For convenience, here is the full text of the ability in question:
Animate Trees (Sp) A treant can animate any trees within 180 feet at will, controlling up to two trees at a time. It takes 1 full round for a tree to uproot itself, after which it moves at a speed of 10 feet and fights as a treant (although it has only one slam attack and lacks the treant’s animation and rockthrowing abilities), gaining the treant’s vulnerability to fire. If the treant that animated it terminates the animation, moves out of range, or is incapacitated, the tree immediately takes root wherever it is and returns to its normal state.
Here's my understanding of the procedure:
- As the ability is a spell-like ability with no specified action, the treant spends a standard action which provokes attacks of opportunity (but can cast defensively) to activate the ability.
- The treant selects either one or two (this is the crux of my question) trees within 180 ft.
- If it would not result in the having more than two trees animated and under its control at once, the selected tree(s) animates.
- One full round later (not an action on the treant's part), the tree uproots and can begin taking actions as directed by the treant.
Since the ability does not say "can animate a tree ... at will", but "can animate any trees ... at will", does that mean it can choose any number of trees as long as it does not exceed its control limit?