Source: VILLANOVA UNIV submitted to
CHRISTMAS TREES AND SOIL CARBON STORAGE: MAXIMIZING ECOSYSTEM MANAGEMENT AND SUSTAINABILITY IN A FUTURE CARBON ECONOMY
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0214036
Grant No.
2008-35101-19128
Project No.
PENR-2008-00732
Proposal No.
2008-00732
Multistate No.
(N/A)
Program Code
23.1
Project Start Date
Jul 15, 2008
Project End Date
Jul 14, 2012
Grant Year
2008
Project Director
Chapman, S. K.
Recipient Organization
VILLANOVA UNIV
800 LANCASTER AVENUE
VILLANOVA,PA 19085
Performing Department
(N/A)
Non Technical Summary
Scientists agree that continuing increases of atmospheric carbon dioxide concentrations will cause climatic change with potentially devastating effects. Interest in mitigating this imminent climate change will foster the emergence of a global carbon economy. Management of carbon dioxide will require a diversity of strategies, including carbon sequestration in U.S. ecosystems. Soil contains 200 times the amount of carbon emitted by humans annually and four times as much as plant biomass globally. Management of ecosystems for the purpose of manipulating soil carbon could be a viable strategy for countering rising atmospheric carbon dioxide concentrations and thereby mitigating climate change. Optimizing carbon storage in agricultural ecosystems will likely be a part of the strategy and thus may provide a new economic niche for farmers and foresters. Soil in Christmas tree farms has great potential to absorb carbon from the atmosphere for several reasons. First the trees planted typically produce low quality litters, which should favor accumulation of soil carbon. Second, because these farms are not plowed, as in other highly managed farms, soil carbon may be allowed to accumulate in the long term. We propose to investigate carbon storage on Christmas tree farms in the Appalachian mountains of North Carolina, an important economic driver in these rural communities. Currently, the Christmas tree industry is in a general decline, primarily due to a significant proportion of consumers buying artificial Christmas trees. Proper management of these farms could be a viable approach for countering rising atmospheric carbon dioxide concentrations while maximizing sustainability of the agroforestry industry.
Animal Health Component
50%
Research Effort Categories
Basic
25%
Applied
50%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1010110106020%
1010699106010%
1250110106025%
1250699106020%
1310110106015%
1310699106010%
Goals / Objectives
We will investigate the carbon storage potential of Christmas tree farms in the southern Appalachian Mountains, a rural region economically dependent on agroforestry. We intend to determine whether these multifunctional agricultural systems can remain an economically viable crop while providing the salient ecosystem service of carbon storage. Using proven soil incubation techniques and soil biogeochemical analyses, we will examine the size of carbon pools. We will also partition tree farm soil carbon into fractions delineated by stability, an important determinant of sequestration potential. We will explore the long-term effect of tree farming using a chronosequence of cultivation histories to compare soil carbon stocks to those in adjacent, native forests. We also intend to investigate the effects of two common management strategies that are likely to impact soil carbon stocks: weed control technique and dominant crop species. Our findings will inform future, manipulative projects examining the links between management, soil carbon sequestration, and climate change in high elevation agroecosystems. We will answer the following questions: Q1: How does the cultivation of Christmas trees in the southern Appalachians influence net soil carbon storage? Q2: Does the use of herbicide, which eliminates interspace plants, alter soil carbon storage potential? Q3: How does dominant crop species impact net soil carbon storage on Christmas tree farms?
