Skin
This radical is the same as the kanji. It means skin.
Here's a mnemonic refresher just in case: You go down a slide made of branches and your skin scrapes right off — ouch! Lucky for you, it was just your old outer layer of skin, and now you've got a fresh shiny layer. Yay for exfoliation! You're not sure what to do with this big, floppy layer of old skin, though…