Is topping trees good? Is it true tree topping can significantly reduce the potential of falling branches from trees that are in poor structural condition or that have grown too tall? Can it also improve the health of trees that are damaged or diseased?
Topping trees is definitely not good. And here’s why: topping (removing the top of a tree or a significant portion of the upper main stem, including much of the crown) can severely damage or outright kill a tree, impacting the health of your other plants and reducing curb appeal.
The loss of foliage from the crown after topping may cause the tree to starve, as its ability to produce nutrients through the process of photosynthesis is critically impaired. Massive cutting also invites insects, disease, and rampant decay into wounded areas. And for trees that survive the topping process, crown regrowth is compromised: foliage comes back denser as the tree struggles to grow new, stronger limbs, leading to a weaker overall structure with increased potential for falling branches.
It’s important to navigate the myths of tree care in order to avoid making costly and dangerous mistakes. Here are five other common tree care myths.
Myth #1: Stake all young and newly planted trees.
Staking young trees may be necessary for some particular species, as well as newly planted trees that haven’t yet established their root systems or whose trunks aren’t strong enough to stand without support. But most trees don’t require staking—and even for those trees that do, failing to remove stakes after an adequate amount of time, whether that be a season or a year, can inhibit or alter their growth and render trees dependent on outside support.
Unsure if, when, or for how long to stake? Research the age and species of your tree to determine how staking will affect its growth. Consider the season and length of time required for staking. And consult the nursery where you acquired the tree or a professional local arborist, such as Mr. Tree, for more advice.
Myth #2: Prune branches flush with the trunk so they’ll regrow more easily.
Pruning can be necessary to maintain the health and life span of your tree. Structural pruning and properly thinning the crown of mature trees can prevent damage or stress from heavy wind and other extreme weather conditions, as air passes more easily through a thinner, rather than denser, crown. And pruning away dead, decayed, or diseased wood can promote local growth while further reducing safety hazards.
However, there are certainly improper ways of pruning, and cutting the branch flush with the trunk is one of them. When pruning flush with the trunk, the “collar” or base of the branch is removed, causing direct scarring to the trunk and increasing the size of the wound. As trees cannot “regrow” branches, the extensive scarring and wounding of the trunk prevents the tree from effectively compartmentalizing—the process by which a tree protects and seals its wounds, preventing decay and disease from entering the trunk. Once a branch is pruned flush with the trunk, the resulting wound is vulnerable to disease, decay, and infestation.
Myth #3: Trees have deep roots, so it doesn’t matter what happens to the topsoil.
Most people imagine the crown of a tree is a mirror image of its roots or that most trees have one deep taproot from which smaller rootlets grow. Actually, the spread and depth of a tree’s root system depend on the age and species of the tree. Most trees in an urban environment have a lateral root system, and while some have taproots, these central, tapering roots may also grow horizontally, depending on the hardness of the subsoil below and the amount of available space for the roots to extend laterally. So the majority of the root systems of most mature urban trees extend only through the first three feet of soil.
Disturbances, amendments, and even alterations to the topsoil’s physical or chemical structure can critically impact the health of a tree, especially a young one without an established root system. And many trees have shallow root systems, such as conifers common in the Pacific Northwest, which make them susceptible to the effects of disturbed topsoil. That’s why it’s important to maintain an adequately hydrated and chemically balanced surface and topsoil, especially during hotter, drier months, while considering how any changes you make to the topsoil may physically affect the roots and overall health of your tree.
Myth #4: Dressing tree wounds and filling cavities will help prevent decay.
As a rule of thumb, most tree wounds, especially those made while pruning, should be left exposed. Attempting to “dress” a tree wound, whether using paint, tar, or another material, interferes with the process of compartmentalization. And as trees don’t “heal” their wounds but rather isolate and seal off damaged tissue, applying an external dressing to a wound may actually increase unnecessary moisture and prohibit evaporation, promoting fungal growth and providing food for invasive pathogens.
Likewise, filling cavities, a method (traditionally using concrete) of filling and sealing large holes and hollows in trees for cosmetic or structural reasons, may also impact compartmentalization and further damage the tree if done improperly. Also, filling cavities, an already expensive and inadvisable procedure, is generally ineffective at improving the stability of a tree or preventing it from collapsing.
Myth #5: Trees will grow well without my care or attention.
In residential areas, caring for our trees is necessary for a number of vital reasons. Assuming a tree will grow without any attention may result in a malnourished, injured, or dead tree, as trees growing in a human-controlled environment need human care, maintenance, and attention to flourish. But when left alone, a tree in poor condition or at risk of falling becomes an immediate safety and property hazard. That’s when it’s time to call in a local expert for emergency tree removal and clearing, such as Mr. Tree. Hiring a professional, highly skilled, and up-to-date service you can trust may be essential for removing a disaster waiting to happen.