Trees and the Law - Alexandrina Council - SA.Gov.au

How can future problemsbe avoided?A tree can be many things - a gardencentrepiece, an object of beauty, a sourceof food, a structural support, a provider ofshade. For some people a tree can alsobecome a blot on the landscape, an objectof ridicule, a source of frustration and anunending nightmare. Whether a tree isan asset or a liability depends largely onwhether it is a good choice for the site.Choosing a tree is a bit like choosingmembers of a team - they must certainlynot conflict or create problems, theyhave to do the job and, preferably, addsomething special.When selecting a tree for a garden,householders should always get expertadvice on features which may make itunsuitable. Poplars, willows and river redgums, for example, are notorious for theirinvasive water-seeking root systems, anddropping limbs. Elms and poplars producesuckers, eucalypts and pines generatelitter, liquid ambers shed copious leavesand fruit, and lemon scented gum andcamphor laurels grow very tall. Trees likethese need plenty of space and water.Expert advice should be obtained from aqualified arborist or horticulturalist while alocal nursery can give general information.A list of trees suitable for planting insuburban gardens can be helpful as astart. Once an appropriate species hasbeen selected, care should be given to itssiting, planting and maintenance.Obviously large trees should not be plantedclose to buildings if their root system islikely to cause damage.Where trees are already established inthe area, care should also be taken whenconsidering the siting and design ofbuildings, drainage systems, drivewaysand paving. Some types of soils are moreprone to expansion and contraction as themoisture content rises and falls. Drainagesystems also need to be sensibly plannedaround existing site features such as trees.They should be carefully jointed when laidso that a watertight seal is achieved, andproperly backfilled with compacted sandto create a further root barrier. Driveways,paths and paving should be impervious torain water to inhibit moisture concentrationin the soil underneath. Plumbing systemsshould be checked regularly.Well-established trees need to be checkedperiodically for dead, dying or overextendedbranches, the presence of rot,termites or borers, and other indicationsof stress. Any wounds should be properlycleaned. The tree surrounds should allowfor natural levels of absorption of rainfall asmuch as possible. Creepers should not beallowed to grow up the trunk or branches.If problems arise with spreading roots theproblem may be one which can be rectifiedwith a root barrier. Expert advice may beneeded as to the type of barrier whichwill be necessary. In some cases a PVCmembrane may suffice. In other cases, adeep concrete barrier may be required.14