<?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 USFS Southern Research Station</title><link>http://www.srs.fs.usda.gov/pubs/</link><description>20 newest publications from the US Forest Service, Southern Research Station with headquarters in Asheville, North Carolina.  http://www.srs.fs.usda.gov/pubs/</description><language>en-us</language><lastBuildDate>Fri, 20 Aug 2004 01:50:21 CDT</lastBuildDate>

<item>
	<title>
		Natural amenities and rural population migration: a technical document supporting the Forest Service 2010 RPA Assessment	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40081	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40081	</guid>
	<description>
		<![CDATA[Research has suggested that significant relationships exist between rural population change and natural amenities. Thus, understanding and predicting domestic migration trends as a function of changes in natural amenities is important for effective regional growth and development policies and strategies. In this study, we first estimated an econometric model which showed the effects of natural amenities, such as climate and landscape variables, on rural population migration patterns in the United States between 1990 and 2007. The estimated model was then used to predict the effects of changes in these variables on rural county net migration and population growth to 2060 under alternative future climate and land use projections. Results suggest that people prefer rural areas with mild winters and cooler summers; thus we can expect a direct impact of climate change on population migration when areas associated with these conditions change. Results also suggest preference for varied landscapes that feature a mix of forest land and open space (e.g., pasture and range land). During the projection period from 2010 to 2060 in the United States, changes in natural amenities were predicted to have positive effects on rural population migration trends in most parts of the Inter-mountain and Pacific Northwest regions, and some parts of the Southeastern, South Central, and Northeastern U.S. regions (e.g., Southern Appalachian Mountains, Ozark Mountains, northern New England). Changes in natural amenities were predicted to have negative effects on rural population migration trends during the projection period in Midwestern regions (e.g., Great Plains and North Central regions).]]>	</description>
	<pubDate>
		Tue, 07 Feb 2012 13:33:28 -0500	</pubDate>

        <dc:creator>
                Cordell, H. Ken; Heboyan, Vahé; Santos, Florence; Bergstrom, John C.        </dc:creator>
        <dc:subject>
                Amenity migration, climate change, landscapes, natural amenities, rural population change        </dc:subject>
</item> 



<item>
	<title>
		A comparison of growth and survival between sycamore seedlings and cuttings	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40077	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40077	</guid>
	<description>
		<![CDATA[Sycamore seedlings survive better and, when fertilized, outgrow cuttings. These findings were determined from a planting made in 1961 in the Oconee River bottoms in Greene County, Georgia.]]>	</description>
	<pubDate>
		Tue, 07 Feb 2012 10:43:44 -0500	</pubDate>

        <dc:creator>
                McAlpine, Robert G.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		Sycamore produces viable seed after six years	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40076	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40076	</guid>
	<description>
		<![CDATA[In the early stages of any tree improvement program it is desirable to know how soon progenies of selected parents can themselves be included in a breeding program. How soon will they produce viable pollen and seed? In the case of sycamore (Platanus occidentalis L.), the information is meager: the Woody- Plant Seed Manual lists the minimum commercial seedbearing age for sycamore as 25 years.1 Four open-grown trees at Athens, Georgia, however, have produced viable seed during their sixth growing season.]]>	</description>
	<pubDate>
		Tue, 07 Feb 2012 10:37:47 -0500	</pubDate>

        <dc:creator>
                Ike, A. F.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		A dominance-based approach to map risks of ecological invasions in the presence of severe uncertainty	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40025	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40025	</guid>
	<description>
		<![CDATA[Aim Uncertainty has been widely recognized as one of the most critical issues in predicting the expansion of ecological invasions. The uncertainty associated with the introduction and spread of invasive organisms influences how pest management decision makers respond to expanding incursions. We present a model-based approach to map risk of ecological invasions that combines two potentially conflicting goals: (1) estimating the likelihood of a new organism being established at a given locale and (2) quantifying the uncertainty of that prediction. Location Eastern and central Canada. Methods Our methodology focuses on the potential for long-distance, human assisted spread of invasive organisms. First, we used a spatial simulation model to generate distributions of plausible invasion outcomes over a target geographical region. We then used second-degree stochastic dominance (SSD) criteria to rank all geographical locations in the target region based on these distributions. We applied the approach to analyze pathways of human-assisted spread (i.e., with commercially transported goods) of the emerald ash borer (EAB) (Agrilus planipennis Fairmaire), a major pest of ash trees in North America. Results The projected potential of the pest to establish at remote locations is significantly shaped by the amount of epistemic uncertainty in the model-based forecasts. The estimates based on the SSD ranking identified major ‘crossroads’ through which the movement of the EAB with commercial transport is most likely to occur. The system of major expressways in Ontario and Quebec was confirmed as the primary gateway of the pest’s expansion throughout the Canadian landscape. Main conclusions Overall, the new approach generates more realistic predictions of long-distance introductions than models that do not account for severe uncertainties and thus can help design more effective pest surveillance programmes. The modelling technique is generic and can be applied to assess other environmental phenomena when the level of epistemic uncertainty is high.]]>	</description>
	<pubDate>
		Sun, 29 Jan 2012 17:12:41 -0500	</pubDate>

        <dc:creator>
                Yemshanov, Denys; Koch, Frank H.; Lyons, D. Barry; Ducey, Mark; Koehler, Klaus        </dc:creator>
        <dc:subject>
                Agrilus planipennis, epistemic uncertainty, human-assisted spread, invasive species, pathway model, stochastic dominance        </dc:subject>
</item> 



