2010; Dunwiddie et al. 2011). Changes in forest community structure based on pollen and charcoal analyses correspond with termination of the Little Ice Age, decimation of aboriginal populations due to disease (smallpox epidemics),
fire suppression, and European colonization. The pollen and charcoal records also show recent change in forest structure due to logging, clearing and settlement reflecting change in click here natural resource management practices and the displacement of aboriginal people and their land practices. McCoy (2006) also aimed to determine a mean fire return interval (MFRI), or average number SB273005 solubility dmso of fires within learn more a designated area during a specified time (Agee 1993; CIFFC 2002), for each site. An MFRI can be used to define a natural range of variability for fire frequency, which in turn can help refine restoration management strategies (Higuera et al. 2005). MFRIs for Quamichan, Roe and Florence Lakes were 26, 27 and 41 years respectively. Frequent prescribed burning in the Pacific Northwest has been inferred from tree ring and charcoal records, ranging from 3 to 80 years (Agee and Dunwiddie
1984; McCoy 2006; Walsh et al. 2010; Sprenger and Dunwiddie 2011). These data are important in establishing the scientific foundation for prescribed burning in coastal ecosystems and may well be underestimated in frequency due to the low intensity nature of frequent burning in meadow environments (Agee 1993). Stand age and tree ring records The tree ring record of Garry oak and associated trees offers the
opportunity to examine how the cumulative impacts of fire exclusion, climate change, species introductions, and other land management practices have affected the structure and composition of Garry oak ecosystems. Dendroecological analyses of Garry oak are relatively uncommon due to the hardness of the tree, Montelukast Sodium and its presumed low potential for dendroclimatic studies. Nonetheless, studies have been undertaken, and their results reveal several recent important changes to Garry oak ecosystems. Gedalof et al. (2006) examined changes in stand structure and composition at Canadian Forces Base Rocky Point on southern Vancouver Island in a 0.9 ha plot using tree-ring analysis and historical techniques (i.e., historical air photographs and documents) (Fig. 1b).