<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"  xmlns:dc="http://purl.org/dc/elements/1.1/"><channel><title>New Publications Online From The US Forest Service Research and Development</title><link>http://www.treesearch.fs.fed.us/pubs/</link><description>25 newest publications from the US Forest Service, Research and Development.  http://www.treesearch.fs.fed.us/pubs/</description><language>en-us</language><lastBuildDate>Fri, 8  Aug 2008 13:51:27 EDT 2008</lastBuildDate>

<item>
	<title>
		Pre-exposure to drought increases the resistance of tropical forest soil bacterial communities to extended drought	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43525	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43525	</guid>
	<description>
		<![CDATA[Global climate models project a decrease in the magnitude of precipitation in tropical regions. Changes in rainfall patterns have important implications for the moisture content and redox status of tropical soils, yet little is known about how these changes may affect microbial community structure. Specifically, does exposure to prior stress confer increased resistance to subsequent perturbation? Here we reduced the quantity of precipitation throughfall to tropical forest soils in the Luquillo Mountains, Puerto Rico. Treatments included newly established throughfall exclusion plots (de novo excluded), plots undergoing reduction for a second time (pre-excluded) and ambient control plots. Ten months of throughfall exclusion led to a small but statistically significant decline in soil water potential and bacterial populations clearly adapted to increased osmotic stress. Although the water potential decline was small and microbial biomass did not change, phylogenetic diversity in the de novo-excluded plots decreased by B40% compared with the control plots, yet pre-excluded plots showed no significant change. On the other hand, the relative abundances of bacterial taxa in both the de novo-excluded and pre-excluded plots changed significantly with throughfall exclusion compared with control plots. Changes in bacterial community structure could be explained by changes in soil pore water chemistry and suggested changes in soil redox. Soluble iron declined in treatment plots and was correlated with decreased soluble phosphorus concentrations, which may have significant implications for microbial productivity in these P-limited systems.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 16:55:57 -0400	</pubDate>

        <dc:creator>
                Bouskill, Nicholas J.; Lim, Hsiao Chien; Borglin, Sharon; Salve, Rohit; Wood, Tana E.; Silver, Whendee L.; Brodie, Eoin L.        </dc:creator>
        <dc:subject>
                resistance; pyrosequencing; drought effects; temporal; tropical soils; Luquillo; Puerto Rico;         </dc:subject>
</item> 



<item>
	<title>
		Performance of high temperature heat flux plates and soil moisture probes during controlled surface fires	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43524	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43524	</guid>
	<description>
		<![CDATA[Natural and prescribed fires play an important role in managing and maintaining most ecosystems in the western United States. The high soil temperatures associated with fire influence forests and their ability to regenerate after a fire by altering soil properties and soil chemistry and by killing microbes, plant roots, and seeds. Because prescribed fire is frequently used to reduce surface fuels, it is important to know how fuel conditions, soil moisture, and soil properties interact to determine the soil temperatures, the depth of the soil thermal pulse, and the response of the soil biota to soil heating. This report presents the results of experimental tests of a high temperature soil heat flux plate and a high temperature soil moisture probe. These sensors are intended to provide data before, during, and after a prescribed burn in support of long term studies of soil microbial response to fires.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:25:28 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Frank, F. M.; Massman, S. M.; Shepperd, W. D.        </dc:creator>
        <dc:subject>
                heat flux plates, soil temperatures, soil properties, soil chemistry, surface fires        </dc:subject>
</item> 



<item>
	<title>
		Summary and synthesis of recommendations of the AmeriFlux Workshop on standardization of flux analysis and diagnostics; Corvallis, Oregon; August 2002	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43523	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43523	</guid>
	<description>
		<![CDATA[A DOE sponsored workshop was held August 27 - 30, 2002 at Oregon State University, Corvallis, Oregon. It was the second of the international AmeriFlux workshops intended to outline and recommend scientifically preferred procedures for calculating and 'correcting' eddy covariance fluxes for all AmeriFlux sites. The fundamental goals of these workshops are (1) to reduce or eliminate, as much as possible, uncertainties in cross-site comparisons of fluxes resulting from different methods of signal processing, high and low frequency spectral corrections, coordinate systems, data detrending, post-processing QA/QC, etc. and (2) to highlight and explore emerging issues, such as, the influence advection and complex terrain can have on measured fluxes and the types, nature, and influence nighttime or stable atmospheric motions can have on measured fluxes.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:23:04 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Finnigan, J.; Billesbach, D.; Miller, S.; Black, A.; Amiro, B.; Law, B.; Lee, X.; Mahrt, L.; Dahlman, R.; Foken, T.        </dc:creator>
        <dc:subject>
                AmeriFlux sites, eddy covariance fluxes        </dc:subject>
</item> 



