Tuzigoot National Monument

Desert grassland surrounding the Tuzigoot ruins.  National Parks website photo.

When it comes to living off the land as the ancient Sinagua Native Americans did, Tuzigoot National Monument near Cottonwood, Arizona has it all.  Landscape diversity is essential when it comes to finding the products essential for life and Tuzigoot is especially rich when it comes to the landscape.  Think about it.  If you were to live off the land and not be required to wonder around searching for things constantly you would need a variety of different types of habitats that support a variety of different types of plants and materials necessary for life.  You would need food, building products for shelter, material for clothing, and water at least.  At Tuzigoot, all of these things are highly concentrated in a relatively small area. 

If you visit Tuzigoot National Monument you can see four major habitats that would have provided nearly everything the ancient Sinagua's would have needed within about 50 acres, which is about the size of a very small farm.  Tuzigoot is located in the desert grasslands of the Upper Sonoran Desert.  The desert grasslands surrounding these ruins would have provided yucca plants which provided some fiber and some food for the Native Americans.  Food would have been in the form of plants such as cacti fruits that could have been gathered or animals for hunting.  The desert grasslands are the least productive habitats though of this area.  Even more productive would have been the mesquite and acacia bosque downslope and closer to the river and wetland.  This thick brushy habitat grows where soil moisture is higher than in the grasslands and where the river has deposited deep soils.  The mesquite trees provide huge amounts of food in the form of mesquite beans every summer.  These bean pods were ground-up and made into cakes.  Mesquite wood also provided materials for building and tools.  The deep soils of the mesquite bosque are also likely where farming took place.  Of course, farming in these areas provided food mostly in the form of corn, beans and squash, but it also provided cotton to make clothing.  The mesquite bosque was also a great place for animals to hide and was therefore very good for hunting. 

Tavasci Marsh. Photo from National Parks website.

Slightly down slope from the bosque two extremely important habitats can be found.  The first is the large marsh.  The marsh is today known as the Tavasci Marsh and is dense with grassy wetland plants.  The marsh would have provided essential habitat for all kinds of animals that came to it for both water and food, both of which were scarce in the surrounding desert grasslands.  The Native Americans would have used the marsh as a hunting area as well as an area to gather food from plants.  For example, the cattails in the marsh provide huge amounts of potato-like food in their root systems.  Lastly, the perennial flowing Verde River would have provided trees for building materials, water to drink and for watering plants, and wildlife for eating.  Across all of these habitats there of course can be found an abundance of rocks that the Sinagua used for building. 

Organ Pipe Cactus National Monument

View from the visitors center trail at Organ Pipe Cactus National Monument.  In this photo jumping cholla, saguaro, and organ pipe cacti can all be seen with the Ajo mountains in the background.

Organ Pipe Cactus National Monument is located right on the boarder of Mexico as far south as you can go in Arizona. The monument is quite a ways off the beaten path and probably the most dangerous monument in the national park system. There are multiple boarder patrol checkpoints that are actually in or near the park and boarder patrols can be found all over the park. Tragically, a few years back a park ranger was killed in a boarder incident and things were quite dangerous within the park. Today however, a barrier fence has been put into place along the monuments boarder and dangerous sections of the park have been closed to visitors. The park is significantly safer today than it was several years ago. Unfortunately, Senita Basin, the only population of the columnar senita cactus is currently closed due to these issues. Fortunately, other sections of the park such as the Ajo Mountain Drive are open and offer spectacular views of the Sonoran Desert. For a desert, the monument is quite green and hope to a decent amount of vegetation. This unusually green desert is a result of this particular desert being one of the wettest deserts in the world. Organ Pipe receives about 10 inches of rain annually with significantly more falling at higher elevations. Both winter and summer rainfall seasons also contribute to the amount and diversity of vegetation here.

View along the Ajo drive in Organ Pipe Cactus National Monument

A total of 28 species of cacti can be found within the park. Several of these are at their northern most limits, and are prevented from migrating further north due increased number of days with freezing temperatures to the north. Organ pipe cacti are one of these species and can be found in abundance within the park. The amazing diversity of cacti can be found on the Ajo Mountain Drive, and it is spectacular for organ pipe viewing. Most commonly, the organ pipe is found on upper slopes facing south. The sun warms southern slopes just enough to prevent colder freezing temperatures that prevents the cacti from growing on colder northern slopes. Upper slopes also are slightly warmer due to warm air rising up these slopes. If the growing tissue of an organ pipe freezes for too long of a period of time or too many times in the winter it will kill the plant. So these slightly warmer areas give the cacti an added edge so they can become established. I also have a strong suspicion that organ pipes prefer soil types typically found on upper bajada slopes. Even with this added warmth however, conditions are not absolutely perfect. The organ pipe sill needs some help from what is called a nurse plant. Small shrubs, mesquites, ironwoods, and palo verdes all help protect young organ pipes from the intense summer heat and sun. The cooler temperatures and shady conditions also help hold the water in the soil for longer. On occasion, large rocks can even provide these added benefits of shadier, cooler, and slightly wetter conditions. Nurse plant associations can be found for several different species. The saguaro cactus has very similar nurse plant requirements. A different type of nurse plant association that can be found within the park is that of the jumping cholla and pincushion cactus. The jumping cholla is a rather large shrubby-tree like cactus that looses an abundance of spine dense joints. These joints naturally fall from the cholla and often will form a mat around the mother plant. Nothing really wants to go close to these piles of spiny cactus joints making it a perfect place for the small pincushion cactus to live.

Organ pipe cactus

White Tank Mountains Goat Camp Trail

Desert grassland with mainly tobosa grass located at the top of the White Tank Mountains west of Phoenix, Arizona.

Goat Camp Trail in the White Tank Mountains west of Phoenix is the longest trail in the park.  It can be done as a 13 mile loop along with the Mesquite Canyon and Bajada trails or a 12 mile hike from trail head to end and back.  The trail head is just past the park entrance on Black Canyon Road.  The first mile and a half of this trail is pretty easy starting at 1600 feet in elevation and hiking up a bajada.  This bajada is fairly interesting.  It has been highly disturbed by some major flood events along the dry washes that come out of the mountain canyons.  This disturbance is evident increasingly as you hike towards the mountains by the presence of large boulders laying on the surface.  Normally, these boulders would be sitting lower in the sediments of the bajada being at least partially buried in the dirt.  Large floods however coming from the canyons washed away a lot of these sediments but were not strong enough to wash away the larger and heavier rocks.  So the rocks remained in place while the finer textured sediments washed downslope.  These unburied boulders become increasingly common upslope where the flood, or floods, were more powerful.  These floods resulted in increasingly variable disturbed soil conditions higher up on the bajada and closer to the mountain.  As a result of the more variable soil conditions plant diversity also increases up slope.  Sections of undisturbed soils typically have triangle leaf bursage while the disturbed sections brittle brush.  Other species such as palo verde and jojoba also seem to like the flood disturbed soils.

After a mile and a half or so, the trail begins to head up the mountain.  This trail has an elevation gain of about 1700 feet, topping out around 3300 feet.  With the elevational gain, average annual temperature decreases several degrees and rainfall increases several inches.  At the mountain base, rainfall averages about 8 inches annually.  At the higher elevations rainfall probably averages around 14 inches annually.  There is a rain gage at the top of the White Tanks but apparently gusty winds around the peak prevent it from collecting rain properly, so it is difficult to get an exact measurement of rainfall at the peak.  Regardless, the vegetation tells us that rainfall is significantly higher and temperatures slightly lower.  In the past decade or so I have seen snowfall above 3000 feet in the White Tanks only one time and never below that level.  The lower temperatures, specifically lower freezing temperatures in winter, make conditions less ideal for cacti such as the saguaro.  Saguaros are not able to survive freezing tempertures for longer than 24 hours.  While the saguaro does grow near the peak it is quite rare in comparison to lower elevations.  This is at least partially due to the increase in the amount of time freezing temperatures occur at the higher elevations.

I think there may be another, possibly better, explanation for the decrease in cacti towards the top of the White Tanks though.  Around 3000 feet the vegetation strongly shifts towards a desert grassland dense with tobosa grass.  Tobosa increases because of the increased rainfall and because it can survive the freezing temperatures quite easily.  Dense tobosa grass is possible out competing the cacti at these higher elevations.  Another indicator of a problem for cacti at these higher elevations is the presence of charcoal.  Obviously charcoal indicates fire has been present in the area at sometime in the past and cacti in general do not survive fire very well.  Grass, such as tobosa, however, are very flammable and actually encourage fire to some extent.  Grass, unlike cacti, are very adapted to fire through.  While I have never seen or heard of a grass fire at the top of the White Tanks, the charcoal is evidence that it has happened at some time in the past.  Even if fire happens only once every few decades, that is enough to severely limit the population of cacti in the area.

A few other plants that are relatively common at the higher elevations include desert agave and crucifixion thorn.  Most of the desert agaves are pretty small and almost all appear to be clones that have grown from root sprouts of older plants.

Crucifixion thorn.

Desert Agave

December Ephemeral Drainage Flow

A dry wash the morning after a flash flood came though.

The mid-December rain is the most reliable rainfall we receive here in the Sonoran Desert.  This rainstorm is almost like clockwork.  Every December, usually around the 15th or so, a strong Pacific frontal storm system brings rainfall in from the northwest.  One-half to one inch of rain pretty much falls across the entire desert with higher totals in the mountains.  Of the past ten Decembers, only one failed to produce any rainfall and that was during one of the driest winters on record in Arizona.  This year was picture perfect with one-half to one inch of rain falling in the Sonoran Desert between December 13th and 15th.  With this rain being almost like clockwork, the flow of the normally dry washes also flow during this rain almost like clockwork.  This year was a little odd in that the rain was spread out over a three day period making flows a little weaker than normal.  Typically, dry washes require a significant amount of rain over a short period of time in order to generate enough runoff to supply a flow.  A lot of drainages did flow at least a little though. 

Of course, a lot of rain over a short period of time helps these washes to flow in the desert, but there are other factors involved also.  Geology, or geomorphology, are probably the most important factors in determining flow.  Geomorphology is simply a scientific term that describes how landforms came about and how they function.  One of the functions of geology and geomorphology in the landscape is to determine how and where water flows.  For example, shallow unbroken bedrock is going to prevent water from seeping down into the soil and therefore will result in greater amounts of runoff.  Type of soil also matters in the amount of runoff produced.  Rain seeps very slowly into clay soils so a lot of runoff can be generated.  Sandy soils however can quickly absorb a lot of rain so not much will runoff.  Number of rocks also makes a difference.  Soils with fewer rocks have more runoff than soils with more rocks.  Rocks on a soil surface slow the speed of runoff and with slow speeds of runoff the water has more time to be absorbed into the soil.  Size of the dry wash also makes a difference with smaller washes flowing more frequently than larger washes.  However, larger washes tend to run longer than small washes when they do flow.  Larger washes simply need a lot more water to flow. Depending on the combination of these factors some washes will flow a few times annually while others will only flow a few times a decade.

