Well, as i've seen several builds and guides for a jungle maokai, honestly i do not like them >.< hehe
So here goes my build, hope u like it, any comment, plz let me know.
TIA

Well, for Runes...
- Red Marks: Magic Penetration (x9)
Greater Mark of Magic Penetration
- Yellow Seals: Cooldown Reduction (x9)
Greater Seal of Cooldown Reduction
- Blue Glyphs: Ability Power (x9)
Greater Glyph of Ability Power
- Quints: Ability Power (x3)
Greater Quintessence of Ability Power

Maybe a weird combination of masteries, not as normal but focusing on what i feel is the right thing.
7-14-9
As I play Maokai as a jungle/tank, my masterie tree will be focus on Defense and Utility, and focusing AP on the Damage Tree.
- Offense
As Jungler, extra damage to minions and monsters is neccesary, as well as the extra ap given at the start of the tree.
- Defense
As a jungler/tank, Armor, Health Regen, Health and Reducing the incoming damage is neccesary
- Utility
Focusing on Mana Regen, Mov Speed (as Mao is a slow champ) and on Increasing the duration of the buffs.

Starting with Cloth Armor and 5 Health Potion to have a consistent jungling.
Then assuming you have earned enough gold, next items would be Sapphire Crystal and Ruby Crystal , upgrading later to Catalyst the Protector, and later on into Rod of Ages.

Between the Catalyst the Protector and the Rod of Ages, Boots thinking on Mercury´s Treads later on.

After get those two items, next you basically build depending on the enemy team.
If there is a lot of DPS u can upgrade the Cloth Armor of the beggining into a Frozen Heart . Also getting Sunfire Aegis or a Thornmail , both of them are good choices for a anti-dps build.

If the enemy team have a heavy AP line-up or much CC Quicksilver Sash its the perfect item. Also a Force of Nature getting advantage of the mov speed buff that it grants. Also a Banshee's Veil u would be able to evade 2 heavy enemy abilities on the gank.

So far, build would be like this:
- Mercury's Treads
- Rod of Ages
- Frozen Heart / Thornmail
- Sunfire Aegis
- Quicksilver Sash
- Force of Nature

The path u will follow on jungle will be the next.
1. Blue Buff
2. Wolves
3. Wraiths
4. Golems
5. Red buff

As jungler, initiating with Sapling Toss to stack them since 1:21 on the blue buff, since that time you can stack 3 of them before 1:55 an u will have time for other one. Then u reach level 2 getting arcane smash and get wolves. Then go to wraiths and golems, upgrading Sapling Toss by level 3 and on level 4 Twisted Advance Using the pots at the right time will give you a great advantage at the moment of ganking.

After having your 3 abilities you can upgrade them as you wish, if you are focusing on jungle upgrade the Toss first, if focusing on ganks upgrade Smash and Advance.

As jungler Smite needed, use it on Blue buff at the beggining and then on red buff.

Ghost i think its a must be for Mao, as he is slow, ganking at level 4 with Ghost gives u a great advantage =D

Most of the times i play Jungle Mao with friends of mine, so they know which is the right moment for ganks and so on.
Several good champ combos are:
Mao + Teemo
Mao + Skarner
Mao + Irelia
Mao + Jarvan
Mao + Fizz

All those combinations me as jungler and my friend as solo top (except for teemo which was a duo lane)

Right time on snare the enemies, slow them and get them finally will be the diference between a good and bad push, i remember recently a match which we got top tower no more than 5 or 7 minutes after initiate the match.

Well, i hope u guys find this guide helpful.

Any suggestion or comment, feel free to do it xD!