<item>
	<title>
		High-frequency pressure variations in the vicinity of a surface CO2 flux chamber	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43522	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43522	</guid>
	<description>
		<![CDATA[We report measurements of 2Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO2 flux chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface fluxes of CO2. Under the moderate wind speeds, warm temperatures, and dry soil conditions present at the time of our observations, the chamber had no effect on the pressure field in its near vicinity that could be detected above the level of natural pressure fluctuations in the vicinity. At frequencies at or <2 Hz, pressure fluctuations easily penetrated the soil to depths of several cm with little attenuation. We conclude that the presence of the chamber does not introduce pressure perturbations that lead to biases in measurements of surface fluxes of CO2.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:20:50 -0400	</pubDate>

        <dc:creator>
                Takle, Eugene S.; Brandle, James R.; Schmidt, R. A.; Garcia, Rick; Litvina, Irina V.; Massman, William J.; Zhou, Xinhua; Doyle, Geoffrey; Rice, Charles W.        </dc:creator>
        <dc:subject>
                high-frequency, pressure variations, CO2 flux chamber, soil respiration, soil air        </dc:subject>
</item> 



<item>
	<title>
		An in situ investigation of the influence of a controlled burn on the thermophysical properties of a dry soil	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43521	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43521	</guid>
	<description>
		<![CDATA[High soil temperatures associated with fire influence forests and their ability to regenerate after a fire by altering soil properties and soil chemistry and by killing microbes, plant roots, and seeds. Because intense wild fires are an increasingly common component of the landscape (Graham 2003) and because fire is frequently used by land managers to reduce surface fuels, it is important to know if and how soil properties may change as a consequence of the fire-associated soil heat pulse. In particular, it is important to know whether the intrinsic (dry) soil thermophysical properties - volumetric specific heat capacity (Cs) and thermal conductivity ( s) - change as a result of soil heating. Significant changes, particularly in the intrinsic thermal conductivity of fire-affected soils, could indicate changes in the soil's structure, because soil thermal conductivity is strongly influenced by soil structure (Farouki 1986). Furthermore, such changes will lead to changes in the daily energy flow through the soil and the associated patterns and magnitudes of soil temperatures, which in turn may affect soil chemistry, soil aggregate stability, soil biota, and ultimately the nature of the soil's recovery from fire.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:18:52 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Frank, J. M.        </dc:creator>
        <dc:subject>
                soil temperatures, fire, soil properties, soil chemistry        </dc:subject>
</item> 



<item>
	<title>
		Concerning the measurement of atmospheric trace gas fluxes with open- and closed-path eddy covariance systems: The density terms and spectral attenuation [Chapter 7]	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43520	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43520	</guid>
	<description>
		<![CDATA[Atmospheric trace gas fluxes measured with an eddy covariance sensor that detects a constituent's density fluctuations within the in situ air need to include terms resulting from concurrent heat and moisture fluxes, the so called 'density' or 'WPL corrections' (Webb et al. 1980). The theory behind these additional terms is well established. But, virtually no studies to date have examined the constraints imposed on the theory by different instrumentation technologies and by limitations inherent to eddy covariance systems. This study extends the original WPL theory by examining how eddy covariance instrumentation, particularly spectral attenuation and an instrument's basic technology, influences the application of this theory to flux measurement. Specific issues discussed here include the importance of static pressure fluctuations to the WPL theory, the possible systematic overestimation of the WPL vapor term, and the transfer functions associated with signal processing and volume averaging effects of a fast-response closed-path CO2/H2O sensor. This different perspective on the WPL theory suggests that current methods of applying the WPL theory, particularly with closed-path systems, can yield significant biases in the annual carbon balance derived from eddy covariance technology and can cause the surface energy imbalance to increase with increasing wind speed. Furthermore, it is suggested that spectral corrections should be made before applying the WPL theory to estimate fluxes and that high frequency point-by-point conversions from mass density to mixing ratio is not the preferred method for estimating fluxes by eddy covariance.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:16:00 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.        </dc:creator>
        <dc:subject>
                atmospheric trace gas fluxes, eddy covariance systems        </dc:subject>
</item> 