<item>
	<title>
		Sensitivity analysis of the DRAINWAT model applied to an agricultural watershed in the lower coastal plain, North Carolina, USA	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40017	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40017	</guid>
	<description>
		<![CDATA[The DRAINWAT, DRAINmod for WATershed model, was selected for hydrological modelling to obtain water table depths and drainage outflows at Open Grounds Farm in Carteret County, North Carolina, USA. Six simulated storm events from the study period were compared with the measured data and analysed. Simulation results from the whole study period and selected rainfall events assured that the DRAINWAT model reasonably predicted the water table depths and drainage outflow events even though it underestimated outflows in very dry period after 24 April, 2001. The potential evapotranspiration by various calculation methods was found to be the most sensitive parameter in this study. The other three parameters (maximum surface depressional storage, Manning's channel roughness coefficient, and channel bedslope) were not significantly (&#xb1; = 0.05) sensitive to the cumulative outflow as expected. The DRAINWAT model may be a useful tool for water management in flat agricultural areas with high water table if it can be calibrated properly with reliable measurements.]]>	</description>
	<pubDate>
		Tue, 31 Jan 2012 11:17:18 -0500	</pubDate>

        <dc:creator>
                Kim, Hyunwoo; Amatya, Devendra M.; Broome, Stephen W.; Hesterberg, Dean L.; Choi, Minha.        </dc:creator>
        <dc:subject>
                agricultural water management; bedslope; drainage outflow; DRAINWAT; Manning's roughness coefficient; potential evapotranspiration; surface depressional storage; water table depth        </dc:subject>
</item> 



<item>
	<title>
		Leaf area index (LAI) of loblolly pine and emergent vegetation following a harvest	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40016	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40016	</guid>
	<description>
		<![CDATA[Forests provide goods and services to society and, often, refugia for plants and animals; forest managers utilize silviculture to provide ecosystem services and to create habitat. On the Coastal Plain of North Carolina, forest management objectives typically include wood fiber production but may also include the maintenance of environmental quality and, sometimes, species diversity. Silvicultural prescriptions alter stand structure and development trajectories by influencing the competitive interactions among plant species for site resources. Early site intervention may include nutrient additions and/or vegetation control; in coastal loblolly pine (Pinus taeda L.) stands, herbaceous and arborescent species can dominate the site leaf area index (LAI) for many years after a harvest (followed by planting). LAI is an important structural and functional component of a forest stand. Many eco‐hydrologic and water quality models do not accurately account for LAI as the process driver to evapotranspiration (ET), and thus they ignore the ecophysiological effects of LAI on site water balance and nutrient loading. We measured LAI of emergent vegetation following a harvest, mechanical site preparation, and then pine planting for a drained loblolly pine plantation in coastal North Carolina. For six years monthly, growing season estimates of LAI were obtained using a LI‐COR LAI 2000 Plant Canopy Analyzer (PCA) for control (D1), thinned (D3), and harvested (D2) watersheds. In this article, we present results from the D2 treatment. In D2, we “harvested” all emergent vegetation in 18 randomly placed 1 m2 clip plots for three growing seasons where we estimated LAI using species‐pooled estimates of specific leaf area and total leaf dry mass (i.e., LAICLIP); PCA measurements were recorded prior to clipping (LAIPCA). We also simulated loblolly pine seedling growth and development using the biogeochemical process model SECRETS‐3PG to examine site differentiation in LAI. Four years post‐harvest maximum LAICLIP exceeded 8 m2 m‐2 (projected area basis). LAIPCA underestimated LAICLIP; LAICLIP = 1.436 -- LAIPCA (r2 = 0.53; p < 0.0001; n = 195). Corrected LAIPCA estimates exceeded simulated pine LAI (LAISIM) for ~4.5 years post‐planting. Emergent vegetation dominated the site for nearly five years and likely exerted a strong influence over site water balance and nutrient use during early stand development.]]>	</description>
	<pubDate>
		Wed, 11 Jan 2012 09:43:08 -0500	</pubDate>

        <dc:creator>
                Sampson, D.A.; Amatya, D.M.; Blanton Lawson, C.D.; Skaggs, R.W.        </dc:creator>
        <dc:subject>
                Competition, Evapotranspiration, Hydrologic modeling, LAI, Plantation management, Weed control        </dc:subject>
</item> 



<item>
	<title>
		Modeling potential evapotranspiration of two forested watersheds in the southern Appalachians	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40014	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40014	</guid>
	<description>
		<![CDATA[Global climate change has direct impacts on watershed hydrology through altering evapotranspiration (ET) processes at multiple scales. There are many methods to estimate forest ET with models, but the most practical and the most popular one is the potential ET (PET) based method. However, the choice of PET methods for AET estimation remains challenging. This study explored ways to identify appropriate PET models for two small forested watersheds, one dominated by conifer plantation and one dominated by native naturally regenerated deciduous hardwoods, by using long‐term hydrometeorological data collected at the Coweeta Hydrologic Laboratory in the humid Appalachians in the southeastern U.S. Our specific objectives were to: (1) contrast three common PET models (FAO‐56 grass reference ET, Hamon PET, and Priestley‐Taylor PET) and compare these PET estimates with measured AET at monthly and annual temporal scales, and (2)_derive correction factors for the FAO‐56 grass reference ET and Hamon PET models at the monthly scale using the Priestley‐Taylor equation as the standard method for estimating forest PET. We found that different PET models gave significantly different PET estimates. The Priestley‐Taylor equation gave the most reasonable estimates of forest PET for both watersheds. We conclude that the uncorrected Hamon and FAO PET methods would cause large underestimates of forest PET. Annual PET rates of the conifer watershed were higher than those of the native deciduous watershed due to the lower albedo (thus higher net radiation) in the former compared to the latter. Monthly correction factors provided useful tools for forest PET estimation in those areas lacking climatic data (i.e., radiation, humidity, and wind speed).]]>	</description>
	<pubDate>
		Tue, 10 Jan 2012 10:50:54 -0500	</pubDate>

