Regional Assessment of N saturation using foliar and root d15N

N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar than the regional driver of N deposition. Foliar increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root was more tightly coupled to forest floor properties than was foliar . We observed a pattern of decreasing foliar values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar included species composition and climate. Relationships between foliar and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar , due to the importance of ammonium deposition in this region. Our results suggest that examining values of foliage may improve understanding of how forests respond to the cascading effects of N deposition

The impact of general and carbon-related environmental knowledge on attitudes and behaviour of US consumers

Global warming and carbon emissions have gained international attention. However, it would appear that consumers are still unclear about what it encompasses and how it relates to their individual behaviour. Using the Theory of Reasoned Action (TRA) as a guiding framework, this study presents a structural equation model that tests the relationships between carbon and environmental knowledge, environmental attitude and behaviour using a sample of US consumers. The findings of the research suggest that a positive relationship was found between general and carbon-specific knowledge, attitude towards the environment, and general and carbon-specific behaviours. Therefore, general and carbon-specific environmental behaviours are related and may be driven by general attitudes and knowledge (i.e. both carbon-specific and general environmental knowledge). The implications of the study would suggest that marketers, working in tandem with government policymakers, need to focus efforts on developing consumers' knowledge about specific sub-issues, such as global warming. However, additional research needs to be undertaken to develop marketing communication that accurately reflects the environmental impact of consumption behaviour, thereby allowing for considered consumption