All of these things factors also determine what lives where along a dry wash.  Flow is normally very short in duration in a wash.  This is simply because flowing water quickly is lost as it is absorbed into the sediments of the stream bed.  Though flowing water is lost, the water is not entirely lost.  Water is stored in these sediments for long periods of time after surface flow ends.  Depending on the depth of this moisture and the depth of the sediments differing plants will occupy the area.  Typically, deep sediments with relatively frequent flows will be occupied by blue palo verde and desert willow.  Areas of fewer or shorter flows typically have yellow palo verde.  Other plants such as acacia's, ironwood, wolfberry, and mesquites can be somewhere in-between. 

Fall Leaves in a Sonoran Desert Riparian Zone

A Sonoran Desert riparian area in fall along Cottonwood Creek.

The desert is most definitely not known for spectacular fall colors.  Fall colors do however, find their place along some of the wetter desert water courses.  If perennial water sources are available, even if it is hidden below ground a short distance, the roots of large deciduous trees will find there way to it.  Sycamores, cottonwoods, and willows are all relatively common along streams and washes with perennial sources of water.  Even Arizona walnut and ash trees can be found in some of the more stable riparian zones.  These trees do not display the brilliant hues of red and orange common to eastern forests but do show off bright yellows that are in stark contrast to the dried out browns and greens of the desert.    Desert fall leaves are quite a rarity and are quite unique.  Typically, perennial water sources are considered perched water tables.  A perched water table simply is water that accumulated above the surrounding water sources, most often a result of bedrock that prevents water from penetrating deeper into the soil and out of reach of plant roots.

A recent hike I took demonstrated this concept extremely well.  The hike was along Cottonwood Creek near Lake Pleasant north west of Phoenix.  The majority of this hike is along Cottonwood Creek, which really isn't much of a creek considering water only flows in this creek a few hours every year.  The rest of the year the wash remains mostly dry, except for a few locations.  Nearly all washes in the desert are called dry washes, and for good reason: they are completely bone dry the majority of the year.  A few washes, such as Cottonwood Creek are fortunate enough to have areas that always remain wet.  Cottonwood Creek owes this moisture to its underlying geology.  First off, the creek bed lays at the base of two small bajadas between two small mountain ranges.  One bajada lays to the north of the creek bed and one to the south.  These bajadas and bedrock of the mountains are relatively steep and provide ample runoff to Cottonwood creek so it will run during periods of heavy rainfall.  Moisture is quickly lost into the deep sediments of the bajada and placed out of reach of deciduous tree roots.  In areas where bedrock are shallow though, moisture cannot penetrate deeply and remains closer to the surface within reach of plant roots.  Bedrock can also push water flowing underground towards the surface.  At these locations large deciduous trees take advantage of the shallow moisture and can in a few places form small but beautiful wooded areas.

Wildlife may not be obvious in these small wooded areas, but if you look at the ground you are sure to see evidence of animals.  Javelina and mule deer heavily utilize these small areas and their hoof prints are normally abundant.  In some area, such as along Cottonwood Creek, wild donkey's are also abundant and heavily utilize these areas.  The abundance of shade, food, water, and cooler conditions during hot dry summers gives great value to these areas for every creature.

Joshua Trees, Ice Age Sloths, Extinction, and Climate Change Today

With the end of the Ice Age, the giant Shasta ground sloth became extinct in our American Southwest deserts. This extinction happened as a result of the warming of the continent and invasion of humans into the land 13,000 years ago.  Today, the sloth is long gone, but the consequences of its extinction are still being seen to this day.  The Shasta ground sloth was intimately intertwined with every organism they ate, use, or associate with.  Of course, all organisms that inhabit this earth are intertwined in the same way with all the organisms they eat, use, and associate with both directly and indirectly.  This can be extended to show that all organisms are in one way or another connected.  If one organism is removed from an ecosystem, such as the ground sloth, every other part is affected and must adjust their life accordingly.

Unfortunately, not every organism is able to adjust to every change in an environment.  Such was the case of the Shasta ground sloth.  As the climate warmed, plants that inhabited the Southwestern deserts changed, changing the sloths food sources.  As food sources changed, the sloth could not adjust and as a result became extinct.  As a result, the plants and animals affected both directly and indirectly by the sloth had to adjust to "life after the sloth".  For example, the Joshua Tree was a major part of the sloths diet.  At first it may seem that extinction of something that is eating you might be a good thing.  At first, I could guess, the Joshua tree might have benefited greatly by the absence of a giant animal consuming it.  Long term however, the Joshua tree suffered greatly and continues to suffer to this day.  As the sloth ate the Joshua tree, of course this injured the plant.  However, as the sloth ate, it also consumed the Joshua tree seed which would pass all the way through the sloths digestive tract without being damaged.  Once passing though the sloths digestive tract the seed would find itself in a moist pile of fertilizer, which is an extremely ideal location to find yourself if you are a desert seed in desperate need of moisture and nutrients.  

With this association of the sloth and Joshua tree, the sloth benefited with food by eating the tree.  The
Joshua tree made a trade-off though, being damaged by the sloth as it was eaten, but benefiting from the sloth into the next generation.  The sloth aided the success of the Joshua Tree by likely aiding germination and by carrying the seeds to new locations up to ten miles away.  After the extinction, and up to the present day, only desert squirrels and packrats move Joshua tree seeds today, and only at a pace of about six feed per year.  As a result, the Joshua tree cannot adjust its range anywhere near as quickly as it could before and its range has been shrinking for over 10,000 years now.  How do we know all this?  Scientists in the Southwest have examined caves where sloth dung which tells us what the sloth ate.  Ancient packrat middens also have been examined which tell us where the Joshua tree was and when over the last 10,000 plus years.

With the ability to only change their range six feet per year, the Joshua trees range will continue to shrink in coming decades.  Currently, the climate is warming far to fast for the Joshua tree to keep pace.  This does not mean however the Joshua tree will go extinct.  It will be able to survive in cooler high elevation locations.  As the range of the Joshua tree is reduced however, organisms dependent on it will have to adjust.  For example, many species of rodents are dependent on moisture from the tree during times of drought.  These organisms access water from the tree simply by chewing through the bark to access water.  With the trees gone however, there will be far less water available to support rodents.  And so we see the continued consequence of the extinction of the sloth.

Barrel Cactus Part 2

California barrel cactus, Ferocactus cylindraceus.

Barrel cacti are kind of as their names imply, barrels full of water.  The problem is, the water isn't just hanging out in the cactus like a big glass of water.  The water is stored inside of the cells that fill the interior of the cactus.  The best way to get this water is to eat the tissue, though it won't taste very good and probably will make you sick.  The thick layer of hooked spines will also deter any person or animal from easily accessing this water though.  In drought however, the barrel cacti is one of the best sources of water for desert animals there is, that is, if they can get through the spines.  Small animals like rats, chipmunks, or mice can avoid spines by burrowing underground slightly to where there are no spines and then eating up into the cactus.  I have actually found a few barrel cacti that have been entirely hollowed out by rodents, yet have there skin and spines fully intact.  Larger animals such as deer have no such luck though accessing moisture from a standing barrel cactus though.  The spines become just too big of a deterrent.

Red spines of the barrel cactus show up after being wet by rain.

Fortunately, for larger mammals the barrel cactus has a fatal flaw.  As a barrel cactus grows it generally leans towards the southwest, which is the direction from which the most intense sun comes from.  Nearly all barrels lean to the southwest, just as a compass always points north, thus the common name compass barrel.   It might seem that leaning in the direction of the brightest sunlight might mean the cactus is trying to gather as much sunlight as possible.  This is however the exact opposite of what it is doing.  With the top of the cactus pointing directly at the most intense sun, spines at the top actually shade out much of this light and all sides of the cactus actually avoid this direct sunlight.  The sides however gather the most sunlight from the sides, as the sun comes up or goes down, when the sun rays are less intense and therefore less damaging to the cactus.  Pointing tops towards the most intense sunlight is therefore actually a protection mechanism, rather than a gathering mechanism, against intense sunlight.

A barrel cactus that fell over due to leaning towards the southwest.  Even though this cactus fell over, it continues to grow.

Leaning is an important adaptive strategy of the cactus, but is this strength also lays a huge weakness.  As the barrel cacti grows and leans it becomes very off balance.  Older, large cacti will often simply fall over.  Oddly, even when the cactus falls over it will continue to live and grow as it lives laying on the ground.  Once the barrel cactus falls over, the underside of the cactus is exposed which is unprotected by spines.  Large mammals will often start eating the barrel from this unprotected portion during drought.  

Flower of the California barrel cactus Ferocactus cylindraceus.

How To Identify a Cactus

The columnar saguaro cactus.  Note the huge column like shape and ribs lined with spines traversing from the bottom to top.

Cacti are one of the most diverse and interesting plant families in the plant kingdom.  Cacti are native only to North and South America but are prized worldwide by plant enthusiasts.  I once worked with a PH.D who was from England but came to the United States specifically to work with cacti.  While you can go to just about any botanical garden in the world to observe cacti, the Southwestern United States and Mexico are probably the best places to observe cacti in the wild (in North America at least).  Within the United States, cacti can be found in the wild in just about every state.  Where I grew-up in Iowa, every once in awhile I would come across plains prickly pears growing in a dry prairie.  Now, living in the Southwest I come across cacti every single day.  The Sonoran Desert is loaded with all kinds of different cacti ranging from the 50 foot Saguaro cactus to the six inch tall pincushion.  Cacti are really not that difficult to identify, at least to the genus or "group" level.  Just about anyone can learn the major groups of cacti simply by looking at three major traits; the shape, ribs, and spines.

Barrel cacti in foreground.  Named after their barrel like shape.  Barrel cacti also have ribs lined with spines.

Shape is possibly the easiest and best way to categorize a cactus.  The most common cactus group is the prickly pears.  These cacti have stems that are sectioned into flat, pear or pancake shaped pads.  The overall prickly pear plant is joined together by these pads typically forming a shrub shape.  Cholla cacti are similar in that the plant is made up of sections, but instead of these sections being flat and pear shaped, they are cylindrical, and the overall plant also is shrub shaped.  Barrel cacti are barrel shaped.  Columnar cacti such as saguaros form tall columns. Tiny pincushion cacti are small and often shaped like an actual pincushion.  Hedgehog cacti are sort of like small columnar cacti that only grow a few feet tall at most, with the small stems bunching together.

A cylindrical cholla cactus section.

Ribs are the next important way of identifying a cactus.  Saguaros and other columnar cacti have long ribs or pilleates that stretch from the bottom of the cactus to the top.  Hedgehogs and barrels also have ribs.  Pincushions, prickly pears, and chollas do not have ribs. 

Prickly pear cactus with flat pear shaped sections.

Lastly spines.  Spines don't always help us distinguish between different groups of cacti but are extremely useful in determining the actual species of cacti.  A few spines like the tiny hairlike glochid are only found on prickly pears.  Glochids are the tiny spines that get stuck in your skin and have to be taken out with a tweezers.  Pincushions typically have tons of white spins which helps give them a "pincushion" like appearance.  Spine color, number, and shape are essential in learning to distinguish specific species of cacti.

