In our modern era of environmental awareness, it seems contradictory to want to destroy any tree, given that trees consume carbon dioxide, store carbon, help clean the air, and give off oxygen. In spite of those beneficial characteristics, there are times when trees are dying as part of their natural life cycle, are diseased or infested with insects, or severely damaged, and they must be removed. Some species of trees spread and grow in the wrong places and must be removed for aesthetic reasons or convenience.
No matter what the reason for removal may be, it is helpful to know how to kill unwanted or dying trees.
Safely Removing Any Tree
Safety can not be stressed enough! You may choose to fell a tree completely, using chain saws, all safety equipment, protocol and methods necessary, and still end up in very serious trouble.
DO observe the location of all wires, buildings and identify other hazards before you begin the process. Beware!
If wires are too close, do not take unnecessary chances. Felling a tree over electrical wires can be lethal!
Trees do not always fall where even a highly experienced cutter thinks it will. Accidents happen even to the most experienced tree cutters. Do you have any experience cutting trees at all?
Dangerous, decayed tops and branches of dying trees may break off while felling.
Do notify the power authority if the tree is in close proximity to any electrical service!
*Caution: At times it is simply much smarter to hire a trained, professional contractor that will use an elevated "cherry picker bucket" to remove large trees that are dangerously close to electrical wires or buildings. Professionals are specially trained to deal with difficult trees in many difficult situations. For safety the public utility may well choose to have personnel on site to shut off the electricity while the tree is being removed .
Types of Trees and Growth Patterns
You may be successful cutting a tree down and removing it, but depending upon the species, it may quickly sprout sucker replacements at various spots along the roots unless the stump is treated. Poplars, willows, elms, Russian olives, black locust and many other species will generate a virtual forest on the root system very quickly unless action is taken to prevent growth.
Maples, apple trees, oak, ash, and birch trees respond differently. They will quickly sprout numerous suckers directly on the stump itself. A third category of trees includes conifers such as spruce and pine, which will not sprout from either roots or the stump, so are more easily removed.
To effectively remove a tree species that grows sprouts or suckers from the roots, it is more logical to kill the tree first, or it will simply grow dozens of shoots from the roots. It takes some time to prevent that from occurring, but chop a series of cuts angled down deeply through the bark into the wood, ensuring the cuts overlap and surround the tree completely. Pour Roundup or any other liquid treatment chosen liberally into the cuts, re-treating as required. The circulation system of the tree itself will carry the poison into the root system, destroying it. The tree may then be cut down and removed after it is dead without fear of any regrowth.
Alternatively, to remove an unsafe, partially dead tree that must be removed immediately, cut the tree down and treat the stump before it begins to dry. To prevent regrowth, cut the stump off flat and low, and paint the fresh surface of the stump immediately with Roundup, concentrating on the outer 2-3" of the stump.
An old-fashioned method of elimination was to use motor oil diluted with diesel fuel or paint thinner. Used motor oil will suffice for the application. The treatment, again, will act as a systemic poison, soaking into, entering and killing the root system by interfering with the feeding system, and preventing any subsequent sucker growth.
(*Note and Caution: Oil and petroleum products of any type are flammable and also persist and act as environmental contaminants. For environmental and health reasons, do not use any chemical more than necessary!)
Alternative methods include using a strong solution of borax , calcium chloride, or rock salt . Drill holes in the top of the stump around the outside perimeter and fill them with the strong salt solutions, or use any commercial vegetative pesticide containing glyphosate such as Roundup. Again, do NOT use more than is necessary. Oils and salts also tend to preserve the wood to some degree, so plan on removing the stumps later with a stump grinder. (See: " How to remove tree stumps with a grinder ".)
A method to kill a healthy tree that is safe enough to leave standing for some time is to remove a wide band of bark all the way around the tree. Cut deeply into the wood, removing all of the bark , cork, xylem, phloem, and cambium layers. Cut into the wood a couple of inches as a minimum to disturb all natural feeding processes in the tree structure. Doing so prevents the leaves from feeding the tree roots, and similarly, also prevents the roots from obtaining nutrients and feeding the tree. This method is not recommended for trees that spread by the root systems.
Remember, trees try to heal themselves as soon as they are damaged, so do treat the cuts immediately. To be successful, a bare band of wood must be exposed to dry eventually, and no section of bark or cambium layer must remain intact and functional, or the tree will use that as a bridge to sustain and heal itself.
It is paramount to keep in mind that regardless which system is used to kill a tree, even after cutting off the trunk , any treatment applied will continue to act as a systemic poison for some time, disturbing the feeding system and eventually killing the whole root system. It may also function to kill any other trees or sprouts that happen to be remotely connected to it by the root system. The trees on the other side of the fence that your neighbor may happen to treasure may be unintended victims of your remedial treatment program, especially if they are a species that spreads via the root system.
Caution is therefore clearly called for where trees may be interconnected by roots. Prior to killing unwanted trees, and to avoid the possibility of unintentionally destroying your neighbour's tree and friendship in the process, do take the time to dig a very narrow trench along the fence line and chop off any tree roots that are directed across the property line.
Good luck with those trees, and be careful!