Research Programs

Vascular Plant Flora of the Canyonlands Unit of the Big Thicket National Preserve, Tyler County, Texas

Vascular Plant Flora of the Canyonlands Unit of the Big Thicket National Preserve, Tyler County, Texas

Stephan L. Hatch, S.M. Tracy Herbarium (TAES), Texas A&M University
Kelly C. Haile, S.M. Tracy Herbarium (TAES), Texas A&M University

The Big Thicket National Preserve (BITH) acquired the Canyonlands Unit in 1993 which consists of about 1,500 acres on the eastern boundary of Tyler County and is positioned along 3.5 miles of the western bank of the Neches River.  The unique topography of the unit includes several “canyons” with large beech trees and is unlike any of the other units within the preserve. This unit is thought to be the most diverse in the BITH and will be instrumental in understanding the diversity and complexity of the Big Thicket. As part of the National Park Service’s "All Taxa Biodiversity Inventory" the vascular plant flora of this unit is being documented.  Prior to this study, no intensive study of the unit has been undertaken. Voucher specimens of vascular plants, digital images of flowers and fruits are being collected and deposited in the S.M. Tracy Herbarium.

 Funding Organization: Big Thicket Association-Thicket of Diversity

Consolidation of Botanical Research Collections at Texas A & M University, College Station

Consolidation of Botanical Research Collections at Texas A & M University, College Station,Texas

 Stephan L. Hatch, S.M. Tracy Herbarium (TAES), Texas A&M University
Dale A. Kruse, S.M. Tracy Herbarium (TAES), Texas A&M University
Vaughn M. Bryant, Palynology Reference Collection, Department of Anthropology, Texas A & M University

This project will consolidate three existing botany-based research collections on the College Station Campus of Texas A&M University.  Residing in a public university, these collections are committed to transferring research products to the general public through active service and extension programs, promoting collections based research in their respective fields, and preserving extant collections for future generations.  The consolidation of these collections will assemble and preserve a diverse and comprehensive botanical collection of approximately 320,000 specimens, and improve local, regional, and national education and research efforts.  National  Science Foundation funds will be utilized to purchase 135 herbarium cabinets to incorporate the Biology Department Herbarium (TAMU) into the S.M. Tracy Herbarium (TAES), alleviate overcrowding in both collections, merge and update their respective databases, and develop a pollen database and image gallery for the Palynology Reference Collection (PALY). 


Funding Organization:  National Science Foundation, Collections in Support of Biological Research

The Bryophyte Flora of the Big Thicket National Preserve, Southeast Texas
The Bryophyte Flora of the Big Thicket National Preserve, Southeast Texas
Dale A. Kruse, S.M. Tracy Herbarium (TAES), Texas A&M University
Paul G. Davison, Herbarium (UNAF), Department of Biology, University of North Alabama
The “big thicket” region of southeast Texas has long been referred to as a biological crossroads.  Situated as the intersection of several distinct eco-regions; the area harbors a unique mix of plants and animals indicative of the southeastern swamps, eastern forests, central plains, and the southwestern United States.  Its biota includes species from tropical and subtropical biomes, as well as those characteristic of the arid west.  The region also represents the western-most extension of the southeastern evergreen forests, and is the western boundary for distributions of many aquatic insects with largely eastern affinities.  The Big Thicket National Preserve (BITH), founded in 1974, seeks to preserve the fragmented remnants of a once much larger and contiguous region of natural ecosystems.  Comprising nearly 105,000 acres in a disparate mix of land units, and several inter-connecting water corridors, BITH was the first unit of the National Park Service (NPS) to be set aside with the expressed intent of protecting biodiversity. 

Surveys of vascular plants have been reported for most regions of Texas, and in particular, east Texas.  However, many of the earliest east Texas reports made no mention, or only a passing reference to bryophytes, and none provide real inventories or checklists of these groups.  Even reports from surveys conducted much later neglect to include bryophytes as part of their inventories.  Following the establishment of the BITH, a broad survey of plant and fungal groups within the newly established preserve was initiated.  This report included what could be considered the first inventory of bryophytes within the legal confines of the BITH.  This initial survey reported 77 species in 49 genera as occurring in selected units of the preserve.  Following these initial reports, additional authors have periodically supplemented the known bryophyte flora of the BITH.  Despite these subsequent reports, a number of BITH’s operational units have limited, or no, reports of bryophytes. 