        <dc:creator>
                Rao, L.Y.; Sun, G.; Ford, C.R.; Vose, J.M.        </dc:creator>
        <dc:subject>
                FAO-56 grass reference ET, Forest potential evapotranspiration, Hamon equation, Priestley-Taylor equation        </dc:subject>
</item> 



<item>
	<title>
		Increased resin flow in mature pine trees growing under elevated CO2 and moderate soil fertility	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40013	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40013	</guid>
	<description>
		<![CDATA[Warmer climates induced by elevated atmospheric CO2 (eCO2) are expected to increase damaging bark beetle activity in pine forests, yet the effect of eCO2 on resin production"the tree’s primary defense against beetle attack"remains largely unknown. Following growth-differentiation balance theory, if extra carbohydrates produced under eCO2 are not consumed by respiration or growth, resin production could increase. Here, the effect of eCO2 on resin production of mature pines is assessed. As predicted, eCO2 enhanced resin flow by an average of 140% (P = 0.03) in canopy dominants growing in low nitrogen soils, but did not affect resin flow in faster-growing fertilized canopy dominants or in carbohydrate-limited suppressed individuals. Thus, pine trees may become increasingly protected from bark beetle attacks in an eCO2 climate, except where they are fertilized or are allowed to become overcrowded.]]>	</description>
	<pubDate>
		Tue, 24 Jan 2012 08:40:47 -0500	</pubDate>

        <dc:creator>
                Novick, K.A.; Katul, G.G.; McCarthy, H.R.; Oren, R.        </dc:creator>
        <dc:subject>
                bark beetles, carbon allocation, Free Air CO2 Enrichment, Pinus taeda, resin flow, resistance        </dc:subject>
</item> 



<item>
	<title>
		Determination of plant characteristics used in discharge capacity assessment of Turkey Creek watershed on South Carolina coastal plain, USA	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40012	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40012	</guid>
	<description>
		<![CDATA[Riparian vegetation type, composition, structure, and its abundance on floodplains exert a strong influence on riparian surface and subsurface hydrology and discharges of rivers and streams. The conditions of flood waters flow in such valley types are shaped by the existing vegetation cover. In this study, on the basis of vegetation inventory in four selected and representative basins, the substitute geometrical parameters of the medium and tall vegetation were determined and friction coefficients for low vegetation. These parameters were determined for 72 km2 forested watershed draining a 3rd order stream as affected by floodplain riparian vegetation on the Atlantic Coastal Plain in South Carolina, USA. The vegetation parameters, determined directly from the measurements, were verified against the rating curve, that was achieved from discharge measurements as well as from discharge capacity calculations of the valley cross-section. In discharge capacity calculation, the Pasche method was used to calculate the total Darcy-Weisbach friction factor for each cross section according to the type of vegetation and flow interaction between the main channel and vegetated areas. In this approach friction caused by interaction between the main channel and vegetated areas are taken into account. The calculations performed on the basis of determined geometrical parameters of tall vegetation, show good agreement between the model and the measurements.]]>	</description>
	<pubDate>
		Fri, 27 Jan 2012 11:51:27 -0500	</pubDate>

        <dc:creator>
                Miroslaw-Swiatek, Dorota; Amatya, Devendra M.        </dc:creator>
        <dc:subject>
                Francis Marion National Forest, Stream flow, Roughness coefficient, Darcy-Weisbach formula, Pasche method        </dc:subject>
</item> 



<item>
	<title>
		Long-term forest management and climate effects on streamflow	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40011	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40011	</guid>
	<description>
		<![CDATA[Long-term watershed studies are a powerful tool for examining interactions among management activities, streamflow, and climatic variability. Understanding these interactions is critical for exploring the potential of forest management to adapt to or mitigate against the effects of climate change. The Coweeta Hydrologic Laboratory, located in North Carolina, USA, is a 2,185- ha basin wherein forest climate monitoring and watershed experimentation began in the early 1930s. Extensive climate and hydrologic networks have facilitated research in the basin and region for over 75 years. Our purpose was (1) to examine long-term trends in climate and streamflow in reference watersheds, and (2) to synthesize recent work that shows that managed watersheds respond differently to variation in extreme precipitation years than reference watersheds. In the basin and in the region, air temperatures have been increasing since the late 1970s. Drought severity and frequency have also increased over time, and the precipitation distribution has become more variable. Reference watersheds indicate that streamflow is more variable, reflecting precipitation variability. Streamflow of extreme wet and dry years show that watershed responses to management differ significantly in all but a forest with coppice management. Converting deciduous hardwood stands to pine altered the streamflow response to extreme precipitation years the most. High evapotranspiration rate and increased soil water storage in the pine stands may be beneficial to reduce flood risk in wet years, but they create conditions that could exacerbate drought. Our results suggest that forest management can mitigate precipitation years associated with climate change; however, offsetting effects suggest the need for spatially-explicit analyses of risk and vulnerability.]]>	</description>
	<pubDate>
		Thu, 26 Jan 2012 13:57:56 -0500	</pubDate>

        <dc:creator>
                Laird, Shelby G.; Ford, C.R.; Laseter, S.H.; Vose, J.M.        </dc:creator>
        <dc:subject>
                climate, long-term monitoring, streamflow, forest management, watershed        </dc:subject>
</item> 