Project Methods
In order to project how the cultivation of Christmas trees influences long-term soil carbon storage, we will perform soil carbon analyses on a series of farms that vary in cultivation history. Our sampling design will allow us to elucidate the net effect of tree farming, as well as the influence of common management variables, on soil carbon storage. Specifically, we will collect and analyze soils across three types of gradients that take advantage of existing farms as ongoing, long-term experiments. Changes in soil carbon content and quality occur very slowly, particularly in the more stable pools, which are the largest and most important for long-term global C balance. Therefore, we will use a chronosequence approach in which we substitute space for time to estimate the long-term trajectory of soil carbon storage. We have preliminarily identified a series of farms of different cultivation histories, ranging up to 60 years of continuous cultivation of Abies fraserii. In order to account for innate variability among our sites, we will reference all soil measurements to those from plots in surrounding, adjacent forests, which reflect soil carbon accumulation for the climate and soil type of each site in the uncultivated condition. Second, because the presence of vegetation in between focal trees should increase gross productivity of the ecosystem, which has been shown to relate to soil carbon storage, we will explore the influence of inter-space groundcover by comparing sites that have been treated with heavy herbicide application to those with light application. Third, plant species are known to have unique influences on several soil properties. Because Christmas tree farmers often plant different species of conifers, which produce organic matter of varied chemical quality, we believe that the target horticultural species may exert unique control on soil carbon quantity and quality. Therefore, we will examine the unique effects of individual crop species on soil carbon pools. These data will be analyzed using analyses of variance to determine whether specific management techniques and target species impact soil carbon storage. These data will be available to Christmas tree farmers aiming to maximize potential carbon storage in their soils.

Progress 07/15/08 to 07/14/12

Outputs
OUTPUTS: We investigated carbon (C) storage on Christmas tree farms in the Appalachian mountains of North Carolina, an ecosystem that is understudied and an important economic driver in these rural communities. Soil carbon (C) storage can be altered by land-use conversion and by agroforestry management techniques such as weed management and fertilization. The Southern Appalachian Mountains have a mosaic of land uses, including Christmas tree farms, pastures, and unmanaged forests. We contrasted Christmas tree farm (Abies fraseri (Pursh) Poir) soil C pools with those of adjacent pastures and forests to estimate C storage differences due to land-use. We partitioned soil C into fractions delineated by stability, an important determinant of long-term C sequestration potential. Soil C pools were quantified across a chronosequence of tree farms that varied in cultivation duration (3-51 years) and interspace groundcover. We took at least 15 multi-day field sampling trips, during which took soil cores, assess groundcover, deployed microclimatic sensing technology, and used other important field technology such as ground-penetrating radar and a normalized difference vegetation index sensor. We have mentored four undergraduate students and one graduate student who have assisted in the collection and processing of these data. These students gained valuable experience in measuring soil carbon and learning other soil science techniques. One of the above-mentioned undergraduate students served as a co-author on one of the publications listed below. Samantha Chapman presented our findings at four conferences, two of which were invitational. At the American Geophysical Union Annual Meeting and the North American Carbon Program (2 years), she presented posters detailing our understanding of soil C pools in tree farms and other land use types. Chapman also presented at the Soil Ecology Society Meetings in Burlington, VT in July of 2009. This project became an "Affiliated Project" with the North American Carbon Program (NACP) in 2009 and remains so currently. The NACP website now includes a project description and Google Map and Google Earth links to our sites in North Carolina: http://www.nacarbon.org/cgi-nacp/web/investigations/inv_pgp.plpgid=4 31 Our research was featured in "Limbs and Trees," the newsletter of the National Christmas Tree Growers Association. We have established fruitful collaborations with Christmas tree farmers and USDA scientists and extension agents interested in possible C storage. In June of 2012 PIs Chapman and Langley had a wrap-up meeting with one of the tree farmers we worked with to communicate our findings. In September of 2012, co-PI Langley was the featured speaker at the North Carolina Christmas Tree growers association. During his presentation, he highlighted how the results of our study could be translated to potential management applications that extension agents and farmers could use. PARTICIPANTS: The Principal Investigator, Samantha Chapman, has taken responsibility for 1) directing the project and the personnel involved in the project, 2) obtaining necessary equipment and supplies, 3) collecting all field data and samples (with Co-PI Langley), 4) overseeing and participating in lab processing of samples including nutrient and carbon analyses and incubations, 5) disseminating the findings of this research to the scientific community and the Christmas tree farmers, and 6) analyzing and writing up the data collected from these studies. Co-PI Langley has taken responsibility for 1) collecting field data (with PI-Chapman), 2) setting up and maintaining the equipment associated with the incubations and microclimatic monitoring, 3) applying the model to the data collected to obtain the various carbon fractions, 4) analyzing