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Timothy A. Martin  - - - 
Top co-authors See all
Dennis D. Baldocchi

234 shared publications

Department of Environmental Science, Policy and Management; University of California, Berkeley; Berkeley CA

Walter C. Oechel

204 shared publications

Department of Biology; San Diego State University; San Diego CA USA

Gil Bohrer

116 shared publications

Department of Civil, Environmental and Geodetic Engineering, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA

W.P. Cropper

84 shared publications

School of Forest Resources & Conservation, University of Florida, 363 Newins-Ziegler Hall, P.O. Box 110410, Gainesville, FL 32611, USA

Sanford D. Eigenbrode

80 shared publications

Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, Idaho 83844-2329

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Publication Record
Distribution of Articles published per year 
(2004 - 2017)
Total number of journals
published in
 
10
 
Publications See all
Article 0 Reads 5 Citations Spatially-explicit modeling of multi-scale drivers of aboveground forest biomass and water yield in watersheds of the So... Mukhtar Ahmed Ajaz Ahmed, Amr Abd-Elrahman, Francisco J. Esc... Published: 01 September 2017
Journal of Environmental Management, doi: 10.1016/j.jenvman.2017.05.013
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Understanding ecosystem processes and the influence of regional scale drivers can provide useful information for managing forest ecosystems. Examining more local scale drivers of forest biomass and water yield can also provide insights for identifying and better understanding the effects of climate change and management on forests. We used diverse multi-scale datasets, functional models and Geographically Weighted Regression (GWR) to model ecosystem processes at the watershed scale and to interpret the influence of ecological drivers across the Southeastern United States (SE US). Aboveground forest biomass (AGB) was determined from available geospatial datasets and water yield was estimated using the Water Supply and Stress Index (WaSSI) model at the watershed level. Our geostatistical model examined the spatial variation in these relationships between ecosystem processes, climate, biophysical, and forest management variables at the watershed level across the SE US. Ecological and management drivers at the watershed level were analyzed locally to identify whether drivers contribute positively or negatively to aboveground forest biomass and water yield ecosystem processes and thus identifying potential synergies and tradeoffs across the SE US region. Although AGB and water yield drivers varied geographically across the study area, they were generally significantly influenced by climate (rainfall and temperature), land-cover factor1 (Water and barren), land-cover factor2 (wetland and forest), organic matter content high, rock depth, available water content, stand age, elevation, and LAI drivers. These drivers were positively or negatively associated with biomass or water yield which significantly contributes to ecosystem interactions or tradeoff/synergies. Our study introduced a spatially-explicit modelling framework to analyze the effect of ecosystem drivers on forest ecosystem structure, function and provision of services. This integrated model approach facilitates multi-scale analyses of drivers and interactions at the local to regional scale.
Article 0 Reads 2 Citations Loblolly Pine Productivity and Water Relations in Response to Throughfall Reduction and Fertilizer Application on a Poor... Maxwell Wightman, Timothy Martin, Carlos Gonzalez-Benecke, E... Published: 26 September 2016
Forests, doi: 10.3390/f7100214
DOI See at publisher website ABS Show/hide abstract
Loblolly pine (Pinus taeda L.) forests are of great ecological and economic value in the southeastern United States, where nutrient availability frequently limits productivity. The impact of fertilizer application on the growth and water relations of loblolly pine has been investigated by numerous studies; however, few field experiments have examined the effects of drought. Drought is of particular interest due to the potential for climate change to alter soil water availability. In this study, we investigated the impact of fertilizer application and a 30% reduction in throughfall on loblolly pine productivity, transpiration, hydraulic conductance, and stomatal conductance. The study was installed in a ten-year-old loblolly pine plantation on a somewhat poorly drained site in northern Florida. Throughfall reduction did not impact tree productivity or water relations of the trees. This lack of response was attributed to abundant rainfall and the ability of trees to access the shallow water table at this site. Fertilizer application increased basal area production by 20% and maximum leaf area index by 0.5 m2∙m−2, but it did not affect whole-tree hydraulic conductance or the sensitivity of stomatal conductance to vapor pressure deficit. During the spring, when leaf area and vapor pressure deficit were high, the fertilizer-only treatment increased monthly transpiration by 17% when compared to the control. This relationship, however, was not significant during the rest of the year.
Article 1 Read 12 Citations A Range-Wide Experiment to Investigate Nutrient and Soil Moisture Interactions in Loblolly Pine Plantations Rodney E. Will, Thomas Fox, Madison Akers, Jean-Christophe D... Published: 03 June 2015
Forests, doi: 10.3390/f6062014
DOI See at publisher website ABS Show/hide abstract
The future climate of the southeastern USA is predicted to be warmer, drier and more variable in rainfall, which may increase drought frequency and intensity. Loblolly pine (Pinus taeda) is the most important commercial tree species in the world and is planted on ~11 million ha within its native range in the southeastern USA. A regional study was installed to evaluate effects of decreased rainfall and nutrient additions on loblolly pine plantation productivity and physiology. Four locations were established to capture the range-wide variability of soil and climate. Treatments were initiated in 2012 and consisted of a factorial combination of throughfall reduction (approximate 30% reduction) and fertilization (complete suite of nutrients). Tree and stand growth were measured at each site. Results after two growing seasons indicate a positive but variable response of fertilization on stand volume increment at all four sites and a negative effect of throughfall reduction at two sites. Data will be used to produce robust process model parameterizations useful for simulating loblolly pine growth and function under future, novel climate and management scenarios. The resulting improved models will provide support for developing management strategies to increase pine plantation productivity and carbon sequestration under a changing climate.
Article 0 Reads 7 Citations Improved global simulations of gross primary product based on a new definition of water stress factor and a separate tre... Hao Yan, Shao-Qiang Wang, Dave Billesbach, Walter Oechel, Gi... Published: 01 February 2015
Ecological Modelling, doi: 10.1016/j.ecolmodel.2014.11.002
DOI See at publisher website
Article 4 Reads 4 Citations Architectures of adaptive integration in large collaborative projects Lois Wright Morton, Sanford D. Eigenbrode, Timothy A. Martin Published: 01 January 2015
Ecology and Society, doi: 10.5751/es-07788-200405
DOI See at publisher website
Article 6 Reads 0 Citations Individual Tree Diameter, Height, and Volume Functions for Longleaf Pine Carlos A. Gonzalez-Benecke, Daniel J. LeDuc, Salvador A. Gez... Published: 28 February 2014
Forest Science, doi: 10.5849/forsci.12-074
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Currently, little information is available to estimate individual tree attributes for longleaf pine (Pinus palustris Mill.), an important tree species of the southeastern United States. The majority of available models are local, relying on stem diameter outside bark at breast height (dbh, cm) and not including stand-level parameters. We developed a set of individual tree equations to predict tree height (H, m), stem diameter inside bark at 1.37 m height (dbhIB, cm), stem volume outside bark (VOB, m3), and stem volume inside bark (VIB, m3), as well as functions to determine merchantable stem volume ratio (both outside and inside bark) from the stump to any top diameter. Local and general models are presented for each tree attribute. General models included stand-level parameters such as age, site index, dominant height, basal area, and tree density. The user should decide which model type to use, depending on data availability and level of accuracy desired. To our knowledge, this is the first comprehensive individual tree-level set of equations reported for longleaf pine trees, including local and general models, which can be applied to longleaf pine trees over a large geographical area and across a wide range of ages and stand characteristics. The system presented here provides important new tools for supporting future longleaf pine management decisions.
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