Evil tree is an animated tree that has suddenly became alive. Evil trees occur once every 2 to 3 hours the same way as shooting stars.
When cutting it gives you branches which you can exchange to various rewards; more about that below. Occasionally also gives you a birds nest.

We could add a whole new NPC who tells you where and when it appears or use our beloved expert axe seller Bob who is located at Lumbridge.
Adding a whole new NPC would probably be more handier though as it needs to sell rewards as well and they don't really fit to Bob.

Cutting evil tree works the same way as shooting star; starting at level 90 and granting bonus xp to first cutter while scaling down to
lower level requirement all the way to 40 I believe. Or there could be 3 trees that spawn with a static level requirement that doesn't change.
This could be levels 30, 60 and 90. All grant the same amount of branches but the XP you get is higher at higher level evil trees.

As for rewards I'd suggest adding Lumberjack clothing and Infernal Adze.
Lumberjack clothing (cap, shirt, legs and boots) all grant 2% bonus xp when training woodcutting increasing to 10% when wearing all four pieces.
Infernal Adze has 10% chance of burning a log while woodcutting and granting full Firemaking XP when it occurs. Roughly every 10th log is burned.

Thoughts/suggestions/feedback please.

I believe it has been suggested before and already back then got some really positive feedback
I agree

Yeah I remember it being suggested multiple times. However when Kolodion was added it's now possible to add more world events such as these.
Not sure what Thomy mentioned but something along those lines.

Love this idea also makes fire making and woodcutting les boring, would love to see this being added
makes emps more diffrent from other servers so maybey more players to.
Thumbs up from me 

Very good idea, would see this ingame .

You have my support.

That npc should be a spirit tree. We can use GE spirit tree spot for it.
I'd rather keep the layered style we have on shootin star atm. One tree has layers instead of separate trees.

Please explain the tree's mechanics for us. Do you have something specific in mind or should we follow the example we have?
I personally think it should be less afkable and more interactive compared to shooting star.

Should we keep sapling stage? (possible farming xp)
During the tree killing stage, I'd like evil roots to spawn from time to time. Those have an AoE, which stuns the players momentarily and stops them from woodcutting (you have to initiate the process again to continue). Those roots can be avoided or killed for kindling, which can be used to lit fires. Those fires increase the woodcutting xp from the tree until new roots spawn upon them.
After the tree is killed I'd like to see a bonfire. People could burn their logs and tree roots there (tree roots are gained from just wc-ing it) for like 15 minutes.

Rewards:
During the event: Bird's nests, you get a guaranteed crushed nest + you can get all tree seeds, gems etc from them (haven't decided on bird eggs, we could use them if you can only get non-mature birds).
From the shop: Lumberjack's outfit, Forester ring (grants 5% extra wc and fm xp, random ring model can be used for it), xp lamps for both wc and fm, Infernal adze.

It spawning roots and stopping you from cutting it actually sounds quite nice. Maybe cutting the evil tree itself could give you random pyre logs for firemaking which are untradeable instead of birds nests. (same thing as getting uncuts from shooting stars pretty much)
Lighting those logs grant double the xp the regular version of that log would.

Agree! Very good idea.

Suitable event for skilling, I agree.
Hope to see it coming in the game.