By Kim Sebastian, DNR urban forestry coordinator, Milwaukee, Kim.Sebastian@wisconsin.gov, 414-294-8675
Click on “continue reading” or scroll down for the truth about these common myths:
Myth #1: A tree’s root system is a mirror image of what is above ground.
Myth #2: Tree roots are responsible for damaging and blocking sewer lines.
Myth #3: When removing a branch, cut as close (flush) to the trunk as possible.
Myth #4: The branches on a tree move up as the tree grows taller.
Myth #5: Topping is a necessary evil – otherwise the tree will get too big.
Myth #6: If a little fertilizer is good, a lot is better.
Myth #7: After a pruning cut, wound dressing (pruning paint) is necessary.
Myth #8: All newly planted trees must be staked.
Myth #1: A tree’s root system is a mirror image of what is above ground.
A tree and its root system more closely reflect a wine glass on a dinner plate – the tree is the wine glass, the root system is the dinner plate.
Myth #2: Tree roots are responsible for damaging and blocking sewer lines.
Roots are advantageous. They grow where they can get water, air and nutrients. Roots are not physically capable of doing the actual damage; they merely take advantage of the situation. The sewer line must be damaged first.
Myth #3: When removing a branch, cut as close (flush) to the trunk as possible.
A branch should be removed outside of the branch collar (or swelling) so as not to disturb the tree’s ability to callus over and wall off the wound.
Myth #4: The branches on a tree move up as the tree grows taller.
Branches remain where they first break bud. They get larger in diameter – like putting a thick coat of paint over the tree every year.
Myth #5: Topping is a necessary evil – otherwise the tree will get too big.
A topped tree will often exceed height growth of a tree that was left to grow naturally. In addition to that, you have branches that are weakly attached, and an unattractive tree.
Myth #6: If a little fertilizer is good, a lot is better.
Read labels carefully – extra fertilizer will not only leach into ground water, but be taken up by a tree that may be in no condition to use the extra.
Myth #7: After a pruning cut, wound dressing (pruning paint) is necessary.
It is typically not necessary to paint trees after pruning. There is, however, an important exception to this general rule of thumb: it is recommended to paint wounds on oaks during the season when they are susceptible to oak wilt (April-July; see the DNR’s Oak Wilt webpage for details).
Myth #8: All newly planted trees must be staked.
Trees in windy locations, in areas where vandalism may be a problem, trees unable to stand on their own, or bare root trees can be staked, but others probably don’t need to be.