Tree Topping Image Courtesy of Seattle Times

The City of Seattle has prohibited this tree-killing practice in city parks and this is one of the many reasons they now require tree care companies to register with the city. 

Why Is Tree Topping Bad For Trees?

At one time, cutting back the majority of foliage-producing branches severely was thought to encourage leaf and fruit production but it actually has the opposite effect. 

Tree Topping:

• Removes the leaf-producing branches which dramatically reduces the tree’s ability to photosynthesize and nourish itself. 

• Leave newly formed branches susceptible to sun scald.

• Creates an easy pathway for pests and pathogens to enter the cambium of the tree. 

• Leaves your tree susceptible to wood rot which can lead to fatal branch failure.

• Fungi spores can easily penetrate the trunk and root system killing your tree from the inside. 

While some tree species may be able to recover from over-pruning, most cannot, and there are better pruning techniques that encourage healthy leaf and fruit production and structure. 

Alternatives to tree heading include selective canopy pruning, spiral thinning, and other techniques safely remove sail branches, increase light penetration and air circulation, and decrease wind resistance preventing wind throw and branch failure. 

How Much Should You Prune Your Trees?

As a general rule, you should never prune more than 15% of the canopy of your mature trees in a given year (10% for young trees). 

When pruning your trees, the objective is to remove dead, diseased, dying, suckers, and branches that threaten the structural integrity of your tree. 

For how to prune your trees, read our article on pruning techniques. You can also follow the guides created by the City of Seattle found here. 

When Is The Best Time To Prune Your Seattle Trees? 

The best time to prune your Seattle trees is during the winter. 

Trees are dormant during the colder temperatures and so are the parasites, insects, and fungi!

Removing dead, diseased, and potentially hazardous branches during the winter gives your tree time to heal and encourages healthy growth, leaf, and fruit production come spring. 

Summer months are a good time to remove suckers and water sprouts, look for signs of insect infestation and illness, and trim back branches that are not productive. It is easier to identify which branches are dead and diseased during the summer because they won’t produce leaves or the leaves won’t look right. 

If you see signs that your tree may suffer from infestation, blight, or other diseases, have a city-approved arborist inspect your trees. If caught early enough, you may be able to save your tree and prevent the disease from spreading. 

For tips on common diseases affecting Seattle trees, read our article on Common Tree Diseases To Watch Out For In Your Seattle Trees.

PRO TIP: Pruning back overgrown apple trees in the early summer (when it’s easy to identify what branches are not flowering or productive) is effective for controlling structure and form because they are focusing their energy on bearing fruit and don’t have the energy for regrowth. 

Unfortunately, there are tree services that still promote and practice tree topping and over-pruning in the Seattle area. If you see someone heading trees, report it to the city immediately at (206) 684-8850. 

Sound Tree Care is a top-rated, licensed tree care company with a certified arborist on staff serving SeaTac, Seattle, and the surrounding communities. Approved by the City of Seattle and Burien, our tree care specialists can help you keep your trees healthy and strong with regular tree pruning, preventative maintenance, removal, and disease treatment services.