Urban Miami: Preparing Trees for Hurricane Season
It is time to Prepare Trees for Hurricane Season
Learn some important tips on pruning trees in your landscape for hurricane season.
Tree Trunk and Branch Structure
- Topping a tree creates a dangerous tree and is illegal. Topping (“hatracking”) is the term used to describe over-pruning a tree by cutting it so badly that it is left with few or no leaves on the branches. Trees should never be topped. Topping creates hazardous trees because the wood inside the cut branch begins to decay which leads to internal rot. The sprouts which grow in response to topping are not well secured to the topped branch and they can easily split from the tree as they grow larger. To avoid this, always prune a branch back to a living branch crotch.
- Trees with a thick canopy should be thinned. Avoid removing more than 25-30% of the foliage per year. Most trees do not need to be pruned each year. Thin the canopy when it becomes thick (hard to see through). Some interior branches should be removed to allow wind to go through the canopy. The aerial roots of Ficus trees should not be removed.
- A tree with multiple leaders (trunks) will become hazardous to people and property as the tree grows larger. Never allow trees to grow with multiple upright leaders. These trees may look handsome when young but will become hazardous as they grow older. Always prune so that branches are spaced 18-36” apart along the main trunk. In trees with a single trunk be sure the main branches form an angle with the trunk of 40 degrees or more.
- Horizontal oriented branches are better attached to trees than upright branches. Upright branches are poorly attached to trunks. Horizontally oriented branches (45° or greater) are usually well secured to trunks. A branch growing in an upright manner parallel to the trunk becomes a second trunk. The tree is said to have a double leader. Double leaders are dangerous because they can easily split from the tree during a storm.
- Tree roots should not be damaged. Root pruning and digging around tree roots makes the tree more likely to fall during a storm. Also, root injuries increase the occurrence of plant disease. When planting, the top of the root-system should be a little higher than the surrounding soil level. The width of planting holes needs to be a minimum of 2 – 3 times the diameter of the rootball and the depth no deeper than the rootball.
- Buy good quality trees and trees that are adapted to south Florida. Buy “Florida Fancy” or “Grade #1” trees whenever possible. These trees have one trunk and need little additional training to form a good quality tree. Miami- Dade County is in USDA Zone 10. Buy trees that thrive in this zone.
- The best time to train trees is when they are young. Not only are the branches easier to reach, but the resulting wound will be much smaller and callus over more quickly.
- Choose trees that suit the area. Large trees need a large rooting zone. Tree roots extend 3 – 5 times the diameter of the canopy. If the planting area is small or the yard is small, choose a tree species that naturally stays small. Avoid planting trees near septic systems, pools, sidewalks, driveways, utility lines, and buildings. Tree trunks and roots expand in girth as they age. Know the mature height and width of the tree, and take this into account when choosing the planting site. A tree with a 4” trunk caliper needs 200 cubic feet of soil space.
- Never cut a branch flush with the trunk. That is, never make a flush cut. Always cut to the outside of the branch collar which is located at the base of every branch. This collar is sometimes easily seen as a swelling where the branch meets the trunk. When pruning in this manner it may appear as though a small stub is left on the trunk. However, properly done, this technique removes the entire branch and does not injure the trunk.Large limbs should not be removed unless they are obstructing traffic, pedestrians, or are hazardous.
Avoid removing branches that are more than 2” in diameter. The larger the pruning wound, the slower it will callus over (plants don’t “heal they seal”). An open wound is an avenue for disease and insect infestation.
- Wound dressings and pruning paints do not prevent wood rot. Wound dressings do not prevent wood decay behind a pruning cut. They provide no benefit to the tree. Some research indicates that wound dressings promote decay in certain situations. If pruning paints or wound dressings are to be used for cosmetic purposes, apply only a very thin coat. Only proper pruning practices prevent wood rot.Avoid “liontailing” and “overlifting”.
“Liontailing” refers to removing smaller branches on large branches leaving the foliage only on the ends of branches. The limbs will look like a lion’s tail. “Overlifting” refers to removing lower branches of trees. These harmful practices make trees more vulnerable to wind damage and rot. The common guide is that the lower half of the tree needs to have 2/3 of the foliage and branches.
- don’t need hurricane pruning. Palms are adapted to wind storms. Removing fronds is of no benefit and is detrimental to the palm. Even dying leaves benefit the health of the palm and should not be removed until completely brown. Only coconuts and large palm seeds should be removed during hurricane season.