Lua Items appearing after x time

[Hjuston]

Hello, excuse me my noobish question but I didn't found any thread that could explain me this.
Actually I am looking for script that adds event (I guess) which will make item 'respawn'.
It should work like e.g. player cut tree, this tree transform in to hm... let's say log or something.
After x second this log transform in to tree again.
To be honest, I don't need full script, just a tip or sign which will guide me how to do this.
Sorry again and thanks for any help, peace!

 

[Limos]

local function doTransformBack(pos, itemid, transformid)
     return doTransformItem(getTileItemById(pos, transformid).uid, itemid)
end

addEvent(doTransformBack, 30 * 1000, toPosition, itemEx.itemid, 4008)
doTransformItem(itemEx.uid, 4008)