Several weeks back we visited our favorite Chapin Winery in Temecula, then in the midst of pruning. The long branches, accurately called canes, that produce the grapes had been cut back to the spur buds on the laterals, or cordons, that grow horizontally. But some long canes remained, seemingly at random, and we puzzled about the purpose. Then last Sunday we figured much of it out. Most of the long canes were now gone, and we first noticed some…