We all like a good summer, but hopefully that kind of alarm call will not happen too often this year. We don’t need it. We are already short of water. And if the situation doesn’t improve dramatically, commercial landscapes are going to have a very difficult time.
All new planting needs water, but the investment behind planting a big tree makes watering all the more crucial. The roots must be encouraged to grow out and establish. Even a drought-tolerant tree is going to need water after it has been moved. So should we even be thinking of moving trees right now?
Autumn is, of course, the time for planting, but there are occasions when we have to consider planting or moving trees outside of that "sensible zone". For example, when developing land, the choice is simple: move it or fell it.
Moving trees is likely to be the preferred option. It may also be the only way of meeting planning conditions that stipulate similar trees must be planted elsewhere on the site. The cost saving of transplanting trees over purchasing new stock could run into thousands of pounds. But are trees going to survive if moved now?
"If the situation carries on as it is, the lack of water availability is going to make landscape management very difficult this summer," predicts Civic Trees managing director Deric Newman. Based at Tring in Hertfordshire, the company specialises in the production and planting of trees and also offers a relocation service for existing trees.
"Water is the key to good transplantation," Newman says. "If there is an issue about the availability of water on a site, it is best to postpone moving and planting until the autumn. If that is not possible and the move must go ahead, you must work to reduce the stress and increase moisture retention."
When looking to move trees, consider the following:
1. Think about leaving it
Be aware of water availability issues. If the tree cannot be watered, consider postponing moving it until the autumn. In commercial applications you cannot just fill up a watering can from the rain butt like gardeners might do in the first instance. Water has to be freely available on site.
2. Check out the species
Each tree should be considered individually in terms of size, species and health. Shallow-rooted trees such as Sorbus, Prunus and Betula tend to be more difficult and may require a larger rootball to aid survival. Platanus is relatively easy to move, Juglans nigra Award of Garden Merit (AGM) is more difficult and Eucalyptus and Araucaria really hate being moved.
3. Prepare the tree
New planting stock coming from a nursery field will have been prepared over a number of seasons. Regular pruning and undercutting of the roots will have created a dense system of fibrous roots and, at the same time, will have lessened the proportion of severed roots — those roots needing special aftercare to re-establish. Similar preparation of a tree in readiness for relocation is beneficial and should be planned for if time allows, especially for those species that are difficult to move. Sadly, the rapid pace of development work often means that trees are moved with little or no preparation.
4. Consider the rootball size
Tree spades and frames are commonly used for relocating trees. As a rough guide, an 85cm tree spade can be used to move a tree with a girth up to 20cm, a 110cm spade will handle trees up to 35cm and a 160cm spade will shift a tree with a 45cm girth. Larger tree spades are capable of moving trees with girths of 150cm. Above that, the solution is a frame and crane. If the tree has not been prepared in any way, take as big a rootball as possible.
5. Cover rootball in transit
Minimise the time the tree will be out of the ground by ensuring the receiving pit is ready and waiting. Covering the rootball in moist Hessian material will reduce evaporation as the tree is transported to its new home.
6. Prepare the pit
Good pit preparation is a must at any time but is even more essential if the tree is moved without being previously prepared, or if the new site has difficulties such as water availability problems. The pit should be excavated at least 30cm wider than the rootball. The depth should correspond to the depth of the rootball. Make sure the side walls are well forked so they can be easily penetrated by the roots. The base of the pit must be loose and free-draining.
7. Ensure the tree gets water
The opportunities for irrigation will depend on location. The most efficient systems will be automatic, timed systems or those based on drip irrigation. Where their use is permitted, water can be directed to the roots at night, when the ground is cooler and less water lost through evaporation. The other commonly used irrigation system comprises a ring of perforated pipe placed around the roots, the water being replenished via a filler tube connecting to the surface. This system has the advantage of encouraging roots to grow outwards and may suit situations such as golf courses or parks where water can come from an on-site, non-mains source, transported by bowser.
8. Use backfill to retain water
This is the stage that can be modified to suit prevailing conditions. In times of drought, that means ensuring as much moisture retention as possible. A backfill rich in organic matter will help hold water where the roots can get at it. Consider using water-retaining polymers, mychorrizal inoculants and anything else that will help the tree establish.
9. Use mulch to suppress weeds
Apply plenty of mulch to cover the distance from the trunk to a little beyond the extent of the rootball. Mulch material has multiple benefits. Not only will it aid moisture retention in the soil and reduce evaporation from the surface, but it will also control weed seed germination. Weeds will compete with the tree for moisture, and should be eliminated.
10. Keep records
Log the work: the date, the species, methods employed, the type and size of equipment, the materials used and the volumes involved. Further notes taken during regular inspections and maintenance visits will help build a record of valuable information for future reference.
Tree moving from a distance
The world’s first remotely controlled tree spade is available in the UK from Campey Turf Care Systems of Macclesfield, Cheshire.
As a truck-mounted unit, the Dakota 90 Tree Transplanter will be of interest to contractors and landscapers looking for a slice of the tree-moving market. Campey managing director Richard Campey says: "We expect tremendous demand for the Dakota 90. With the ongoing boom in landscaping and garden enhancement, this is the ideal machine for contractors to move trees without damage, and transport them to a new location. And it offers unrivalled operator safety at all times."
Hydraulically operated, the machine digs a 2.28m diameter hole around the tree. Four spades are lowered around the specimen and then they dig down to remove the tree. Using the remote control, the operator can monitor the procedure from all angles, even behind the truck, and at a safe distance from the work. Once lifted out of the ground, the tree is lowered on to the back of the transporter. The spades — made from non-heat-treated steel and powder coated — remain closed tightly around the rootball to prevent any soil loss.
In addition to the remote control, the Dakota 90 has some nice features to maximise precision and durability. A patented telescoping assist-cylinder is intended to reduce wear and strain on the lift track and the hydraulic hoses are carefully routed to avoid any chafing that could lead to failure. For maximum operator safety, external valve locks are fitted on all critical cylinders to prevent the blades falling in the event of a hydraulic-system failure.
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