Poor tree architecture (structure) tops the of list of causes for tree failure. Often failed trees must be removed at high financial and aesthetic costs to landscapes. Pruning is far less expensive than tree removal and, when properly executed, will extend a tree’s life span and save landscaping expense. Tree owners are cautioned that incorrect pruning can do the opposite, causing structural and health problems that lead to tree failure. (see Improper Pruning Techniques below).
In forested environments, competition from other trees is useful, causing trees to develop strong structure (a single leader and smaller lateral branches). Also, forested trees support each other by sharing the work of breaking winds. In “built” environments with unlimited sunlight, trees often need assistance to develop strong structure.
Basics of Structural Pruning
Improper Pruning Techniques
Pruning in late winter, just before spring growth starts, is ideal. Fresh pruning wounds are exposed for only a short period of time to winter temperatures, reducing the chance of winter injury. This all aids in reducing the chances of infection and decay. Pruning in the dormant season also allows branch structure to be easily seen, which makes pruning decisions more clear. Although dormant season pruning is ideal, pruning throughout the year for most species is acceptable.
Species Specific Pruning Restrictions
Contact us for a consultation regarding your pruning project.
A tree with good structure.
When pruning a tree it is important to think about the process of developing the permanent canopy. A young tree has a temporary canopy and develops a permanent canopy as it matures. It is important to keep temporary branches small in diameter to reduce wound size when removed. Throughout the life of the tree, promote and maintain a dominant leader. Once the tree is mature, use reduction cuts to suppress aggressive branches, keeping leverage, weight and drag low to reduce the chance of failure in storms.
We plant trees with the hope and expectation that it will grow long into the future, becoming a healthy, mature tree. However, most trees obtained from traditional nursery stock (in containers or balled and burlapped) come with defects which are rarely corrected prior to planting. Often these trees are planted too deep or have encircling roots which eventually “girdle” the tree and lead to negative outcomes.
To establish a long-lasting tree, it is essential that excess nursery soil be removed from the top of the root system, exposing the root flare and removing any encircling roots. When planting the tree, you must make sure the root flare is left exposed and above the final soil grade. Think of trees in the forest where each flares out at the bottom. A tree that looks like a telephone pole sticking in the ground was likely planted too deeply and potentially has stem girdling roots. (See more information in Planting Resources below)
Basics of Species Selection
Contact us for assistance with species selection or your tree planting needs.
If you are not sure who's property a tree is on, there are some online resources which may help. Check the St. Louis County Land Explorer [website] and zoom to your property. The property lines are reasonably accurate. If the tree looks close to the line you can contact your city or county engineering department who may be able to help.
Trees provide a long list of benefits, but certain defects can turn a tree into a liability. We can provide you a comprehensive Tree Risk Assessment, taking into account the likelihood of tree failure and targets at risk of being damaged by falling debris. In some situations the likelihood of failure can be reduced by pruning and tree support systems (cabling and bracing).
The fact sheets below pertain to the law in Minnesota at the time of their writing in the mid 2000s. The information they contain may not necessarily apply in other states, and they have not been updated since their initial publication. The information included in the fact sheets is intended to be educational, not legal advice. If you have a legal problem, consult a lawyer.
“The nation behaves well if it treats the natural resources as assets which it must turn over to the next generation increased; and not impaired in value.” – Theodore Roosevelt