Over 200 million years ago, during the Late Triassic Epoch, the land that now forms Arizona was on the supercontinent Pangea near the equator, in a tropical climate. Huge conifers towered over a low-lying land cut by rivers and streams. As the trees died and fell, many were carried downstream by the rivers, rolling and breaking off branches as they traveled. Most of the trees decayed, but some were covered by sediment before the decomposition process set in. The land was coated in ash from nearby volcanos. Water dissolved silica from the ash and it percolated down to the buried trees. The silica solution filled the tree cells, eventually crystallizing into agate. Iron, manganese and other minerals present during this process paint the agate a rainbow of colors: iron minerals create red, mustard, orange and black; manganese minerals give blue, purple brown and black colors; even green is sometimes visible, which I suspect copper is responsible for. This process turned the trees into stone, or petrified wood. In hollows of the trees created by cracking or decay, the growth of crystals was unhindered, and large crystals of clear pure quartz, purple amethyst, yellow citrine, and smoky quartz formed. [Source]

John sitting on a large petrified wood log.

John sitting on a large petrified wood log.

A colorful chunk of petrified wood.

A colorful chunk of petrified wood.

Detailed view of a more natural colored petrified log.

Detailed view of a more natural colored petrified log.

Exposed petrified log naturally eroding.

Exposed petrified log naturally eroding.

Closeup of colorful petrified wood.

Closeup of colorful petrified wood. 

Delicate pattern in the colorful agate log.

Delicate pattern in the colorful agate log.

Petrified wood is common, but a small area of northeastern Arizona is special because it has the highest concentration of these fossilized stone trees, and it has been set aside as the Petrified Forest National Park. This land has a long history as a travel corridor for civilizations ranging from ancient to modern. In addition to fossil forests of petrified woods and a striking badlands landscape (more on that below), the small park also houses remnants of ancient Pueblo People, including ruins of a Puebloan Village and petroglyphs. Railroads were laid through the region in the 1880’s to connect to the Pacific Coast, and the railroad still cuts through the park today; a bridge over the tracks connects the north and south parts of the park. In the early 20th century, Route 66, connecting Chicago to Los Angeles, was constructed to also travel through this storied land. Today I-40 cuts through the park near the historic road.

Long logs field, with a particularly high concentration of petrified wood.

Long logs field, with a particularly high concentration of petrified wood.

I am laying on a huge petrified log.

I am laying on a huge petrified log.

More petrified wood is exposed as the land erodes around it. The broken segments of this log are rolling away with further erosion.

More petrified wood is exposed as the land erodes around it. The broken segments of this log are rolling away with further erosion.

A view point commemorating the former location of Route 66. Note the old car in the background. We explored a lot of this park on bikes - it felt great to ride again, and the badlands made for an amazing vista for our ride.

A view point commemorating the former location of Route 66. Note the old car in the background. We explored a lot of this park on bikes – it felt great to ride again, and the badlands made for an amazing vista for our ride.

We walked over to check out the old car sitting on what used to be Route 66.

We walked over to check out the old car sitting on what used to be Route 66.

Petrified Forest National Park is relatively small, as national parks go, and one can see all the sights and walk all the designated trails in a day, if one is so inclined. With an abundance of free camping just outside the park, and me not feeling well for our first couple days there, we took our time and spent four days there. I actually could have spent even more – on that final day we learned that there is a badlands wilderness area with no designated trails, but unlimited hiking and backpacking opportunity.

Jasper Forest lays below this overlook. A few pieces of petrified wood lay strewn about here, but much was removed in the late 19th century. The railroad provided easy access, and the petrified wood was carried out by the wagonfull. Local were outraged by this removal, which they considered theft, which led to the protection of the resource with the declaration of the Petrified Forest National Monument in 1906.

Jasper Forest lays below this overlook. A few pieces of petrified wood lay strewn about here, but much was removed in the late 19th century. The railroad provided easy access, and the petrified wood was carried out by the wagonfull. Locals were outraged by this removal, which they considered theft, and pushed to protect the petrified wood. The Petrified Forest National Monument was declared in 1906.

