The first trees showed up about 385 million years ago during a time called the Devonian Period. Four-legged amphibians were walking around in the forests, probably eating insects. The world was warmer then. The earliest trees had leaves like ferns. They reproduced using spores. Seeds evolved later. Some early trees developed cones around the seeds. Their pollen travelled on the wind.

Trees that produce flowers didn’t show up until much later, about 200 million years ago. Ginkgo trees have been around for about 100 million years ago and still look about the same as they did then.

Trees had an advantage over their shorter ancestors. They could get the sunlight before their short neighbors. Their spores would fall farther away, so they wouldn’t compete with the parent plants. Grass is a latecomer. It didn’t show up until about 40 million years ago, but it was very successful. What are some traits that might have helped grasses survive and spread?

You may want to study plant ecology and evolution.
Thanks for asking.

The first trees evolved during the Devonian period, about 380 million years ago. Those trees were different from any living tree, though (they are extinct). The oldest type of tree that still lives on Earth is ginkgo which has been around for 200 million years.