<item>
	<title>
		Impact of seasonality on artificial drainage discharge under temperate climate conditions	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40010	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40010	</guid>
	<description>
		<![CDATA[Artificial drainage systems affect all components of the water and matter balance. For the proper simulation of water and solute fluxes, information is needed about artificial drainage discharge rates and their response times. However, there is relatively little information available about the response of artificial drainage systems to precipitation. To address this need, we analyzed 11 datasets from artificial drainage study sites (daily or hourly resolution), one daily dataset from an open ditch system, and three datasets from rainfall simulations on tile-drained fields. When we considered all 11 artificial drainage study sites, we found that artificial drainage discharge responded to 70% of all rainfall events during the year, and that the response rate differed significantly between 56% summer and 84% in winter. A median of 23% of the yearly precipitation rate is discharged by artificial drainage systems, varying from 9% of the precipitation in summer to 54% of the precipitation in winter. The artificial drainage systems usually started to respond within the first hour under rain fed conditions, and the response time increased at lower rainfall intensities ( < 1 mm h"1). The peak outflow normally occurred within the first two days. The influence of soil texture and land use on artificial drainage discharge rates could not be reproduced properly, due to the spatial high variability caused by other site-specific properties.
]]>	</description>
	<pubDate>
		Fri, 27 Jan 2012 14:44:05 -0500	</pubDate>

        <dc:creator>
                Hirt, Ulrike; Wetzig, Annett; Amatya, Devandra; Matranga, Marisa        </dc:creator>
        <dc:subject>
                Model for artificially drained soils, PVC, Polyvinylchloride, WFD, European Water Framework Directive        </dc:subject>
</item> 



<item>
	<title>
		Long– and short-term precipitation effects on soil CO2 efflux and total belowground carbon allocation	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40009	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40009	</guid>
	<description>
		<![CDATA[Soil CO2 efflux (Esoil), the main pathway of C movement from the biosphere to the atmosphere, is critical to the terrestrial C cycle but how precipitation and soil moisture influence Esoil remains poorly understood. Here, we irrigated a longleaf pine wiregrass savanna for six years; this increased soil moisture by 41.2%. We tested how an altered precipitation regime affected total belowground carbon allocation (TBCA), root growth, soil carbon, and Esoil. We used two methods to quantify Esoil: daytime biweekly manual measurements and automated continuous measurements for one year. We hypothesized that the low-frequency manual method would miss both short- and long-term (i.e., subdaily to annual, respectively) effects of soil moisture on Esoil while the high-frequency data from the automated method would allow the effects of soil moisture to be discerned. Root growth was significantly higher in irrigated plots, particularly at 0"20 cm depth. Irrigated annual Esoil was significantly greater than that of the control when estimated with the continuous measurements but not when estimated from biweekly measurements. The difference in annual Esoil estimates is likely due to (1) the delayed increase in Esoil following irrigation pulses of soil moisture (i.e., variation that the biweekly manual measurements missed) and (2) the diel timing of biweekly manual measurements (they were completed early to mid-day before peak efflux). With irrigation, estimates of TBCA increased almost two-fold with automated measurements but only 36% with intermittent measurements. Relative to controls, irrigated treatments stored almost 2 Mg C ha'1 year'1 more in soils and 0.26 Mg C ha'1 year'1 more in roots. High-frequency measurements of Esoil were essential to estimate total belowground carbon allocation. With irrigation, soil carbon pools were not at steady-state, so shifts in soil carbon storage must be considered in TBCA estimates.]]>	</description>
	<pubDate>
		Wed, 25 Jan 2012 14:01:30 -0500	</pubDate>

        <dc:creator>
                Ford, Chelcy R.; McGee, Jason; Scandellari, Francesca; Hobbie, Erik A.; Mitchell, Robert J.        </dc:creator>
        <dc:subject>
                Carbon allocation, Climate change, Longleaf pine, Irrigation, Root demography, Soil respiration        </dc:subject>
</item> 



<item>
	<title>
		Forest dynamics following eastern hemlock mortality in the southern Appalachians	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40008	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40008	</guid>
	<description>
		<![CDATA[Understanding changes in community composition caused by invasive species is critical for predicting effects on ecosystem function, particularly when the invasive threatens a foundation species. Here we focus on dynamics of forest structure, composition and microclimate, and how these interact in southern Appalachian riparian forests following invasion by hemlock woolly adelgid, HWA, Adelges tsugae. We measured and quantified changes in microclimate; canopy mortality; canopy and shrub growth; understory species composition; and the cover and diversity in riparian forests dominated by eastern hemlock Tsuga canadensis over a period of seven years. Treatments manipulated hemlock mortality either through invasion (HWA infested stands) or girdling (GDL) hemlock trees. 
Mortality was rapid, with 50% hemlock tree mortality occurring after six years of invasion, in contrast to more than 50% mortality in two years following girdling. Although 50% of hemlock trees were still alive five years after infestation, leaf area lost was similar to that of girdled trees. As such, overall responses over time (changes in light transmittance, growth, soil moisture) were identical to girdled stands with 100% mortality. Our results showed different growth responses of the canopy species, shrubs and ground layer, with the latter being substantially influenced by presence of the evergreen shrub, rhododendron Rhododendron maximum. Although ground layer richness in the infested and girdled stands increased by threefold, they did not approach levels recorded in hardwood forests without rhododendron. Increased growth of co-occurring canopy trees occurred in the first few years following hemlock decline, with similar responses in both treatments. In contrast, growth of rhododendron continued to increase over time. By the end of the study it had a 2.6-fold higher growth rate than expected, likely taking advantage of increased light available during leaf-off periods of the deciduous species. Increased growth and dominance of rhododendron may be a major determinant of future responses in southern Appalachian ecosystems; however, our results suggest hemlock will be replaced by a mix of Acer, Betula, Fagus and Quercus canopy genera where establishment is not limited by rhododendron.
]]>	</description>
	<pubDate>
		Wed, 25 Jan 2012 14:46:10 -0500	</pubDate>

