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Home HortScience Ornamental Horticulture Addresses Climate Change
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AUBURN, AL—Researchers from Auburn University and the USDA-ARS National Soil Dynamics Laboratory say that increases in greenhouse gases are important factors causing global warming and note that emissions from agriculture account for an estimated 20% of the annual increase in global greenhouse gas emissions. And, they add, the ornamental horticulture industry may play an important part in finding a solution to the planet's problem.

Chris Marble, a PhD student at Auburn University and lead author of a study published in HortScience, notes that atmospheric concentrations of the three most important long-lived greenhouse gases—carbon dioxide, methane, and nitrous oxide—have increased dramatically over the past 255 years. "Fossil fuel combustion along with land use changes such as deforestation, biomass burning, soil cultivation, and drainage of wetlands have increased carbon emissions approximately 80% from 1970 to 2004," the review said. "When these land use changes are included, the overall radiative forcing from agriculture production accounts for one-third of the manmade greenhouse effect."

Though finding ways to reduce greenhouse gas (GHG) emissions in agriculture has been extensively researched, scientists believe that emissions reduction alone will not be sufficient to curtail the negative impacts on the environment; they say that long-term capture and storage (sequestration) of carbon (C) are necessary. The Auburn study investigated practices in ornamental horticulture container-grown plant production that could be altered to increase C sequestration and mitigate greenhouse gas emissions. "The ornamental horticulture industry has the potential to benefit financially from reducing GHG emissions and its C footprint by altering management practices," the researchers noted.

The report features extensive reviews of three important horticultural practices: media used in container-grown plant production, fertilization procedures, and the ability of ornamental species to sequester C after being planted into the landscape.

Interestingly, the authors found no research that has addressed the potential environmental benefits of shrubs, perennials, and other ornamental nursery species, including their abilities to store carbon, or act as "C sinks". "Most ornamental shrubs require little or no management inputs and often accumulate biomass quickly, making them a potential major C sink. Since most landscapes have more shrubs than trees, it is possible that, in any given landscape, the total C accumulated in shrubs could be greater than that in trees," they noted.

The review determined that ornamental horticulture professionals still have plenty of uncertainty about best practices for lowering GHG emissions and increasing C storage. Citing potential incentives which may be offered by various agencies and proposed federal energy tax incentives designed to promote GHG emission reductions, the authors recommend further research to provide industry professionals with tools for adapting to legislation that could cap GHG emissions and provide opportunities in the emerging C trading and offsets market.

The research team said that continued investigation is also needed to discover profitable and environmentally sustainable ways to grow ornamental plants. "Determining C sequestration potential of various landscape species when planted into urban and suburban landscapes could provide homeowners a means of directly contributing to mitigation of climate change."


The complete study and abstract are available on the ASHS HortScience electronic journal web site:

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at


Original Article:

The Importance of Determining Carbon Sequestration and Greenhouse Gas Mitigation Potential in Ornamental Horticulture
S. Christopher Marble, Stephen A. Prior, G. Brett Runion, H. Allen Torbert, Charles H. Gilliam, and Glenn B. Fain
HortScience 46:240–244. [Abstract] [Full Text] [PDF]

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