Advice on trees required, false pepper, mediterannean pine

I'm not sure if this is posted in the right category. I couldn't find one specifically on gardens, so I'm sorry if this is the wrong place to ask this question.

I would like to plant a false pepper tree (Schinus Molle) which is quite a popular tree in Spanish gardens and parks.

I read on Wikipedia that these come in male and female varieties.

http://en.wikipedia.org/wiki/Schinus_molle

How can I tell the tree's sex when buying a sapling? The folks at the garden centre just stare blankly when i ask.

Also, what are the roots like. I am a bit concerned as we have a (masonry) septic tank so I'd like to know what the minimum distance is with respect to that if I want to avoid the roots invading or damaging the tank.

Also, we are considering a Medieterranean pine tree. I've noticed you see them a lot in parks but rarely in gardens. I was wondering if there is a reason why?

 I am not an expert on this by any means but it just happens that not so long ago I was being told the answer to this very question as one of my friends has one in his garden. Apparantly you can't tell until it is old enough to flower and bear fruit. The male trees do not bear fruit and the female trees will only bear fruit if they have a male tree close to them to pollenise the flowers.  So I suppose that has made it even more complicated. 

amogles

You can only really determine the sex of unisexual trees (like the Pepper Tree) by looking at their blossom. Female tree have flowers which have seeds but no pollen. Male trees have pollen but no seeds. Not the easiest thing to spot, but it can be done.

Both the Pepper Tree and the Med Pine have vigerous root systems and really need to be at least 25 feet away from house foundations, drainage pipes and septictanks...... one of the reasons you may not see them in gardens. The Med Pine in particular has a habit of lifting patio stones etc as the roots can often grow upwards.

JJ

Don't forget some house insurance companies might ask how close are any trees?, if you get a foundation problem, or any problem for that matter the insurance company don't like, it might say your not insured because of that tree.

Insurance companies look for any get out clause these days.