        <dc:creator>
                Ford, Chelcy R.; Elliott, Katherine J.; Clinton, Barton D.; Kloeppel, Brian D.; Vose, James M.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		Modeling water, carbon, and nitrogen dynamics for two drained pine plantations under intensive management practices	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40007	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40007	</guid>
	<description>
		<![CDATA[This paper reports results of a study to test the reliability of the DRAINMOD-FOREST model for predicting water, soil carbon (C) and nitrogen (N) dynamics in intensively managed forests. The study site, two adjacent loblolly pine (Pinus taeda L.) plantations (referred as D2 and D3), are located in the coastal plain of North Carolina, USA. Controlled drainage (with weir and orifice) and various silvicultural practices, including nitrogen (N) fertilizer application, thinning, harvesting, bedding, and replanting, were conducted on the study site. Continuous collection of hydrological and water quality data (1988"2008) were used for model evaluation. Comparison between predicted and measured hydrologic variables showed that the model accurately predicted long-term subsurface drainage dynamics and water table fluctuations in both loblolly pine plantations. Predicted mean and standard deviation of annual drainage matched measured values very well: 431 &#xb1; 217 vs. 436 &#xb1; 231 mm for D2 site and 384 &#xb1; 152 vs. 386 &#xb1; 160 mm for D3 site. Nash"Sutcliffe coefficients (NSE) were above 0.9 for drainage predictions on annual and monthly basis and above 0.86 for predictions of daily water table fluctuations. Compared to measurements in other similar studies, the model also reasonably estimated long-term dynamics of organic matter pools on forest floor and in forest soil. Predicted mean and standard deviation of annual nitrate exports were comparable to measured values: 1.6 &#xb1; 1.3 vs. 1.5 &#xb1; 1.5 kg ha-1 for D2 site, and 1.4 &#xb1; 1.3 vs. 1.3 &#xb1; 1.1 kg ha-1 for D3 site, respectively. Predicted nitrate export dynamics were also in excellent agreement with field measurements as indicated by NSE above 0.90 and 0.84 on annual and monthly bases, respectively. The model, thus successfully tested, was applied to predicted hydrological and biogeochemical responses to drainage water management and silvicultural practices. Specifically, the model predicted reduced rainfall interception and ET after clear cutting, both of which led to increased water yield and elevated water table, as expected. The model also captured temporary changes in nitrogen transformations following forest harvesting, including increased mineralization, nitrification, denitrification, and decreased plant uptake. Overall, this study demonstrated that DRAINMOD-FOREST can predict water, C and N dynamics in drained pine forests under intensive management practices.]]>	</description>
	<pubDate>
		Fri, 27 Jan 2012 15:27:03 -0500	</pubDate>

        <dc:creator>
                Tian, Shiying; Youssef, Mohamed A.; Skaggs, R. Wayne; Amatya, Devendra ; Chescheir, George M.        </dc:creator>
        <dc:subject>
                Forest hydrology; C and N dynamics; Silvicultural practices; Forest ecosystem modeling; DRAINMOD-FOREST        </dc:subject>
</item> 



<item>
	<title>
		Long-term hydrology and water quality of a drained pine plantation in North Carolina	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40006	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40006	</guid>
	<description>
		<![CDATA[Long-term data provide a basis for understanding natural variability, reducing uncertainty in model inputs and parameter estimation, and developing new hypotheses. This article evaluates 21 years (1988-2008) of hydrologic data and 17 years (1988-2005) of water quality data from a drained pine plantation in eastern North Carolina. The plantation age was 14 years at the beginning of the investigation (1988) and 34 years at the end (2008). The 21-year average rainfall of 1517 mm was 9% higher than the 50-year (1951-2000) long-term average of 1391 mm observed at the nearest U.S. Weather Bureau station in Morehead City, North Carolina. Annual rainfall varied from 852 mm in the driest year (2001) to 2331 mm in the wettest year (2003) during the study period and was affected by several hurricanes and tropical storms. The runoff coefficient (ROC; drainage outflow expressed as a fraction of rainfall) varied from 0.05 in the driest year to as high as 0.56 in the wettest year (2003), with an average ROC of 0.32. Annual outflow (runoff) on this watershed was primarily subsurface flow to drainage ditches and was strongly correlated with rainfall (R2 = 0.81). Outflows were greater, more continuous, and longer in winter than in other seasons. Outflow in winter was 59% of rainfall on average. March was the only month that never produced zero outflow. The lowest mean outflow occurred in the spring and was significantly different from the other three seasons. Consistent with theory for subsurface drainage, outflow from this poorly drained land is dependent on water table elevation and occurs when the water table is within about 1.1 m of the surface. The water table tended to be close to the surface during the winter and early spring with low ET demands, and during summer with hurricanes and tropical storms producing large outflows, but was drawn down to depths much deeper than the drains during long dry periods in summer and fall. As a result, annual outflow and annual average water table depth were only weakly correlated (R2 = 0.52). There was no relationship (R2 = 0.01) between the annual average water table depth and the annual average evapotranspiration (ET), calculated as the difference between annual rainfall and outflow. The estimated average annual ET of 1005 mm was close to the Penman-Monteith based average annual potential ET (PET) of 1010 mm for a grass reference. Although nitrogen (N) levels in the drainage water were elevated after fertilization of the stand in late 1988, these elevated levels declined substantially by 1995. Average annual concentrations of total N ranged from 0.51 to 2.23 mg L-1 with a long-term average of 1.10 mg L-1. Annual average values for total P ranged from 0.01 to 0.12 mg L-1 with an average of 0.04 mg L-1. The highest average annual concentrations for N and P occurred in 1989 (N) and 1990 (P) following fertilization in spring of 1989. The average annual total N and P loadings were 6.5 &#xb1;5.3 kg ha-1 and 0.17 &#xb1;0.11 kg ha-1, respectively. Both concentrations and annual loadings were similar to other forested sites in the region. These long-term data should be useful for assessing the effects of land use change and management treatments on the hydrology and water quality of similar lands in the coastal region.]]>	</description>
	<pubDate>
		Tue, 10 Jan 2012 14:30:59 -0500	</pubDate>

