What is the annual visitation at Petrified Forest National Park? The park averages about 600,000 visitors each year. You can visit the Public Use Statistics Office website for all park visitation statistics.

What is the best time to view wildflowers? Wildflowers bloom from late April through September. The best months, depending on rainfall over the winter, are May, July, and August. Different flowers bloom at different times of the year.

Is the park road OK for my RV? Yes. Our road and parking areas are suitable for larger RVs, even those with tow vehicles. The only points to avoid, due to a tight turn around if other vehicles are present, are Pintado Point and Agate Bridge.

Where can I camp? Petrified Forest does not have a campround and does not allow overnight parking. Backpacking is allowed for the more adventurous. Several options for RV/tent camping exist outside the park.

What is the park's pet policy? Pets must be kept on a leash and are allowed on developed trails, with the exception of the Wilderness Access Trail. Pets are not allowed in buildings or within the Wilderness Area. Please help keep the park clean and clean-up after your animals.

When is the best time to visit? The park's highest visitation occurs in the summer months, but winter offers visitors the chance to experience the park on crisp, cool days with unlimited visibility. The weather page shows average annaul temperatures and precipitation that might help you to decide.

Where can I ride my bicycle? Bicycles are allowed on any of the paved park roads, but are not allowed on or off trails.

Questions Commonly Asked about Petrified Wood

Why do the petrified logs look like someone cut them with a saw? Petrified wood is mostly quartz. The physical characteristics of cylindrical quartz cause it to break cleanly when stressed.

Where does the petrified wood sold in the rock shops outside the park come from? Petrified Forest National Park may protect only about 10% of all the petrified wood in northeastern Arizona. It occurs on privately owned land from which it can be collected and sold. It also is found on state land, Bureau of Land Management land, and in the Navajo Nation.

How can the Fred Harvey Company (Xanterra) sell petrified wood within the park? Xanterra is an independent concessionaire acquiring petrified wood from areas outside the park. We allow this because we feel that if the visitors have the opportunity to obtain petrified wood legally, they may be less likely to try and take it illegally from within the park.

Why are so many logs concentrated here? This was a large river system with forests upstream and in the vicinity. The mineralogical conditions of the groundwater were conducive to the petrification process. Some researchers offer a “log jam” theory accounting for the concentration.

Why are all of the petrified logs lying down? The logs were not preserved in a standing position. Most of them were transported for some distance before being buried.

Are there any standing trees? Standing stumps are known throughout the park.

What kinds of trees were these? They were coniferous trees, tree ferns, and some gingkoes.

How many different types of trees are found petrified in the park? Seven types of petrified wood have been formally described. There are probably many more species, but we cannot distinguish them using only the tree trunk because the woody cell structure is identical in many species.

Do the trees found in the park resemble any of the tropical conifers growing in the world today? Some researchers say they are an extinct form of conifer and not related to anything alive today. Others suggest a relationship to Araucaroid-like trees (Araucaria, Bunya Pine Tree,Monkey Puzzle Tree, Norfolk Island Pine) growing in South America and Australia.

How old are these trees? The fossil trees do not possess annual rings. Even if they did, you could not date them using that method because you need an unbroken series back from the present. Currently, tree-ring dendrology only extends back for 10,000 years. Dr. Sidney Ash reported some rings indicate drought periods. Where observed, cells appear to be equal-size indicating no changes in seasons.

Do the rings we see in some of the petrified wood represent annual growth rings? No. This suggests that the trees grew year-round. There were no seasons indicating lots of warmth, humidity, and water.

Geologically how old are these trees? Isotopic geological data for the Black Forest Bed equal 209–214 million years old. The trees in Crystal Forest, Rainbow Forest, and Blue Mesa Forest are older but we have no isotopic data for those deposits.

How tall were these trees? Dr. Judy Parrish and a University of Arizona geology student doing a log orientation study at Long Logs measured two trees 137 feet and 141 feet long. This indicates that the trees approached at least 200 feet tall when alive.

