The stump will start to decompose once it is dead. The short answer is yes, burying a tree with too high material around its base will kill it. However, it takes a few years.

Will covering a tree stump kill it?

Plastic Bag or Tarp

Without sunlight, the tree stump will die, accelerating the decomposition process. Rotting should start to take place in two to three months. Here's how to kill a tree stump with a plastic bag or tarp: ... Cover the stump with a black trash bag.

Why is it illegal to bury stumps?

Burying a tree stump is illegal in some areas. Due to the danger of sinkholes, some communities prohibit tree stump burying. Other places require official permission before covering up a tree stump. Make sure that you speak with your local government authorities if you're thinking about burying a tree stump.