        <dc:creator>
                Amatya, D.M.; Skaggs, R.W.        </dc:creator>
        <dc:subject>
                Evapotranspiration, Nutrient concentration, Nutrient loading, Outflow, Potential evapotranspiration, Rainfall, Runoff coefficient, Water table        </dc:subject>
</item> 



<item>
	<title>
		Evaluating the SWAT model for a low-gradient forested watershed in coastal South Carolina	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40005	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40005	</guid>
	<description>
		<![CDATA[Modeling the hydrology of low‐gradient forested watersheds on shallow, poorly drained soils of the coastal plain is a challenging task due to complexities in watershed delineation, microtopography, evapotranspiration, runoff generation processes and pathways including flooding and submergence caused by tropical storms, and complexity of vegetation species. The main objective of this study was to calibrate and validate the GIS‐based spatially distributed hydrologic model SWAT for the 72.6 km2 low‐gradient, third‐order Turkey Creek watershed within the Francis Marion National Forest in the South Carolina Coastal Plain. Model calibration used GIS spatial data of the watershed and 2.75 years (2005‐2007) of streamflow and climate data, and the model was validated with 2.5 years (2008‐2010) of data. Based on limited field measurements, results showed that the SWAT model with an improved one‐parameter “depletion coefficient” for plant evapotranspiration in the SCS curve number (CN) estimate can predict the daily and monthly streamflow processes of this watershed reasonably well and better than the CN method. The model performance was “good” (E = 0.68; RSR = 0.56) to “very good” (E = 0.90; RSR = 0.31) for the monthly calibration and validation periods but only “satisfactory” (E = 0.59; RSR = 0.64) to “good” (E = 0.70; RSR = 0.55) for the daily calibration and validation periods. Better predictions were found for the validation period that included two wetter years than the calibration with two drier years. The model's predictions of the zero or near‐zero flow days of summer were also in agreement with the measurements for 60% of the time. However, it was concluded that the refined SWAT model was still unable to accurately capture the flow dynamics of this forest ecosystem with shallow, high water table soils for events preceded by wet saturated conditions during the dry summer and wet winter periods, warranting further investigations on these forest systems. The five‐year average annual runoff coefficient of 19% with a baseflow amount of 27%, on average, of the runoff (streamflow) and ET of 987 mm predicted by the model were found reasonable compared to the estimated values and other published data for the region. Further improvements in estimates of forest potential evapotranspiration, rainfall spatial variability, and antecedent moisture as a function of water table should reduce uncertainties in flow predictions, allowing the model to be used in hydrologic impact assessments of land use change, land management practices, and climate change in coastal landscapes.]]>	</description>
	<pubDate>
		Tue, 10 Jan 2012 11:16:06 -0500	</pubDate>

        <dc:creator>
                Amatya, D.M.; Jha., M.K.        </dc:creator>
        <dc:subject>
                Baseflow, Evapotranspiration, Poorly drained soils, Rainfall variability, Santee Experimental Forest, Streamflow, Water balance, Water table        </dc:subject>
</item> 



<item>
	<title>
		Advances in forest hydrology: challenges and opportunities	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40004	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40004	</guid>
	<description>
		<![CDATA[Forests are an integral component of the landscape, and maintaining their functional integrity is fundamental for the sustainability of ecosystems and societies alike. Tools, innovations, and practices, analogous to those developed to improve agricultural production and quantify environmental impacts, are needed to ensure the sustainability of these forested landscapes as well as the ecosystem goods and services they produce. This article introduces ten technical articles on critical ecohydrologic processes, protection and restoration, and the effects of management practices on the hydrology and water quality of forests and forested wetlands, using both monitoring and modeling approaches. Prepared by experts in forest science, forest and agricultural hydrology, and water management, the studies reported in this special collection are concentrated in the Atlantic Coastal plain and focus on forests with shallow water tables. Experimental studies describe the effects of riparian vegetation harvest, human disturbance, and future climatic change on groundwater, the significance of emergent vegetation after harvest, and long‐term hydrologic water balance of a managed pine forest. Modeling studies use the SWAT model to predict streamflow dynamics of a less disturbed, coastal forested watershed, and DRAINMOD to determine the impacts of minor silvicultural drainage on wetland hydrology and to improve wetland restoration. Finally, a study describes potential uncertainties associated with infrequent water sampling of nutrient loads from drained forested watersheds. This introductory article summarizes these studies of shallow water table forests and relates them to the broader field of forest hydrology, including its challenges and opportunities, while identifying pressing issues of land use and climate change. The results from these studies should help guide management and restoration of forest wetland ecosystems and direct future forest hydrologic research, including research in large prior converted agricultural landscapes.]]>	</description>
	<pubDate>
		Tue, 10 Jan 2012 15:14:36 -0500	</pubDate>

        <dc:creator>
                Amatya, D.M.; Douglas-Mankin, K.R.; Williams, T.M.; Skaggs, R.W.; Nettles, J.E.        </dc:creator>
        <dc:subject>
                Agricultural landscape, Best management practices, DRAINMOD, Evapotranspiration, Forested wetlands, Hydrologic processes, Nutrient loading, Riparian buffer, Shallow water table, SWAT        </dc:subject>
</item> 



