Arborist Further Advice Response Letter

In response to the Information Request, the design of the section of boundary wall adjacent to
the tree has been reviewed and redesigned with an emphasis on the use of lighter construction
materials and a soft touch methodology. It is now proposed that the stone wall section at the
tree will be replaced with a lightweight metal fence. This section of the fence is supported by
fixing it to the wall end with central support from spaced posts. This design avoids the majority
of the strip fountains inside the tree’s calculated TPZ, resulting in a short section only of
intrusion at the western end. This would be deemed as less than 10% root zone intrusion and
with additional contiguous ground available throughout the council road reserve this is deemed
acceptable.

The post holes within the TPZ can be kept to a diameter of 150-200mm and to an approximate
depth of 1m to provide increased stability. These holes can be slightly flexible in positioning to
avoid larger roots over 75mm in diameter. The Project Arborist should oversee and guide the
works to create the post holes which can be undertaken by a hydro vacuum excavator with
the water pressure below 100 psi.

Please see the Aboda Design Group plans 231005 2205 Kelly Arakoon Cres (DRFI 06) for
details.

With the majority of the tree’s natural root growth within a garden bed on the opposite side of
the property, calculating an accurate root zone intrusion percentage is not achievable. Trees
are adaptive and opportunistic, growing roots where conditions are more favourable rather
than in a geometrically even radius. Over recent years the property owner has mulched and
irrigated the garden bed occupying the Council road reserve, actions that would have
encouraged root growth in these favourable and improved conditions. This care is planned to
continue after the project has been completed.

While root zone intrusion is not ideal, a project design and the tree can co-exist with care
during the construction phase, and mitigation measures implemented, particularly if a tree has
good vigour and a natural ability as a species to adapt, and the soil conditions present are
favourable to root growth.




23_10_06_IR_Adapt_2Arakoon                                                              Page 3 of 5