Question
I'm considering planting a Japanese fern tree about 8 feet away from my shimming pool and I would like to know if the roots of this tree grows very large and would damage my
pool please can you help me I live in Miami Thanks

Answer
ello, Lilliam ~

Filicium decipiens - Japanese Fern Tree

This is a hard-to-find elegant shade tree that bears unusual foliage and maintains a spherical crown. Medium growth rate. Zones 10 & 11. From Sri Lanka and southern India. An evergreen, it will eventually grow to about 30 feet in height.

It self-sows freely; deadhead (pull up or mow down seedlings) if you do not want volunteer trees next season.  As it is a rare plant that grows only in zones 10 & 11 (Hawaii, parts of lower CA, and Southern Florida) not much is know about it, and I know even less ~ Sorry.

Here are some basic links with limited information:
http://davesgarden.com/guides/pf/go/67773/
http://www.hear.org/gcw/species/filicium_decipiens/

It is a noxious weed in Hawaii, probably because of its self-sowing properties.  I would also imagine that it will dump a lot of leaf litter, twigs, seeds, and such into your pool in a few years if planted too close to the edge of the deck.  Keep it back from the concrete work a minimum of at least 5 feet, just to be safe.

~Marc