THE CARBON CYCLING RESPONSE OF SOUTHERN PINE FORESTS TO WEED CONTROL, FERTILIZATION, AND GENETIC SELECTION

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: MCINTIRE-STENNIS
• Reporting Frequency: Annual
• Accession No.: 0223291
• Project Start Date: Nov 1, 2010
• Project End Date: Oct 31, 2015
• Program Code: [(N/A)]- (N/A)

Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001

Performing Department
Ecosystem Science & Management

Non Technical Summary
The carbon cycling of southern pine forests is closely related to the economy of the southern U.S. The carbon stored in southern forests comprises a significant portion of the U.S. carbon budget, with estimates near 36% of the total forest carbon in the continental United States (Turner et al. 1995). Modeling estimates suggest that forests in the region annually remove from the atmosphere the equivalent of 13% of regional greenhouse gas emissions (Han et al. 2007), and that the forests have the potential to sequester more carbon through afforestation, reforestation, and improved forest management (Johnsen et al. 2001). From an economic perspective, the near tripling of tree production over the last century in response to management has made the southern United States region alone more productive, in terms of wood production, than any other country). In part as a result of this increased production, southern pine forests are a critical to the economies of the region, supporting nearly 7.5% of total industrial output in the south (Wear and Greis 2002). This economic importance could increase with the advent of carbon trading or the use of pine biomass as a fuel for energy production, making it important that the response of carbon cycling to management decisions is well understood. If ecosystem carbon accumulation simply increased with wood production, then it would be relatively straightforward drawing conclusions as to how forest carbon storage would respond to management. Indeed, over the last 50-years there should have been a 3-fold increase in carbon storage in southern pine forests as management has increased wood production (Jokela et al. 2004). However, the forest floor and mineral soil carbon pools may respond differently to management than does pine biomass. For example understory biomass is a relatively small carbon pool in a managed pine forest, nonetheless a number of studies have observed decreased mineral soil carbon with the implementation of understory or weed control, even though weed control has generally increased pine productivity and biomass. This effect could be due to decreased root input of carbon to the soil from understory plants, or because the root litter of deciduous plants is more recalcitrant to decomposition than pine litter. In addition, the forest floor has also been observed to decrease with weed control, but has increased in response to fertilization (Vogel et al. in review), and in some cases mineral soil carbon has increased in response to fertilization. Increases in soil carbon storage with fertilization may develop from greater carbon inputs due to increased productivity or because microbial decomposition of soil organic matter is suppressed by the increase in nutrient availability. Alternatively, soil carbon could be lost from an ecosystem as nutrient limitations to microbial activity are reduced by fertilization. Thus, understanding the effect of management on ecosystem carbon cycling and storage requires that all pools be examined (aboveground and belowground) and that the mechanisms controlling the dynamics of these pools are linked directly to management decisions.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
123	0610	1070	100%

Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0610 - Conifer forests of the North;

Field Of Science
1070 - Ecology;

Keywords

loblolly pine

soil carbon

nitrogen

soil respiration

microbial respiration

net primary productivity

management

carbon sequestration

Goals / Objectives
The overall objective of this research is to develop a mechanistic understanding of the controls on ecosystem carbon cycling in southern pine forests. Most previous research has focused on the net effect of these mechanisms in terms of pool changes (e.g. Vogel et al. in review), rather than the mechanisms themselves. For this research, both above- and belowground ecological processes will be directly related to three management activities: weed control, fertilization, and the deployment of inherently fast growing genetic stock. Specific research objectives that will be met over the 5-year duration of this experiment for managed pine forests in Texas, Louisiana, and Florida include: 1)Estimates of aboveground pine and understory productivity and associated carbon pools, and belowground (roots and soil to 1 meter) carbon pools. 2)Estimates of fine root contribution to soil carbon accumulation, and the contribution of root respiration to soil CO2 efflux. 3)Estimates of soil carbon turnover and its response to experimental manipulation both in the lab and the field. Probable duration: Meeting all three main objectives will require at maximum 5 years. Timeline: Objective 1 will be realized between Jan 1, 2011 and August 31, 2013. Complete C budgeting of existing pools and the productivity of vegetation will be assessed during this time period. Major activities (methods detailed in next section for all of the following major activities) 1)Estimate of tree diameters and understory biomass, and associated net primary production through consecutive measurements 2)Soil coring for estimates of soil and root carbon 3)Laboratory analysis for total C and N Objective 2 will be realized between July 31, 2012 and July 31, 2014. Semi-continuous monitoring of soil CO2 efflux will occur during this timeframe. Major activities 1)Installation of soil CO2 efflux collars and root exclusion collars 2)Monitoring of soil temperature and moisture Objective 3 will be realized between July 31, 2013 and July 31, 2014. Analysis of results from 2 and 3, and a new laboratory experiment will take place during this timeframe. Major activities 1)Estimates of total soil carbon and in-situ heterotrophic respiration will be used to estimate soil C turnover in the field 2)A laboratory incubation of microbial respiration will be performed which will be used to estimate soil C turnover The write-up phase of this project will take place from September 1st 2014 to Jan 1st, 2016.

