Best Management Practices

• International Society of Arboriculture’s Tree Care Information

Don’t Top Trees

• Never cut main branches back to stubs. Many people mistakenly "top" trees because they grow into utility wires, interfere with views or sunlight, or simply grow so large that they worry the landowner.
• The topping process is often self-defeating. Ugly, bushy, weakly attached limbs usually grow back higher than the original branches.
• Proper pruning can remove excessive growth without the problems topping creates.
• Many arborists say that topping is the worst thing you can do for the health of a tree. It starves the tree by drastically reducing its food-making ability (by removing all the leaves) and makes the tree more susceptible to insects and disease.

Use Pruning Rules

• Never remove more than 1/3 (33%) of a tree's crown (total number of leaves in the canopy) in a season. Typically it is best to remove less than ¼ (25%) of the leaves.
• Where possible, try to encourage side branches that form angles that are 1/3 off vertical (10:00 or 2:00 positions) from the parent stem.
• For most species, the tree should have a single trunk, a central growing stem, taller than the other lateral branches that grow off of the trunk.
• Ideally, the size of main side branches should not exceed 2/3 the diameter of the parent stem.
• If removal of a main branch is necessary, cut it back to where it is attached to another large branch or the trunk (see make proper pruning cuts below).
• Do not truncate a branch or leave a stub or small sprout.
• If the branch is removed at a lateral branch rather than the trunk - the lateral branch, which will become the new terminal shoot, should be at least ½ the diameter of the parent branch.
• For most deciduous (broadleaf) trees, don't prune up from the bottom any more than 1/3 of the tree's total height.

Make Proper Pruning Cuts

Large Limbs

1. Make a partial undercut from beneath.
2. Make a second cut from above several inches out and allow the limb to fall.
3. Complete the job with a final cut just outside the branch collar.

Small Branches

• Make a sharp clean cut, just beyond a lateral bud or other branch.

Use Mulch

• Mulch is a tree's best friend. It insulates soil, retains moisture, keeps out weeds, prevents soil compaction, reduces lawnmower damage, and adds an aesthetic touch to a yard or street.
• Spread mulch to a diameter of at least 3 feet, up to 10 feet depending on the tree size. Remove any grass within this area.
• Spread wood chips or bark pieces 2 to 4 inches deep within the circle, but not touching the trunk.

Preserve Tree Roots

Understanding how and where roots grow will help you avoid tree damage from trenching and construction.

• Because roots need oxygen, they don't normally grow in the compacted oxygen-poor soil under paved streets.
• The framework of major roots usually lies less than 8 to 12 inches below the surface.
• Roots often grow outward to a diameter one to two times the height of the trees.

Girdling Kills Trees

• Girdling is any activity that injures the bark of a tree trunk and extends around much of the trunk's circumference.
• Girdling is often caused by lawnmowers and weed trimmers.
• Girdling destroys the tree's most vital membranes, the layers that conduct water and minerals from the roots to the leaves and return the food produced by the leaves to the rest of the tree.

Planting Containerized Trees

If a tree is planted correctly, it will grow twice as fast and live at least twice as long as one that is incorrectly planted.

• Dig or rototill an area one foot deep and approximately 5 times the diameter of the root ball. The prepared soil will encourage root growth beyond the root ball and results in a healthier tree.
• When transplanting, be sure to keep soil around the roots.
• Always handle your tree by the ball, not by the trunk or branches.
• Don't let the root ball dry out.
• Help prevent root girdling by vertically cutting any roots that show tendencies to circle the root ball.
• After placing the tree, pack soil firmly but not tightly around the root ball.
• Water the soil and place a protective 3-foot circle of mulch around the tree. Do not pile mulch up around the trunk of the tree.

Planting Bare-Root Trees

It is best to plant bare-root trees immediately, in order to keep the fragile roots from drying out. If you can't plant because of weather or soil conditions, store the trees in a cool place and keep the roots moist.

• Unpack tree and soak in water 3 to 6 hours. Do not plant with packing materials attached to roots, and do not allow roots to dry out.
• Dig a hole, wider than seems necessary, so the roots can spread without crowding. Remove any grass within a three-foot circular area. To aid root growth, turn soil in an area up to 3 feet in diameter.
• Plant the tree at the same depth it stood in the nursery, without crowding the roots. Partially fill the hole, firming the soil around the lower roots. Do not add soil amendments.
• Shovel in the remaining soil. It should be firmly, but not tightly packed with your heel. Construct a water-holding basin around the tree. Give the tree plenty of water.
• After the water has soaked in, place a 2-inch deep protective mulch area 3 feet in diameter around the base of the tree (but not touching the trunk).
• Water the tree generously every week or 10 days during the first year.

This page has been adapted from the National Arbor Day Foundation’s “9 Things You Should Know About Trees” and is gratefully acknowledged.