On Mon, 02 Nov 2009 08:43:46 +1100, Trish Brown wrote:

I have three young casuarinas near my fence line. I'm thinking of adding
more garden beds along there, but that would entail piling about 40cm
more soil on top of the casuarina roots to build up the beds. My husband
reckons this will kill them. Since the trees are now about fifteen feet
tall and doing well, I'd rather not do that. But I want my garden beds
too!

Any ideas? Solutions? Comments?

IME it will not affect casuarinas in the slightest. They will quite
happily suck up everything you throw on the garden.