Hedgehog cactus

Pincushion cactus.

Fall Bird Migrations: Where do all the birds go?

From grade school we are taught that birds fly south for the winter to where it is warmer and north for the summer to where it is cooler.  Of course this is true but is obviously over simplified.  Birds don't just go south or north, they actually go to specific locations.  Scientists and bird watchers have tracked the migratory movement of birds in an effort to answer the question: where do birds actually go?  By tagging birds at their breeding grounds and then tracking the tagged birds as they migrate scientists were able to answer the question.  Watch the following video to see where birds go after they migrate south from Alaska for the winter.  It is amazing how Alaska has such a huge concentration of breeding birds in the summer that populate so much of the world as they migrate south.  This leaves us with very good reason to protect Alaska bird breeding grounds in order to protect many bird populations throughout the world.  It is also interesting that not all birds actually migrated south in the study, some actually migrated north from Alaska.  I suppose they migrated north across the North Pole so they could migrate south on the other side of the world. 

The colored dots in the video represent locations where birds originating in Alaska were found as the migrated.

Creosote Bush

The Creosote Bush (Larrea Tridentata) is a relentless desert plant growing in the deserts in both North and South America.  In North America it is found in the hot Mojave, Sonoran, and Chihuahuan Deserts where it is possibly out numbers all other perennial plants.  The only North American desert where it is not found is the Great Basin, simply because it is too cold.  The Creosote is so relentless it can occupy the poorest soils in flat basin areas between the mountain ranges of these deserts.  Driving through the flat lands of these deserts you can drive mile after mile past near mono-cultures of this plant.  Its roots are so effective at extracting moisture from the soil that it is often very difficult for other plants to become established near Creosote.  Creosote roots can extract water from soil that is seemingly dry, surviving up to two years without rainfall.  They can also extract nearly all water from the soil, thus preventing any from ever reaching the water table. Creosotes are so good at all this that they can in-fact survive for over 11,000 years!

Bringing back the Wooly Mammoth

The last known population of Wooly Mammoths went extinct about 4,000 years ago.  The last population existed on Wrangel Island off the coast of Siberia.  Wooly Mammoths were extremely elephant like in both size and shape.  The big differences though between the two lies in their adaptation to climate.  Modern day elephants are adapted to the tropics.  Wooly Mammoths had fur similar to yaks and a thick layer of fat to help hold in heat.  Mammoths also had smaller ears which helped them hold heat in better.  These adaptations are of course why the mammoth lived in the icy tundra and thrived during the ice age.  As the world warmed, bringing the ice age to an end, suitable habitat and areas of food shrunk significantly for the mammoth.  The warming climate along with increased human hunting pressure at the end of the ice age led to the extinction of this huge mammal. 

Even though the mammoth has been extinct for 4,000 years now, scientists are working to clone one back to life again.  The process is simple in theory.  Scientists must first find a living mammoth cell and extract the nucleus.  The nucleus of a modern day elephant embryo must be removed and replaced with the mammoth nucleus.  Then, this embryo must be impregnated into an elephant mother.  If the embryo survives, a baby mammoth will be born to the mother elephant.  All of these processes are well known and have been successfully carried out, but never for wooly mammoths.  In practice however, this process appears nearly impossible.  The first step of finding living mammoth cells is what makes this so difficult.  But once living cells are found, the rest of the process would be relatively simple.

The preference of mammoths for icy cold habitats is what makes this entire process possible in theory.  As mammoths died in the frozen tundra, there is the very likely possibility their bodies would have frozen very quickly, thus preserving living cells in a frozen state.  Indeed, many frozen specimens of ancient mammoths have been found.  Not a single living cell in these frozen specimens has been found though and the probability of a cell surviving thousands of years even in a frozen state isn't very high.  It is still possible though.  And just the fact that it is possible makes at least a few people want to try.  Just think how awesome it would be to go visit a living wooly mammoth at the zoo.  Or see a wooly mammoth performance when the circus comes to town.  OK, that's sort of silly but just think...

Post Summer 2012 Sonoran Desert Monsoon Season Photos

The high humidity and rain from monsoon season seems to be gone from the Sonoran Desert this year.  There is always a chance that it can come back, but as far as monsoon seasons go, this year was a good one.  The vast majority of the Sonoran Desert received more than the normal amount of rain and cooler than normal temperatures over a two and a half month period.  This had a great effect on greening the desert, wildflower blooms, an explosion in bugs, and increased wildlife activity and reproductive success.  Below I have shared a number of photos I took on a recent hiking trip the day after the last rainstorm we received. 

A leafed out ocotillo. 

Not sure what this catapillar is but I found thousands of these along the trail.

Butterflies are quite abundant now as a result of the rains.

Viguiera

A green desert grassland of Tobosa located near the top of the White Tank Mountains.

Trailing four o'clock

Monsoon Season: Breaking the Desert Drought

About two months ago I posted on how a 4th of July storm broke a severe drought we had been experiencing throughout all of 2012 (Monsoon Season and the Drought).  As always with desert rain patterns though, you never know if the rain is going to keep coming or if a single rainfall event was just a fluke.  Fortunately, we have had a pretty good monsoon season that began with an earlier than normal large rainfall event and still seems to be going.  As of now, most of the desert surrounding Phoenix has received about three inches of rain in the past two months, which is slightly above average.  As a result of the rain and additional humidity, temperatures have actually been cooler than normal.  We of course have had our 110 degree plus days, but nothing like what we have had the past several years. 

The effects of rainfall on the desert over the past two months has been quite dramatic.  The drought had been so severe that mesquites and acacias had gone leafless which is fairly rare.  Ironwoods also were loosing many leaves and yellowing, which is extremely rare.  Other plants such as wolfberry and palo verdes were also leafless.  Creosotes were loosing leaves quickly and leaves that did remain were often brown or yellowish.  Nearly all triangle leaf bursage looked as if it were completely dead and often brittle bush was just a bush of white crispy sticks.  As you looked out across the desert in late June it appeared to be a crispy brown landscape without much life.  The rain however changed all this very quickly.  Within days of the first rain, new bright green leaves began to sprout.  The sustained rain allowed for these leaves to keep growing and for new stems to begin growing also.  Creosotes show this dramatic change quite well.  Creosotes still retain some of the old more brownish leaves from the drought period.  Directly above these brown leaves though bright green leaves are growing like crazy.  Ironwoods, palo verdes, wolfberries, mesquites, and acacias are also all full of leaves.  One thing I love about the desert after rain is all the different shades of green that color the landscape.  Each one of these plants has a slightly different shade, from the dark thick green of the ironwood, to the yellowish light green of the palo verde.  There also has been enough rain for the wolfberries and creosotes to flower.  Many wolfberries are in-fact loaded with fruit right now as a result of the rain.

All of this has had very positive effects on the wildlife.  I have noticed good populations of gambles quail as well as some healthy rabbit populations.  I am also sure many of the song birds are benefiting by the increase in berries and bugs.  The additional water and grass growth should also be having a positive effect on mule deer, hopefully increasing fawn survival.

So for now, the drought has been broken and with continued rainfall we can hopefully keep from returning back to drought conditions.  As of now, the National Weather Service is predicting the return of El Nino this fall and winter, which often means more rainfall.  A lot of weather scientists hold La Nina responsible for the drought in the Southwest over the last few years. 

Life of a Maple Part 5: Maple Incline and Decline

Healthy sugar maple forest.

It is very likely that prior to European settlement that deciduous forests of eastern North America were actually more disturbed than they are today.  This presettlement disturbance however was much different from the disturbance we see in our forests today.  Today, we see grazing, logging, invasive species, and widespread agriculture as the major forms of disturbance.  During presettlement days fire was the most common type of disturbance of the forest.  Just like the modern disturbances, it is very likely that fire was also human caused in a vast majority of cases.  Given the wet nature of eastern deciduous forests, it is extremely unlikely that fire could have been anything other than human caused.  While today's disturbances are typically an after though to land use, Native Americans purposely used fire to manipulate the landscape, increasing its productivity, and health. 

Fire however, strongly works against the maple tree.  Remembering back to previous installments of this series on maple trees, you might remember that maples prefer very stable, undisturbed habitats.  Anytime fire comes around one of these habitats where maples have become established, the maples are killed off.  As a result, prior to European settlement of the eastern deciduous forest oaks, a fire adapted species were far more abundant, and maples, a fire intolerant species were far less abundant.  By some estimates in some locations there may be up to three times more maples today than there was in the 1800's.  The increase of maples over the last century is a result of fire suppression by European settlers.  It was only on the best soils, in the most ideal habitats where fire didn't touch that maples were found in the 1800's and prior. 

Sugar Maples in fall.

As fire was suppressed and forests began to stabilize, maples began to expand there range.  Maples increased, invaded, and replaced forests that historically had been filled with oaks.  Oak forests typically are far drier and have poorer soil than ideal maple forests.  Oak forests were naturally more prone to fire and therefore easily survived.  But without fire maples moved in. 

Maples moving into areas of less than ideal soil wasn't the best thing for the forest.  Being maples are extremely picky about their environment, living in these less than ideal soils made them especially sensitive to drought.  Oaks are adapted to drought but maples are not.  Maples ideally overcome drought simply by living in the best soils in the forest.  But in less than ideal soils, the maples were damaged during drought.  The damage did not end with drought though.  Drought damage made the tree more susceptible to other problems such as fungal infections and insect damage which often end up killing the tree.  So the incline of maples was a direct result of fire suppression allowing maples to move into marginal habitats.  Maple decline is a result of maples living in these marginal habitats.

Forest where many of the maple trees are dying due to "maple decline".

Life of a Maple Part 4: Maple Syrup

If the Sugar Maple tree is famous for anything, it is famous for maple syrup.  Early each spring as the snow melts, maple syrup farms spring to life from the Midwest U.S., Northeast U.S., and Southeast Canada.  I personally have payed a few visits to these farms and they are always quite an interesting experience.  The weather is typically beautiful with temperatures between 30 and 50 degrees.  This is at least beautiful compared to the previous winter months.  Snow is typically on the ground but melting, which is producing the next most memorable thing about most maple syrup farms: mud.  The farms I've visited are always unbelievably muddy.  They are so muddy in-fact that horses are often used to gather sap.  Horses are used rather than tractors or other vehicles simply because they don't get stuck in the mud! 

The story of how maple syrup is made begins with the previous late summer.  Late in the summer, the maple tree stops growing and instead stores energy in the form of starch.  This starch is stored in the trees sapwood through the winter.  Come spring when sapwood temperatures reach about 40 degrees the starch is converted to sugar by an enzyme and moves out of the wood and into the tree sap.  Rising temperatures, particularly in the morning as the sun comes up, cause the sap to rise through vessels.  The sap rises towards the trees twigs and branches where the sugar will help the tree to begin flowering and budding. 

A large maple tree with two taps and buckets for collecting sap.

