Burns Bog (the Bog) is a 2800 ha protected peatland in Delta, British Columbia. Globally unique due to its form, size, chemistry, flora and fauna the Bog is distinct and managed as a wetland. In 2005, a large fire consumed 200 ha of peatland after which birch (Betula pendula) and pine (Pinus contorta) trees grew in great densities. Within the fire zone piezometers were installed to monitor water levels below the surface. A high water level promotes peat-forming processes and in 2009 water levels dropped significantly. In 2010, a 75m x 50m experimental plot within the fire zone was cleared of birch and pine trees to investigate the impacts of tree removal on bog hydrology and plant communities. Higher water levels and positive bog plant growth at the experimental site was observed in 2010 and 2011 when compared to the control site where trees remained intact.

<p>This thesis focuses on responses in raised bogs to changes in the effective humidity during the Holocene. Raised bogs are terrestrial deposits that can provide contiguous records of past climate changes. Information on and knowledge about past changes in climate is crucial for our understanding of natural climate variability. Analyses on different spatial and temporal scales have been conducted on a number of raised bogs in south-central Sweden in order to gain more knowledge about Holocene climate variability.</p><p>Peatlands are useful as palaeoenvironmental archives because they develop over the course of millennia and provide a multi-faceted contiguous outlook on the past. Peat humification, a proxy for bog surface wetness, has been used to reconstruct palaeoclimate. In addition measurements of carbon and nitrogen on sub-recent peat from two bogs have been performed. The chronologies have been constrained by AMS radiocarbon dates and tephrochronology and by SCPs for the sub-recent peat.</p><p>A comparison between a peat humification record from Värmland, south-central Sweden, and a dendrochronological record from Jämtland, north-central Sweden, indicates several synchronous changes between drier and wetter climate. This implies that changes in hydrology operate on a regional scale.</p><p>In a high resolution study of two bogs in Uppland, south-central Sweden, C, N and peat humification have been compared to bog water tables inferred from testate amoebae and with meteorological data covering the last 150 years. The results indicate that peat can be subjected to secondary decomposition, resulting in an apparent lead in peat humification and C/N compared to biological proxies and meteorological data.</p><p>Several periods of wetter conditions are indicated from the analysis of five peat sequences from three bogs in Värmland. Wetter conditions around especially c. 4500, 3500, 2800 and 1700-1000 cal yr BP can be correlated to several other climate records across the North Atlantic region and Scandinavia, indicating wetter and/or cooler climatic conditions at these times. Frequency analyses of two bogs indicate periodicities between 200 and 400 years that may be caused by cycles in solar activity.</p>

This thesis focuses on responses in raised bogs to changes in the effective humidity during the Holocene. Raised bogs are terrestrial deposits that can provide contiguous records of past climate changes. Information on and knowledge about past changes in climate is crucial for our understanding of natural climate variability. Analyses on different spatial and temporal scales have been conducted on a number of raised bogs in south-central Sweden in order to gain more knowledge about Holocene climate variability. Peatlands are useful as palaeoenvironmental archives because they develop over the course of millennia and provide a multi-faceted contiguous outlook on the past. Peat humification, a proxy for bog surface wetness, has been used to reconstruct palaeoclimate. In addition measurements of carbon and nitrogen on sub-recent peat from two bogs have been performed. The chronologies have been constrained by AMS radiocarbon dates and tephrochronology and by SCPs for the sub-recent peat. A comparison between a peat humification record from Värmland, south-central Sweden, and a dendrochronological record from Jämtland, north-central Sweden, indicates several synchronous changes between drier and wetter climate. This implies that changes in hydrology operate on a regional scale. In a high resolution study of two bogs in Uppland, south-central Sweden, C, N and peat humification have been compared to bog water tables inferred from testate amoebae and with meteorological data covering the last 150 years. The results indicate that peat can be subjected to secondary decomposition, resulting in an apparent lead in peat humification and C/N compared to biological proxies and meteorological data. Several periods of wetter conditions are indicated from the analysis of five peat sequences from three bogs in Värmland. Wetter conditions around especially c. 4500, 3500, 2800 and 1700-1000 cal yr BP can be correlated to several other climate records across the North Atlantic region and Scandinavia, indicating wetter and/or cooler climatic conditions at these times. Frequency analyses of two bogs indicate periodicities between 200 and 400 years that may be caused by cycles in solar activity.