Forreals? Yamato mid diff. Asuma isn't breaking through wood that restrained Naruto's four tailed form. Yamato can use his wood for mobility, so there goes CQC.
Asuma's wind chakra knifes should be able to cut through Yamato's wood with ease. Just because it restrained Naruto doesn't mean much. I mean, it is hard to break a shoelace by pulling it in half but a knife can cut it easily.
OT: Yamato wins mid difficulty. His suiton should extinguish Asuma's katon. Wood locking wall blocks any of Asuma's long ranged attacks as does Yamato's doton. Yamato can make wood clones to pressure Asuma from multiple directions as well as fool him. Yamato can use attack prevention to dodge Asuma's attacks or if Asuma gets too close in order to create distance between them. Yamato can grow mokuton arms to keep Asuma at bay if he manages to come close to Asuma.
Anyway it is quite unlikely for Asuma to come close anyway because Yamato can grow forests right underneath Asuma which also make it harder for him to close the distance.