and synthesizing the data for publication, and 5) writing publications (with PI-Chapman). Reena Palanivel, an undergraduate student hired to process soils and assist in analyzing soil carbon fractions, worked on the project from May 2010-May 2012. Reena took responsibility for sieving soils, measuring % moisture in soils, setting up the initial incubations and doing acid-hydrolysis digestions on soils. Three other undergraduate students, Roger Shaw (2008), Bethanne Albert-Bruninga (2009), and Courtney Curran (2012) have also assisted with soil processing and incubations. A graduate student, Rachel Jones, assisted in the processing and analyses of soils in 2009. The students associated with this project all gained experience running the Lachat flow ion analyzer (soil nutrients) and infra-red gas analyzers (CO2 evolution in incubations) and learned general techniques commonly used in ecosystem science. All the above-mentioned personnel are associated with Villanova University, a partner academic institution, which provides consumables to Chapman for her lab and employs Chapman, Langley, and Jones. Throughout the duration of this project, we have developed fruitful collaborations with three Christmas tree farmers: Harry Yates, Cline Church, and Sam Church. These farmers have generously allowed us to sample for soil C across their large suite of farms and have provided invaluable information on farm age and management. We have met with these farmers multiple times and have shared the progress of our project and our results to date with them. We have also built collaborations with other researchers examining C storage in plant biomass on Christmas tree farms. Dr. Jeff Owen and Dr. Ron Gehl of NC State University each lead separate research teams examining Christmas tree farms and soil fertility. Dr. Ryan Emmanuel has been using a flux tower to examine the total C footprint of Christmas tree farms. We have met with each of these scientists and discussed our reciprocal interests. We are collaborating with Ron Gehl on sampling at his herbicide manipulation plots to further assess the contribution of groundcover to soil C storage. Finally, we have collaborated and performed field work with Wes Tuttle (USDA-NRCS-NSSC, Soil Scientist) who has taken ground penetrating radar measurements at our sites. TARGET AUDIENCES: As was discussed in the "Participants" and "Outputs" sections, we have built strong relationships with our main target audience, Christmas tree farmers, both at the level of the individual farmer and at the level of the major organization, The National Christmas Tree Growers Association. Through articles in the association newsletter, individual meetings with farmers, meetings with groups of farmers and extension agents, and presentations at association meetings, we continue to collaborate and share ideas and data on soil carbon in tree farms and adjacent land use types with these groups of people. Another target audience includes the undergraduate students Chapman teaches at Villanova University. Chapman has used this research project to demonstrate how land management influences on soil carbon in courses at both the introductory and graduate level at Villanova. The data from our project was also used as a case study for a biogeochemistry class taught by Dr. Keith Reinhardt at Idaho State University. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Throughout this study, the funding that has supported our sampling trips, lab incubations, and chemical analyses has also allowed us to build fruitful collaborations, disseminate knowledge of this research, and generate the methodological advances and results detailed below. In a recent publication in the Soil Science Society of America Journal (in press) we document our major findings. We found that duration of tree cultivation did not alter tree farm soil C pools. However, recalcitrant C pools were twice as high when interspace groundcover increased from 35% to 70%. Total, active, slow and recalcitrant soil C pools were highest in forests, as compared to pastures and tree farms. Tree farm soils had about 25% less C concentration than the adjacent forest soils, but because there no downward trend with duration of cultivation, the reduction likely occurred rapidly upon initial clearing. Tree farms and forests had longer mean residence times for active and slow C than pastures, potentially indicating an influence of woody root production. Our findings suggest that maintaining tree farm interspace vegetation, possibly through reduced herbicide usage, can enhance soil C sequestration. In performing this research, we have made various methodological advances including but not limited to 1) assessing soil depth in various North Carolina mountain ecosystems using ground penetrating radar (GPR; Wes Tuttle, USDA-NRCS-NSSC), 2) improving CO2 respiration incubation techniques for tree farm soils 3) using a green-seeker NDVI sensor to measure vegetation greenness index in Christmas tree farms. Each of these advances will help scientists better assess the carbon (C) storage potential of these, and other related ecosystems. Our technique for using NDVI sensors on tree farms can help farmers assess the current status of their understory coverage and dominant crop productivity. This knowledge might, in turn, allow decreased herbicide and fertilizer usage. These findings, as presented at both scientific meetings and meetings with farmers and extension agents, can help inform land management decisions and soil carbon sequestration strategies. In an ongoing investigation of experimentally manipulated herbicide usage, we are studying the direct impacts of groundcover on soil C storage. This study will help us to cement our findings on herbaceous cover management and further inform our extension agent collaborators on how farm management can alter C sequestration potential. Overall, our research is assisting scientists, land managers, and farmers in determining whether Christmas tree farms can concurrently provide an economically viable crop and the salient ecosystem service of carbon storage.

