|Tree Problems and Disease|
Regular tree pruning and maintenance prevents tree disease and structural problems.
Branches (sometimes entire trees) often split at the junction of two codominant stems - branches which are competing for strength - and neither of the branches achieve 100% of their needed vigor and strength. You often see these splits happen during or after heavy gusts of wind or wind storms. Sometimes the tree appears to have literally been split in half.
With early maintenance, those tendencies are eliminated because the tree is "trained" how to grow. But in trees that have grown up with these issues, pruning and cabling techniques can be used to help secure areas experiencing codominant main-lines, ensuring the tree remains secure and safe.
"Included bark forms when two branches grow at sharply acute angles to one another, producing a wedge of inward-rolled bark between them (see images). Included bark prevents strong attachment of branches, often causing a crack at the point below where the branches meet. Codominant stems that are approximately the same size and arise from the same position often form included bark.
Removing some of the lateral branches from a codominant stem can reduce its growth enough to allow the other stem to become dominant" (source: US Forest Service).
The acute "V" shaped angles at junctions with codominant stems are "bad joints" because they do not allow natural branch or bark formation. The bark becomes "included", like folds of skin. Other causes of acute joints and included bark are from improper trimming and pruning techniques (topping or pollarding a tree, for example).
These "bad joints" also collect deadwood and debris, inviting rot and insect damage that hastens the tree's structural failure.
Common diseases affecting western trees include: (source: US Forest Service)