Dear Station Members,
Attached is the latest Root Barriers research in 2008 published by ISA for your interesting information & studies.
Root barriers are increasingly used in our territory for root control especially for trees. However over the years, the Station Manager has not seen the effectiveness of the chosen root barriers to control roots of invasive species, e.g. Ficus, in our territory. He has also seen grass barriers used in place for controlling tree roots which turned out to be an expensive joke.
Most of the root barriers research around the world has been focusing on temperate tree species so far, & very little has been published on tropical species unfortunately. It is a known fact that tropical trees would grow faster, become more aggressive & more tolerant to abuses than temperate trees in their adaptation to environmental stresses. Just look at how our roadside trees are surviving is evident enough to suggest that more research should be carried on tropical trees. Unfortunately, it appears that Singapore is the only country in our region carrying out any valid research on tree care for this purpose. No research has been published internationally from HK in this area despite our resources.
Engineers & plumbers working for underground utilities have always found blocked drains by tree roots a nightmare in our territory. In our city where everyone & everything would fight for space, & with our public wanting trees wherever there is an open space, if the wrong trees are put on top of a leaking drain, even the best root barriers so available up to date may not control the problem. Tree roots would somehow find their way into the wet & cool environment created by drains. Species selection appears to be the paramount consideration, with proper pipe sealing & careful workmanship to be next.
Under current research, there appears to be no definite guidelines into how & which root barrier is best for a designated underground condition. Suggestions are flying everywhere, but it would be still up to the trail & error of the practitioners to find out what is going to work best for them. More research would go on in this topic & hopefully the future Arborists would find a way to try to deal with the ever challenging situation in the underground world.
The ISA Mission - Through research, technology, and education, promote the professional practice of arboriculture and foster a greater public awareness of the benefits of trees. (http://www.isa-arbor.com/)