Publications

  • Chapman, S.K., R.U. Palanivel, and J.A. Langley. 2012 in press. Soil carbon stability responds to land-use and groundcover management in Southern Appalachian agro-ecosystems. Soil Science Society of America Journal.
  • Chapman, S.K. and Langley, J.A. 2011. Soil carbon storage in Christmas tree farms, pastures and forests of the Southern Applachian mountains. Online Conference Proceedings (Abstract) North American Carbon Program Meeting, New Orleans, LA
  • Chapman, S.K. Shaw R. and Langley J.A. 2009. Soil carbon and Christmas tree farms: Investigating carbon across a gradient of land use in the Southern Appalachians. Online Conference Proceedings (Abstract) North American Carbon Program Meeting, San Diego, CA.
  • Chapman, S.K., Shaw R.and Langley J.A. 2009. Soil carbon storage across a gradient of land us e in mountain ecosystems. Abstract Book, Soil Ecology Meetings Burlington, VT, July 2009
  • Chapman, S.K., Shaw R. and Langley, J.A. 2008. Soil Carbon Storage in Christmas Tree Farms: Maximizing Ecosystem Management and Sustainability for Carbon Sequestration. Program and Abstract Book, American Geophysical Union Annual Meeting, San Francisco, CA **since this is a final report we included all publications


Progress 07/15/09 to 07/14/10

Outputs
OUTPUTS: Outputs We had proposed to investigate carbon (C) storage on Christmas tree farms in the Appalachian mountains of North Carolina, an ecosystem that is understudied and an important economic driver in these rural communities. After one year, and over the course of four field trips to North Carolina, we have sampled five core sites (a site includes a Christmas tree farm and reference forest and pasture plots) and 25 peripheral sites for soil C storage, % herbaceous cover, and NDVI (vegetation "greenness"). We outfitted each of these sites with microclimatic monitoring devices and collected soil cores for chemical analyses. We performed two incubations to assess medium and labile C pools: a pilot incubation to assess methodology, and an assessment of C pools at various soil depths. We have also measured recalcitrant soil C pools and extractable NO3 and NH4 from tree farm and reference soils. Two undergraduate students and one graduate student have assisted in the collection and processing of these data, yielding valuable experience in measuring soil parameters, and resulting in one of the undergraduates serving as a co-author the presentations listed below. Samantha Chapman presented our findings at four conferences, two of which were invitational. At the American Geophysical Union Annual Meeting and the North American Carbon Program (2 years), she presented posters detailing our understanding of soil C pools in tree farms and other land use types. Chapman also presented at the Soil Ecology Society Meetings in Burlington, VT in July of 2009. This project became an "Affiliated Project" with the North American Carbon Program (NACP) in 2009 and remains so currentlyThe NACP website now includes a description and Google Map and Google Earth links to our sites in North Carolina: http://www.nacarbon.org/cgi-nacp/web/investigations/inv_pgp.plpgid=4 31 Last year, our research was featured in "Limbs and Trees," the newsletter of the National Christmas Tree Growers Association. We have established fruitful collaborations with Christmas tree farmers and USDA scientists and extension agents interested in possible C storage on . Finally, our findings to date were presented at a meeting of the regional chapter of the National Christmas Tree Growers Association in Boone, NC. Finally, we have written the first manuscript resulting from this project, entitled "Soil carbon storage on Christmas tree farms, " which will be submitted in August 2011. PARTICIPANTS: The Principal Investigator, Samantha Chapman, has taken responsibility for 1) directing the project and the personnel involved in the project, 2) obtaining necessary equipment and supplies, 3) collecting all field data and samples (with Co-PI Langley), 4) overseeing and participating in lab processing of samples including nutrient and carbon analyses and incubuations, 5) disseminating the findings of this research to the scientific community and the Christmas tree farmers, and 6) analyzing and writing up the data collected from these studies. Co-PI Langley has taken responsibility for 1) collecting field data (with PI-Chapman), 2) setting up and maintaining the equipment associated with the incubations and microclimatic monitoring, 3) applying the model to the data collected to obtain the various carbon fractions, 4) analyzing and synthesizing the data for publication, and 5) writing publications (with PI-Chapman). Reena Palanivel, an