As the sap rises, if a tap is in place, some of the sap will drip out of the tree.  This sap generally contains about 2-3 percent sugar and is collected in buckets hanging from the tap.  One Sugar Maple tap can produce 5 to 15 gallons of sap.  Once the sap is gathered from multiple trees it is boiled down to evaporate off the water and concentrate the sugars to form maple syrup.  Typically 40 gallons of sap will produce about 1 gallon of maple syrup.  While sugar maples are the most common tree for producing syrup, red maples, black maples, silver maples, and even boxelder trees (also in the maple family) all can produce syrup. 

Maple syrup was first discovered by and utilized by Native Americans.  Europeans quickly picked-up on the practice and refined it to the practice we see today. 

Earthworm Invasion

Northern Maple forest without earthworms.

As odd as it might sound, earthworms are not native to the northern United States and Canada.  Why? Well, as glaciers receded from the northern portion of North America 11,000 years ago, they left behind a bitterly cold and extremely muddy waste land.  These glaciers reached from the north to their southern the extent of present day norther Iowa, Illinois, and Indiana.  Along this southern extent of the glacial line and northward there have been no earthworms until recently.  Worms simply couldn't survive the frigidly cold temperatures and frozen tundra when glaciers were present in these areas.  Further south however, where glaciers never reached, earthworms have been around for a long time. 

Within recent decades however, earthworms began showing-up in these formerly glaciated soils of the north.  This might not seem that weird until you realize that earth worms travel an average of 5 or 6 yards a year.  Over 11,000 years that equals only about 40 miles, which is a ridiculously slow rate that wouldn't have even allowed them to travel across an entire state.  Even if you double or triple that distance it doesn't even come close to the distance the worms would need to travel to show up in these northern forests.  So how did they move thousands of miles in just a few decades?  The only explanation is that humans carried them.  Fishermen and gardeners are especially notorious for carrying earthworms long distances.  As a result, worms were accidentally introduced to new locations hundreds of miles away from the nearest native worms. 

Northern Maple forest with earthworms.

Most people might think this is a good thing.  Worms are very good for garden soil after all.  The reality is though, worms are not very good for northern forest soils.  Worms are extremely efficient at what they do, which is break down organic materials such as dead leaves.  They do this extremely rapidly, moving nutrients from dead organic materials into the soil quickly.  As a result, plants cannot absorb the nutrients as fast as need and much is lost when water washes it out of the soil.  The burrowing action of worms also functions to compact forest soils, making it more difficult for plants to survive.  While some plants are well adapted to earthworms crawling around through their roots, other plants are extremely sensitive.  Sugar Maples, one of the dominant plants in these northern forests, is extremely sensitive to earthworms. Establishment of maple seedlings where earthworms are present becomes very difficult.  Northern forests with earthworms have far fewer plants than forests without earthworms.  Simply by changing soil and forest floor structure, the earthworm has a huge effect on the overall habitat. 

Fortunately, earthworms have not taken over every single forest in these northern areas.  Also fortunate is the fact that worms only travel about 6 yards a year.  This means, if people quit transporting worms to new areas in the north, populations of worms aren't going to expand much. 

Great Lakes Worm Watch

Life of a Maple Part 3: The Maple Tree and Sunlight

When it comes to soil, Sugar Maples are pretty picky.  When it comes to sunlight however, maples aren't picky at all.  Other trees, such as oaks, prefer to have as much sunlight as possible through out their entire lifespan.  Maples however can do quite well with very low levels of light early on in life.  This is a very fortunate adaptation being the most ideal soils for maples are typically going to be located in the shade of large trees.  Lots of, but not complete, shade aids the germination and early sprouts of maples.  However, maple seedlings will often have stunted growth in very low light situations.  Small seedlings and saplings are capable of surviving many years in the shade of larger trees.  Other sun loving trees such as oaks simply would die due to lack of sunlight.  These small maple trees simply wait until the larger tree dies and is removed by ice storms, wind, or disease.  The wait for an older maple to die can be a long one though being they are capable of living 500 years. 

Once these over-story trees are out of the way, smaller trees that had waited patiently in the shade for years suddenly make a bolt for the sky until becoming a dominant tree in the forest canopy.  This cycle can then repeat itself many times over with younger maples replacing older maples.  This self sustaining process of the Sugar Maple forest will continue unless significant disturbance such as fire or major drought take place.  If disturbance does happen, plants that require more light, such as grasslands or oak forests, will replace the maple trees.  Given time though, and lack of disturbance, after a hundred or more years the maples will replace sun loving trees such as oaks and will again dominate the forest.  This process of one plant community replacing another plant community is called succession.  Maple forests typically are the last stage in succession, which is called the climax plant community. 

Slow growth, long life, and tolerance for shade are what make the maple a climax forest species.  Faster growing trees with shorter lives typically require lots of light and occupy areas after a major disturbance such as fire.  The slow growing maple tolerates the shade and out live these faster short lived species.   Shade tolerance is one of the most important adaptations maples have to being a late successional climax tree.  There are a number of more minor adaptations that aid in the overall shade tolerance of maple.  First off, maples form large thin leaves that gather light very well.  Leaves lack pubescence, or hairiness, which would block light.  These leaves also grow to orient themselves in a manner that helps them gather the most sun light.  Pigments inside of the leaves also are especially adapted to gathering far red light which is abundant in shady environments.  Lastly, maples produce a huge number of leaves in their canopies in order to catch as much light as possible.  Such a great density of leaves are produced by Sugar Maples that the top 10 percent of leaves gather 60 percent of the total sunlight. 

Life of a Maple Part 2: Soil and Roots

A moist maple forest with rich soil.