Is this the largest concentration of petrified wood in the nation? In the world? Probably the largest concentration in the nation and possibly the largest concentration in the world.

What mineral[s] replaced the wood? The mineral silica, dissolved from volcanic ash and hardened into crystalline quartz, replaced 80-90% of the organic wood. Minor minerals, such as iron, manganese, and carbon add the rainbow of colors.

Where were the volcanoes that provided the ash and silica to petrify these logs? We don’t know. Probably somewhere to the south or to the west. No remnants of volcanos have thus far been found.

What do all the colors in the petrified wood represent? The various colors represent the mineralogical differences in the quartz. Iron and manganese account for much of the coloration. Jasper (red) wood shows hematite inclusions in the silica.

Why do some of the petrified logs look like “real wood”? In some cases the wood has not been completely agatized. The “woody” structure has been preserved and the fossilization process is called, “permineralization.” When a small chip is dissolved in hydrofluoric acid, a small percent of lignin is still observed with biologic staining.

What happened to the roots, branches, bark, and cones from the trees? None have been found physically attached to the logs. However, we do have preserved leaves and reproductive structures which indicate that the trees may belong to the genus Araucarioxylon. We have a single preserved specimen with bark from the entire park. When a tree dies, the bark falls off quickly because it is only held on by a thin membrane called the cambium. Leaves, needles, and blades fall off as well. Roots, branches, and remaining bark are knocked off by transportation in waterways.

Why do some logs have “holes” in them? Some of the open spaces are due to decomposition before petrification began. Also, as in forests today, some logs may be hollow naturally.

Is petrified wood good for anything? It is used as a semi-precious gemstone in jewelry and as an ornamental stone in book ends, clocks, furniture, etc. Petrified wood is valuable scientifically since it tells us there have been trees on Earth for a very long time. It also allows us to create a climatic reconstruction of the Triassic Period.

How heavy is petrified wood? It depends on the chemistry - agatization vs. permineralization. On average the petrified wood is about 150 pounds per cubic foot.

How hard is petrified wood? Very hard. Petrified wood rates between 7 and 8 on Moh’s Hardness Scale. Only topaz, corundum (ruby and sapphire), and diamonds are harder.

What thickness of the Chinle Formation contains the fossilized wood, plants, reptiles, amphibians, etc? The Chinle Formation in the park is approximately 600 meters thick. This formation contains fossils throughout.

How long does it take wood to petrify? Probably less than 100 years. These logs were petrified during the Upper Triassic and have remained so until the present. The organic matter needs to turn to stone before it rots completely.

Will petrified wood ever decompose?  Petrified wood does not decompose or decay. It will physically disintegrate through weathering and erosion, just like any rock. 

Is the petrification process taking place today? Anywhere organic matter buried by rivers, lakes, and oceans is found with dissolved silica, petrification may be occurring.

Has amber ever been found in the park? Yes. This fossil resin is hard, brittle, and once exposed, breaks down rapidly.

Why did these trees turn to stone and not coal? The geologic conditions were not right for coal. Depth of burial of organic matter responds to elevated pressure and high temperatures for coal.

Do the petrified logs provide homes for any of the desert wildlife? Yes. Birds, mice, and insects live or nest in the hollow openings. Snakes and lizards live under them.

Is there any petrified wood or plant material in the park that is carbonaceous, charcoalified, or coalified? In the Tepees area there are layers of plant material turned to a black carbon residue. Several localities in the park contain minor amounts of what appears to be charcoalified wood (calcium carbonate). No true coalified wood has been found in the park. This requires pressure and high temperatures.

What will it cost me to have my own piece of petrified wood cut and polished? According to Jim Gray, of the Petrified Wood Company, the going industrial price [2004] is approximately $1.00 per square inch cut and polished. Contour polishing is much more expensive and requires more man hours. A 12 inch in diameter piece may cost as much as $300, according to Chuck Scott of the Rock Factory.

Did the logs shrink or expand as they were petrified? No, the size of the logs today is most likely the size of the logs before petrification.