The objective of this inventory was to provide an overall inventory of extant bryophyte taxa within the entirety of the BITH.  In the context of this inventory, bryophytes include taxa from the Bryophyta (moss), Marchantiophyta (liverwort), and Anthocerotophyta (hornwort) phyla. 

This floristic inventory was conducted from January 2007 to September 2011 and resulted in an updated checklist of 179 species of hornworts, liverworts, and mosses, in 98 genera and 54 families.  Thirteen potentially new state records, twelve (12) liverworts and one (1) moss, are reported.

Funding Organizations: Western National Parks Association and the Big Thicket Association-Thicket of Diversity




A multi-scale approach using lidar and MODIS products for assessing forest carbon

PIs and collaborators: Dr. Sorin Popescu

Brief statement of activities, goals, and accomplishments: Integrate lidar data on multiple platforms and optical MODIS imagery for assessing forest biophysical parameters, including forest biomass and carbon

Funding organization: NASA

Academy for Ranch Management

PIs and collaborators: Dr. Charles A. Taylor, Jr., Mr. Ray T. Hinnant, Dr. Mort Kothmann

Brief statement of activities, goals, and accomplishments: The Academy for Ranch Management is based at the Texas AgriLIFE Research Station at Sonora. The goal of the Academy is to provide education and training to ranchers for more effective rangeland management. We utilize the resources of the Station that reflects 60 years of rangeland management research as a teaching laboratory to provide hands-on experiences. The primary course we are now teaching is Prescribed Burning for Rangelands, which we offer as two basic courses and one advanced course per year. Each course runs from Thursday noon to Saturday noon. Participants who complete a basic course and the advanced course and pass the written exam meet the training requirement for the Certified Prescribed Burn Manager. The Academy also supports landowners through providing training for Prescribed Burn Association members.

Association Genetics of Natural Genetic Variation and Complex Traits in Pine

PIs and collaborators: Charles Langley, David Neale (U.C. Davis), Barry Goldfarb (NC State), John Davis, Gary Peter, Dudley Huber, Matias Kirst, George Casella (U. Florida), Carol Loopstra, Tom Byram (Texas A&M and Texas Forest Service).

Brief statement of activities, goals, and accomplishments: A group of four universities, an association population of loblolly pine covering much of the natural range was generated, a unigene set representing transcribed sequences was resequenced, single nucleotide polymorphisms were discovered and the association population was genotyped and the association population and/or an alternative population were analyzed for disease resistance, wood characteristics, water use efficiency, metabolites, and gene expression. Association genetics analyses were performed to find relationships between genetic polymorphisms and the measured phenotypes. At TAMU, we analyzed expression of 200 genes thought to be involved in xylem development or responses to drought or disease in the association population. We used this data to develop transcriptional networks, examine how expression varied between individuals or regions and to do association analyses. We found a large number of positive associations between genes giving us a better understanding of genes involved in wood development and response to stresses. We also conducted a study in a smaller number of plants to examine the relationship between drought and pitch canker. Many of the same genes were induced by the two different stresses. The promoters of 12 transcription factors were cloned to determine if polymorphisms in them affect expression of that particular gene or genes downstream in the signal transduction cascade. Preliminary data was promising and we are now waiting for genotyping data from the association population.

Funding organization: National Science Foundation

Burning Risk Advisory Support System (BRASS-MIL) to Assess Fire Behavior: The CNRIT Fort Hood, Texas project

PIs and collaborators: Wayne Hamilton, Senior Lecturer, Department of ESSM J. Richard Connor, Professor, Departments of ESSM and AGEC Will Shaw, Assist. Research Scientist and BRASS Project Lead Scientist, ESSM

Brief statement of activities, goals, and accomplishments: Work by CNRIT on the current project began in 2006 when the VFMS project (Vegetation and Fire Monitoring System) was initiated with the objective of utilizing the PHYGROW model to provide continuous forage inventory data for assessment of livestock stocking rates and fine fuel loads for assessment of fire risk. Since 2006, this objective has grown into the BRASS-MIL project. Funding by DOD for the project has been continuous since 2006 for a total of $1.35m over the five year period. The project will end September 30, 2010 when the completed BRASS-MIL application is installed in the radio room at Ft. Hood Range Control as a fire management decision support system.