<item>
	<title>
		Uncertainty in eddy covariance flux estimates resulting from spectral attenuation [Chapter 4]	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43519	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43519	</guid>
	<description>
		<![CDATA[Surface exchange fluxes measured by eddy covariance tend to be underestimated as a result of limitations in sensor design, signal processing methods, and finite flux-averaging periods. But, careful system design, modern instrumentation, and appropriate data processing algorithms can minimize these losses, which, if not too large, can be estimated and corrected using any of several different approaches. However, no flux-correction method is perfect so methodological uncertainties are inevitable. This study addresses the uncertainties in surface flux measurements that have been corrected for spectral attenuation with the transfer function approach. The sources of the errors in the estimates of flux attenuation examined here include the (flux-averaging) period-to-period variablity of cospectra, the departure of real cospectra from presumed smooth curves, the inherent variability in maximum frequency (fx) of the frequency weighted cospectra, and possible imprecision in instrument related time constants. A method is proposed to estimate the uncertainty resulting from combining these effects. Also included in this study are a general mathematical relationship to describe spectra or cospectra, comparisons of observed cospectra for cospectral similarity, and discussions about including high-pass filters (associated with the flux-averaging procedures) when accounting for low frequency losses.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:14:16 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Clement, R.        </dc:creator>
        <dc:subject>
                eddy covariance flux estimates, surface exchange fluxes, spectral attenuation        </dc:subject>
</item> 



<item>
	<title>
		Toward an ozone standard to protect vegetation based on effective dose: A review of deposition resistances and a possible metric	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43518	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43518	</guid>
	<description>
		<![CDATA[Present air quality standards to protect vegetation from ozone are based on measured concentrations (i.e., exposure) rather than on plant uptake rates (or dose). Some familiar cumulative exposure-based indices include SUM06, AOT40, and W126. However, plant injury is more closely related to dose, or more appropriately to effective dose, than to exposure. This study develops and applies a simple model for estimating effective ozone dose that combines the plant canopy's rate of stomatal ozone uptake with the plant's defense to ozone uptake. Here the plant defense is explicitly parameterized as a function of gross photosynthesis and the model is applied using eddy covariance (ozone and CO2) flux data obtained at a vineyard site in the San Joaquin Valley during the California Ozone Deposition Experiment (CODE91). With the ultimate intention of applying these concepts using prognostic models and remotely sensed data, the pathways for ozone deposition are parameterized (as much as possible) in terms of canopy LAI and the surface friction velocity. Results indicate that (1) the daily maximum potential for plant injury (based on effective dose) tends to coincide with the daily peak in ozone mixing ratio (ppbV), (2) potentially there are some significant differences between ozone metrics based on dose (no plant defense) and effective dose, and (3) nocturnal conductance can contribute significantly to the potential for plant ozone injury.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:12:30 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.        </dc:creator>
        <dc:subject>
                air quality standards, effective dose, dry deposition resistances, ozone        </dc:subject>
</item> 