Project Methods
Research sites have been established in Florida, Louisiana, and Texas by the Forest Biology Research Cooperative (described below). These sites include varying levels of weed and genetic control (clonal vs. family blocks), under different levels of fertilization. Multiple research installations in Texas, Louisiana, and Florida will be measured using the following protocols. Vegetation sampling will follow the protocol outlined for southern pine plantation stands by Vogel et al. (in review). Sampling will occur on previously-established inventory measurement plots, which typically range from 0.01 to 0.10 ha, with plot size depending on the study design. This protocol includes measurements of standing live and dead trees, understory vegetation, coarse and fine woody detritus, forest floor, and soil organic matter and roots. The C and N concentrations of all tissues and soils will be analyzed at the Soil and Crop Testing Lab, Texas A&M, along with soil physical properties. Soil samples will be analyzed that are collected at 0-10, 10-20 cm depths and then additional 40 cm depth intervals to 1 m. Total soil CO2 efflux will be measured using a Li-Cor 820 portable CO2 flux system (Li-Cor Inc., Lincoln, Nebraska). A critical component to reaching the research objectives outlined earlier is the separation of soil CO2 efflux into heterotrophic and autotrophic respiration. These two components of respiration will be separated using the root exclusion or trenching approach. The approach is analogous to stem girdling in that it separates the roots from the recently-fixed carbohydrates, which drive most root respiration (Hogberg et al. 2001). A comparison of total soil CO2 efflux before and after root exclusion is then used to partition the heterotrophic (rate after trenching) and autotrophic components (difference of before and after trenching) of soil CO2 efflux. This partitioning approach will be compared to root respiration estimates derived from the radiocarbon partitioning method (Schuur and Trumbore 2006) on 16 plots in central Florida recently funded through USDA (award #2009-65107-05810 to Jokela, Schuur and Vogel). Soil from each of the plot's sampled for objective 1 will be placed in a 237-ml canning jars that have, in the airtight top, two ports from which to sample microbial respiration. Using the access ports on the jar lids, microbial respired CO2 will be pulled from the headspace of the jar with a 30-ml syringe and CO2-free air drawn into the jar to replace the volume removed. The CO2 collected in the syringe will then be injected into an infra-red gas analyzer (IRGA)(LI-820, Licor Biosciences, Lincoln NE) attached to Vici Valco Instruments (Houston, TX) sampling loop.