Funding organization: Department of Defense

Carbon and water responses to woody plant encroachment in karst terrain

PIs and collaborators: Moore, Heilman, McInnes, Litvak

Brief statement of activities, goals, and accomplishments: Compare ecosystem and tree level ET and carbon exchange between grassland, Savanna, and woodland sites

Funding organization: DOE

Chinese tallow tree invasions of the southeastern United States

PIs and collaborators: Dr. Bill Rogers (TAMU), Evan Dr. Evan Siemann at Rice University, Dr. Saara J. DeWalt at Clemson University, Dr. Jianwen Zou at Nanjing Agricultural University, Dr. Maria Hartley at Chevron Energy.

Brief statement of activities, goals, and accomplishments: These ongoing studies are examining the causes and consequences of non-native Chinese Tallow Tree  (Triadica sebifera, formerly Sapium sebiferum) invasions in a variety of habitats throughout the southeastern United States.  Utilizing a large number of experimental studies, we are attempting to understand how local environmental factors (e.g., herbivores, fungal pathogens, resources, mycorrhizal symbionts, disturbance regime and recruitment limitation) interact with post invasion evolutionary adaptations to determine the mechanisms responsible for Triadica invasions of forests and grasslands.   We have also been comparing the invasive genotype of the tree to the native genotype in both the introduced North American range and the native in China.  These efforts are the continuation of my long-term collaboration with colleagues at Rice University and other academic, state and federal agencies.  Additionally, we are assessing a variety of control and restoration methods for mitigating the negative effects of this aggressive invader.

Funding organization: NSF

Conifer Translational Genomics Network

PIs and collaborators: Tom Byram and Kostya Krutovsky Texas Forest Service and Texas A&M University, others at Oregon State, U C Davis, NC State, U of Florida, USFS.

Brief statement of activities, goals, and accomplishments: The objective is to make marker assisted breeding a reality in southern pine breeding programs. We are completing our third year of a four year grant. During the first three years, we have collectively sampled about six thousand trees and characterized each of them for 4500 genetic markers. WGFTIP sampled almost 2000 trees in the East Texas breeding population managed by Arborgen, Campbell, Hancock, and the TFS. Graduate students directed by Dr. Krutovsky have been using this data combined with the progeny test performances provided by the tree improvement cooperative to look for marker-trait associations, evidence of natural selection, and population structure. This information will be used to more efficiently manage our breeding population and improve the rate of genetic gain in our deployment population. The ultimate goal is to make East Texas forests healthier and more productive.  Partial support has been provided for two graduate students.

Funding organization: Coordinated Agricultural Project funded by USDA NRI and USFS

Cost-Benefit Analysis of Severe Invasive Plants in Southern Forests (2006-2010)

PIs and collaborators: Jianbang Gan; USDA Forest Service collaborators: James Miller and John Taylor, Jr.

Brief statement of activities, goals, and accomplishments: The objective of this project was to develop a Cost-Benefit Analysis Report of the most severe stand-replacement invasive plants using the FIA Survey data with further analysis combined with spread estimates and published findings on the socioeconomic and ecological impacts with projections. Major activities and accomplishments include:

  • Completed the modeling of occupation of major invasive plants in southern forests including Chinese tallow trees, Chinese and European privets, and Japanese honeysuckle and their impact on pine growth/yield.
  • Estimated the population dynamics of these invasives.
  • Developed a spatial stochastic model for simulating the spread of invasives.
  • Developed a modeling framework for developing the optimal detection and control of invasives.
  • One paper was published in the Canadian Journal of Forest Research, and two manuscripts are about to be submitted to Ecological Applications and Forest Ecology and Management.
  • Produced one PhD dissertation.
  • One paper was presented at the 2008 Natural Areas conference, and another one (invited) at the 2009 Society of American Foresters convention.
  • Two posters (one each in 2008 and 2009) were presented by the graduate student hired under this project at the Texas A&M University graduate students research week and received the second prize.

Funding organization: USDA Forest Service, Southern Research Station

Data management for vascular plant inventories of three national park collections


Stephan L. Hatch, S.M. Tracy Herbarium (TAES), Texas A&M University
Dale A. Kruse, S.M. Tracy Herbarium (TAES), Texas A&M University

Processing, data entry, and permanent housing of herbarium specimens collected as vouchers for a vascular plant survey of the Big Thicket National Preserve (ca. 9500 specimens), Palo Alto Battlefield National Historic Site (ca. 250 specimens), and Padre Island National Seashore (ca. 1200 specimens).

Funding Organization: US National Park Service, Gulf Coast Inventory and Monitoring Network


Eco-hydrology of Tropical Montane Forest

PIs and collaborators: C Houser, PI, T Cahill, co-PI (Texas A&M University)

Brief statement of activities, goals, and accomplishments: 
C Houser, PI, T Cahill, co-PI (Texas A&M University). GW Moore, R Washington-Allen, and MG Tjoelker are among 13 named collaborators on this funded grant proposal to Texas A&M University to provide a multidisciplinary research experience and mentorship to 30 undergraduate students (10 per year for three years) in quantifying the hydrologic and biogeochemical fluxes in the watershed of a tropical montane cloud forest in central Costa Rica at the Texas A&M University Soltis Center.
Funding organization: National Science Foundation
Expansion of Texas Land Use/Land Cover Through Crosswalking and Lidar Parameterization of Arboreal Vegetation

PIs and collaborators: Dr. Sorin Popescu (TAMU)

Brief statement of activities, goals, and accomplishments: Assess forest area, canopy surface roughness, and crown dimensions for assessing and modelling biogenic emissions of Texas forests

Funding organization: Texas Commission for Environmental Quality

Family selection and fertilization effects on loblolly pine allocation and the subsequent effects of pine allocation on soil carbon dynamics

PIs and collaborators: Jason Vogel, Texas A&M University, Eric Jokela, School of Forest Resources and Conservation, University of Florida and Edward Schuur, Department of Zoology, University of Florida

Brief statement of activities, goals, and accomplishments: The objectives of this research are to estimate how the belowground carbon (C) allocation of loblolly pine shifts in response to changes in nutrient availability, and how this response varies among 3rd generation loblolly pine families derived from the Atlantic Coastal Plain and Texas.  Shifts in allocation and nutrient availability will then be linked soil C dynamics.  Early results from this research have been presented at a USDA organizational meeting and a meeting for the Forest Biology Research Cooperative in Florida.

Funding organization: USDA Soil Processes program

Genome mapping, structural genomics, and molecular cytogenetics of important forest tree species and their most damaging disease and insect pests

PIs and collaborators: Dr. Nurul Faridi (USFS, Southern Research Station, attached with the Department of Ecosystem Science and Management at Texas A&M).

Brief statement of activities, goals, and accomplishments: Recent advances in molecular cytogenetics have made it possible to unequivocally identify individual chromosomes and to visualize the location of specific genes.  This has come about due to a process, known as Fluorescent in situ Hybridization (FISH).  FISH is a molecular cytogenetics technique that can be used to address questions concerning genome structure, organization, evolution, behavior, nuclear organization, gene expression, wide hybridization, karyotype development, integrated mapping, comparative mapping, and gene cloning.  Such studies strengthen our ability to improve trees for growth rate and wood quality as well as resistance to diseases and insect pests.  Understanding basic biological issues is also useful for the study of the structure and health of natural ecosystems.  The primary focus of the newly created FTMCL is to study the cytogenetics of forest trees, beginning with the major southern pine species.  Secondary foci include similar studies on poplar (the model forest tree species), American chestnut, and two of the most devastating forest diseases: fusiform rust and chestnut blight fungi.

Funding organization: USFS

Individual impact of tree species on carbon dynamics on tropical environments

PIs and collaborators: Drs Ann Russell and J. Raich (Iowa State University), R. Bedoya (Organization for Tropical Studies, Costa Rica), Dr. Eugenio Gonzalez - Texas A&M University (Costa Rica, Soltes Field Station)

Brief statement of activities, goals, and accomplishments: Our main objective was to evaluate the extent to which various C-cycling traits differed among tree species, the mechanisms by which species influenced the forest C balance, and the consequences for forest development and C sequestration. The experiment contained replicated plantations that had been established in abandoned pasture that had been deforested and pastured for 30 years. Although the species in this experiment were originally planted as monocultures, all plots had diverse understories at the time of this study, 15-17 years into the experiment. Our results indicated that differences in species effects on forest C balances were related primarily to differences in growth rates, partitioning of C among biomass components, tissue turnover rates, and tissue chemistry. (See Ecological Applications, 20(4), 2010, pp. 1087-1100).

Funding organization: National Science Foundation

Landowner Response to State-Sponsored Wildfire Mitigation Policy in the Southern Black Belt (2005-2009)

PIs and collaborators: Jianbang Gan; USDA Forest Service collaborator: Cassandra Johnson

Brief statement of activities, goals, and accomplishments: The objectives of the project were to: 1) identify state-level wildfire hazard mitigation policies and procedures across five southern states: Alabama, Florida, Georgia, Mississippi, and South Carolina; 2) develop a list and description of wildlife educational programs administrated by state forestry agencies in each state; 3) model the knowledge of state wildfire policy, implementation of wildfire mitigation procedures and constraints to implementation of wildfire procedures via regression analysis.  Major activities and accomplishments include:

  • Compiled a database of nonindustrial private forestland owners in selected counties in five southern states (Alabama, Florida, Georgia, Mississippi, and South Carolina).
  • Completed the mail surveys of 2500 landowners in the five states and received 585 valid responses.
  • Completed analyses of the survey data to link landowners' awareness, perception, and behavior to demographic and other variables.
  • One paper was published in the Journal of Forestry, two are in press (Journal of Sustainable Forestry and Forest Policy and Economics), and two are in review (Environmental Management and International Journal of Wildland Fire).
  • Produced one MS thesis.

Funding organization: Joint Fire Science Program

Leaf respiration under drought: A global perspective

PIs and collaborators: OK Atkin (PI), JR Evans (co-PI), MG Tjoelker (co-PI), SA Sitch, JJ Lloyd.

Brief statement of activities, goals, and accomplishments: Tjoelker will contribute data from the Texas warming and rainfall manipulation experiment (WaRM) in post oak savanna to this global research effort.

Funding organization: Australian Research Council.

Lidar-assisted Forest Inventory and Analysis (FIA)

PIs and collaborators: Dr. Sorin Popescu (TAMU) and Dr. Demetrios Gatziolis, USDA Forest Service

Brief statement of activities, goals, and accomplishments: Integrate terrestrial lidar scans of FIA plots with airborne lidar data for assessing forest inventory measuments commonly collected through field measurements by the FIA program

Funding organization: USDA Forest Service

Maintenance and Enhancements of the BRASS System

PIs and collaborators: J. Richard Conner Wayne Hamilton, Senior Lecturer, Department of Ecosystem Science and Management, Will Shaw, Assistant Research Scientist and BRASS Project Lead Scientist

Brief statement of activities, goals, and accomplishments: Texas AgriLife Research and USFS Region 3 have been working together since 2005 to produce a Burning Risk Advisory Support System (BRASS).  The system provides users with near real-time fuel loading, fuel moisture content, and fire behavior on individual plant communities within a National Forest. To date, the system has been integrated on 3 national forests, the Coconino, the Prescott, and the Lincoln. Three primary areas of advancement include linking the BRASS and FSVeg databases together for transparent data transfer capabilities, creating a way to transfer data collected on tablet PCs using the VGS software to TAMU, and to design and develop our own Most Similar Neighbor process for relating sampled areas to unsampled areas.  The MSN process has been accomplished by the Forest Service in the past, but for future processing we will implement the entire modeling process - calibration, validation, and MSN into a single user friendly application.  In addition to making enhancements, The TAMU team will provide the day-to-day operations of maintaining the computers and integrity of the data.    The TAMU team's work with Region 3 is aimed at eventually accomplishing a technology transfer of the BRASS system to the Forest Service.

Funding organization: US Forest Service, USDA

National Needs Fellowships for PhDs: Forest Management and Global Change

PIs and collaborators: Drs. Krutovsky, Wilcox, Moore, Washington-Allen, Gan, Tjoelker, Rogers, Kreuter, Popescu, Wu.

Brief statement of activities, goals, and accomplishments:  The Department of Ecosystem Science and Management is seeking exceptional individuals who can excel in a challenging interdisciplinary academic environment.  Applicants who aspire to become scientific leaders whose research solves socio-ecological problems related to global change in forest and woodland ecosystems.  These fellowships provide a $30,000 / year stipend, a $10,500 cost of education allowance, and a $1,500 / year travel allowance over a three year period.  The total award per student over three years is $126,000.

Funding organization: USDA, National Institute of Food and Agriculture, Department of Ecosystem Science and Management and College of Agriculture and Life Science at Texas A&M University.

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Response of black spruce growth and carbon allocation to variation in temperature and moisture

PIs and collaborators: Edward Schuur, University of Florida, Department of Zoology, Stith T. Gower, University of Wisconsin-Madison, Department of Forest and Wildlife Management, and Dustin Bronson, University of Wyoming, Department of Renewable Resources.

Brief statement of activities, goals, and accomplishments: Black spruce is the most widespread and economically important conifer in the North American boreal forest. Its response to climate change could have a profound influence on biome level C cycling and economic activity.  The objective of this research is to determine how climate affects black spruce growth and allocation, and whether this response then significantly affects C cycling in the soil and forest floor of boreal ecosystems.  Results from this research have been presented at meetings of the American Geophysical Union and Ecological Society of America.

Funding organization: Department of Energy, National Initiative for Climate Change Research program

Riparian forest impacts of flow alterations on the Sabine River

PIs and collaborators: Georgianne Moore

Brief statement of activities, goals, and accomplishments: Link changes in species composition to altered flood frequency, timing, and duration after construction of Toledo Bend Dam

Funded by: Texas Water Development Board

Satellite and airborne profiling laser sensors for multiscale vegetation assessment

PIs and collaborators: Dr. Sorin Popescu.

Brief statement of activities, goals, and accomplishments: Develop software tools and statistical methods for processing airborne profiling lidar data for assessing forest inventory parameters over multiple scales, from local to regional.

Funding organization: NASA

Sea level rise impacts to a rare wetland forest and the Puerto Rican community

PIs and collaborators: Rusty A. Feagin & Ricardo J. Colon-Rivera

Brief statement of activities, goals, and accomplishments: In the next century, rare Pterocarpus officinalis forested wetlands are likely to be lost in Puerto Rico, due to climate change-induced sea level rise.  Our research questions on this topic include: How much of the largest remaining forest tract is currently subjected to saltwater intrusion, via sea level rise and how will this change in the future?  What will be the impacts to the Latino community? How can we integrate undergraduate students from the University of Puerto Rico into both Pterocarpus research at the undergraduate level, and Texas A&M University's graduate program upon graduation?

Funding organization: Mexican American and US Latino Research Center (MALRC), Texas A&M University; National Science Foundation; Hispanic Leaders in Agriculture & the Environment program, TAMU, USDA.

Soil Carbon Storage and Dynamics in the Western Gulf Coastal Plain as Impacted by Forest Management

PIs and collaborators: Thomas Boutton, Regents Professor and Texas AgriLife Senior Faculty Fellow; D. Andrew Scott, Research Soil Scientist Southern Research Station, USDA Forest Service

Brief statement of activities, goals, and accomplishments: Soil organic carbon is the largest reservoir in the terrestrial carbon cycle, and holds 2 and 3X more C than the atmosphere and terrestrial biomass, respectively.  Carbon sequestration by forest ecosystems provides an important ecosystem service by regulating atmospheric CO2 concentrations and influencing Earth's climate system, and disturbances due to land management practices could have a profound effect on carbon storage and turnover within these ecosystems.  The purpose of this study is to determine the effects of prescribed fire on carbon storage and dynamics in the forest floor and mineral soil of loblolly pine forest in the western Gulf Coastal Plain.  Carbon storage in whole soil and in soil size/density fractions will be quantified to a depth of 30 cm in replicated stands of burned and unburned loblolly pine.  Results from this work will be of immediate significance to forest managers for developing monitoring criteria in conjunction with the Long-Term Soil Productivity Study.

Funding organization: USDA Forest Service Cooperative Agreement

Strategies for propagation of the federally endangered orchid, Navasota ladies tresses (Spiranthes parksii) in Texas post oak savannas

PIs and collaborators: Drs. Rogers and Smeins

Brief statement of activities, goals, and accomplishments: These studies are examining numerous variables in factorial experiments including woody encroachment and light availability, nitrogen and phosphorus resource additions, soil disturbances, cattle grazing, deer browsing, prescribed fire, and seed recruitment limitation.  We are also developing methods for in-vitro germination of NLT seeds and transplanting intact rhizomes as a means of propagating individuals in protected areas. Finally, we have initiated a large number of studies focused on plant-soil interactions, mycorrhizal associations, feedback loops, and ecosystem processes. These latter studies will involve interdisciplinary collaborations with faculty and students in other departments (e.g., Plant Pathology and Microbiology, Soil and Crop Sciences, Horticulture, Entomology, Wildlife and Fisheries Sciences, and Geography) and at other universities (e.g., Rice University, Illinois College) and will uniquely position our team to compete for external resources and funds in an emerging area of scientific investigation.