undergraduate student hired to process soils and assist in analyzing soil carbon fractions, worked on the project from May 2010-current. Reena took responsibility for sieving soils, measuring % moisture in soils, setting up the initial incubations and doing acid-hydrolysis digestions on soils. Two graduate students, Lorae Simpson and Rachel Jones have each assisted in the processing and analyses of soils. The three students associated with this project all gained experience running the Lachat flow ion analyzer (soil nutrients) and infra-red gas analyzers (CO2 evolution in incubations) and learned general techniques commonly used in Ecosystem Science. Throughout this second year of the project, we have maintained fruitful collaborations with three Christmas tree farmers: Harry Yates, Cline Church, and Sam Church. These farmers have generously allowed us to sample for soil C across their large suite of farms and have provided invaluable information on farm age and management. We have met with these farmers multiple times and have shared the progress of our project and our results to date with them. We have also built collaborations with other researchers examining C storage in plant biomass on Christmas tree farms. Dr. Jeff Owen and Dr. Ron Gehl of NC State University each lead separate research teams examining Christmas tree farms and soil fertility. Dr. Ryan Emmanuel is using a flux tower to examine the total C footprint of Christmas tree farms. We have met with each of these scientists and discussed our reciprocal interests. Finally, we have collaborated and performed field work with Wes Tuttle (USDA-NRCS-NSSC, Soil Scientist) who has taken ground penetrating radar measurements at our sites. TARGET AUDIENCES: As was discussed in the "Participants" and "Outputs" sections, we have built strong relationships with our main target audience, Christmas tree farmers, both at the level of the individual farmer and at the level of the major organization, The National Christmas Tree Growers Association. Through articles in the association newsletter, individual meetings with farmers, and meetings with groups of farmers and extension agents, we continue to collaborate and share ideas and data on soil carbon in tree farms and adjacent land use types with these groups of people. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Outcomes/ Impacts During the second year of this study, the funding that has supported our sampling trips, lab incubations, and chemical analyses has also allowed us to build fruitful collaborations, disseminate knowledge of this research, and generate the methodological advances and results detailed below. In performing this research, we have made various methodological advances including but not limited to 1) assessing soil depth in various North Carolina mountain ecosystems using ground penetrating radar (GPR; Wes Tuttle, USDA-NRCS-NSSC), 2) improving CO2 respiration incubation techniques for tree farm soils 3) using a green-seeker NDVI sensor to measure vegetation greenness index in Christmas tree farms. Each of these advances will help scientists better assess the carbon (C) storage potential of these, and other related ecosystems. Our technique for using NDVI sensors on tree farms can help farmers assess the current status of their understory coverage and dominant crop productivity. This knowledge might, in turn, allow decreased herbicide and fertilizer usage. After two years of field and lab research, we have generated the results listed here. First, total soil carbon was about 3.5% in Christmas tree farms. Second, labile soil C respiration rates were significantly higher in pastures and forests than in tree farms. Third, recalcitrant soil C pools were significantly greater in the forests than in the pastures and tree farms, which had similar amounts of recalcitrant soil carbon. Fourth, total soil C seemed to decrease slightly with increasing tree farm age. Finally, percent cover (as a proxy for herbicide management) increases the amount of recalcitrant soil C on tree farms. These findings, coupled with our ongoing presentations at scientific meetings and meetings with farmers, can help inform land management decisions and soil carbon sequestration strategies. A proposed ongoing investigation of herbicide usage impacts on C storage will help us to cement our findings on herbaceous cover management and inform our extension agent collaborators on how farm management can alter C sequestration potential. Overall, our research should assist scientists, land managers, and farmers in determining whether Christmas tree farms can concurrently provide an economically viable crop and the salient ecosystem service of carbon storage.

