Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

The potential of utilizing boreal forests for carbon storage has gained momentum, a recognition reflected in both the Paris Agreement and science. Research on the consequences of climate policy on sustainable forest management delineate, rather inadequately, the complexities of policy-human-environment interactions. These studies are limited in terms of integrating various land user with different values sharing the same forest resource, such as indigenous peoples. This paper uses a semi-quantitative Fuzzy Cognitive Mapping (FCM) approach to capture interdisciplinary knowledge by comparing different scenarios regarding forest management strategies and power regimes, driven by the Paris Agreement or Forest Stewardship Council (FSC). Given these scenarios, this paper aims to analyze the possible effects on quality of winter grazing grounds for reindeer relative to forest biomass yield. The findings of this study confirm that a scenario with more intensively managed forest is most likely to harm terrestrial and arboreal lichen availability, which is the basis for sustainable winter grazing for reindeer. The study also suggests that more indigenous influence would enhance the sustainability of reindeer herding. Based on these results and given this era of industrially intensified forest management, now partly justified by climate change mitigation, it can be argued that the livelihood of Sami herders is vulnerable due to multiple direct and indirect climate stressors. The results are discussed to explore possible policy implementations, as well as environmental decision making.   Keywords: climate policy, climate mitigation, boreal forests, indigenous herding, power regimes

The factors affecting tree establishment in boreal forests after fire will help determine the community composition of the regenerating forest. These may have large consequences on the community dynamics for years after the fire disturbance. Factors such as burn severity and soil moisture among others have been shown to play a key role in influencing several facets of establishment. However, tree establishment after megafire in boreal forest in Europe has not yet been fully understood. Here I capitalise on a megafire in Sweden in 2014 to investigate the relative impact of different abiotic factors and preconditions on tree establishment six years after the fire. This study used a systematic survey of tree saplings (height >30cm) at 625 locations inside the nature reserve set up within the burnt area. Tested factors were: The number of dead trees lying down, slope and slope aspect, elevation, soil wetness, pre-fire standing volume, distance to fire perimeter, forest stand age, stand productivity index, previous stand dominant tree species, humus thickness after fire and depth of burn. Generalized Linear Mixed Models (GLMMs) were used to estimate the effect of these factors on specific tree species abundance. Strong influences from previous wood volume, soil wetness, elevation, and dead wood lying down had an effective influence on sapling abundance but were typically species-specific. Only elevation and wood volume had a consistent effect on all species’ abundances. Habitat context was important on a landscape scale. These results support the pattern of increasing boreal deciduousness caused by high burn severity and shorter disturbance intervals, in turn, caused by hotter, drier weather, which will have implications on the composition of boreal forests of tomorrow.

Modern forestry practices have negative effects on many organisms because they change the forest’s disturbance dynamics, makes the forest’s structure less complex, and fragments old-growth forests. This study examined how commercial forestry practices affect the diversity of wood-decaying fungi, by comparing two closely related forests with different management in Östergötland, Sweden. The eastern forest is commercially managed while the western forest is unmanaged and protected since the 1920’s. Ten sample plots in each forest were inventoried for CWD and wood decaying fungi. Statistical analyses showed that the unmanaged natural forest had higher species abundance and more dead wood per hectare. All red-listed species were exclusive to the natural forest. Species abundance was shown to be positively correlated with the amount of dead wood. In four cases, the presence of a species could be predicted by the diameter of the substrate. These results align with previous findings and show that natural forests with large amounts of dead wood are needed to sustain the diversity of wood decaying fungi in Swedish forests.

Forests account for a large portion of global carbon storage. Almost half of this carbon is stored underground. Roots, especially fine-roots (diameter ≤ 2 mm) are an important part of soil carbon, and play a number of ecological roles. Yet, the below-ground parts of trees are still poorly understood. The aim of this report was to understand environmental controls over plants traits. I tested if plants shift their root traits towards a resource conservative strategy when environmental conditions are challenging (dry and cold). Furthermore, the contribution of different fine-root diameters to total root length (TRL), surface area (SA) and root volume (VO) was assessed. Root traits such as TRL, SA, VO, fine-root diameter, specific root length (SRL) and root tissue density (RTD) were quantified. The root samples are taken from 11 old growth Swedish forests across a climate gradient in three different soil moisture categories per forest (dry, intermediate, wet). Fine-roots were scanned, and analysed with the RhizoVision Explorer Software (Version 2.0.3). Uni-factorial ANOVAs, combined with Tukey’s posthoc test, or linear regressions were conducted, and the results revealed no significant effects of the summer air temperature on root traits. However, higher soil moisture was found to decrease RTD, but increase fine-root diameters significantly. These findings did not confirm the plants aim on building resource conservative root traits in challenging conditions. Instead, they highlighted variability among and within forests suggest that multiple factors influence root morphology and function. This study contributes to our understanding of how fine-roots respond to environmental conditions.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2009. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser.