Forest dynamics is about how forests change over time. forests are made up of lots of different plants, animals and insects that all need to be in balance for the forest to be healthy. The changes in a forest happen naturally because of things like storms, fires, changes in temperature and seasons, or the animals and insects living within it. As these things change, the population and types of plants, animals and insects in the forest also change. Over time, some species will come and go, while others will stay the same. This makes forests dynamic, or always changing.