Polk County Conservation

Tree Pruning

What do children and trees have in common? They both need nurturing to ensure that they grow and become respectable citizens in our community. Trees, like children need guidance. Early intervention can stop most problems, correct minor problems and even prevent future problems.

An old proverb states “a good time to prune is when the saw is sharp.” Unfortunately many people still believe this is correct. There is a good time to prune, but it is dependent upon the species of tree and your pruning objective.

Objectives for Pruning


The safety aspect is the number one reason for pruning. This involves removing dead and structurally unsound wood. Other examples would be removing branches that interfere with utility lines or block the line of sight at intersections. The majority of these problems could be eliminated if the proper tree was planted in the right location.


Pruning for health involves the removal of diseased and rubbing branches. We might thin the crown of the tree to increase airflow and reduce pest problems. Pruning can encourage trees to develop a good framework, which will reduce the likelihood of storm damage.


Pruning for aesthetics involves enhancing the natural form and character of trees. Stimulating flower production can also be achieved by pruning. Pruning for aesthetics is usually based on individual taste but trees that are allowed to retain their natural shape will require less maintenance.

As stated earlier, the time for pruning depends on the species of plant and pruning objective. Trees unlike humans, do not heal, they seal. Trees do not have the ability to generate new tissue and must seal over wounds. This sealing prevents decay causing organisms and rot. The ability to seal wounds is dependent on the trees energy reserves. These reserves are usually highest in the spring before growth resumes and this is why the late dormant season (February-April) is commonly regarded as the “best” time to prune.

Maple, birch, and elm exhibit sap flow (bleeding) in the late winter and early spring. At one time, the sap flow was thought to be an injury to the tree. Although unsightly, this causes no damage but can be avoided by pruning these trees in midsummer after the leaves have matured.

Dead wood can be removed at any time. Broken and diseased branches should be removed when they are noticed. There are two times when no pruning should take place. First, in the spring when the leaves are forming specifically from bud expansion to the time the leaves are fully expanded. Secondly, in the fall when the leaves are falling.

Late winter is a great time to prune. In addition to the reasons mentioned above there are other reasons to prune in the winter:

  • No leaves make it easier to see what you are doing.
  • Tree services are often less busy and some offer reduced rates in the winter.
  • Frozen ground eliminates the damage to the turf.

When hiring a professional to perform tree work look for the following:

  • Consult the yellow pages under the heading of Tree Service.
  • Ask for references and check completed pruning jobs.
  • Check if they belong to any professional organizations.
  • Make sure they have sufficient insurance.
  • Obtain a written estimate of the work and ask if they follow professional tree pruning standards.
  • Obtain a contract stating the work that will be done.

For more information on pruning contact your local extension agent, city or county forester.

Contact Us

Administration Office
12130 NW 128th St
Granger, IA 50109

P: (515) 323-5300
F: (515) 323-5354

Monday – Friday, 8:00 a.m. – 4:30 p.m.

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