Two branches left after pruning by Ausgrid

Two branches left after pruning by Ausgrid

I found a very interesting article on the practice of tree topping in American newspaper the Richmond Register called, ‘Topping Trees is a Bad Practice.’  See –

It is especially interesting in terms of the topping of street trees done by power company Ausgrid, as mentioned in the City of Sydney Council Minute I posted here last week.

  • “Topping involves the drastic removal or cutting back of large branches in mature trees leaving stubs. Topping can make a tree hazardous and reduce its life.”
  • Removing much of the tree canopy upsets the crown-to-root ratio and can cause serious interruption of the tree’s food supply as well as exposing the bark to the sun. For example: a 20-year-old tree has developed 20-years-worth of leaf surface area, therefore that much area is needed to feed the 20-years-worth of branches, trunks and roots that have developed.”
  • “Large branch stubs left from topping seldom close or callus. Nutrients are no longer transported to large stubs and that part of the tree becomes unable to seal off the injury. This leaves stubs vulnerable to insect invasion and fungal decay. Once decay has begun in a branch stub, it may spread into the main trunk, ultimately killing the tree.”
  • “Topping removes all existing buds that would ordinarily produce normal sturdy branches and instead stimulates regrowth that is dense and upright just below the pruning cut. The growth that results from topping is not well integrated into the wood of the tree. Because of the weak connections, these branches are more vulnerable to breaking.”

We know there is another way because Energy Australia managed our street trees for many decades with a pruning cycle of 7-8 years, while now Ausgrid has a pruning cycle of every 18-months.

Food for thought.