Progress 11/01/10 to 10/31/15

Outputs
Target Audience:The target audience was industrial forest landowners and university students. The following presentations were provided by either myself or students to industrial groups. "Western Gulf Pine Productivity Interactions on Experimental Sites (PPINES): Family and silviculture effects on growth and stand dynamics through age 12 years." 2015. Jason G. Vogel. Forest Biology and Research Cooperative, Gainesville, FL. 17th September (talk). "Overview of PINEMAP ecophysiology and silviculture studies at Texas A&M."2015. Jason G. Vogel. CAMCOREmeeting, Texas A&M University, 12th November (talk). "'Getting there from here': Better forest growth predictions using PINEMAP data and modeling". 2015. Jason G. Vogel. Western Gulf Tree Improvement Program, College Station, TX. 19th May. (talk) Bacon, A.B, Akers K., Cucinella J., Grunwald S., Jokela E., Markewitz D., Laviner M., Vogel J.G., Martin T.A., Fox T., Kane M., Davis J.M., C.W. Ross. 2015. "Implications of Using USDA-NCSS Bulk Density to Estimate Carbon Stocks in Forest Soils Across the Southeastern United States." American Geophysical Union, San Francisco, CA. December 17th (poster presentation). Ross, C.W., Grunwald S., Vogel J.G., Jokela E.J., Gerber S., Del Grosso S., Bacon A., Cucinella J., Akers K.M., Maggard A., Laviner M., Gonzalez-Benecke C.A., Martin T.A., Bracho R.A., Markewitz D., Fox T., Burkhart H., Kane M., Peter G.F., Davis J.M. "Region-Wide Soil Carbon Assessment Across "the Land of Pines."" American Geophysical Union, San Francisco, CA. December 17th (poster presentation). Prehn, B., Berrios F., Zhang Y., Meek C., Will R., J.G. Vogel. 2015. Root Biomass Response to Fertilization and Throughfall Reduction in a Loblolly Pine (Pinus taeda L.) Forest. Society of American Foresters, Baton Rouge, LA. November 4th (poster presentation). Results were incorporated into forestry courses taught by Vogel. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has supported 3 graduate students (in combination with other sources) and 4 undergraduate students in the measurement of ecosystem C and nutrient cycling. How have the results been disseminated to communities of interest?The results have been disseminated through the scientific literature and at scientific and professionalmeetings. These presentations have been carried out by Vogel and both graduate and undergraduate students. These venues will continue to be used to disseminate results after the reporting period has ended. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We found that soil C is relatively insensitive to nutrient additionbut its chemical nature can be altered by the planting of genetic material. However, this alteration by treegeneticsdid not affect total amounts of soil C. Some soil processes, root biomass growth and respiration, are sensitive to nutrient addition but there is no evidence this also affects soil C. In general, the C accumulation benefits of encouraging faster loblolly pinegrowth do not appear to negatively affect soil C amounts.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Vogel, J.G., !He D., Jokela E.J., Hockaday W., and Schuur E.A.G. 2015. The effect of fertilization levels and genetic deployment on the isotopic signature, constituents, and chemistry of soil organic carbon in managed loblolly pine (Pinus taeda L.) forests. Forest Ecology and Management. 355:91100. doi:10.1016/j.foreco.2015.05.020
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Will, R.E., Fox T., Akers M., Domec J.C., Gonz�lez-Benecke C., Jokela E.J., Kane M., Laviner M.A., Lokuta G., Markewitz M., McGuire M.A., Meek C., Noormets A., Samuelson L., Seiler J., Strahm B., Teskey R., Vogel J.G., Ward E., West J., Wilson D., Martin T.A. 2015. A Range-wide experiment to investigate nutrient and soil moisture interactions in loblolly pine plantations. Forests. 6(6), 2014-2028; doi:10.3390/f6062014
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Zhai, L., Jokela E.J., Gezan S., and Vogel J.G. 2015. Family, Environment and Silviculture Effects in Pure- and Mixed-Family Stands of Loblolly (Pinus taeda L.) and Slash (P. elliottii Engelm var. ellitotttii) Pine. Forest Ecology and Management. 337:2840. doi:10.1016/j.foreco.2014.10.030

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: The target audience has primarily been large-scale forest landowners in the southeastern United States. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Multiple presentations have been made related to this work. "Bringing it together: How to Think About the timing and application of technologies to optimize pine productivity". 2014. Jason G. Vogel. Western Gulf Silvicultural Technology Exchange, Louisiana Technological University, Shreveport, LA. 12th Dec. (talk) "Divergent response of plants and soil organic matter to warming: Implications for ecosystem carbon dynamics". 2014. Jason G. Vogel. University of Georgia, Crop and Soils Department, Athens, GA. 17th Oct. (talk) "Can silviculture and genetic deployment affect stand sensitivity to disturbance?" 2014. Jason G. Vogel. Western Gulf Tree Improvement Program, Jasper, TX. 6th May. (talk) "Silviculture and genetic deployment effects on the sensitivity of managed pine forests to disturbance" 2014. Jason G. Vogel. Society of American Foresters, Texas Chapter, Lufkin, TX. 9th April. (talk) What do you plan to do during the next reporting period to accomplish the goals? Ongoing publication efforts will continue as willcommunity outreach through scientific presentations.

Impacts
What was accomplished under these goals? A paper has been submitted related to the goals in this project.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Zhai, L., Jokela E.J., Gezan S., and Vogel J.G. 2015. Family, Environment and Silviculture Effects in Pure- and Mixed-Family Stands of Loblolly (Pinus taeda L.) and Slash (P. elliottii Engelm var. ellitotttii) Pine. Forest Ecology and Management

