Evaluation of Salvage and Replanted Native Plants on ADOT Projects.

摘要

ADOT has transplanted thousands of saguaros during the construction of roadway projects, and although the projects are typically tracked for two years, the long-term survivability of saguaros has never been documented. The purpose of this study is to examine ADOT projects in which saguaros were transplanted as part of the revegetation effort, and to evaluate the factors that contribute to the survival and good health of saguaros. The development of more successful techniques for salvaging saguaros will help ensure the long-term viability of transplanted saguaros and will enable ADOT to spend monies more effectively. Four projects involving saguaro salvage and replanting were selected for evaluation: State Route 86 Covered Wells, State Route 87 Tombstone Hill, State Route 188 Resort Road to Devore Wash, and US Route 93 Kaiser Spring. The projects occurred over a broad geographic area, with elevations ranging from 2,018 to 3,190 feet. An inventory of all saguaros, both alive and dead, was conducted in 2008. Each plant was assigned a number, its location was recorded using GPS equipment, a photograph was taken, and information was recorded regarding plant size and health and surrounding environmental conditions. Consistent among the four projects inventoried was the finding that the taller saguaros had a lower survival rate and exhibited poorer health after transplantation. Saguaros up to 12 feet in height typically exhibited good health. A sharp decrease in the percentage of plants in good health was observed in the 12-foot-plus saguaros, and particularly in the 20-foot-plus size. The presence of arms had a negative effect on saguaro survivability and overall health, an observation that held true for all the projects. A third variable affecting saguaro survivability and health was planting depth. A marked decrease in health was observed among saguaros that did not exhibit taper at the base of the plant, an indication that the saguaro was planted too deep. Recommendations are discussed regarding saguaro salvage and replanting techniques.