For as long as the caster concentrates, any desired portion of her skin sticks to wooden surfaces as though glued in place. The caster can change the locations so affected, for example, to free one hand after the other for purposes of climbing. The spell makes climbing easier but slower because of the extra concentration required. The character gains a +8 bonus to all Climb check rolls to climb wooden objects or structures. If the character moves at a leisurely pace (one-half normal climbing speed), no Concentration check is necessary. If the character is moving faster that that, she must make a Concentration check with every Climb check with a DC equal to the Climb check DC.
Note that a single hand or foot does not have enough surface area to support a character's entire weight by itself. Any character foolish enough to try to hang from a ceiling or wall by one hand will tear the skin off their hand and suffer 1d4 damage (plus any falling damage that might result).