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: The target audiences for this research and its results are forest industry landholders, non-industrial private landowners, university and high school students, and policy makers. Both myself and my graduate students have interacted with a number of different types of forest landowners and scientific entities in the southeastern United State's region. We have presented our research results at regional meetings (Forest Biology Research Cooperative), thePine Integrated Network: Education, Mitigation, and Adaptation project (PINEMAP) annual meeting and local Society of American Forester's meeting. Through these activities, we have interacted with a diverse group of landowners. In addiiton, we have presented research results at the Soil Science Society of America Meeting, the Ecological Society of America Meeting, and American Geophysical Union meeting. We believe our impact has been significant across a number of interest groups. Changes/Problems: None to report What opportunities for training and professional development has the project provided? The research is still too preliminary to be useful in training. How have the results been disseminated to communities of interest? Both myself and my graduate students have interacted with a number of different types of forest landowners and scientific entities in the southeastern United State's region. We have presented our research results at regional meetings (Forest Biology Research Cooperative), thePine Integrated Network: Education, Mitigation, and Adaptation project (PINEMAP) annual meeting and local Society of American Forester's meeting. Through these activities, we have interacted with a diverse group of landowners. In addiiton, we have presented research results at the Soil Science Society of America Meeting, the Ecological Society of America Meeting, and American Geophysical Union meeting. Ongoing research results have been presented to university students and high school students. What do you plan to do during the next reporting period to accomplish the goals? I have a graduate student and a post-doctoral associate dedicated to achieving these goals. In addition, a student at the University of Florida should be finishing her research in the upcoming year.

Impacts
What was accomplished under these goals? Under each goal, the current progress is listed in ALL CAPS. 1)Estimates of aboveground pine and understory productivity and associated carbon pools, and belowground (roots and soil to 1 meter) carbon pools. THIS HAS BEEN ACCOMPLISHED FOR 25 DIFFERENT RESEARCH SITES IN FLORIDA, LOUISIANNA, AND TEXAS. IN THE NEXT YEAR, THIS DATA WILL BEGIN TO BE WORKED UP. 2)Estimates of fine root contribution to soil carbon accumulation, and the contribution of root respiration to soil CO2 efflux. THIS IS PART OF AN ONGOING THESIS PROJECT UNDERWAY AT THE UNIVERSITY OF FLORIDA (CHELSEA GILL). INFORMATION FROM THIS PROJECT WILL BE USED TO ASCERTAIN THE REASONS FOR PATTERS IN (1). 3)Estimates of soil carbon turnover and its response to experimental manipulation both in the lab and the field. Probable duration: Meeting all three main objectives will require at maximum 5 years. THIS PART OF THE PROJECT IS NEARLY COMPLETED FOR FLORIDA SOILS BUT IS ONLY BEGINNING FOR TEXAS AND LOUISIANA SOILS. 1)Estimate of tree diameters and understory biomass, and associated net primary production through consecutive measurement COMPLETED FOR SOME TEXAS SITES AND IS PART OF MASTER'S STUDENT'S THESIS (NOW COMPLETED). 2)Soil coring for estimates of soil and root carbon SAME AS ABOVE 3)Laboratory analysis for total C and N Objective 2 will be realized between July 31, 2012 and July 31, 2014. Semi-continuous monitoring of soil CO2 efflux will occur during this timeframe. THIS WORK IS COMPLETED IN FLORIDA AND A SECOND PHASE WILL BEGIN THIS SPRING IN LOUSIANA AND TEXAS. 1)Installation of soil CO2 efflux collars and root exclusion collars SIMILAR TO ABOVE, THIS WORK IS COMPLETED IN FLORIDA AND A SECOND PHASE WILL BEGIN THIS SPRING IN LOUSIANA AND TEXAS. 2)Monitoring of soil temperature and moisture Objective 3 will be realized between July 31, 2013 and July 31, 2014. SIMILAR TO ABOVE, THIS WORK IS COMPLETED IN FLORIDA AND A SECOND PHASE WILL BEGIN THIS SPRING IN LOUSIANA AND TEXAS.

Publications

• Type: Theses/Dissertations Status: Published Year Published: 2013 Citation: Family, Environment and Silviculture Effects on Stand Growth, Disease, Damage, and Competition Dynamics in Pure- and Mixed-Family Loblolly Pine Stands

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: The growth response of 6 loblolly pine families and one slash pine family were compared under different management regimes in three installations in the western gulf region. These results were presented to representatives from the U.S. Forest Service and forest industry at a conference in Gainesville, FL. PARTICIPANTS: Lu Zhai is a MSc student at Texas A&M University who is funded by the Forest Biology Research Cooperative. Dr. Eric Jokela is a professor at the University of Florida who established and designed the experiments that we are working on. He is also a co-director of the Forest Biology Research Cooperative. TARGET AUDIENCES: The target audience for this facet of the research is the forest industry. PROJECT MODIFICATIONS: There are currently no major modifications to the research.

