Trent from Heibel Ranch Vineyards talks a bit about Canopy Management and trimming of the vines. Although it was not so easy to keep up with Trent with the video, we see how the vines are trained and managed. The idea is that the “Canopy” or leafy growth will naturally grow outward, and needs to be kept toa harmonious size and location, such that the plant has energy to thrive, but that this energy can be concentrated and channeled into ripening the fruit.
Trent mentions how a week prior you could not see doen the “aisle” between the vines. His vineyard crew came in and literally tucked all of the leafs and branches up under the trellis system. Trent then talks about wanting to grow a 4′ tall shoot. The 4′ is measured from the “cordon”. Trent also tucks about he talks about “Suckers” and how to shed the canopy and condense the plant energy into the fruit. Suckers are rogue branches that grow from the stem and absorb a lot of energy, that could otherwise go to the grapes.
I hope this helps any Viticulture Students out there. :) Here is a link to a diagram of a vine.