Dataset Needed

I am a student at Michigan State University where I am taking a class in
data analysis this semester.  I need to find a dataset to analyse for a
term project, but I'm not having much luck.

My preferred topic is tree improvement in agroforest species in
Brazil--if not in Brazil, then in the tropics.  I have to be somewhat
flexible in this because so far I'm not finding what I want.

Can someone help me to locate a dataset I can download and use for this
class?  Any assistance would be GREATLY appreciated.

Thank you,

Leigh Ann Spence