Tree Animation

[Dispatcher]

Hey guys i just downloaded a tree called Crannies Summer and Winter and as you know from this doodad it has a rock at the back of the tree and i only just need the tree so i edited it using Reteras Modeling Studio and saved it and then i notice that if i import this tree in the object editor and go to Destructables and trees when i try to import this model on a tree for example ashenvale tree it never shows up but when i have tried it on a barrel it worked it seems mysterious so can someone tell me why? Ok so moving on i copied all the data of a normal tree to the barrel making the barrel an actual tree so i did it succesfully but the only problem is that the tree has no death animation or if it is dead it would be a stump and when i try to make my workers harvest that tree and my workers are now chopping that tree it has no swing animation it just stay still and by the way the tree has only one variation so the trees are all the same.
So Overall what I am trying to say is that how would i make a death (when the tree would turn into a stump)and swing(when tree is being harvested) animation of the Crannies tree i just downloaded and how would i make variations of those trees so that the trees would look good if it has different variations.