Should wire baskets be removed from trees at planting?
Wire baskets provide the best system of handling, planting, and establishing newly planted trees while maintaining a high quality tight root system. Wire baskets have been used for at least 40 years in our industry and millions of trees have been planted with wire baskets during that time. We believe that wire baskets are not detrimental to trees after planting. There is evidence that trees planted in wire baskets hold up better during strong storms than trees that were not.
The design of wire baskets
Wire baskets were designed to support a root ball on the top and sides. The top and side wires support the root ball during loading, shipping, and transplanting, insuring the root ball arrives at its planting site intact. They also provide support to the tree during the time it is establishing in the landscape. This support provided by the basket, along with the weight of the root ball, is the reason trees rarely need to be staked. When wire baskets are removed entirely or the top tiers of wire are removed the advantage of the weight of the root ball helping to hold the tree in the ground is lost. After removal of the wire the trees will need to be staked (like most container trees are) and will be subject to blowing over during significant storm events. Not only does staking add significant cost to a tree planting project it can also add liability with guy wires becoming tripping and mowing hazards. Also, we have all seen staking materials not removed in a timely manner that eventually can girdle and destroy a tree.
Wire baskets are made for lifting
The wire basket also serves one other very important purpose; it provides a means for lifting the tree by the root ball so that the tree is not lifted by strapping on the trunk. The significance of this advantage to using wire baskets cannot be overstated. In fact, some of the largest container nurseries have looked into using a type of wire basket inside of the container to help provide a safe way of handling larger container trees. A wire basket is designed to support the tree by distributing the weight over the entire root ball. Professionals agree this is the preferred method of lifting trees; lifting the entire weight of a tree by strapping directly around trunk can cause damage to the trunk and cambium. Sometimes this damage may not be noticed immediately and symptoms of this unseen damage can appear years later as the tree declines or dies in the landscape.
Wire baskets and tree roots
A concern frequently expressed about wire baskets is how the basket may or may not interfere with the tree’s root system. The question is, does the wire girdle the tree’s root system or trunk and cause the tree to decline? The simple answer to this question is NO. Research has shown that a root growing near the wire will eventually grow into the wire. It will initially be indented by the wire and, as it continues to grow, will grow around the wire completely. The root then grows new tissues on the other side of the wire and the xylem vessels reconnect. Researchers considered several factors to determine if this was damaging to the tree. The researchers did not assume that because the root grew completely around the wire it was still a functioning root. They compared xylem vessels in roots that grew around wire to roots that did not grow around wire and found them to be nearly similar. They also used dye flow tests to show that water movement through these roots was not impeded.
Removing wire baskets at planting time is not necessary to assure growth and survival of large tree roots. However, you should remove any rope across the top of the ball, and bend back or remove basket loops. Using a correctly sized basket for each root ball is imperative. The top horizontal wire should be at least several inches below the top of the soil ball. Otherwise, you are safe to leave the wire basket on the root ball.
source: Marshall Tree Farm