<item>
	<title>
		Influence of high-frequency ambient pressure pumping on carbon dioxide efflux from soil	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43517	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43517	</guid>
	<description>
		<![CDATA[We report measurements at 2Hz of pressure fluctuations at and beneath the soil in an agricultural field with dry soil and no vegetation. The objective of our study was to examine the possible role of pressure fluctuations produced by fluctuations in ambient wind on the efflux of CO2 at the soil surface.We observed that pressure fluctuations penetrate to 50 cm in the soil with little attenuation, thereby providing a mechanism for bulk transport of trace gases throughout the porous medium. Concurrent measurements of CO2 fluxes from the soil surface produced systematically larger values for larger values of root-mean-square pressure, pumping rate, and mean wind speed. Soil CO2 fluxes measured under conditions conducive to pressure pumping exceeded the diffusional fluxes, estimated from use of Fick's Law and concurrent vertical profiles of soil CO2, by a factor of 5-10. Extrapolation of measured fluxes to conditions uninfluenced by pressure pumping revealed that other mechanisms, such as thermal expansion of soil air caused by soil heating or flushing by evaporating water deep in the soil, may be contributing up to 60% to measured fluxes. Ambient meteorological conditions leading to flux enhancement may change on scales of hours to months, so these results underscore the need to report concurrent meteorological conditions when surface CO2 efflux measurements are made. They further suggest that fluctuations in the static pressure fields introduced by wind interactions with terrain and vegetation may lead to pressure pumping at the surface and hence large spatial inhomogeneities in soil fluxes of trace gases. Although our measurements were made at an agricultural field site and focused onCO2 efflux, the pressure pumping mechanism will be active on other sites, including forest environments, snow-covered surfaces, and fractured rocky surfaces. Furthermore, the physical processes examined apply to movement of other trace gases such as oxygen, water vapor, and methane.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:10:20 -0400	</pubDate>

        <dc:creator>
                Takle, Eugene S.; Massman, William J.; Brandle, James R.; Schmidt, R. A.; Zhou, Xinhua; Litvina, Irina V.; Garcia, Rick; Doyle, Geoffrey; Rice, Charles W.        </dc:creator>
        <dc:subject>
                soil ventilation, soil gas transport, soil CO2 flux        </dc:subject>
</item> 



<item>
	<title>
		The temporal dynamics of carbon dioxide under snow in a high elevation Rocky Mountain subalpine forest and meadow	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43516	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43516	</guid>
	<description>
		<![CDATA[Carbon dioxide (CO2) concentration under snow was examined through two winter seasons at a 3100 m elevation subalpine site in the Snowy Range of Wyoming. CO2 was monitored every half hour at the soil/snow interface, and at about 25 cm soil depth the second year, in a meadow and in an adjacent forest. CO2 under snow in the meadow was significantly higher than that in the forest. CO2 at 25 cm depth in the soil was significantly higher than soil surface CO2. The CO2 under snow increased rapidly as snow melted and snowmelt began in the spring. CO2 concentration under snow depended primarily on amount occurring during the previous 24 or 48 h. However, CO2 concentration was related to snow depth and soil temperature, and indirectly to several seasonal environmental factors, especially solar radiation. Solar radiation, snow depth, and CO2 under snow all increase concurrently as the winter season progresses. CO2 flux was consistently higher in the meadow than in the forest and increased in late winter for both sites. Snow covered subalpine meadows and forests contribute considerable amounts of CO2 to the atmosphere in the winter.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 15:08:08 -0400	</pubDate>

        <dc:creator>
                Musselman, R. C.; Massman, W. J.; Frank, J. M.; Korfmacher, J. L.        </dc:creator>
        <dc:subject>
                carbon dioxide (CO2) concentration        </dc:subject>
</item> 



<item>
	<title>
		Water scarcity and urban forest management: introduction	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43515	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43515	</guid>
	<description>
		<![CDATA[Between 1997 and 2009 a serious drought affected much of Australia. Whether reasoned or unintentional, water policy decisions closed the tap, turning much of the urban forest’s lifeline into a trickle. Green infrastructure became brown infrastructure, exposing its standing as a low priority relative to other consumptive sources. To share new solutions to water scarcity and urban forest management Greg McPherson, Robert Prince, Nelda Matheny and Larry Costello convened a symposium in conjunction with the 2011 ISA Annual Conference in Sydney, Australia. The articles in this recent special issue of the <em>Arboriculture & Urban Forestry</em> offer “lessons learned” to inform future policy, research, design and management. ]]>	</description>
	<pubDate>
		Thu, 23 May 2013 13:41:27 -0400	</pubDate>

        <dc:creator>
                McPherson, E. Gregory.; Prince, Robert.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		Comparison of different stomatal conductance algorithms for ozone flux modelling [Proceedings]	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43514	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43514	</guid>
	<description>
		<![CDATA[The ozone deposition model (D03SE) that has been developed and applied within the EMEP photooxidant model (Emberson et al., 2000, Simpson et al. 2003) currently estimates stomatal ozone flux using a stomatal conductance (gs) model based on the multiplicative algorithm initially developed by Jarvis (1976). This model links gs to environmental and phenological parameters with a set of response functions. However, there exist a number of alternative and well established methods to calculate gs, with the photosynthesis-based algorithm becoming increasingly more popular in situations where carbon-energy flux modelling is required at the regional or global scale.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 13:09:51 -0400	</pubDate>

