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2014 ASHS Annual Conference

16829:
The Relationship Between Costs and the Carbon Footprint of Flowering Trees and Shrubs

Tuesday, July 29, 2014: 5:45 PM
Salon 5 (Rosen Plaza Hotel)
Dewayne L. Ingram, University of Kentucky, Lexington, KY
Charles R. Hall, Professor and Ellison Chair, Texas A&M University, College Station, TX
University researchers have recently quantified the value of carbon sequestration provided by landscape trees (Ingram, 2012; Ingram, 2013). However, no study to date has captured the economic costs of component horticultural systems while conducting a life cycle assessment of any green industry product. This study attempts to fill that void. The nursery production system modeled in this study was a field-grown, 5-cm (2 in) caliper Cercis canadensis ‘Forest Pansy’ in the Lower Midwest. Partial budgeting modeling procedures were also used to measure the sensitivity of related costs and potential benefits associated with short-run changes in cultural practices in the production systems analyzed (e.g. transport distance, post-harvest activities, fertilization rates, and plant mortality). Total variable costs for the seedling and liner stages combined amounted to $2.93 per liner, including $1.92 per liner for labor, $0.73 for materials, and $0.27 per liner for equipment use. The Global Warming Potential (GWP) associated with the seedling and liner stages combined included 0.3123 kg of carbon dioxide equivalents (CO2e) for materials and 0.2228 kg CO2e for equipment use. Total farm-gate variable costs (the seedling, liner, and field production phases combined) amounted to $37.74 per marketable tree, comprised of $9.90 for labor, $21.11 for materials, and $6.73 for equipment use, respectively. However, post-harvest costs (e.g. transportation, transplanting, take-down, and disposal costs) added another $33.78 in labor costs and $27.08 in equipment costs to the farm-gate cost, yielding a total cost from seedling to end of tree life of $98.60. Of this, $43.68 was spent on labor, $21.11 spent on materials, and $33.81 spent on equipment use during the life cycle of each marketable tree. As per an earlier study, the life-cycle GWP of the described redbud tree, including GHG emissions during production, transport, transplanting, take down and disposal would be a negative 63 kg CO2e (Ingram et al., 2012). These combined data can be used to communicate to the consuming public the true (positive) value of trees in the landscape.