Fuels treatment and wildfire effects on runoff from Sierra Nevada mixed-conifer forests

We applied an eco-hydrologic model (Regional Hydro-Ecologic Simulation System [RHESSys]), constrained with spatially distributed field measurements, to assess the impacts of forest-fuel treatments and wildfire on hydrologic fluxes in two Sierra Nevada firesheds. Strategically placed fuels treatments were implemented during 2011–2012 in the upper American River in the central Sierra Nevada (43 km2) and in the upper Fresno River in the southern Sierra Nevada (24 km2). This study used the measured vegetation changes from mechanical treatments and modelled vegetation change from wildfire to determine impacts on the water balance. The well-constrained headwater model was transferred to larger catchments based on geologic and hydrologic similarities. Fuels treatments covered 18% of the American and 29% of the Lewis catchment. Averaged over the entire catchment, treatments in the wetter central Sierra Nevada resulted in a relatively light vegetation decrease (8%), leading to a 12% runoff increase, averaged over wet and dry years. Wildfire with and without forest treatments reduced vegetation by 38% and 50% and increased runoff by 55% and 67%, respectively. Treatments in the drier southern Sierra Nevada also reduced the spatially averaged vegetation by 8%, but the runoff response was limited to an increase of less than 3% compared with no treatment. Wildfire following treatments reduced vegetation by 40%, increasing runoff by 13%. Changes to catchment-scale water-balance simulations were more sensitive to canopy cover than to leaf area index, indicating that the pattern as well as amount of vegetation treatment is important to hydrologic response

Variation in plant moisture stress associated with forest communities in the H. J. Andrews Experimental Forest

Measurement of plant moisture stress of 1-2 m understory conifers was made in "reference stands" on the H. J. Andrews Experimental Forest in 1970-1972. Maximum stress each year (measured between midnight and dawn) is closely correlated with the position of each community along one axis of an ordination of the vegetation. In some stands, stress decreases during rainless periods, for uncertain reasons. Apparently, use of different species in different plots does not, of itself, lead to differences in stresses measured at the plots

An estimate of carbon emissions from 2004 wildfires across Alaskan Yukon River Basin

© 2007 Tan et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Phylogenetic Constraints Do Not Explain the Rarity of Nitrogen-Fixing Trees in Late-Successional Temperate Forests

Symbiotic nitrogen (N)-fixing trees are rare in late-successional temperate forests, even though these forests are often N limited. Two hypotheses could explain this paradox. The 'phylogenetic constraints hypothesis' states that no late-successional tree taxa in temperate forests belong to clades that are predisposed to N fixation. Conversely, the 'selective constraints hypothesis' states that such taxa are present, but N-fixing symbioses would lower their fitness. Here we test the phylogenetic constraints hypothesis.Using U.S. forest inventory data, we derived successional indices related to shade tolerance and stand age for N-fixing trees, non-fixing trees in the 'potentially N-fixing clade' (smallest angiosperm clade that includes all N fixers), and non-fixing trees outside this clade. We then used phylogenetically independent contrasts (PICs) to test for associations between these successional indices and N fixation. Four results stand out from our analysis of U.S. trees. First, N fixers are less shade-tolerant than non-fixers both inside and outside of the potentially N-fixing clade. Second, N fixers tend to occur in younger stands in a given geographical region than non-fixers both inside and outside of the potentially N-fixing clade. Third, the potentially N-fixing clade contains numerous late-successional non-fixers. Fourth, although the N fixation trait is evolutionarily conserved, the successional traits are relatively labile.These results suggest that selective constraints, not phylogenetic constraints, explain the rarity of late-successional N-fixing trees in temperate forests. Because N-fixing trees could overcome N limitation to net primary production if they were abundant, this study helps to understand the maintenance of N limitation in temperate forests, and therefore the capacity of this biome to sequester carbon

Positive Art: Artistic Expression and Appreciation as an Exemplary Vehicle for Flourishing.

