Approved Plans and Documents - OPW22/0303

                                                                                  Consult Arborist

8 G ENERAL E XCAVA TION M ETHOD OLOG IES
Details below give examples of works methodology to excavate a trench or general excavation
when working in proximity to trees.

When using a mechanical excavator ground protection is advisable to minimise compaction
and damage to the surrounding soil and roots. With a combination of a small buck et and ripper,
the spoil from the trench can be carefully extracted. General excavation is to be undertaken ,
when possible, with the bucket positioned perpendicular to the tree, and the spoil dug away
from the tree, this helps to minimise roots being accidentally torn or fractured.

When excavations are being undertaken within a tree's root zone, all necessary precautions
are to be adhered to. The Project Arborist will advise on the progression of the works and
undertake root pruning as required.

Roots deemed to be pruned and removed are to be carefully cut using a sharp saw and/or
secateurs. Root removal is carried out by the Project Arborist on a root-by-root basis taking
into consideration the type of tree, distance from the cut to the tree, and the size and number
of roots found.

Where possible trenches and excavations are to be carefully backfilled using topsoil from the
site or imported topsoil with a low organic matter content and lightly compacted by hand within
the tree zone. Ideally, the ground is then irrigated to increase moisture in the soil (not
waterlogged) and where possible 100mm of mulch is spread to cover the surface area.

Where possible create a preliminary trench/excavation at the outer edges of the required cut
line using a Hydro-vacuum excavator. Roots found can be cleanly cut by the Project Arborist.
Once the preliminary cut line is completed excavation of the remaining area outside the cut
line can be dug using the appropriate excavator with all due care and attention to the adjacent
protected trees.




                       Figure 10: Example of preliminary trench/excavation cuts




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