Coming from Megamek.
Pilot has Melee Master (CO pg 77) and picks up a tree as a club.
Melee Master says - "When executing a physical attack, a MechWarrior with this ability can deliver one extra punch, kick, club, or hatchet attack during a physical attack phase (so long as all other restrictions are met, such as not fi ring weapons in the attacking limb)."
The first attack will break the tree TW pg 146. What happens to the second attack.