Petrified wood and stumps are relatively common throughout the fossil record because wood is durable and prone to be deposited in conditions that favor deposition such as streams or buried rapidly by geologic events such as lahars. At Florissant Fossil Beds, petrified woods are preserved by a lahar, or volcanic mudflow, that flowed into the valley before the second lake formed. The mudflow ultimately killed the trees, but preserved them as stumps still in their upright position. There are basically two types of petrified wood found in Florissant Fossil Beds: conifers and flowering plants.

It is unknown how many petrified trees Florissant once contained, because beginning more than a century ago collectors began removing them little by little until there are only the few we see in the park today. Even Walt Disney purchased one in 1956 (before Florissant was a National Monument) for Frontierland in California's Disneyland amusement park. Early reports of settlers in the area spoke of how difficult it was to pass through Florissant valley due to the large amount of petrified wood that was littering the ground. Today, pieces of petrified wood continue to be removed, illegally, from within the park.