a larger register of harvesting tracts. A small register of harvesting tracts might be sufficient, but it is then more important to be able to prediet the customer demand. The composition of the register of harvesting tracts becomes more important if the register of harvesting tract is small. A large register of harvesting tracts gives more options and is therefore valuable. • The study also indicates that the possibilities to satisfy the demand tall y with any given register of harvesting tracts requires about the same tree species composition in the demand log tall y and register of harvesting tracts

Increase in dead wood, large living trees and tree diversity, yet decrease in understory vegetation cover: The effect of three decades of biodiversity-oriented forest policy in Swedish forests

In Sweden, the majority of forest area has been altered by industrial forestry over the decades. Almost 30 years ago, a shift towards biodiversity-oriented forest management practices occurred. Here we took advantage of long-term data collected by the Swedish National Forest Inventory to track developmental changes in forest structural components over this time. We assessed changes in structural components that play an important role in biodiversity (dead wood, large living trees, tree species composition, and understory vegetation) in four forest types with descending tiers of biodiversity protection: protected areas, woodland key habitats, low-productivity forests and production forests. Overall, we found a positive trend in the volumes of dead wood and large living trees, as well as in tree species diversity, while there was a general decline in understory vegetation coverage. Most observed changes were consistent with the intended outcomes of the current forest policy, adapted in the early 1990s. The implementation of retention forestry is likely driving some of the observed changes in forest structural components in the south. In contrast, we observed no changes in any of the focal structural components in the north, which could be attributed to the ongoing clear-cutting of forests previously managed less intensively. Dead wood and large living trees increased not only in managed, but also in unmanaged forests, likely reflecting historical management. The increased tree species diversity can be explained through current forest management practices that encourages maintenance of additional tree species. Decreasing understory vegetation coverage in both dense managed and unmanaged forests suggests that factors other than forestry contribute to the ongoing changes in understory vegetation in Swedish forests. Overall, the observed increase in structural components has not yet been reflected in documented improvements for red-listed forest species, which may be due to delays in species responses to small improvements, as well as a lack of detailed monitoring. Similarly, the increased availability of forest structural components might still be insufficient to meet the specific habitat requirements of red-listed species

Domestic Workload and Multiple Roles. Epidemiological findings on health and sickness absence in women

Aim: The objective of this thesis was to analyse the importance of specific exposures in women’s lives to health and sickness absence; more precisely to study the association between domestic work, multiple roles and the experience of being sick-listed, and self-rated health, psychiatric disorders and sickness absence. Method: The thesis was based on two datasets. ‘Women’s health and living conditions’ (WHL) is a cross-sectional study on 1 417 employed women aged 17 to 64 years old. Data was collected with a questionnaire, and register and employee data on sickness absence. ‘Women and alcohol in Göteborg’ (WAG) is a prospective cohort study on 1 799 women in eight age cohorts born from 1925 to 1980. Data was collected with a screening questionnaire, interviews and register-based sickness absence. Several aspects of domestic work, multiple roles and experience of sickness absence were analysed in relation to self-rated health (SF-36), psychiatric disorders (DSM-III and IV) and sickness absence. The study on multiple roles emanated from the role strain and role enhancement hypotheses and roles were analysed as single roles and as combinations of roles. Changes in self-rated physical health were assessed in relation to experience of sickness absence over five year. Cross-sectional and longitudinal analyses were conducted using multivariate regressions analyses. Results: Domestic job strain and a lack of domestic work equity and marital satisfaction were associated with lower self-rated health particularly vitality and mental health. The former was not associated to sickness absence, but the latter was. Women with domestic workload due to children and adults with special needs had higher odds for medium-long sick-leave spells, while parental responsibility gave lower odds for any sick-leave spell. Occupation was related to lower odds for poor self-rated physical health and sickness absence, while the parental role was associated with higher odds for sickness absence. Compared with women who had all three roles women with occupation and partner role had lower odds for negative health outcomes. Support was found for the role strain hypothesis in the cross-sectional analyses of role combinations while neither of the hypotheses was supported in the five year follow up. A lower proportion of those who had experience of being sick-listed reported good health at both baseline and follow up. Women with psychiatric disorders had higher odds for a change from poor to good self-rated physical health over the five years if they had been sick-listed. Conclusion: Domestic workload was associated to health and sickness absence in women, but there were inconsistencies in the findings on children and being a parent and on multiple roles. From a public health perspective, deeper knowledge on the importance of women’s engagement domestic work and its different dimensions is important for promoting women’s health. A multidimensional assessment of domestic work is important and the content and complexity of domestic work and of different roles needs to be further explored in relation to health and sickness absence in women

Can high psychological job demands, low decision latitude, and high job strain predict disability pensions? A 12-year follow-up of middle-aged Swedish workers.

OBJECTIVES: The aim of this study was to investigate whether job strain, psychological demands, and decision latitude are independent determinants of disability pension rates over a 12-year follow-up period. METHODS: We studied 3,181 men and 3,359 women, all middle-aged and working at least 30 h per week, recruited from the general population of Malmö, Sweden, in 1992. The participation rate was 41 %. Baseline data include sociodemographics, the Job Content Questionnaire, lifestyle, and health-related variables. Disability pension information was obtained through record linkage from the National Health Insurance Register. RESULTS: Nearly 20 % of the women and 15 % of the men were granted a disability pension during the follow-up period. The highest quartile of psychological job demands and the lowest quartile of decision latitude were associated with disability pensions when controlling for age, socioeconomic position, and health risk behaviours. In the final model, with adjustment also for health indicators and stress from outside the workplace, the hazard ratios for high strain jobs (i.e. high psychological demands in combination with low decision latitude) were 1.5 in men (95 % CI, 1.04-2.0) and 1.7 in women (95 % CI, 1.3-2.2). Stratifying for health at baseline showed that high strain tended to affect healthy but not unhealthy men, while this pattern was reversed in women. CONCLUSIONS: High psychological demands, low decision latitude, and job strain were all confirmed as independent risk factors for subsequent disability pensions. In order to increase chances of individuals remaining in the work force, interventions against these adverse psychosocial factors appear worthwhile

Insomnia Symptoms, Sleep Duration, and Disability Pensions: a Prospective Study of Swedish Workers.

BACKGROUND: Previous studies have found insomnia and long sleep duration to be independently associated with subsequent disability pension (DP). However, the issue of a possible gender-based pattern in this context has received little attention. PURPOSE: This study aims to assess the impact of insomnia symptoms and sleep duration on the DP rates among Swedish women and men during a 12-year follow-up period. METHOD: The participants, from the general population of Malmö, Sweden, were enrolled from 1992 to 1994 (n = 4,319; participation rate 41 %), aged 45-64, healthy, and employed ≥30 h per week. Baseline inquiry data concerning psychosocial circumstances and self-reported sleep habits were compared with official register-based DP rates. RESULTS: Five hundred and nine persons were granted a DP. Insomnia symptoms, affirmed by 33 % of the men and 41 % of the women, were associated with receiving a DP; the hazard ratios in the fully adjusted model were 1.4 for both men [95 % confidence interval (CI) 1.1, 1.9] and women (95 % CI 1.1, 1.7). The fully adjusted hazard ratio for women sleeping ≥9 h was 7.8 (95 % CI 3.7, 16.6) for DP due to a mental disorder. In the age-adjusted analyses, the sub-domain "difficulties falling asleep" was related to DP due to mental disorders in men and DP due to cardiovascular diseases in women. CONCLUSION: The findings suggest that preventing and treating insomnia symptoms could reduce DP and that disease mechanisms linking sleep disturbances to DP may differ by gender