31 Mar Mistletoe and Basal Growth

Tree Surgery Request

In this case study Out There Trees was asked by a client to remove dead wood, basal growth and crown lift several large, deciduous, broadleaf Lime trees. Additionally, well established mistletoe was to be removed from the Lime trees. These tree care services were carried out by our trained professional arborists in Englefield Green, Surrey.

Basal Growth

Growth or shoots that appear at the base of a tree (shown in the photo above). This growth can occur at the base of the tree – an offset – or grow from the root of tree – a sucker – and therefore appear some distance away from the parent tree. This growth can become invasive and form a thicket quickly reducing the land accessible around the base of a tree. This is very typical with certain species such as Lime, Oak, Willow and Poplar. This growth can be a nuisance in garden and urban environments and can be maintained regularly with pruning to keep the stem and surrounding area clear.

This differs from epicormic growth which grows from a bud underneath the bark of the tree trunk or stem.

Mistletoe

Parasitic evergreen shrub which forms large spherical balls up to 1m wide in the tops of trees. Mistletoe is found on certain deciduous trees, such as Apple, Lime, Hawthorn and Poplar, as well as fir and pine trees. As they are evergreen mistletoe are more obviously visible in the winter when deciduous trees have lost their leaves. Mistletoe is native to the British Isles. A very heavy infestation can kill the host plant. They do this by killing nearly an entire crown of a tree and replacing the tree’s crown with the mistletoe’s growth. Taken to the extreme the host tree is left as nothing more than a trunk providing structural support for the mistletoe which supplies water and mineral nutrients to the parasite.

Mistletoe is spread by birds eating the seeds and then leaving their droppings in a potential host tree. The very sticky seeds may also stick to the birds bills, the birds then wipe the berries on the branch of a tree. The sticky material on a berry eventually hardens, laving the seed firmly attached to the host tree allowing it to germinate through the bark of the tree.

Mistletoe can add significant weight to the host tree and being evergreen subject host trees to high winds in the winter when deciduous trees would normally have less of a sail for winter storm winds to catch. This can subject the host tree to new fractures or worsen existing fractures and ultimately compromise the structural integrity of a section of the tree or indeed the entire tree.

All parts of the mistletoe are poisonous – berries, stem and leaves – to humans and pets. The toxin is concentrated in the leaves. Though effects are rarely fatal, if decorating with them it is advisable to remove the berries and place them at a height out of the reach of children and animals. Common effects of consumption may include blurred vision, diarrhoea, nausea, and vomiting. These adverse effects will be more pronounced in children and animals.

Eradicating the Parasite

So, once mistletoe establishes itself in a host tree can it be eradicated?

It is usually possible to save the host branch by pruning the invaded wood. That is if it is caught early enough. Some mistletoe can regenerate if the tree pruning leaves any of the root structure alive in the host wood.

Method of Removal

Basal growth was removed from the ground.

Removing the mistletoe and dead wood was performed by a combination of cherry picker and using a rope and harness to climb the Lime trees.

The finished product was a dramatic change and leaves the Lime trees in a healthier state with more nutrients for the trees and reduced susceptibility to fracture in high winds from the weight of the prominent mistletoe. Wood chip was left on site at the request of the client.