During the past few summers I worked on my grandpa's big nursery near Portland - S. Farms. I worked with my cousin ryan and our job was to mow the rows in between the trees and everything else. Our mowers were John Deere 1445 models. The four wheel drive really comes in handy sometimes: notice ryan driving up the slope at the beggining 0:38 . They are powered by Yanmar engines. This video shows the mowers in action. I will be uploading 3 more of a demo for running the mowers.