The Petrified Tree @ Yellowstone!! Guess I told you about the trees eating minerals and living for ages!! Well this redwood has been around for 50 Million years!!! Volcanic eruptions in this region during the Eocene epoch (50 million years ago) triggered massive landslides into mountain and valley streams. The mixture of ash, water and sand buried entire forests, including redwood trees very similar to those of coastal California. Before the wood decayed, silca from the volcanic mud flow replaced the cell contents (lumens), literally creating forests of stone. Unlike other petrified woods that are completely replaced with minerals, the petrified wood of this region has lignified cell walls of the original xylem tissue that are still intact.