Does ‘decurrent’ mean that your fruit and nut trees have gone out of fashion?
No, that would be démodé and left entirely to personal opinion. Decurrent may refer to a tree's (or a leaf’s) overall growing behavior, or it may mean you have some pruning to do.
Trees are described as either decurrent or excurrent. Excurrent trees have a single trunk all the way to the top. Pines and most other gymnosperms are examples of excurrent trees. Most shrubs and angiosperm trees are decurrent. Decurrent trees get most of their structure from scaffold branches. Scaffold branches are lateral (side) branches that are no more than half the diameter of the main trunk (less than one-third is even better). Most fruit and nut trees are decurrent. The decurrent growth is caused by weak apical dominance. Apical dominance simply means that the main central stem grows faster than everything else.
Some leaf blades wrap themselves around a length of stem. These are decurrent leaves. The grass in your lawn is decurrent, as is mullein. The gills of a mushroom are also described as decurrent because the gills of many varieties are attached downward on the stem.
Pruning decurrent trees
Decurrent trees should be pruned in such a way that the main trunk is kept to approximately two-thirds of the tree’s overall height. The trunk, or central leader, should not be topped or headed back unless necessary to control for size. Secondary trunks are removed and the overall structure of the tree is developed with scaffold branches. Decurrent trees with multiple trunks are more prone to storm damage, but they tend to grow that way naturally. These extra trunks should be removed.
Branches that grow upward get more sun and tend to be mostly vegetation (leaves). Branches that are predominantly horizontal produce the most fruit. Decurrent branches, the ones growing from the bottom of supporting branches, tend to lose vigor and generally only produce small fruit. This is not the same thing as a heavily laden branch being pulled downward by the weight of its harvest. Decurrent branches should be removed as soon as they are seen, taking care to not damage the branch collar. Decurrent branches can also increase the chances of torn limbs, if the crop is particularly heavy. Removing these downward facing branches will redirect your tree’s efforts toward the more productive branches.
Decurrent is not the same thing as those squash plants that someone forgot water last August. That’s wilting. Decurrent is a growing behavior, not a dying behavior.
You can grow a surprising amount of food in your own yard. Ask me how!
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