John looking over the Jasper Forest.

John looking over the Jasper Forest.

The logs in Crystal Forest have large cavities where quartz crystals form. Sadly, the crystals have been stolen over the years, so today the site does not live up to its name. This specimen does still house some small crystals.

The logs in Crystal Forest have large cavities where quartz crystals form. Sadly, the crystals have been stolen over the years, so today the site does not live up to its name. This specimen does still house some small crystals.

Closeup of the crystals.

Closeup of the crystals.

This rock decorated with ancient petroglyphs is located at Peurco Pueblo, but nearby an overlook offers a view down onto “Newspaper Rock”. Hundreds of petroglyphs are visible here - but bring binoculars if you can. A few large binoculars are available, but a personal set may offer better viewing.

This rock decorated with ancient petroglyphs is located at Peurco Pueblo. Nearby an overlook offers a view down onto “Newspaper Rock” where hundreds of petroglyphs are visible. To best see them, bring binoculars. A few large binoculars are provided, but a personal set offers better viewing.

Blue mesa offers a mile long interpretive trail through an impressive section of badlands.

Blue mesa includes a mile long interpretive trail through an impressive section of badlands.

If you are thinking that the Badlands are in South Dakota, as I was, let me clarify. The word ‘badlands’ has been generalized to refer to the type of landscape found in the famous Badlands. Indigenous people of Montana and the Dakotas called the land ‘mako siva’ and Spanish trappers referred to it as “el malpais”, both literally translating to “badland[s]”. Badlands are comprised of soft shale and sandstone that are subject to severe erosion. These severely eroded layers are also spectacularly colorful, as the layers of sediment built up under different environmental conditions (mineral composition, pH) that create variously colored layers over time. Erosion exposes the differently colored layers as striped hills. It is really striking!

I am happy to be cycling into the badlands.

I am happy to be cycling into the badlands. 

Just before I posed for that last picture, we came across this large beetle who stopped and stuck its backside in the air at the sight of us. I learned at Whitesands National Monument that this means it is about to spray us with something stinky enough to keep birds from eating it! This beetle is one of the few creatures living in whitesands that did not evolve a light color, because its stink is protection enough.

Just before I posed for that last picture, we came across this large beetle who stopped and stuck its backside in the air at the sight of us. I learned at Whitesands National Monument that this means it is about to spray us with something stinky enough to keep birds from eating it. This beetle is one of the few creatures living in whitesands that did not evolve a light color for camouflage, because its stink is protection enough.

Red, blue and grey stripes on display in the Blue Mesa badlands.

Red, blue and grey stripes on display in the Blue Mesa badlands.

The mineral composition is actually pretty constant through the different colored layers in the Blue Mesa. The color difference arose from environmental differences. A high water table  created a reducing environment so the iron minerals are green or blue, while a low water table led to the red iron oxide (e.g. rust).

The mineral composition is actually pretty constant through the different colored layers in the Blue Mesa. The color difference arose from environmental differences. A high water table created a reducing environment so the iron minerals are green or blue, while a low water table led to red iron oxide (e.g. rust).

The northern part of the park is called the “Painted Deesrt” due to the colorful badlands.

The northern part of the park is called the “Painted Deesrt” due to the colorful badlands.

We were not planning on doing any hiking in the park until we were at the Painted Desert Inn museum and the ranger staffing the information booth recommended a hike to us. I am really glad he did! We got the opportunity to hike out into the badlands and to experience firsthand where they get the name. Each of us fell once from sliding on the soft slope of the eroded land. Our hike was just over a mile to a log called the Onyx Bridge because it spans a wash. The petrified wood in this part of the park is primarily black, lacking the rainbow colors of the more developed areas of the park, but the hike was a really fun experience and I would love to do more exploring there.

The Black Forest Wilderness Area from the Painted Desert Inn. There are no trails, so hiking through this land requires some orienteering skills.

The Black Forest Wilderness Area from the Painted Desert Inn. There are no trails, so hiking through this land requires some orienteering skills.

