Autumnwatch presenter Martin Hughes-Games carried out the tree-planting demonstration ahead of the BBC Tree O'Clock world record attempt on 5 December.
Arboricultural Association director Nick Eden said: "The BBC is there to provide a public service, but sadly, it has failed on this occasion. The BBC need only have contacted any one of the Arboricultural Association's 2,000 members to have obtained the right advice about planting trees. Trees are critical to our future and we must get it right."
He highlighted seven key errors made during the tree-planting demonstration.
- The pit should have been wider to give the roots the best chance possible of growing and spreading.
- The pit should have been shallower to avoid "suffocating" the roots and causing trunk damage from changes in soil level.
- The soil at the sides and bottom of the pit should have been loosened to help the roots to develop into the soil surrounding the pit.
- The roots should have been checked for any damage or disease, which should have been pruned out to eliminate serious defects in the future.
- Neat compost should not be added to a tree pit as a matter of course — most soils don't need it. If compost is needed for a truly impoverished soil, it must never be placed directly under the root system — the compost will rot down so that the tree could sink into the ground and become waterlogged during heavy rain. If compost is added, it must first be mixed with the soil that was excavated from the pit. This will encourage the roots to venture outwards and will avoid "scorching" the delicate roots that enable the tree to "drink" and "feed".
- The size of tree shown should have been staked with a short stake of an appropriate diameter to give the tree the best chance of establishing essential anchoring roots.
- Viewers should have been advised to consider protection against mammals such as rabbits, voles and deer and so on to ensure that the tree is not killed by bark stripping.
A BBC spokesperson told HW: "Tree O'Clock was developed in close collaboration with expert partners including The Woodland Trust, The Forestry Commission, Trees for Cities, the Wildlife Trusts. Guidance was sought from them on all key areas of content to ensure it followed best practice guidelines.
"A number of different sources of information were provided for people new to tree planting. Information was supplied to all tree distribution points and experienced staff were on hand to advise. The event has been a great success and a significant number of trees have been planted, leaving lasting benefits for native wildlife, for people and the environment for generations to come."
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