Props, Crutches and Big Sticks
by Derek Patch, Tree Advice Trust
These are not terms usually associated with trees, but look around at young trees planted in your area. You will find examples of trees propped up by stakes, others where the stakes act like a crutch, while in others the stakes are simply a useless big stick. The common element is that sooner or later all will cause damage to the trees they are intended to protect. The challenge is to act before damage actually occurs.
Stakes and ties are used with newly planted trees to "reduce the losses due to vandalism" and to provide support and protection for the tree - so what goes wrong?
Starting from new
A tree lifted from a nursery bed will have lost up to four fifths of its root system. What remains is insufficient to anchor the tree securely once it is replanted. A container grown tree has a similar problem because its roots are within a package of compost in which the roots will at first remain. The compost will slip in the backfill soil around it. There is, therefore, a need to provide temporary anchorage to hold upright newly planted trees until new roots develop into the surrounding soil.
Achieving an anchorage does not call for a stout stake with a 25 year design life reaching well into the branches. Securing the tree to the stake with two or more ties - with a design life fewer than five years - does not ensure a tree's safety. Too often the tree is able to rub on the stake - either at the top or part way down as the branches flex in a wind. Further more this movement, which is transmitted through a freely moving tree, stimulates diameter growth in the trunk and major roots. So holding a tree still with a stake and ties can be doubly detrimental.
To crown it all, the best intentions that accompany tree planting are forgotten within weeks and the props are left unfulfilled. Ties equally become grown into the stem and act as garrotes and abrasive damage increases. All because there is no aftercare.
To hold a tree steady until the new anchorage has developed only a short stake is needed - it should reach no more than one third of the height of the trunk. A simple tie at the top of the stake will reduce the most excessive swaying that would tear new roots out of the soil. If a tree grows healthily it should produce sufficient new roots in one growing season to hold the tree upright. Nevertheless it would be prudent to leave the tree with the 'prop' until the beginning of the second growing season after planting. At that time release the tie and gently push the tree to one side and provided the soil does not break away from around the roots, the support can be removed. By the time the next autumn storms occur the natural anchorage should have developed.
Coping with older problems
Where a tree has had a crutch for several years or it extends into the branches of the tree some caution may be needed. This is because trees that do not sway may develop an imbalance with the leading shoot growing taller and the stem diameter being greater above the tie than below it. As a result when the crutch is removed the tree leans - possibly dangerously in streets and pedestrian areas.
The trick is then to release the tie(s) to see if the tree leans. If it does lean find the position on the stem at which the leading shoot remains vertical. Position a new tie at that point and most importantly saw of the excess stake. This process is repeated at the start of each growing season until the stake has been removed or reduced to ground level.
If a tree is planted into poor soil conditions then it is unlikely to become stable and self supporting. Artificial support may then be needed throughout the tree's life.
Reducing or removing stakes should be done with care so as to avoid damaging the tree. A saw being used to reduce the height of the stake can very easily lacerate the bark of a young tree. It may be appropriate to wrap a cloth around the stem to give some protection while the cut is made. The removal of a stake should not involve shaking and wriggling the stake around. This could damage the roots by splitting them apart. A crow bar inserted into a cut made at the base of the stake can be used as a lever. Create a pivot by placing a brick or block of wood under the crow bar. The stake will then usually lift straight out of the ground. Once removed fill the hole with soil or other open rooting material.
With timely attention to the small details the stakes and ties intended to 'protect' trees can be prevented from being damaging props, crutches, or simply big sticks.
There is just one word of warning - don't remove stakes or ties without permission of an owner. There is a report of a well intentioned man being fined for cutting a too high tree tie that would otherwise have irreparably damaged the tree. Where is there justice?
You will find that without stakes the trees will look better and experience has shown that surprisingly there has not been any increase in the physical breakage or up rooting of trees. In future issues we shall deal with ties and tree guards.
If you want help on this or other tree matters check out The Arboricultural Association