The relevance of the arts to wellbeing has been recognised within clinical fields, as reflected in therapeutic forms based on various art modalities, from music to drama therapy. However, there has hitherto been little appreciation in fields such as positive psychology of the broader potential of the arts as a vehicle for flourishing and fulfilment. As such, this paper proposes the creation of ‘positive art’ as a field encompassing theory and research concerning the wellbeing value of art. To show the scope and possibilities of this proposed field, the paper provides an indicative summary of literature pertaining to four major art forms: visual art, music, literature and drama. Moreover, the paper identifies five main positive outcomes that are consistently found in the literature across all these forms: sense-making, enriching experience, aesthetic appreciation, entertainment, and bonding. The paper aims to encourage a greater focus on the arts in fields like positive psychology, enabling science to more fully understand and appreciate the positive power of the arts

Zen and the Art of Living Mindfully: The Health-Enhancing Potential of Zen Aesthetics

Amidst the burgeoning enthusiasm for mindfulness in the West, there is a concern that the largely secular ‘de-contextualized’ way in which it is being harnessed is denuding it of its potential to improve health and well-being. As such, efforts are underway to ‘re-contextualize’ mindfulness, explicitly drawing on the wider framework of Buddhist ideas and practices in which it was initially developed. This paper aims to contribute to this, doing so by focusing on Zen Buddhism, and in particular on Zen aesthetic principles. The article concentrates on the seven principles identified by Hisamatsu (1971) in his classic text Zen and the Fine Arts: kanso (simplicity); fukinsei (asymmetry); koko (austere sublimity); shizen (naturalness); daisuzoku (freedom from routine); sei-jaku (tranquillity); and yūgen (profound grace). The presence of these principles in works of art is seen as reflecting and communicating insights that are central to Buddhism, such as non-attachment. Moreover, these principles do not only apply to the creation and appreciation of art, but have clear applications for treating health-related issues, and improving quality of life more generally. This paper makes the case that embodying these principles in their lives can help people enhance their psychosomatic well-being, and come to a truer understanding of the essence of mindful living

Constraining the relative importance of raindrop‐ and flow‐driven sediment transport mechanisms in postwildfire environments and implications for recovery time scales

Mountain watersheds recently burned by wildfire often experience greater amounts of runoff and increased rates of sediment transport relative to similar unburned areas. Given the sedimentation and debris flow threats caused by increases in erosion, more work is needed to better understand the physical mechanisms responsible for the observed increase in sediment transport in burned environments and the time scale over which a heightened geomorphic response can be expected. In this study, we quantified the relative importance of different hillslope erosion mechanisms during two postwildfire rainstorms at a drainage basin in Southern California by combining terrestrial laser scanner-derived maps of topographic change, field measurements, and numerical modeling of overland flow and sediment transport. Numerous debris flows were initiated by runoff at our study area during a long-duration storm of relatively modest intensity. Despite the presence of a well-developed rill network, numerical model results suggest that the majority of eroded hillslope sediment during this long-duration rainstorm was transported by raindrop-induced sediment transport processes, highlighting the importance of raindrop-driven processes in supplying channels with potential debris flow material. We also used the numerical model to explore relationships between postwildfire storm characteristics, vegetation cover, soil infiltration capacity, and the total volume of eroded sediment from a synthetic hillslope for different end-member erosion regimes. This study adds to our understanding of sediment transport in steep, postwildfire landscapes and shows how data from field monitoring can be combined with numerical modeling of sediment transport to isolate the processes leading to increased erosion in burned areas.National Geographic Society [Proposal002929-2009-0046-1]; National Science Foundation [02-39749, 09-34131]; U.S. Geological Survey (USGS) Landslide Hazards Program6 month embargo; First Published: 22 November 2016This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Studying the change in fAPAR after forest fires in Siberia using MODIS

Disturbance events such as fire have major effects on forest dynamics, succession and the carbon cycle in the boreal biome. This paper focuses on establishing whether characteristic spatio-temporal patterns of the fraction of Absorbed Photosynthetically Active Radiation (fAPAR) occur in the initial two years after a fire event in Siberian boreal forests. Time-series of MODIS fAPAR were used to study post-fire dynamics during the year of the fire and the following two years. Three forest types (evergreen needle-leaf, deciduous needle-leaf and deciduous broadleaf) grouped in three latitudinal regions, ranging from 51° N to 65° N, were studied by analysing a sample of fourteen burned areas. For each of the burned areas an adjacent unburned control plot was selected with the aim of separating inter-annual variations caused by climate from changes in fAPAR behaviour due to a burn. The results suggest that (i) the forest types exhibit characteristic fAPAR change trajectories shortly after the fire, (ii) the differences in the fAPAR trajectories are related to the forest type, (iii) fAPAR changes are not significantly different among the latitudinal regions, and (iv) the limited temporal variability observed among the three years of observations indicates that fAPAR varies very little in the initial years after a fire event