        <dc:creator>
                Buker, P.; Emberson, L. D.; Ashmore, M. R.; Gerosa, G.; Jacobs, C.; Massman, W. J.; Muller, J.; Nikolov, N.; Novak, K.; Oksanen, E.; De La Torre, D.; Tuovinen, J. -P.        </dc:creator>
        <dc:subject>
                ozone flux modelling, ozone deposition model, EMEP photooxidant model        </dc:subject>
</item> 



<item>
	<title>
		The development, evaluation, and application of O3 flux and flux-response models for additional agricultural crops	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43513	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43513	</guid>
	<description>
		<![CDATA[Currently, stomatal O3 flux and flux-response models only exist for wheat and potato (LRTAP Convention, 2004), as such there is a need to extend these models to include additional crop types. The possibility of establishing robust stomatal flux models for five agricultural crops (tomato, grapevine, sugar beet, maize and sunflower) was investigated. These crops were selected on consideration of their distribution across Europe, sensitivity to ozone and economic value.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 13:06:19 -0400	</pubDate>

        <dc:creator>
                Emberson, L. D.; Massman, W. J.; Buker, P.; Soja, G.; Van De Sand, I.; Mills, G.; Jacobs, C.        </dc:creator>
        <dc:subject>
                O3 flux, flux-response models        </dc:subject>
</item> 



<item>
	<title>
		Consequences of incomplete surface energy balance closure for CO2 fluxes from open-path CO2/H2O infrared gas analyzers	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43512	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43512	</guid>
	<description>
		<![CDATA[We present an approach for assessing the impact of systematic biases in measured energy fluxes on CO2 flux estimates obtained from open-path eddy-covariance systems. In our analysis, we present equations to analyse the propagation of errors through the Webb, Pearman, and Leuning (WPL) algorithm [Quart. J. Roy. Meteorol. Soc. 106, 85­100, 1980] that is widely used to account for density fluctuations on CO2 flux measurements. Our results suggest that incomplete energy balance closure does not necessarily lead to an underestimation of CO2 fluxes despite the existence of surface energy imbalance; either an overestimation or underestimation of CO2 fluxes is possible depending on local atmospheric conditions and measurement errors in the sensible heat, latent heat, and CO2 fluxes. We use open-path eddy-covariance fluxes measured over a black spruce forest in interior Alaska to explore several energy imbalance scenarios and their consequences for CO2 fluxes.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 13:03:52 -0400	</pubDate>

        <dc:creator>
                Liu, Heping; Randerson, James T.; Lindfors, Jamie; Massman, William J.; Foken, Thomas        </dc:creator>
        <dc:subject>
                carbon dioxide flux, eddy covariance, error analysis, open-path CO2/H2O infrared gas analysers (IRGA), surface energy imbalance, WPL algorithm        </dc:subject>
</item> 



<item>
	<title>
		Effects of controlled burns on the bulk density and thermal conductivity of soils at a southern Colorado site	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43511	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43511	</guid>
	<description>
		<![CDATA[Throughout the world fire plays an important role in the management and maintenance of ecosystems. However, if a fire is sufficiently intense, soil can be irreversibly altered and the ability of vegetation, particularly forests, to recover after a fire can be seriously compromised. Because fire is frequently used by land managers to reduce surface fuels, it is important to know if and how soil properties may change as a consequence of the fire-associated soil heat pulse.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 13:01:37 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Frank, J. M.        </dc:creator>
        <dc:subject>
                fire, controlled burns, bulk density, thermal conductivity, soil properties        </dc:subject>
</item> 



