The saws of tree topper machines are displayed at the ADI Hydraulic Pruning Tools exhibit at the 47th Annual World Ag Expo in Tulare, California February 13, 2014. The expo takes place as a third year of drought plagues California farmers with the driest year on record and prompting California Governor Jerry Brown to declare a state wide drought emergency. REUTERS/David McNew (UNITED STATES - Tags: ENVIRONMENT AGRICULTURE BUSINESS)