Impacts
It is expected that these results are used to guide family level planting decisions by the U.S. Forest Industry. However, they cannot share specific information with the researchers involved.

Publications

• Zhai L., Jokela E.J., and J.G. Vogel (2012) "Western Gulf Pine Productivity Interactions on Experimental Sites (PPINES): Family and silviculture effects on growth and stand dynamics through age 10 years" Forest Biology Research Cooperative Report, Gainesville, FL, September 22-24th.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: We continue to measure forest soil and ecosystem carbon (C) and nitrogen (N) dynamics. Soil C or organic matter (SOM) cycling between soils and the atmosphere affects a wide range of important ecosystem functions. However the key processes controlling this cycle, fine root inputs and heterotrophic respiration, are poorly understood primarily because they are difficult to directly measure in the field. Radiocarbon measurements of SOM light and heavy fractions, and of microbial respiration, have been used to estimate SOM dynamics. Ecosystem N has been measured for a forest in north Central Florida receiving weed control and fertilizer. These results suggest that fertilizer is more readily retained in forests that do not have weed control. Measurements of ecosystem N, N mineralization, and N-fixation are currently underway on soils and plant tissues from new locations in Florida and Texas. Results so far have been incorporated into the two forestry classes that I teach (Silviculture and Forest Ecology). Approximately 100 students have been taught about the forest's C and N dynamics as represented by results from these studies. In addition, results have been presented to individuals from the forest industry through the University of Florida's Forest Biology Research Cooperative and to the greater scientific community in a three talks listed below. "Radiocarbon measurements of soil organic matter (SOM) and soil CO2 efflux provide unique insights into the SOM dynamics of managed loblolly pine plantations" December 7, 2011. Jason G. Vogel, Eric J. Jokela, Rosvel Bracho, and Edward Schuur. American Geophysical Union Fall Meeting, San Francisco, CA. "Ecological Insights From Longterm Pine Silvicultural Experiments in the Southeastern United States" June 21, 2011. Jason G. Vogel, Eric J. Jokela, and Timothy A. Martin. North American Forest Ecology Workshop, Roanoke, VA. Invited. "Southern Pine Forestry and Climate Change" May 10, 2011. Jason G. Vogel. Western Gulf Tree Improvement Program, Jasper, TX. Invited. PARTICIPANTS: Individual project participants are myself and graduate students in forestry at Texas A&M University: Lu Zhai (MSc), Ignacie Tumushime (PhD), and Erin Fiero (PhD). Although not counted in my student hours, I am advising two students at the University of Florida (Chelsea Gill and Praveen Subendi) who are working on related topics. My students and I are also working in collaboration with the Forest Biology Research Cooperative at the University of Florida and with the Texas Forest Service. All of these contacts are either directly or indirectly connected to the PINEMAP project (pinemap.org/). This project consists of 52 investigators, myself included, at 12 institutions of higher learning in southeastern United States. PINEMAP is providing learning opportunities to professionals working on topics related to C and N cycling in southern forests, and my student Lu Zhai has contributed to this service. TARGET AUDIENCES: To impact the larger economy, our primary target audience is the forest industry and small non-industrial forest landowners. This project is affiliated with the PINEMAP project (pinemap.org/), which is valuable immediate conduit for making our results reach the larger public. For education, we are focused on disseminating our findings among the graduate and undergraduate students at Texas A&M University through my courses, and the teaching assistant appointments of my graduate students. I have also hired 2-3 undergraduates in my laboratory each year, offering them valuable work and an "in-depth" educational experience. Finally, PINEMAP is collaborating with "Project Learning Tree" to develop a module on the importance of southern pine forests that is targeted towards school children. I expect our results to be incorporated into this product. PROJECT MODIFICATIONS: None have occurred

Impacts
Some of these results have been published (Vogel et al. 2011) and some are in preparation. In addition, there is a slowly developing appreciation by the forest industry for understory plants in how they affect nutrient cycling in subsequent rotations. Although not broadly quantified, financial support has been garnered from the forest industry for this research line. With more data, our goal is to create guidelines that will assure sustainable forest practices in southern pine forests under intensive forest management.

Publications

• Vogel, J.G, Suau, L.J., Martin, T.A. and Jokela E.J. 2011. Long-term effects of weed control and fertilization on the carbon and nitrogen pools of a slash and loblolly pine forest in north-central Florida. Canadian Journal of Forest Research. 41(3): 552-567