Agathis is the name of a tree that looks really tall and strong. It can grow super tall - like a giant - in places where it is hot and moist. The tree has leaves that are like big needles and they don't fall off the tree all at once like some other trees. Instead, the leaves stay on the tree for a long time until they get old and turn brown.
One special thing about agathis is that it is really good at making something special called resin. Resin is like a sticky goo that comes out of the tree when it is hurt or cut. Think of it like a band-aid that the tree makes to cover its cuts and keep out germs. People can use this resin for many things like making medicine, glue, and even some musical instruments.
Some people also really like the way agathis looks because it has a pretty red-brown color and cool patterns inside the wood. So, sometimes people chop down the agathis trees to use as lumber for building houses or furniture. But, we have to be careful not to cut down too many trees or else there won't be enough agathis left for the trees, animals, and people who need them.