Publications

  • Publications Chapman, S.K. and Langley, J.A. 2011. Soil carbon storage in Christmas tree farms, pastures and forests of the Southern Applachian mountains. Online Conference Proceedings (Abstract) North American Carbon Program Meeting, San Diego, CA. Chapman, S.K. Shaw R. and Langley J.A. 2009. Soil carbon and Christmas tree farms: Investigating carbon across a gradient of land use in the Southern Appalachians. Online Conference Proceedings (Abstract) North American Carbon Program Meeting, San Diego, CA. Chapman, S.K., Shaw R.and Langley J.A. 2009. Soil carbon storage across a gradient of land use in mountain ecosystems. Abstract Book, Soil Ecology Meetings Burlington, VT, July 2009 Chapman, S.K., Shaw R. and Langley, J.A. 2008. Soil Carbon Storage in Christmas Tree Farms: Maximizing Ecosystem Management and Sustainability for Carbon Sequestration. Program and Abstract Book, American Geophysical Union Annual Meeting, San Francisco, CA


Progress 07/15/08 to 07/14/09

Outputs
OUTPUTS: We had proposed to investigate carbon (C) storage on Christmas tree farms in the Appalachian mountains of North Carolina, an ecosystem that is understudied and an important economic driver in these rural communities. After one year, and over the course of four field trips to North Carolina, we have sampled five core sites (a site includes a Christmas tree farm and reference forest and pasture plots) and 25 peripheral sites for soil C storage, % herbaceous cover, and NDVI (vegetation "greenness"). We outfitted each of these sites with microclimatic monitoring devices and collected soil cores for chemical analyses. We performed two incubations to assess medium and labile C pools: a pilot incubation to assess methodology, and an assessment of C pools at various soil depths. We have also measured recalcitrant soil C pools and extractable NO3 and NH4 from tree farm and reference soils. Two undergraduate students and one graduate student have assisted in the collection and processing of these data, yielding valuable experience in measuring soil parameters, and resulting in one of the undergraduates serving as a co-author the presentations listed below. Samantha Chapman presented our findings at three conferences this year, one of which was invitational. At the American Geophysical Union Annual Meeting and the North American Carbon Program, she presented posters detailing our understanding of soil C pools in tree farms and other land use types. Chapman also presented at the Soil Ecology Society Meetings in Burlington, VT in July. In September, this project became an "Affiliated Project" with the North American Carbon Program (NACP). Chapman made many contacts at the NACP meetings, including with biogeochemical modelers, with whom we plan to collaborate with to model C storage in agroforests in the future. This meeting provided an excellent opportunity to discuss synthesizing methods and disseminating soil C data with other scientists. The NACP website now includes a description and Google Map and Google Earth links to our sites in North Carolina: http://www.nacarbon.org/cgi-nacp/web/investigations/inv_pgp.plpgid=4 31 This year, our research was featured in "Limbs and Trees," the newsletter of the National Christmas Tree Growers Association. We have also been asked to write an article for this publication this winter. We have established fruitful collaborations with Christmas tree farmers, USDA scientists, and other researchers examining C storage and we continue to meet with each of these groups to present and discuss our current findings and future research collaborations. Finally, our findings to date were presented at a meeting of the regional chapter of the National Christmas Tree Growers Association in Boone, NC. PARTICIPANTS: The Principal Investigator, Samantha Chapman, has taken responsibility for 1) directing the project and the personnel involved in the project, 2) obtaining necessary equipment and supplies, 3) collecting all field data and samples (with Co-PI Langley), 4) overseeing and participating in lab processing of samples including nutrient and carbon analyses and incubuations, 5) disseminating the findings of this research to the scientific community and the Christmas tree farmers, and 6) analyzing and writing up the data collected from these studies. Co-PI Langley has taken responsibility for 1) collecting field data (with PI-Chapman), 2) setting up and maintaining the equipment associated with the incubations and microclimatic monitoring, 3) applying the model to the data collected to obtain the various carbon fractions, 4) analyzing and synthesizing the data for publication, and 5) writing publications (with PI-Chapman). Roger Shaw, an undergraduate student hired to process soils and assist in analyzing soil carbon fractions, worked on the project from July 2008-October 2008. Roger took responsibility for sieving soils, measuring % moisture in soils, setting up the initial incubations and doing acid-hydrolysis digestions on soils. Two graduate students, Lorae Simpson and Rachel Jones have