<item>
	<title>
		Long term consequences of a controlled slash burn and slash mastication to soil moisture and CO2 at a southern Colorado site	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43510	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43510	</guid>
	<description>
		<![CDATA[Thinning of forest stands is frequently used to reduce the risk of catastrophic fire. But thinning requires that the refuse (or slash) be removed from the site, which can be done either by burning it or by mastication and dispersal. Either method has long term consequences to the soil and to soil moisture and soil CO2 levels. For example, after the initial drying of the soil by a fire, soil moisture in burned areas tends to exceed that of unburned areas because the loss of vegetation reduces or eliminates transpiration (Neary and Ffolliott, 2005). This situation may persist until the vegetation is reestablished. In general, burning also tends to reduce soil respiration (Amiro et al., 2003) and, therefore, soil CO2 amounts and fluxes. Nevertheless, some environmental conditions will allow the soil respiration of a burned area to exceed that of an unburned area (Andersson et al., 2004). In fact, exposing soil to a severe fire may actually increase heterotrophic respiration (Bisset and Parkinson, 1980; Richter et al., 2000). In this situation the consequences to soil CO2 and soil fluxes is less clear because nearby unburned areas may still support autotrophic respiration. This increase in heterotrophic respiration in the burned area is thought to result from the stimulation of the soil microbiota by increased soil temperatures (Bisset and Parkinson, 1980; Richter et al., 2000) and/or elevated levels of bioavailable nutrients (Fyles et al., 2001; Choromanska and DeLuca, 2002; Certini, 2005).]]>	</description>
	<pubDate>
		Thu, 23 May 2013 12:59:32 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Frank, J. M.; Jimenez Esquilin, A. E.; Stromberger, M. E.; Shepperd, W. D.        </dc:creator>
        <dc:subject>
                fire, thinning, slash burn, slash mastication, soil moisture, CO2        </dc:subject>
</item> 



<item>
	<title>
		An analysis and implications of alternative methods of deriving the density (WPL) terms for eddy covariance flux measurements	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43509	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43509	</guid>
	<description>
		<![CDATA[We explore some of the underlying assumptions used to derive the density or WPL terms (Webb et al. (1980) Quart J RoyMeteorol Soc 106:85-100) required for estimating the surface exchange fluxes by eddy covariance. As part of this effort we recast the origin of the density terms as an assumption regarding the density fluctuations rather than as a (dry air) flux assumption. This new approach, which is similar to the expansion/compression approach of Liu (Boundary-Layer Meteorol 115:151-168, 2005), eliminates the dry-air mean advective vertical velocity from the development of theWPL terms and allows us to directly compare Liu's assumptions for deriving the WPL terms with the analogous assumptions appropriate to the original expression of theWPL terms.We suggest, (i) that themain difference between these two approaches lies in the interpretation of the turbulent exchange flux, and (ii) that the originalWPL formulation is the more appropriate approach. Given the importance of the WPL terms to accurate and reliable measurements of surface exchange fluxes, a careful analysis of their origins and their proper mathematical expression and interpretation is warranted.]]>	</description>
	<pubDate>
		Thu, 23 May 2013 12:56:58 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Tuovinen, J. -P.        </dc:creator>
        <dc:subject>
                air parcel expansion/compression, mass conservation equations, trace gas fluxes        </dc:subject>
</item> 



<item>
	<title>
		Glossary: Definitions of relevancy for the 'flux concept' in ozone risk assessment	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43508	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43508	</guid>
	<description>
		<![CDATA[The following definitions have been formulated with reference, in particular, to Musselman et al. (2006; see below).]]>	</description>
	<pubDate>
		Thu, 23 May 2013 12:54:45 -0400	</pubDate>

        <dc:creator>
                Wieser, G.; Matyssek, R.; Musselman, R. C.; Lefohn, A. S.; Massman, W. J.        </dc:creator>
        <dc:subject>
                glossary, flux concept, ozone risk assessment        </dc:subject>
</item> 



<item>
	<title>
		Turbulent pressure fluctuations measured during CHATS	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43507	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43507	</guid>
	<description>
		<![CDATA[Fast-response pressure fluctuations were included in the Canopy Horizontal Array of Turbulence Study (CHATS) at several heights within and just above the canopy in a walnut orchard. Two independent systems were intercompared and then separated. We present an evaluation of turbulence statistics - including the pressure transport term in the turbulence kinetic energy budget equation - within this canopy.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 18:19:51 -0400	</pubDate>

        <dc:creator>
                Oncley, Steven P.; Massman, William J.; Patton, Edward G.        </dc:creator>
        <dc:subject>
                turbulence, pressure fluctuations, Canopy Horizontal Array of Turbulence Study (CHATS)        </dc:subject>
</item> 



