Wikipedia's philosophy is fairly skeptical about using all capitals even when "everybody in the subject" uses all caps - but I see that at least currently they call their page [Leaf Area Index](http://en.wikipedia.org/wiki/Leaf_Area_Index). It could be that no "expert Wikipedian" has seen that page yet...

The most important thing is to include enough redirects that people can link to this page using all caps or all lower case or first word capitalized.