California raisin-type grapes using the overhead trellis management system totaled 18,702 acres (bearing and non-bearing) during 2009, according to the Sacramento, Calif., Field Office of the National Agricultural Statistics Service (NASS).

This amounted to 8.9 percent of the total raisin-type grape acreage.

The Fiesta and Dovine varieties had the highest percentage of acreage using the overhead trellis at 52.6 percent and 45 percent, respectively.

Approximately 44 percent of the total raisin type acreage planted since 2002 was managed using this system.

Most California raisins are produced by sun drying after laying the bunches on paper trays on terraces between vine rows.

The overhead trellis system has led to increased production of dried-on-the-vine raisins, increased machine harvesting, and decreased hand labor use, NASS reports.