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Clear-cut logging is the most widely practised forestry method in Sweden. This often conflicts with nature conservation and leads to issues where economic interests are pitted against ecological values. Bryophytes are a group of organisms commonly used as indicators of change in the environment, and several species of this group are also used as tools for assessing conservation values in the habitats they occur in. These are termed indicator or signal species, as they demand certain prerequisites regarding for example climate or substrate that are characteristic for the specific habitat type. In this thesis, the effects of clear-cut logging on five Red-Listed bryophyte species specialised in old-growth forests were tested, to see if they can survive such an intervention. This was done in ArcGIS, by overlaying layers containing 13 years of species observations from Artportalen.se and spatio-temporally matched clear-cut areas from the Swedish Forest Agency. There were 229 logged areas containing a total of 401 observations of the selected bryophyte species, of which 25 were found post-logging. Additionally, 64 % of the post-logged findings were located within a 10 m buffer strip along the edge of the logged areas. The results provide strong evidence that clear-cut logging does impact these species negatively. At the same time the data suggest that developing adequate mitigation measures, for example retention patches along the edges, and evaluating those already in use, can help these species to some extent, by mitigating the negative impact. This is the most important implication from this study, because forestry will continue to be a necessary contribution to the ongoing transition towards a fossil free society. Therefore, the practice needs to shift towards a more biodiversity-friendly management, where alternative forestry methods that are less destructive, are promoted and used to a wider extent. Furthermore, the weight of these species as indicators of high conservation value for the habitats they grow in requires special caution when planning for logging such areas. Otherwise, there is risk of losing species to regional extinction, with specialist species like the ones in this study being of greatest concern. / Den vanligast förekommande skogsbruksmetoden i Sverige är idag trakthyggesbruket. Denna metod är inte alltid kompatibel med naturvårdsintressen och leder ofta till konflikter mellan ekonomiska och ekologiska värden. En organismgrupp som ofta används som indikatorer på förändringar i naturmiljön är mossor. Flertalet mossarter är dessutom så kallade signalarter, vilket betyder att de kan användas som ett mått på naturvärden i den biotop de förekommer i, då de har artspecifika krav på särskilda förutsättningar, som till exempel klimat och substrat. I den här studien testades därför hur slutavverkning påverkar fem Rödlistade mossarter strikt knutna till äldre kontinuitetsskogar. Syftet var att undersöka om de överhuvudtaget kan överleva ett sådant ingrepp. Detta utfördes genom att analysera rumsligt matchade geodatalager i ArcGIS, innehållande 13 års artobservationer från Artportalen.se samt utförda avverkningar från Skogsstyrelsen. Det fanns 229 avverkade områden med totalt 401 artobservationer, varav 25 var funna efter utförd avverkning. Av dessa 25 fynd var 64 % observerade inom en 10 m bred buffertzon utmed det avverkade områdets kant. Resultaten visar tydligt att slutavverkning påverkar dessa arter negativt, men pekar samtidigt på att utvecklingen av lämpliga metoder för naturvårdshänsyn (till exempel hänsynsytor längs med avverkningsområdenas kantzoner) och utvärdering av de metoder som redan används kan mildra problemet. Detta är därmed den viktigaste slutsatsen från denna studie, då skogsnäringen även fortsättningsvis kommer att vara ett viktigt bidrag till den pågående gröna omställningen och det är därför nödvändigt att främja även andra, mindre destruktiva, skogsbruksmetoder för att bibehålla och stärka ekologiska värden, som biodiversitet. Dessutom bör de här arternas värde som signalarter väga tungt vid planering av avverkning i dessa områden, då de ju visar att habitaten har höga naturvårdsvärden. Annars är det risk att vissa arter dör ut, i synnerhet sådana arter som är specialiserade på de miljöer som är mål för exploatering.

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I investigated the impacts of a catastrophic ice storm on the old-growth, hardwood forests of Mont St. Hilaire, Quebec. The mass of litter resulting from the ice storm of January 1998 was estimated using equations relating the basal diameter of fallen branches with branch mass for each of the ten major species. The ice storm of January 1998 produced 19.9 metric tonnes or 33.6 m3 of woody-litter per hectare. These losses of woody biomass are approximately 20 times greater than what is expected in a normal year and correspond to between 7--10% of the total above-ground biomass of the prestorm forest. This level of litter production positions the ice storm of 1998 as the most severe ice storm on record and amongst the most powerful forms of climatic disturbance experienced in forested ecosystems. / I also investigated differences in the magnitude and nature of the biomass losses sustained by each study species. While the magnitude of biomass lost by the study species was not related to either wood strength or stiffness, the nature of the biomass lost was. All species primarily lost branches less than 5 cm in diameter, but it was the relatively few branches greater than this diameter that accounted for the majority of downed biomass. Smaller branches were lost in relation to differences in species-specific mechanical properties, while larger branches appear to be lost in response to weakening by decay and other age-dependent factors. The ecological and evolutionary implications of these results emphasise the need for an analysis of the interplay between mechanical properties and canopy architecture in determining overall susceptibility to ice damage.

One of the human activities impacting biodiversity is the cutting of old-growth forests. In response to the controversy surrounding the cutting of old-growth in the coastal rainforest of BC, the Ministries of the Environment and Forests have produced biodiversity guidelines that are to be applied when manipulating stands in the provincial forest. This study augments these guidelines by investigating the diversity differences between second-growth and old-growth forests in relation to site quality. We demonstrate how standlevel plant diversity differs between 40-year-old and old-growth stands in the Very Wet Coastal Western Hemlock subzone (CWHvm) on Vancouver Island. This information is intended to provide foresters with an understanding of the effects of age, disturbance and site quality on stand-level plant diversity, thereby allowing for informed professional management decisions.

