Appendix B - Arborist Report 22 August 2025 · OPW16/0303.02

Arboricultural Impact Assessment - Palm Lakes Resort Cooroy - Revision 1 - IAS17818 - 22 August 2025


Appendix 5: Normal Function of a Tree
Background Note: The following diagrams and explanatory notes are useful to illustrate the structure of
a tree in a normal growing environment. This information is taken from AS4970-2025 Protection of
trees on development sites which has been released subsequently to AS4373-2007 Pruning of amenity
trees.




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                        Figure 2: Structure of a tree in a normal growing environment

Leaves
The main function of leaves is photosynthesis, that is, the production of sugars. The sugars produced by
the leaves (and any other green tissue) are the source of chemical energy for all living cells in the entire
plant and as such are essential for the normal functioning and survival of the tree. Anything that directly
or indirectly damages the leaves will interfere with photosynthesis.

Trunks and branches
Branches and trunks are composed of many tissues with specialized functions including the bark
(protection), phloem (transport of sugars from the leaves), vascular cambium (growth of new transport
tissues), sapwood (transport of water and nutrients from the roots), heartwood (strength and structural
support) and rays (internal transport and storage of sugars). Damage to branches or trunks may allow
infection by plant pathogens (disease causing organisms), disrupt the movement of vital materials and
structurally weaken the tree.

Roots
The main functions of roots include the uptake of water and nutrients, anchorage, storage of sugar
reserves and the production of some plant hormones required by the shoots. For roots to function, they
must be supplied with oxygen from the soil. The root system of trees consists of several ‘types’ of roots
found in different parts of the soil and is generally much more extensive than commonly thought. The
importance of roots is easily overlooked because they are not visible, that is ‘out of sight, out of mind’.
Damage to the root system is a common cause of tree decline and death and is the most common form
of damage associated with development sites.

Root systems consist of three main parts:

    1. The structural woody roots (anchorage, storage and transport);
    2. Lower order roots (anchorage, storage and transport); and
    3. Non-woody roots (absorption of water and nutrients, extension, synthesis of amino acids and
       growth regulators) (see Figure).




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