Samsray
I'm not too sure what kind of help I can be in finding a forestry school. I see you're from Cameroon. I don't know what sort of forests you have, but I bet they're tropical. Here is a list of forestry schools in the US:
http://www.wvforestry.com/schools.cfmAll of those forestry schools offer very good courses in growing timber. The schools in the southern and western US have more of a leaning in growing softwoods in plantations. Those in the northern US lean more to hardwood forests that aren't grown in plantations. I don't know of any schools in the US that have a course dedicated to tropical forest management. Have you considered other countries? Australia has a lot of tropical wood. I even had a professor that was from Australia who taught in the US.
As for wood processing, many of the US universities offer courses in wood processing. The northern states offer much in processing hardwoods. The information can be used in tropical production.
Keep on asking questions and we'll try to keep on giving answers. If you have something a little more specific, we have folks that are pretty good right here on this site. Don't be a stranger.