Central to the issue of harvest feasibility on the outer BC coast (CWHvh) is the question of whether sites, once harvested, can be regenerated, and whether the time period for replacement and subsequent growth is economically and environmentally acceptable. Since low productivity sites have not been harvested in the past, there is a lack of data to answer this question. We tried to provide an answer by assessing regeneration following natural disturbances. Small scale gap disturbances are the norm within old-growth stands. If regeneration is not a problem in gaps, then we have some evidence that regeneration should not be a problem upon implementation of our management practices. The objectives of this study were: (1) to develop baseline information on the mechanisms and the patterns of regeneration across a sequence of forest types; (2) to assess regeneration success with respect to productivity; and (3) to estimate future growth and productivity.

The objective of this thesis was to understand the spatial patterns and processes responsible for canopy and understorey spider (Arachnida: Araneae) diversity at multiple spatial scales in north-temperate hardwood forests. I sampled tree trunks (sticky traps) and foliage (beating) of sugar maple and American beech tree canopies and their understorey saplings in old growth forests near Montreal, Quebec. Results show the composition of canopy and understorey assemblages differed significantly, and so did sugar maple and American beech canopy assemblages. Each stratum was also dominated by different species. The rank-abundance distribution of species from each habitat wsa also verticaly stratified because it fit different distribution models. Different factors likely structure assemblages in both habitats, particularly since the canopy is a less stable environment. Spiders from canopy and understorey foliage were tested in a laboratory for their propensity to balloon. General linear models indicated that small sized web-building spiders of the RTA and Orbicularia clades have the highest propensity to balloon. Small bodied species initiated ballooning regardless of the habitat they were collected in or their developmental stage. My results support the mixed evolutionarily stable strategy theory and indicate the absence of risk-spreading in the dispersal strategy of canopy spiders. My last chapter focused on dispersal capacity and diversity patterns of spiders at multiple spatial scales. Analyses of the species diversity of limited and high dispersal capacity species subsets through nested-multivariate ANOVA, additive diversity partitioning, and species-abundance distribution curves all point towards species-sorting processes as the main driver of local community spider diversity at the tree and stand spatial scales. Mass-effects and patch-dynamic processes drive site and regional scale diversity patterns. This thesis demonstrates that spiders provide good models to test many biological hypotheses. The research chapters of this thesis test hypotheses on the vertical stratification of forest spider diversity, the evolution of local dispersal adaptations, and the importance of dispersal capacity on species diversity patterns through a metacommunity framework.

This thesis addresses the situation of First Nations people in forestry of British Columbia. Aboriginal people in British Columbia have been involved in the forest industry as laborers since the 1850s when the commercial logging operations began in the province, but have been politically and economically marginalized in the industry. The institutional and economic factors not only have restricted aboriginal people to control over forest resources on their traditional lands but have affected their forest management practices. For aboriginal communities, it is a critical issue that protecting old growth forests, with which they are culturally associated, without giving up economic benefit generated from harvesting these forests. In order to suggest possible changes and approaches for shaping native forest management in the existing institutional and economic frameworks, I examined the issues of provincial forestry and analyzed how these issues effect and interact with aboriginal people. It is important but difficult for First Nations to obtain forest tenure because their resource management is related to their land rights. However, the issues of aboriginal people in forestry overlap with those of the province. Thus, perspectives and participation of aboriginal people is critical for the government and the industry. Forestry of British Columbia is in transition and has begun to consider the potential contribution of aboriginal people to sustainable forestry. Therefore, aboriginal people have a significant role to play in the future of forestry.

The dynamics in Fagus-Acer forest have been frequently investigated, a particular interest being the replacement patterns and coexistence of the two dominant species, Fagus grandifolia Ehrh. and Acer saccharum Marsh. This thesis examines whether the community pattern and dynamics in a Fagus-Acer forest at Mont. St. Hilaire, Quebec, are consistent with predictions made by the disturbance hypothesis. This conceptual model explains the mechanisms underlying the coexistence and replacement patterns of the two dominant species. While the hypothesis suggests disturbance frequency and interspecific differences in growth under variable light conditions to be the key factors that determine the dynamics in Fagus-Acer forests, I demonstrate that edaphic factors and regeneration of Fagus by root sprouts can also play a significant role. Based on the findings, I propose an alternative model for the coexistence and replacement patterns in Fagus-Acer forest to better account for the influence of edaphic factors and of Fagus root sprouts.

This thesis addresses the situation of First Nations people in forestry of British Columbia. Aboriginal people in British Columbia have been involved in the forest industry as laborers since the 1850s when the commercial logging operations began in the province, but have been politically and economically marginalized in the industry. The institutional and economic factors not only have restricted aboriginal people to control over forest resources on their traditional lands but have affected their forest management practices. For aboriginal communities, it is a critical issue that protecting old growth forests, with which they are culturally associated, without giving up economic benefit generated from harvesting these forests. In order to suggest possible changes and approaches for shaping native forest management in the existing institutional and economic frameworks, I examined the issues of provincial forestry and analyzed how these issues effect and interact with aboriginal people. It is important but difficult for First Nations to obtain forest tenure because their resource management is related to their land rights. However, the issues of aboriginal people in forestry overlap with those of the province. Thus, perspectives and participation of aboriginal people is critical for the government and the industry. Forestry of British Columbia is in transition and has begun to consider the potential contribution of aboriginal people to sustainable forestry. Therefore, aboriginal people have a significant role to play in the future of forestry. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate