The Southeastern Cooperative Wildlife Disease Study has provided continuous service since 1957 for the health of this nation’s wildlife resources, domestic livestock, and people.

Overview

The Georgia Master Naturalist program is a series of weekly programs with specific environmental topics. This program is a hands-on environmental education course that explores habitats and ecosystems in Georgia and human impacts on those environments. The sessions are customized to local habitats such as swamps, ponds, rivers, wetlands, mountains, forests, farms, urban landscapes and the issues affecting these habits. This program is a combination of lectures and outside hands-on learning through field studies and relevant resources. The program subject matter follows a standard format but is adjusted to meet local conditions and draw upon local expertise in the instructors. An informed person can help make changes in their lives as well as their community and safeguard the environment. After completing this fun and interactive program, Georgia Master Naturalists are encouraged to share their knowledge with their communities by volunteering in local schools or nature centers. This program is a fun and informative environmental education program. There is no certification attached to this program. The program requires a minimum of 48 hours of instruction.

PURPOSE 

The Georgia Master Naturalist program is an adult environmental education course developed by the UGA Warnell School of Forestry & Natural Resources and UGA Cooperative Extension for people who wish to be more informed about habitats, natural resources and the natural environments of our state.

MISSION

The mission of the Georgia Master Naturalist program is to provide unbiased, scientifically accurate information about environmental issues for adults.

AREAS OF DISCOVERY

Topics may include:

• Geology
• Hydrology
• Ecological Principles
• Water Quality
• Native Plants
• Forestry
• Wildlife
• Birding
• Agriculture
• Urban Forestry
• Environmental Awareness

The Tree Health Care Outreach Laboratory synthesizes and integrates research information on tree biology, pest/tree dynamics, and soil/tree relations. New methods for assessing tree health are designed as well as prescriptions for treatments developed. Results are communicated through various media and means to professionals, agencies, and specific non-professional audiences.

Whitehall Forest covers approximately 840 acres in the piedmont region's Clarke and Oconee Counties, approximately 4 miles from downtown Athens, Ga. The forest is comprised of natural pine, planted pine, pine hardwood, hardwood pine, upland hardwood, and bottomland hardwood. The property is bordered on the north by Whitehall Road, on the east by the North Oconee River and the Norfolk Southern Railroad, on the south by the North Oconee and Middle Oconee Rivers, and on the west by the Middle Oconee River. The Georgia Rural Rehabilitation Corporation acquired the property on 1936 and subsequently deeded it to the University of Georgia Board of Regents on July 15, 1936.

An addition to Whitehall Forest was made on December 15, 1978 with the gift on the Nat D. Arnold Memorial Forest. The property was deeded to the University of Georgia Board of Regents by Nathaniel A. Hardin, Hazel M. Harden Wright, and Catherine J. Hardin Newton. This Memorial consists of 46 acres. Whitehall Forest is home to several research facilities including the L.L. Pete Phillips Wood Utilization Plant Sciences Building, the Whitehall Deer Research Facilities, the Aquatic Biotech Environmental Lab, and the Whitehall Fisheries Lab. There are also several Federal offices and labs located at Whitehall Forest including the USFS, USGS, and USDA APHIS. Located on the most southern part of Whitehall Forest, Flinchum's Phoenix is used by state and federal agencies and UGA departments for meetings, classes and related functions.

Directions from Warnell's buildings to Whitehall/Flinchum's Phoenix

Our research centers around the physiology and ecology of trees and other woody species. We are particularly interested in water transport in plants, which is essential for plant survival. Plant water transport properties are directly related to plant distributions and plant carbon capture (and many other things).

Research

Leaf Hydraulics Research

We are interested in the pathway of water movement inside leaves. The bottlenecks for water flow through leaves has only recently been explored and there is a lot left to figure out! Since the leaf is the organ that is primarily responsible for controlling the water balance of the plant, this is a critical area of research.  Check back soon for some very cool images.....

Whole Plant Hydraulics

We are interested in the water transport properties of entire plants - leaves, branches, roots, trunks. Sometimes this means sampling destructively, but hey, it's for science.

The vast majority of our understanding of plant hydraulics is based on studies of terminal branches. This offers us a very limited understanding of how water moves through whole plants and how drought might affect whole plants.

