is buying tree victory dominant strategy?

[Loranger]

To my experience, it also depends on players level. For beginners (and 2 players), flames often win. For advanced players, trees win often.
Flames are easy to block (but should be blocked early enough).
With all strategies, trees are necessary.
When I feel late in trees, I've switched to lotus, and it has worked sometimes.
With kodama extension, it's very different. I don't know which one wins more. Lotus, maybe? More unpredictable anyway.

[Shobu]

Are there similar stats, for the expansion?

[Weeksy]

I'm not the best of the best, but I've been in and out of the top 100. I find that in games without the expansion, the base level dominant strategy is trees, but that fires are a close second, and flowers a distant third. In my experience, the best way to win with fires involves polluting people's decks with fire varans, in order to slow them down and stop them affording the more expensive trees. With more players, fires get better and flowers even worse, although it does all depend a bit on opponent behavior and the market. As players get better, it's more and more likely that at least one opponent will get to 12 trees on the turn you do, so playing for tiebreakers matters more as well.

Once you add the expansion, things change quite a bit. It's harder to win, which means slower games, and means there's more room for really busted turns. Going hard on the kodama cards is really powerful, and if you have a deck with enough kodama cards and gregarious animals, you can draw huge numbers of cards all at once, and from there figure out how you are going to win. The tree that gives +1 lotus for each kodama you have makes winning with flowers a lot easier, but once you can do everything, exactly which way you decide to win is trivial.

[Magrim42]

Only played few games, but I think buying trees is the most efficient way to win.
Is that true? Any way to counter this strategy?

If someone gets ahead in trees then going for speed can work, if you can get to 8-9-10, in 4-3-2 player, you can loop the board, getting the 11 tree let's you do this twice. Stealing their tree sets them back a turn and puts you ahead a turn. The other strat is to go for lotuses, save your tokens so you can draw your entire deck. I play mostly 3 player and trees win most of the time, flames probably the least. The reason is, it's such an easy strategy to shut down. You don't buy guardians when their turn is next and before their turn just make sure you or the other player buys them all.

Kodamas can be a bit different and sometimes flames does lead to an early win. But in that one, I usually win with lotuses because I stock up on kodamas and then get the 11 tree kodama=lotuses.

Good luck!