Bienvenue
I have never been to Reunion, but once went past it on a ship...homeward bound from India.
I was very curious...wished we could break down and have a reason to stop there.
I understand that it is very much like Hawaii as far as climate (and volcanoes).
That should be a wonderful place to practice permaculture.
I don't know if these free downloads would be of any help to you. They are traditional trees of the Pacific Islands. Many were imported into the region, and may have also been imported (or natural) to your region by early explorers/colonizers:
http://www.agroforestry.net/tti/index.html
And a listing of free publications in the same climate/region:
http://agroforestry.net/pubs/index.html
Many of these publications could help you in your climate (and volcanic soils).
I'm glad to see members joining from new (to us) regions.
Welcome, and I hope you can find some helpful information here. All of it is not regional specific.
Perhaps you can share some information on your region. The broader our information becomes, the more people can learn from it. It improves our community.