<item>
	<title>
		The interaction between propagule pressure, habitat suitablility and density-dependent reproduction in species invasion	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40003	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40003	</guid>
	<description>
		<![CDATA[Seedling recruitment limitations create a demographic bottleneck that largely determines the viability and structure of plant populations and communities, and pose a core restriction on the colonization of novel habitat. We use a shade tolerant, invasive grass, Microstegium vimineum, to examine the interplay between seed and establishment limitations " phenomena that together determine recruitment success but usually are investigated individually. We add increasing amounts of seed to microhabitats containing variable levels of leaf litter thickness " with reduced leaf litter simulating disturbance " to investigate whether reduced seed limitation overcomes the establishment limitation posed by litter cover. We do this across gradients in understory light, moisture and temperature, and quantify germination, survival, and then per capita adult biomass and reproduction in order to understand the implications for invasion across the landscape. We find that the combined effects of seed and establishment limitation influence recruitment; however, propagule pressure overwhelms the inhibitory effects of leaf litter thickness. Leaf litter reduces germination by 22"57% and seedling survival by 13"15% from that observed on bare soil. However, density-dependent reproduction compensates as 1"3 plants can produce far more seeds (approx. 525) than are required for persistence. As such, just a few plants may establish in understory forest habitat and subsequently overwhelm establishment barriers with copious propagule production. These results, for a widespread, invasive plant, are consistent with the emerging perspective for native plants that seed and establishment limitation jointly influence recruitment. The ability for an exotic plant species to compensate for low population densities with high per capita seed production, that then overrides establishment limitations, makes its invasive potential daunting. Further work is required to test if this is a common mechanism underlying plant invasions.]]>	</description>
	<pubDate>
		Fri, 27 Jan 2012 10:59:02 -0500	</pubDate>

        <dc:creator>
                Warren, Robert J. II; Volker, Bahn; Bradford, Mark A.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		Structural attributes of two old-growth Cross Timbers stands in western Arkansas	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40002	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40002	</guid>
	<description>
		<![CDATA[Comprised of largely non-commercial, xeric, oak-dominated forests, the Cross Timbers in Arkansas have been heavily altered over the last two centuries, and thus only scattered parcels of old-growth timber remain. We inventoried and mapped two such stands on Fort Chaffee Military Training Center in Sebastian County, Arkansas. The west-facing Christmas Knob site is located on an isolated hill, while the southerly-facing Big Creek Narrows site is on a long, narrow rocky outcrop called Devil’s Backbone Ridge. These sites occupied rocky, south- to southwest-facing sandstone-dominated slopes, with primarily post oak (Quercus stellata) and blackjack oak (Q. marilandica) overstories. Post oak dominated the largest size classes at both sites. Increment cores indicated that some post oaks exceeded 200 y of age, and tree-ring dating also confirmed an uneven-aged structure to these stands. Both locations had irregular reverse-J shaped diameter distributions, with gaps, deficiencies, and excesses in larger size classes that often typify old-growth stands. On average, the post oaks at the Big Creek Narrows site were taller, larger in girth, and younger than those on the Christmas Knob site, suggestive of a better quality site at Big Creek. The application of neighborhood density functions on stem maps of both sites found random patterns in tree locations. These stands are very similar in their structure to old-growth examples in other parts of the Cross Timbers ecoregion.]]>	</description>
	<pubDate>
		Tue, 17 Jan 2012 09:17:50 -0500	</pubDate>

        <dc:creator>
                Bragg, Don C.; Stahle, David W.; Cerny, K. Chris        </dc:creator>
        <dc:subject>
                Arkansas, Cross Timbers, oak, Quercus marilandica, Quercus stellata, uneven-aged structure, old growth        </dc:subject>
</item> 



<item>
	<title>
		Texas, 2010 forest inventory and analysis factsheet	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40001	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40001	</guid>
	<description>
		<![CDATA[This science update summarizes the findings of the statewide annual inventory conducted by the Southern Forest Inventory and Analysis (FIA) Program in cooperation with the Texas Forest Service of the forest resource attributes in Texas. The 254 counties of Texas are consolidated into seven FIA survey units " southeast (unit 1), northeast (unit 2), north central (unit 3), south (unit 4), west central (unit 5), northwest (unit 6), and west (unit 7). East Texas is made-up of units 1 and 2, while the central and west Texas consists of units 3 thru 7 (fig. 1). This overview represents the 2006-10 moving average for east Texas and 70 percent of the first forest survey for central and west Texas. The 2010 survey provides a remeasurement of annual inventory plots for east Texas and the initial establishment of plots in central and west Texas.]]>	</description>
	<pubDate>
		Tue, 31 Jan 2012 11:52:31 -0500	</pubDate>

        <dc:creator>
                Bentley, James W.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		North Carolina, 2010 forest inventory and analysis factsheet	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/40000	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/40000	</guid>
	<description>
		<![CDATA[North Carolina’s first annualized forest survey was completed in 2007 and results were published in e-Science Update SRS"029. There were 5,800 ground based samples distributed across the State. At that time, field measurements were collected on 20 percent (a panel) of these plots annually until all plots were completed. This factsheet is an annualized update of panel data collected in 2007 and updated by reprocessing with 2009 and 2010 data. Currently, the 5,800 samples are being collected on a 15-percent panel annually until all plots are completed. The new data represents 5 years of data, 30 percent of which are new since the last factsheet produced for 2007. The new data results in a “moving” average, and keeps the inventory more up to date than if reported every full cycle of panels (currently 7 years). However, the strongest and most reliable trend information comes from comparing data from two full cycles of completed panels. This factsheet is based on data for 2007, 2009, and 2010 extracted from the FIA Evalidator interface on the SRS FIA Web site on September 13, 2011 at http://apps.fs.fed.us/Evalidator/tmattribute.jsp.]]>	</description>
	<pubDate>
		Tue, 31 Jan 2012 11:47:33 -0500	</pubDate>

