Mike Turner wrote:Even ignoring the vine's leaves shading the tree's leaves, one problem with tendril climbers like grapes is that the tendrils can wrap around and girdle small branches and twigs on the tree. The tendrils will also wrap around and girdle parts of the grape vine as well, which is how an unpruned vine can end up strangling itself unless pruned annually. In nature, when they climb a tall tree and can spread unchecked on the tree, the strangling/girdling tendency is reduced, but in most settings, grapes are cut back to a greater or lesser extent to limit their spread, which encourages vine branching and tendril girdling.
Mike, so if I understand you correctly, if left unchecked and unpruned its actually less of an strangling effect on the tree than if pruned. But in any case, another factor of concern I had was exactly that, in one of the trees, indeed, the top layer of leafs of the grapes seems to almost cover half the top canopy, so shading a lot the tree... on the other hand, I guess the idea is that in nature it normally works like that... still a little confused on this aspect.
