Conducive Termite Environments

Mature Trees

Most mature trees represent a significant risk of sustaining a termite colony or becoming a feeding site in the future, or may contain a concealed nest within and particularly so if they are of a Eucalypt variety.  

As a precautionary measure, it is recommended that where mature trees are on site, they should all be drilled through to the centre towards the base using a maximum 10mm dia. auger drill bit to try and establish if any termite cavities/excavations exist.  If there are any internal excavations, the drill bit will suddenly have no resistance and this would indicate cavities and either past or current termite activity. 2-4 drill holes spaced around the tree should be sufficient.  

Where any termite activity is found then obviously the injection of Termiticide via the drill holes into the brick crown of the tree should be carried out. All holes to be sealed after drilling, and after any recommended termiticide treatment, to assist the tree and minimise any harm or damage to it. The Termiticide itself will not overly affect the tree, and certainly nowhere near the effect that a herbicide variety of chemical would have. When carrying out termite control measures it should be considered critical to ensure all safety measures are adhered to and that everything possible is done to ensure the health and protection of the tree and obviously the contractors carrying out the work.

Infested trees especially of the Eucalypt variety, may not reveal any outward signs of termite infestation despite the fact that significant activity may be present within.  It is from ideal to have concealed nest sites within mature trees, anywhere near the residence, as subject to the genus type and size of colony etc, some termites are known to travel for up to 80 m from their nest site (according to published expert opinions), looking for any available and susceptible species of timber as a food source.

It is recommended you immediately consult a qualified arborist, or other botanical expert, proficient in this area so that they can carry out an accurate assessment of the trees on the block and therefore give you a suggested action plan of what may need to be required for the trees and any possible costs that may be necessary. Aside from the risk of harbouring termites, mature trees can also present threats to the structure and the safety of its occupants (mostly in the event of serious storm events). By carrying out an assessment you would be properly informed of the condition of the trees within the block and obviously as to whether or not there may be any potentially unsafe trees.  This would enable you to be proactive, in terms of eliminating current safety risks and in doing so increasing the safety levels for any users of the block.

Retaining Walls and Fences

Termites often nest at the base of hardwood fence posts and within and around hardwood sleepers, regardless of whether or not the timbers appear to have been treated.  As hardwood as such a durable material, in many cases the CCA treatment applied at the time of milling does not fully penetrate all areas of the timber leaving vulnerable to future termite attack and providing an opportunity for a nest site creation.  During our inspections it is extremely common to find termite indicators, either in active or active, within these kinds of landscaping timbers.  Regardless of whether or not any termite indicators were identified during our inspection of this property, we recommend you consider having termite control measures installed so that the best levels of protection may be in place for these timbers.  Obviously where termite indicators are identified within any hardwood fencing or retaining timbers, then this recommendation must be treated as critical, as there would be increased termite risks to the structure from this activity within the block. This type of proposed treatment does have limitations, which are outlined in AS3660.2.  This is because the base of timber fence posts are almost without exception set in concrete, which means that any Termiticide applied is unable to bind with foundation material at the base of the post.  The sheer volume and mass of foundation material being retained by retaining walls that are in service, and particularly those that are large, means that to access and effectively treat every area of soil behind the walls, is almost impossible.  Often the costs of treating large retaining walls can be extremely high, because there is such a high volume of Termiticide application required.  Despite the limitations, clearly carrying out the treatment(s) would provide the most optimum level of termite controls for the timbers and subsequently for the structure.  The best method of termite control in relation to landscaping practices is to use termite resistant materials e.g. steel, masonry or treated pine to a minimum grade of H4.  
Spade away ground from fencing. Where possible, there should be a minimum of 75mm between the base of each fence paling and ground level.

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