Does it have to be attached? (Shabbos 103a)

The mishna says that if you gather wood on Shabbos to make the tree or ground you're chayav for any amount but if you do it for firewood then you need enough to cook an egg. Rashi comments that you are only chayav if it's attached. The Tiferes Yisrael says the Mishna is talking about where it's detached. You're chayav if you take it to improve the tree for zoreia and for the land for charisha. If you do it because you want the wood then it's meamer.

Rashi only means it has to be attached in order to be chayav for a kol shehu for zoreia or charisha. You don't need it to be attached for the chiyuv of meamer but that chiyuv is only if you take it to use it. If you are just taking it to clean up the field then there is no isur of meamer. The Tiferes Yisrael is a bigger chidush because he's saying that it's called charisha or ketzira even though the wood is not attached. I would have thought (like Rashi) that the definition of those melachos is taking something attached.