WHAT IS A TREE PRESERVATION ORDER (TPO)?
A Tree Preservation Order is a legal instrument put in place by a local planning authority in the United Kingdom to protect specific trees, groups of trees or woodlands in the interests of amenity. An order prohibits the:
- cutting down
- wilful damage
- wilful destruction
of trees without the local planning, authority’s written consent. If consent is given, it can be subject to conditions that have to be followed.
RESTRICTING ROOT DAMAGE
Of particular note is the fact that cutting or otherwise damaging roots via excavation around them is also a restricted activity under TPOs. However actual cutting of the tree roots is not required for the tree to suffer the ill effects of construction. As many tree roots are found within the first metre of soil, trees see a decline in health when the areas surrounding the trees are not protected from trafficking by vehicles and plant. The trafficking not only crushes the roots but also compacts the soil around and above them reducing the permeability to water, air and also restricting the activity of burrowing insects and other fauna, which normally maintain a nutrient-rich healthy soil structure.
NO DIG SOLUTION
As a consequence of all of the above, so-called ‘no dig’ solutions are sought which provide a stabilised raft or stiffened layer above the root zone capable of spreading the load of trafficking vehicles and inhibiting the effects on the soil and roots below. TCS’s Techcell cellular confinement system offers just such a solution. When filled with a 4mm – 20mm or 20mm – 40mm clean angular gravel, Techcell creates a permeable stable surface which distributes the loads imposed by vehicular traffic whilst allowing water, air, and nutrients to reach the tree roots preserving the health of the tree.
The British Standards Institute BS 5837:2012 provides recommendations relating to tree care, with a view to achieving a harmonious and sustainable relationship between new construction/existing structures and their surrounding trees. Techcell not only complies with BS 5837:2012 but also with Arboriculture practice note 12 (APN12).
If the final road surface requires a more formal permeable finish, this could be provided above the Techcell via permeable block paving, porous asphalt or polymer paviours such as Bodpave 85 or Techpave R which can be filled with gravel or seeded soil to provide a green finish.