DPsycho understands the mechanical intent perfectly:3
As for the fluff, trees which produce ramets wouldn't in turn produce much petrified wood or other gems of any sort. They dry too slow and once they did, they rot within days. Their lumber on the other hand is durable, but only suitable for furniture or tools, not, say, building a whole house out of aspen logs(which you can, but when you have another option, you really shouldn't), hence the low resource gain overall.
Ah, and petrification reminds me.