each assisted in the processing and analyses of soils. The three students associated with this project all gained experience running the Lachat flow ion analyzer (soil nutrients) and infra-red gas analyzers (CO2 evolution in incubations) and learned general techniques commonly used in Ecosystem Science. Throughout this first year of the project, we have established fruitful collaborations with three Christmas tree farmers: Harry Yates, Cline Church, and Sam Church. These farmers have generously allowed us to sample for soil C across their large suite of farms and have provided invaluable information on farm age and management. We have met with these farmers multiple times and have shared the progress of our project and our results to date with them. We have also built collaborations with other researchers examining C storage in plant biomass on Christmas tree farms. Dr. Cari Furiness and Dr. Eric Hinesley of NC State University each lead separate research teams examining Christmas tree C storage. We have met with each of these scientists and discussed our reciprocal interests. We have had meetings with Della Deal, Extension Agent and Jeff Owen, Forestry Extension Specialist to discuss our research in Christmas tree farms and plan to continue collaborating with these agency scientists. Finally, we have collaborated and performed field work with Wes Tuttle (USDA-NRCS-NSSC, Soil Scientist) who has taken ground penetrating radar measurements at our sites. TARGET AUDIENCES: As was discussed in the "Participants" and "Outputs" sections, we have built strong relationships with our main target audience, Christmas tree farmers, both at the level of the individual farmer and at the level of the major organization, The National Christmas Tree Growers Association. Through articles in the association newsletter, individual meetings with farmers, and presentations to groups of farmers and extension agents, we continue to share ideas and data on soil carbon in tree farms and adjacent land use types. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
During the first year of this study, the funding that has supported our sampling trips, lab incubations, and chemical analyses has allowed us to build fruitful collaborations, disseminate knowledge of this research, and generate the methodological advances and results detailed below.In performing this research, we have made various methodological advances including but not limited to 1) assessing soil depth in various North Carolina mountain ecosystems using ground penetrating radar (GPR; Wes Tuttle, USDA-NRCS-NSSC), 2) improving CO2 respiration incubation techniques for tree farm soils 3) using a green-seeker NDVI sensor to measure vegetation greenness index in Christmas tree farms. Each of these advances will help scientists better assess the carbon (C) storage potential of these, and other related ecosystems. Our technique for using NDVI sensors on tree farms can help farmers assess the current status of their understory coverage and dominant crop productivity. This knowledge might, in turn, allow decreased herbicide and fertilizer usage. After one year of field and lab research, we have generated the preliminary results listed here. First, total soil carbon was about 3.5% in Christmas tree farms. Second, labile soil C respiration rates were significantly higher in pastures and forests than in tree farms. Third, recalcitrant soil C pools were significantly greater in the forests than in the pastures and tree farms, which had similar amounts of recalcitrant soil carbon. Fourth, recalcitrant soil C was similar across a chronosequence of tree farms. Finally, total soil C seemed to increase slightly with increasing tree farm age, however these findings need to be refined with the increased sampling we are currently performing. These findings, coupled with our ongoing presentations at scientific meetings and meetings with farmers, can help inform land management decisions and soil carbon sequestration strategies. Ongoing investigations of herbicide usage impacts on C storage will help us to assess how farm management can alter C sequestration potential. Overall, our research should assist scientists, land managers, and farmers in determining whether Christmas tree farms can concurrently provide an economically viable crop and the salient ecosystem service of carbon storage.

Publications

  • Chapman, S.K. Shaw R. and Langley J.A. 2009. Soil carbon and Christmas tree farms: Investigating carbon across a gradient of land use in the Southern Appalachians. Online Conference Proceedings (Abstract) North American Carbon Program Meeting, San Diego, CA.
  • Chapman, S.K., Shaw R.and Langley J.A. 2009. Soil carbon storage across a gradient of land use in mountain ecosystems. Abstract Book, Soil Ecology Meeting, Burlington, VT
  • Chapman, S.K., Shaw R. and Langley, J.A. 2008. Soil Carbon Storage in Christmas Tree Farms: Maximizing Ecosystem Management and Sustainability for Carbon Sequestration. AGU Program and Abstract Book, American Geophysical Union Fall Meeting, San Francisco, CA