<item>
	<title>
		The Canopy Horizontal Array Turbulence Study (CHATS)	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43506	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43506	</guid>
	<description>
		<![CDATA[Turbulence in the planetary boundary layer (PBL) well above the surface has been shown to be independent of the details of the surface roughness. In this region well-quantified similarity relationships work well when characterizing turbulent fluxes (e.g., Raupach, 1979). However, in the near-surface layer which is directly influenced by roughness elements, i.e., the roughness sublayer, turbulence exhibits dramatically varying properties depending on the detailed structure of the roughness elements (Shaw et al., 1974; Raupach, 1981; Raupach et al., 1996). Turbulence in the roughness sublayer is largely responsible for transporting momentum, heat and scalars between the surface and the flow aloft, and is directly coupled with the overlying larger-scale turbulence. Therefore, accurate characterization of fluxes within the roughness sublayer is crucial for predicting larger-scale atmospheric flow and scalar transport.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 18:17:12 -0400	</pubDate>

        <dc:creator>
                Patton, Edward G.; Horst, Thomas W.; Lenschow, Donald H.; Sullivan, Peter P.; Oncley, Steven; Burns, Sean; Guenther, Alex; Held, Andreas; Karl, Thomas; Mayor, Shane; Rizzo, Luciana; Spuler, Scott; Sun, Jielun; Turnipseed, Andrew; Allwine, Eugene; Edburg, Steven; Lamb, Brian; Avissar, Roni; Holder, Heidi E.; Calhoun, Ron; Kleissl, Jan; Massman, William; U, Kyaw Tha Paw; Weil, Jeffrey C.        </dc:creator>
        <dc:subject>
                turbulence, planetary boundary layer (PBL), surface, atmospheric flow, scalar transport        </dc:subject>
</item> 



<item>
	<title>
		Transport of CO2 and other combustion products in soils during slash-pile burns [Presentation]	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43505	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43505	</guid>
	<description>
		<![CDATA[The most obvious indication of transport of mass during a fire is flames and smoke. Furthermore it is well known that localized heating during the fire creates 3-D convective currents in the atmosphere and that these currents carry the combustion products away from the fire.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 16:44:36 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Nobles, M. M.; Butters, G.; Mooney, S. J.        </dc:creator>
        <dc:subject>
                transport, soils, slash-pile burn, combustion        </dc:subject>
</item> 



<item>
	<title>
		Mineralogical and micromorphological modifications in soil affected by slash pile burn	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43504	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43504	</guid>
	<description>
		<![CDATA[Silvicultural practices, such as slash pile burning, are commonly used for fire and ecosystem management. This management technique can drastically alter chemical, physical and biological soil properties due to the high temperatures achieved during the prolonged severe burn. Little is known, however, about the impact of high-temperature slash pile burning on soil mineralogical and micromorphological properties. Soil changes were investigated in Manitou Experimental Forest in Rocky Mountains of Central Colorado to identify possible temperature-induced modifications in mineralogical and micromorphological properties that can impact thermal conductivity in soil affected by slash pile burning. Prescribed burning did not affect clay and silt fraction mineralogy. However, changes in post-burn mineralogical composition were evident in sand fractions, when compared to the pre-burn mineralogy. These differences were attributed to the formation of Mn oxide/hydroxide coatings by the process of mass transport through soil with convective air current during the fire. Resinous pine species used as fire fuel were thought to be the source of Mn input. Micromorphological analysis also confirmed the presence of Mn coatings on sand-sized grains, as well as the presence of Mn nodules and microfabric enrichment.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 16:39:52 -0400	</pubDate>

        <dc:creator>
                Nobles, M. M.; Massman, W. J.; Mbila, M.; Butters, G.        </dc:creator>
        <dc:subject>
                slash pile burning, fire mineralogy, fire micromorphology        </dc:subject>
</item> 



