Introduction to the Message Tree: During the Anti-Japanese War, in order to deal with the Japanese invaders, the common people had a message tree on the hillside of each village. The first sentry who saw the Japanese invaders would knock the tree down, and the others who saw it would Villagers can prepare and respond in time. The message tree is actually a tool for transmitting information. Because the tree is relatively tall, it is easy to see clearly, and it is less likely to be spotted by enemies than fireworks, and there is no need to waste time lighting them. After the situation stabilizes, the tree can be erected again and used repeatedly. It has been widely used in people's war.