The hike we went on was fairly easy, following a huge wash most of the way. It was fun to spot animal prints in the soft land in the wash, especially near the small puddles of water.

The hike we went on was fairly easy, following a huge wash most of the way. It was fun to spot animal prints in the soft land in the wash, especially near the small puddles of water.

When the directions said to turn left and climb up out of the wash at the “rock slide”, a hillside full of petrified wood is not what I expected.

When the directions said to turn left and climb up out of the wash at the “rock slide”, a hillside full of petrified wood is not what I expected.

Nonetheless, we found it! The log we see here looks just like the one in the picture. The only change in the scene is that someone rotated one of the shorter pieces in the foreground.

Nonetheless, we found it! The log we see here looks just like the one in the picture. The only change in the scene is that someone rotated one of the shorter pieces in the foreground.

John enjoying a rest at our destination, the Onyx Bridge.

John enjoying a rest at our destination, the Onyx Bridge. 

Superman in front of the Onyx Bridge.

Superman in front of the Onyx Bridge.

For those of you inclined to visit, I should explain more about the free camping. Many shops compete for tourist souvenir business just outside the park boundaries, and since these shops have abundant land, one way they try to lure in business is by offering free camping. This is basically just a place to park, no hookups or amenities (except treacherously decaying picnic tables), but we were literally just outside the park gates, parked for free with no worry about a late-night knock on the door. So each day we did a little touring, and a lot of relaxing.

We stayed at this free campground, located at the south gate of the park.

We stayed at this free campground, located at the south gate of the park.

Our van in the free campground. Those wooden tepees are actually functional - one night a couple came in and loaded their sleeping bags into the tepee to camp for the night.

Our van in the free campground. Those wooden tepees are actually functional – one night a couple came in and loaded their sleeping bags into the tepee to camp for the night.

The park may be small, but it does not lack in educational information. A museum of geology and fossils is located at the southern end of the park, and a cultural museum in a former inn at the northern end of the park. At the Rainbow Forest Museum we played in box of rubber pieces where bone casts were buried, meant to introduce kids to paleontology. Brushes were provided to uncover bones like paleontologists do. I just wanted to yank the bone out, not painstakingly brush away the debris. I probably do not have the patience to be as careful as a paleontologist!

The park is filled with fossils from the Triassic period in addition to the petrified wood. Out of curiosity, I asked at the information desk if there were any fossils we could see on a trail, and after one person grabbed another from the back, who called in yet another who wasn’t even in the building, the answer was essentially no. There is a fossil clam bed, but the part of the park it is in is not currently open to the public (a large portion of the park is currently off limits because it was only recently acquired and is not yet fully incorporated). She did say there is a plant fossil on the backside of the tepees (a badlands formation with a viewpoint parking area). The following day we walked to the backside of the tepees, passing signs admonishing visitors to not climb on the formations. Does “not climb” include not walk around off trail, even at the base? All over the park signs warn visitors to stay on the trails, so it really seemed we were walking where we shouldn’t be, and we didn’t even know what to look for. After looking at the back of the tepees, we determined that seeing a fossil would be like finding a needle in a haystack, made even more difficult by looking over our shoulders for rangers coming to kick us out. Sadly, we gave up and left. 

A placers hesternus skelton. The sign says “Placerias hesternus (plu-SAYR-ee-us-hess-TERN-us) was a dicynodont therapsid. Therapsids were large “reptiles” that possessed many mammalian characteristics including a “cheek” bone, enlarged canine teeth, and a specialized attachment of the skull to the spine. This massive plant-eater was up to 9 feet long and might have weighted as much as two tons. Like other dicynodonts, Placerias had a short neck, barrel-shaped body, small tail and large tuck-like bones protruding from its upper jaw. The beak-like jaws helped to pull up and tear tough plants and root. A large number of Placerias fossils were founding a single quarry near the town of St. Johns, just southeast of the park.