<item>
	<title>
		An instrument to measure turbulent eddy fluxes in the atmosphere of Mars	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43503	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43503	</guid>
	<description>
		<![CDATA[Turbulent eddies in the planetary boundary layer of the terrestrial planet atmospheres are the primary mechanism by which energy, momentum, gasses, and aerosols are exchanged between the surface and the atmosphere [1]. The importance of eddies has long been recognized by the Earth atmospheric science community, and turbulent theory for Earth has a long history with a massive amount of literature backed by over half a century of detailed field campaigns. Every climate and weather forecasting model in existence relies extensively on turbulent eddy theory supported through observational validation. The importance of eddies in atmospheric dynamics, chemistry, and climate science cannot be overstated.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 16:37:20 -0400	</pubDate>

        <dc:creator>
                Rafkin, S.; Banfield, D.; Dissly, R.; Silver, J.; Stanton, A.; Wilkinson, E.; Massman, W.; Ham, J.        </dc:creator>
        <dc:subject>
                turbulent eddies, terrestrial planet atmospheres, Mars        </dc:subject>
</item> 



<item>
	<title>
		Reply to comment by Mauder on "How well can we measure the vertical wind speed? Implications for fluxes of energy and mass"	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43502	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43502	</guid>
	<description>
		<![CDATA[In Kochendorfer et al. (Boundary-Layer Meteorol 145:383-398, 2012, hereafter K2012) the vertical wind speed (w) measured by a non-orthogonal three-dimensional sonic anemometer was shown to be underestimated by 12%. Turbulent statistics and eddycovariance fluxes estimated using w were also affected by this underestimate in w. Methodologies used in K2012 are clarified here in response to Mauder's comment. In addition, further analysis of the K2012 study is presented to help address questions raised in the comment. Specific responses are accompanied with examples of time series, calculated correlation coefficients, and additional explanation of the K2012 methods and assumptions. The discussion and analysis included in the comment and in this response do not affect the validity of the methods or conclusions presented in K2012.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 16:35:17 -0400	</pubDate>

        <dc:creator>
                Kochendorfer, John; Meyers, Tilden P.; Frank, John M.; Massman, William J.; Heuer, Mark W.        </dc:creator>
        <dc:subject>
                angle-of-attack error, cosine error, eddy covariance, energy balance closure, sonic anemometer, transducer shadowing        </dc:subject>
</item> 



<item>
	<title>
		In situ soil temperature and heat flux measurements during controlled surface burns at a southern Colorado forest site	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/43501	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/43501	</guid>
	<description>
		<![CDATA[This study presents in situ soil temperature measurements at 5-6 depths and heat flux measurements at 2-5 depths obtained during the fall/winter of 2001/ 2002 at seven controlled (surface) fires within a ponderosa pine forest site at the Manitou Experimental Forest in central Colorado. Six of these burns included three different (low, medium, and high) fuel loadings under both a closed-canopy forested site and an open forest with a grassy meadow understory. The fuel loading for the seventh burn was a conical pile of slash about 6 m in height and 9 m in diameter and was intended to duplicate the structure and loading of a slash pile resulting from mechanical harvesting activities. One basic purpose of this initial experiment was to assess how well some commercially available soil heat flux plates would perform at high temperatures. The data presented here include soil temperatures, heat fluxes, and depth and duration of the thermal energy penetration into the soils. The maximum surface heat fluxes were estimated to be about 2400 Watts/meter2 [Wm-2] at the slash pile burn site, 2300 Wm-2 at the high fuel meadow site, and 3000 Wm-2 at the high fuel forested site. Extrapolated surface temperatures are about 436 C at the slash burn site, 359 C at the high fuel meadow site, and 95 C at the high fuel forested site. Recovery of a normal daily temperature cycle depended on fire duration and fuel loading. The recovery times were between 16 and 20 hours at the high fuel sites, about half this time at the medium fuel sites, and less that 2 hours at the low fuel sites. However, the recovery time at the slash pile site was about 2 weeks. Although further tests and refinements are planned, the present results suggest not only that soil heat flux can be reliably measured during controlled burns, but that soil temperatures and heat flux can differ significantly with different fuel loadings.]]>	</description>
	<pubDate>
		Wed, 22 May 2013 14:41:13 -0400	</pubDate>

        <dc:creator>
                Massman, W. J.; Frank, J. M.; Shepperd, W. D.; Platten, M. J.        </dc:creator>
        <dc:subject>
                fire, fuel treatment, ecological restoration, hazard reduction, restoration projects        </dc:subject>
</item> 

 
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