Funding organization: Brazos Valley Solid Waste Management Agency

Sustainability and carry-over effects of forest management practices on the growth and nutrient dynamics of southern pine stands

PIs and collaborators: Jason Vogel, Texas A&M University, Timothy Martin and Eric Jokela, School of Forest Resources and Conservation, University of Florida

Brief statement of activities, goals, and accomplishments: Intensive forest management practices (weed control, fertilization) are being investigated for their sustainability and whether there are significant carry-over effects of past treatments on subsequent tree growth. The objective of this research is to determine how current forest practices may affect future forest productivity.  A long-term study (26 years) that had examined weed control, fertilization, and their interaction was recently harvested and replanted to loblolly pine (Vogel et al. submitted).  Measurements of tree growth, understory competition, and nutrient release from soil organic matter are planned for the next 3 years.

Funding organization: Forest Biology Research Cooperative, University of Florida.

The vascular flora of Natchez Trace Parkway: Franklin, Tennessee to Natchez, Mississippi
The Vascular Flora of the Natchez Trace Parkway: Franklin, Tennessee to Natchez, Mississippi 
Stephan L. Hatch, S.M. Tracy Herbarium (TAES), Texas A&M University
Dale A. Kruse, S.M. Tracy Herbarium (TAES), Texas A&M University
Nena M. Phillips, S.M. Tracy Herbarium (TAES), Texas A&M University
The “Natchez Trace” has played an important role in transportation, trade, and communication in the region since pre-historic times.  As the development and use of steamboats along the Mississippi River increased, travel on the Trace diminished and the route began to be reclaimed by nature.  A renewed interest in the Trace began during, and following, the Great Depression.  In the early 1930’s, then Mississippi congressman T. J. Busby promoted interest in the Trace from a historical perspective and also as an opportunity for employment in the area.  Legislation was introduced by Busby to conduct a survey of the Trace and in 1936 actual construction of the modern roadway began.  Development of the present Natchez Trace Parkway (NATR) which follows portions of the original route has continued since that time.  The last segment of the NATR was completed in 2005.  The federal lands that comprise the modern route total about 52,000 acres in 25 counties through the states of Alabama, Mississippi, and Tennessee.  The route, about 445 miles long, is a manicured parkway with numerous associated rest stops, parks, and monuments.  Current land use along the NATR includes upland forest, mesic prairie, wetland prairie, forested wetlands, interspersed with numerous small agricultural croplands.

The National Park Service contracted the S. M. Tracy Herbarium to conduct an inventory of vascular plants over the entire length of the NATR.  The inventory objectives were to document vascular plant diversity within the NATR, ascertain the location of threatened and endangered vascular plant taxa, and determine which of the extant plant species were invasive.  These objectives were achieved through a combination of a literature search, a herbarium search, and an intensive field inventory.

Five (5) trips to the NATR were conducted beginning in August 2004 and ending in October 2005, to make field collections.  Collections were made over the entire length of the NATR on each of the five trips.  Vouchers were collected and processed in the field for subsequent identification at the S. M. Tracy Herbarium.  Vouchers for the study comprise a total of 167 families, 750 genera, and 2197 taxa (including infraspecific taxa).  Significant increases in the number of grasses (Poaceae) and sedges (Cyperaceae) were added by the study team.  Field observations were made of two possible locations in Tennessee where Apios priceana B.L. Robbins (a federally listed endangered species) may exist.

 Funding Organization: US National Park Service, Gulf Coast Inventory and Monitoring Network



Warming and rainfall redistribution effects on linkages between plant functional traits and ecosystem processes in oak savanna

PIs and collaborators: MG Tjoelker, DD Briske, A Volder

Brief statement of activities, goals, and accomplishments: The proposed research seeks to understand how plant functional traits mediate tree-grass interactions in response to climate change in oak savanna. The objectives are to: 1) evaluate the independent and combined effects of annual rainfall distribution and warming on the function, growth, and competitive interactions of dominant tree and grass species, and 2) investigate the linkages between plant traits and ecosystem processes, including coupled carbon, nitrogen, and water fluxes. Our rationale is that integrated studies of physiological mechanisms, tree-grass interactions, and their consequences for ecosystem processes are central to predicting the effects of climate change on savanna ecosystems. The overarching hypothesis is that trait-mediated plant responses to seasonal changes in temperature and soilwater availability will govern tree-grass interactions, which drive savanna ecosystem processes under altered climate change scenarios.

Funding organization: US Department of Energy, National Institute for Climatic Change Research