Ecological roofing.

What is Ecological roofing?
Well for me it using a roofing material that does not need to be changed for a long long time and that even after its life span will be recycleable or will easily fit back in to nature. Such materials are:

Clay tiles should last about 50-60 years and will easily find there way back into the earth after their life span.
Zinc This must be pure Zinc and is a fabulous metal to use for roofs. It will not rust and will never need to be painted, but can be after it has oxidized. Should last over 100 years or more and is easily melted down and reused again after its lifespan.
Copper again is a beautiful roofing material which will never rust. It turns a beautiful moss green color after a while and is easy to melt down after use and even has a great resale value as scrap material. It is however more expensive to buy than Zinc.
Natural turf or grass roofs, are beautiful and great to install. Only draw back is their weight. Plan a good roof structure if you intent to use one.
Straw or reed are to me the most beautiful and obviously very environmentally friendly. Unfortunately in a lot of countries now they ask you to put gypsum board as the ceiling material under these roofs to act as a fire detterent, which defeats the purpose of having such a wonderful roof in the first place.
Wooden roofs are beautiful, easy to make and install. The may need to be coated with tar or some oils such as cooked linseed to protect them. Are obviously easy to repair or replace and are environmentally friendly if the wood is local.

Can you think of any more??