The above image shows one way of measuring embolism (air bubble formation) in leaf xylem - this method is acoustic emission (super-sensitive microphones). Below is a set of tropical liana stems being prepared for hydraulic measurements.

Seedlings

In nature, most newly-germinated seedlings die.

Mortality in young seedlings is typically >99%!

In order for species to migrate with climate change, seedlings have to establish beyond the current species boundary. Yet, the newly germinated seedling stage is the life stage of trees that we know least about.  We are currently studying the physiology and anatomy of newly-germinated seedlings as they develop during their first year of life.

Drought

Severe droughts are predicted to become more frequent with climate change. Northern Idaho experienced its worst drought on record in 2015 (record keeping began in 1895) and central TX experienced its worst drought in over 1200 years in 2011-2015.

We are trying to understand what this might mean for different tree species in different habitats. Above is an image showing the impact of the 2011-2015 Texas drought. This picture was taken in July of 2013 - everything in grey is dead. We are also working on what happens after drought when precipitation returns. For example, is there a physiological legacy of drought or do plants just go back to business as usual? 

We are using field- and greenhouse-based studies, along with process-based models, to try to understand the mechanisms of drought induced mortality and plant responses to drought alleviation. 

Select Publications

Visit my Google Scholar page

2022

Johnson DM, Katul G, Domec JC. 2022. Catastrophic hydraulic failure and tipping points in plants. Plant, Cell and Environment (accepted, in press)

Benson MC, Miniat CF, Oishi AC, Denham SO, Domec JC, Johnson DM, Missik JE, Phillips RP, Wood JD, Novick KA. 2022. The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric co-dominants . Plant, Cell and Environment (accepted, in press)

Trueba S, Theroux-Rancourt G, Earles JM, Buckley TN, Love DM, Johnson DM, Brodersen C. 2022.The 3d construction of leaves is coordinated with water use efficiency in conifers. New Phytologist 233:851-861.

2021

Mrad A, Johnson DM, Love DM, Domec JC. 2021. The roles of conduit redundancy and connectivity in xylem hydraulic functions. New Phytologist 231:996-1007.

Domec JC, King JS, Carmichael MJ, Overby AT, Wortemann R, Smith WK, Maio G, Noormets A, Johnson DM. 2021. Root water gates and not changes in root structure provide new insights into plant physiological responses to drought, flooding and salinity. Journal of Experimental Botany 72:4489-4501.

Sonawane BV, Koteyeva N, Johnson DM, Cousins A. 2021. Differences in leaf anatomy determines temperature response of leaf hydraulic and mesophyll CO2 conductance in phylogenetically related C4 and C3 grass species. New Phytologist 230:1802-1814.

Hammond WM, Johnson DM, Meinzer FC. 2021. A thin line between life and death: radial sap flux failure signals trajectory to tree mortality. Plant, Cell and Environment 44:1311-1314.

Feltrin RP, Smith AMS, Adams HD, Kolden CA, Johnson DM. 2021. Short- and long-term effects of fire on stem hydraulics in Pinus ponderosa saplings. Plant, Cell and Environment 44:696-705.

2020

Feltrin RP, Johnson DM, Sparks AM, Adams HD, Kolden CA, Nelson AS, Smith AMS. 2020. Drought increases vulnerability of Pinus ponderosa saplings to fire-induced mortality. Fire 3:56.

Miller ML, Roddy AB, Brodersen CR, McElrone AJ, Johnson DM. 2020. Anatomical and hydraulic responses to desiccation in emergent conifer seedlings. American Journal of Botany 107:1177-1188.

Halbritter AH, De Boeck HJ, plus 113 co-authors (including DMJ). 2019. The handbook for standardized field and laboratory measurements in terrestrial climate-change experiments and observational studies (ClimEx). Methods in Ecology and Evolution 11:22-37.

 

TimberMart-South publishes quarterly and annual reports used by private companies, consultants, landowners, and others to assess market prices in the US South. We have been surveying and reporting timber prices since 1976, and market news since 1996. 

Our quarterly news and prices are available by subscription or by individual issue to provide information on timber market changes in the US South as well as average prices in 22 areas of the southeastern timber markets.