In this paper, we propose a particle-based simulation method to create the animations of swaying and breaking trees. Since the shapes of trees and their realistic motions are usually complex, it is difficult for us to create an animation of a swaying tree manually. Therefore, to produce films and image contents which contain a natural scene of swaying and breaking trees, it takes a lot of work to create the animation. To solve this problem, it is important that how to calculate interactions between a tree and wind to automatically generate the swaying and breaking motions of a tree by using a physical simulation. We model both a tree and wind as particles to simulate the interactions. The advantage of the particle-based method is that the method is robust for changing of the topology of wind and the branching structure of a tree. Our results show that the proposed method can naturally represent the breaking behavior of a tree and the wind flow around the tree by using the particle-based simulation of the wind.