here's my guide for Jungle tank maokai, copied from another thread and edited for typos/clarity.
Maokai has a variety of good jungle routes and is a very capable ganker, tank and initiator. Below is the primary route, but you can also start at wolves/blue or their wraiths if you want to be aggressive.
WARNING: Maokai is VERY mana hungry, especially if you want to be aggressive. you likely can't give blue away (and still effectively gank and counter jungle) until the 3rd or 4th blue if you're not able to steal theirs.
In terms of runes, I play with attack speed marks, movement quints, armour yellow and mr/lvl blues.
Masteries are 0/21/9 http://leaguecraft.com/masteries/000...31130001000000
I start with the 15hp/5 item + 1 hp pot and I chuck one sapling in base so as to get 1 stack + mana back. Then I go to wraiths to near 1 shot them. Chuck your first box around 1:08, second on cd and then chuck the 3rd at 1:39-40 so that it'll deal the initial damage + explosion, just hit the big wraith, it'll die in 1-2 hits.
run to blue, you should get there around 1:55-2:00 depending on how used to this route you are.
DEMAND a hard leash from mid (or damage if they're incapable of getting blue to spin on the spot). You'll probably pop your pot there otherwise.
lvl2 rank up Q. lvl.3 rank up E (sapling) again. lvl.4 grab 1 point in W and leave it as that till the end.
Once Blue is dead, go Wolves > Wraiths again > Gollums > Red (DING LVL 4). At this point you can either gank mid/bot IF they're in a good position to do so and you have the health (more than 1/3 health). if not, go wraiths (they'll spawn within a few seconds of getting there after red) and then either gank mid or go wolves then gank mid/top if possible. If not possible and you have more than half health, counter jungle their wraiths.
B > phil stone + boots if you haven't ganked. If you have ganked successfully and got enough money (around the 1200 mark I believe) ignore the boots and get a heart of gold.
From this point onwards it's all about 1. farming your jungle. 2. warding up their jungle and stealing their big minions. 3. ganks
Initiate with W, instantly move ahead of them and use your Q to knock them up towards your team and while doing this chuck a sapling slightly ahead of them.so they'll have to run into it. Presuming your team is on the ball and you haven't just tried to gank their tank, the target will be dead very soon.. if not, chase as far as willing with your W and Q to keep them close.
Once you have your ult, also put this ahead slightly so that they either have to run through it (and so you can pop it just before they leave it) or try to run around it
Ability level route
lvl 2 gank (unlikely as mao as ganking usually requires Q and W and you really can't start with anything except E. This will only work with say a blitz bot or others with roots/stuns) E > W
lvl 4 ganks E > Q > E > W
Post lvl4. you want to level up Q and E first. it really is personal preference as to which you do first. I generally either alternate or go Q predominantly after E hits rank 3.
1. philo.stone +boots (or Heart of Gold instead if you can afford)
2.merc treads/ninja tabi depending on their team comp
3. Catalyst/chalice. (Maokai is very mana hungry, even with blue you can go oom fast, especially with your ult up). Your choice between the two is personal preference / whether you have the gold. Personally I've been going catalyst for the extra hp (good for your passive) and then either upgrading it early (either rod of ages or banshies) or sell it very late to get something specific to counter their team.
4. giant's belt
5. warmogs (if you're good at ganking you can sometimes skip 4 for this straight off)
6. depending on who's the damage output on their side, either upgrade your heart to a randuin's or go for a force of nature.
7. upgrade whatever you haven't upgraded / get specific items to counter their team (frozen heart/thornmail/banshies/etc.
By the time you hit point 6 on the above list you can tank a full team under a turret as long as everyone keeps on spamming abilities and you keep on meleeing while standing within your ult.
Your purpose in team fights is to jump on their adc/ap and make sure they can't get away from your own dps. It also is to protect your team from those chasing them by using W and Q to keep them rooted/slowed. There has been numerous times I have saved a low health team mate because I jumped the chaser and just stayed close enough to them to spam slow and root them.