        <dc:creator>
                Brown, Mark J.; New, Barry D.        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		Florida, 2010 forest inventory and analysis factsheet	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/39999	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/39999	</guid>
	<description>
		<![CDATA[Forest Inventory and Analysis (FIA) factsheets are produced periodically to keep the public up to date on the extent and condition of the forest lands in each State. This factsheet is an annualized update of the full 5-year cycle of panel data completed in 2007 and updated by reprocessing with new 2009 and 2010 panel data. It represents 5 years of data, 40 percent of which are new since the last factsheet produced for 2007. The new data results in a “moving” average, and keeps the inventory more up to date than if reported every 5 years at the end of the next full cycle of panels. Because these data represent a sample rather than a complete inventory of conditions, the most reliable trend information is obtained by comparing data from two full cycles (5 years of data) of completed panels. This factsheet is based on data collected in 2007, 2009, and 2010. The data herein was extracted from the FIA Evalidator interface on the SRS FIA Web site on September 19, 2011 at http://apps.fs.fed.us/Evalidator/tmattribute.jsp.]]>	</description>
	<pubDate>
		Tue, 31 Jan 2012 11:40:08 -0500	</pubDate>

        <dc:creator>
                Brown, Mark J.; Nowak, Jarek        </dc:creator>
        <dc:subject>
                        </dc:subject>
</item> 



<item>
	<title>
		The Sine Method: An Alternative Height Measurement Technique	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/39981	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/39981	</guid>
	<description>
		<![CDATA[Height is one of the most important dimensions of trees, but few observers are fully aware of the consequences of the misapplication of conventional height measurement techniques. A new approach, the sine method, can improve height measurement by being less sensitive to the requirements of conventional techniques (similar triangles and the tangent method). We studied the sine method through a couple of comparisons. First, we demonstrated the validity of the sine method under idealized conditions by comparing tangent and sine measurements on a stationary object of a known height. Then, we compared heights collected via climbing and lowering a tape from the highest point of a number of forest-grown trees with heights measured with the sine method. The sine method offers a viable, cost effective alternative to traditional measurement approaches, especially for large or leaning trees, and for trees with broadly spreading crowns.]]>	</description>
	<pubDate>
		Thu, 26 Jan 2012 11:43:46 -0500	</pubDate>

        <dc:creator>
                Bragg, Don C.; Frelich, Lee E.; Leverett, Robert T.; Blozan, Will; Luthringer, Dale J.        </dc:creator>
        <dc:subject>
                Height measurement, hypsometers, similar triangles, sine method, tangent method, trigonometry        </dc:subject>
</item> 



<item>
	<title>
		Louisiana’s Palustris Experimental Forest: 75 years of research that transformed the South	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/39980	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/39980	</guid>
	<description>
		<![CDATA[The Palustris Experimental Forest, located on Kisatchie National Forest, has been in existence for 75 years. Research at Palustris has focused on southern pine reforestation technology, including seed production, bareroot nursery production, direct seeding, and planting container seedlings. After establishing pine plantations, researchers developed stand management guidelines for thinning, fertilizing, use of fire, stocking levels, and modeling of growth projections. Researchers elucidated knowledge of soil influences and plant competition, factors key to optimizing and maintaining plantation stand productivity. Researchers also emphasized range management that established guidelines for livestock utilization on forest ranges across the South. Today’s forest industry across the South maximizes productivity with the management practices developed by researchers on the Palustris Experimental Forest.]]>	</description>
	<pubDate>
		Thu, 26 Jan 2012 11:34:13 -0500	</pubDate>

        <dc:creator>
                Barnett, James P.; Haywood, James D.; Pearson, Henry A.        </dc:creator>
        <dc:subject>
                Agroforestry, history of southern forestry, pine plantation management, reforestation of southern pines, seed and seedling physiology        </dc:subject>
</item> 



<item>
	<title>
		Forest health monitoring: 2007 national technical report	</title>
	<link>
		http://www.srs.fs.usda.gov/pubs/39953	</link>
	<guid>
		http://www.srs.fs.usda.gov/pubs/39953	</guid>
	<description>
		<![CDATA[The Forest Health Monitoring Program produces an annual technical report that has two main objectives. The first objective is to present information about forest health from a national perspective. The second objective is to present examples of useful techniques for analyzing forest health data new to the annual national reports and new applications of techniques formerly used. The report’s organizational framework is the Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests of the Montreal Process. Here, we present an approach to examining landscape context of forest and grassland in the United States. We explore the influence of environmental factors such as climate and air quality on a lichen species diversity indicator across the continental United States. This includes an analysis of the potential for monitoring changes in these environmental factors. We use Forest Inventory and Analysis phase 3 data to describe aspects of forest communities such as understory species composition, richness, and distribution, including discussion of invasive and introduced species. Tree mortality, which has been examined in previous Forest Health Monitoring reports, is analyzed in this report using a more intensive dataset to demonstrate the utility of Forest Inventory and Analysis phase 2 data. We explore spatial modeling of ozone injury risk, along with microscale and landscape-scale ancillary data that can be used in the modeling analyses. A discussion of redbay ambrosia beetle/laurel wilt risk includes current beetle/ wilt distribution, host species distributions, climate matching, and spread modeling. Progress in monitoring and analyses of Phytophthora ramorum and sudden oak death is presented along with results from two different monitoring techniques.]]>	</description>
	<pubDate>
		Wed, 25 Jan 2012 16:03:12 -0500	</pubDate>

        <dc:creator>
                Conkling, Barbara L.        </dc:creator>
        <dc:subject>
                Air pollution, biodiversity, Criteria and Indicators, invasive insects and pathogens, landscape lichens, ozone        </dc:subject>
</item> 

 
</channel>
</rss>