A placerias hesternus skeleton. The sign says “Placerias hesternus (plu-SAYR-ee-us-hess-TERN-us) was a dicynodont therapsid. Therapsids were large “reptiles” that possessed many mammalian characteristics including a ‘cheek’ bone, enlarged canine teeth, and a specialized attachment of the skull to the spine. This massive plant-eater was up to 9 feet long and might have weighted as much as two tons. Like other dicynodonts, Placerias had a short neck, barrel-shaped body, small tail and large tuck-like bones protruding from its upper jaw. The beak-like jaws helped to pull up and tear tough plants and root. A large number of Placerias fossils were found in a single quarry near the town of St. Johns, just southeast of the park.”

A pueblo is building that houses a village, essentially like an apartment building with very small individual rooms and a large communal area. Maybe more like dorms, come to think of it. (At least this is what I understand from the little information provided on plaques in the park). Puerco Pueblo was a 100-125 room pueblo on the Puerco River, the remains of which are open as a visitor site in the Petrified Forest National Park.

Remains of the Puerco Pueblo.

Remains of the Puerco Pueblo.

This rock near the Puerco Pueblo  has a few petroglyphs, including fun footsteps on the side facing the camera. The important mark is the spiral around the corner to the left of the feet. This side faces a crack in the boulder to the left, and is placed so that a finger of light points into the center of the spiral at the moment of summer solstice.

This rock near the Puerco Pueblo has a few petroglyphs, including fun footsteps on the side facing the camera. The important mark is the spiral around the corner to the left of the feet. This side faces a crack in the boulder to the left, and is placed so that a finger of light points into the center of the spiral at the moment of summer solstice.

 It is interesting to learn about how the park system has changed over the years. A large petrified tree, named “Old Faithful” was hit by lightening in the 60’s, and park staff “repaired” it by cementing it back together. That would not happen in today’s National Park Service, which protects natural resources by  letting nature take its course. Another example of artificially preventing erosion is that Agate Bridge, a log spanning a wash similar to the Onyx Bridge. An even more surprising development that is counter to modern park service policies is the Agate House, a partial reconstruction of a pueblo built of petrified wood. Archeologists excavated the remains of the pueblo and determined the floor plan of it. In the 1930’s the building was reconstructed.

Old Faithful in the Rainbow Forest. Note the cement supporting the large end - more is visible from the end where the pieces were cemented tighter following a lightening strike.

Old Faithful in the Rainbow Forest. Note the cement supporting the large end – more is visible from the end where the pieces were cemented tighter following a lightening strike.

Agate Bridge. The land eroded from below this log, leaving it spanning the gap as a natural bridge. Cement support was built in the early 20th century to prevent the log from breaking and falling. Current National Park philosophy would let nature take its course, and not build this kind of support.

Agate Bridge. The land eroded from below this log, leaving it spanning the gap as a natural bridge. Cement support was built in the early 20th century to prevent the log from breaking and falling. Current National Park philosophy would let nature take its course, and not build this kind of support.

Agate house, a 1930’s reconstruction of a pueblo built from petrified wood, based on archeological findings.

Agate house, a 1930’s reconstruction of a pueblo built from petrified wood, based on archeological findings.

A wall of the agate house.

A wall of the agate house.

Closeup of an agate house “brick”.

Closeup of an agate house “brick”.

 This was a really beautiful and informative stop! Another national park I recommend you visit.

Here we are, happy at the end of a fun park visit.

Here we are, happy at the end of a fun park visit.

A bonus bunny, hopping through the parking lot as we drive out.

A bonus bunny, hopping through the parking lot as we drive out.

4 Thoughts on “Stone Trees

  1. Beautiful pictures. The agate/petrified wood close-ups are stunning. And I liked the superman action shot!

  2. Louisa Treskon on March 23, 2014 at 9:25 am said:

    Hey – I visited here when I was a kid!

  3. Tamar on April 8, 2014 at 9:56 am said:

    I’m in awe about how colorful the petrified wood is! Thanks or sharing the beautiful pictures/experience!

  4. I always wondered what petrified wood was!

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