A Sugar Maple seed doesn't get to choose where and what type of soil it gets to land on.  Typically, where the seed lands is a result of wind direction and strength at the time it falls.  Where ever the seed germinates and begins to grow is where it will spend the rest of its life.  The unfortunate majority will die long before reaching a foot in height.  Often, predators such as deer and squirrels, find the young seedling far to appetizing to pass it by.  Many seedlings will also unfortunately find themselves in soil that is less than ideal.  As far as deciduous forest trees go, the Sugar Maple is quite picky, much like Goldilocks.  The soil can't be too wet or the roots will suffocate as they drown in the water soaked soil.   Neither can the soil be too dry or the roots will dehydrate.  Nor can the soil have too much clay or too much sand.  They soil has to be just right. Even when the soil has just the right texture (meaning the right amounts of clay and sand) and the right amount of water, the soil might not be good enough.  The soil also has to have high levels of nutrients.  Soils with low nitrogen or calcium may prevent healthy growth and longevity of maples.  Even then, maples seem to prefer very deep soils deposited by glaciers over any other type of soil.  The maple is very picky...

The reason the maple is so very picky is because of its roots.  Just like branches of deciduous trees shed their leaves annually, larger roots also shed tiny roots annually and with dry weather.  Maples produce an abundance of these fine roots at very shallow depths, right where the nutrients are highest.  It has been estimated that 60 percent of annual productivity of maples is actually contained within these roots.  This is quite amazing when you consider the great density of leaves maple trees produce annually.  The fact that so much of the tree is in-fact these very sensitive tiny roots makes the whole tree very sensitive to whatever happens on or in the most shallow layers of soil.  Trampling by foot traffic, vehicles, or cattle can damage these roots as well as cause the soil to dry out, killing the roots and potentially killing the whole tree.  If fire burns across the ground, the surface soil will be significantly dried out also potentially killing the roots.  The heat of the fire can also kill the roots very easily.  Pollution, such as acid rain, can change the chemistry of the soil, also killing fine roots and damaging the overall tree.

Fortunately, the maple tree does have some adaptations that help make it at least a little less sensitive to changes in the surface soil.  For one, the overall root system of maples is capable of hydraulically redistributing moisture from deep within the soil to more shallow soils.  The thick shade of maples also helps to prevent evaporation of moisture from the soil.  Also, the fact that maples transpire, or "exhale", large amounts of water vapor while photosynthesizing helps cool the environment and increase humidity.  Fallen leaves are very absorbent and are a very effective mulch that help hold moisture in the soil.  All of this helps moisture to be retained within the soil where it can be utilized by the tree and prevents moisture from evaporating into the environment.  All around, the maple works to keep its environment as moist as possible.

Sugar Maple tree in fall.

Life of a Maple Tree: Part 1 Seed to Sprout

I'll be starting a new series on the blog about the life cycle of the maple tree, specifically the sugar maple.  This is sort of a follow-up to the series on oaks and hickory trees.  Maples are sort of a logical follow-up to the oak-hickory forest being they are later successional species to the oaks and hickories.

Sugar Maple leave

The life of a maple tree begins with the charismatic "whirlybird" seed which fall like helicopters from the mother maple.  Often masses of these seeds will blow off of mature maples and twirl to the ground on windy fall days.  Technically, these "whirlybird" seeds are called samara, which are simple seeds with a flattened papery wing-like portion.  The whirlybird nature of these seeds helps the wind to carry them a long to new locations, often hundreds of yards away.  Then hopefully, the seed will be able to sprout and develop into a new tree.

Once on the ground, the maple seed prefers moist and undisturbed locations, such as in a maple forest or an oak-hickory forest that has not been disturbed by fire.  This is because the maple seed is not well protected.  While the wing portion of the samara is good for transporting the seed with the wind, it doesn't do much else.  The seed requires a moist area, and is easily killed by damage from trampling animals, dehydration, or heat from fire.  Once on the ground though the seed becomes actively searched out for by numerous small animals such as rabbits, squirrels, and mice.  Predation really isn't too much of a problem though, the maple tree typically produces so many seeds that it overwhelms predators.  Predators have plenty to go around and there are still plenty of seeds left over to germinate and sprout. 

Sugar Maple samara seeds.

If not found by seed predators on the ground, the seed than requires the cold of winter in order for it to germinate.  Without cold, the seed will not germinate.  Many species of trees, such as oaks, have a difficult time establishing themselves in soil covered with a thick layer of leaves.  Oaks therefore require the ground to be disturbed by fire so their acorns can sprout and grow.  The maple however, does not have this problem and prefers undisturbed forest ground cover, often thickly covered with dead leaves.  Once germinated, the root easily penetrates through thick moist layers of leaves from the previous year. 

Another oddity of the maple is that it prefers shade.  The maple does not like competition with other small plants such as grasses and shrubs.  It does to quite well though when growing under the canopy of mature trees that shade-out other plants.  In-fact, maple seeds germinate and grow best where there is 50 percent or more shade.  In these areas tiny maple seeds can sprout by the thousands, often leading to a carpet of young maple trees.  The problem though is, once germinated there is so little light in these areas the trees will not grow very large and growth will be stunted.  Again though, the maple is adapted to this situation, being able to survive, but not grow, in minimal light retirements for many years.  The tiny stunted tree simply waits until older larger trees casting shade on the forest floor die.  Once these larger trees die, the tiny maple tree grows rapidly in the new sunlight. 

During the potentially long period of time that a maple seedling remains a small stunted tree it is important that the forest remains undisturbed.  Fire and drought both will easily kill these seedlings.  Predators, such as deer, also heavily browse on "carpets" of small maple seedlings.  Usually though, plenty of seedlings survive predation with drought and fire being the big killers. 

grounded design by Thomas Rainer: Why I Don't Believe in Low Maintenance Landscapes

I love this blog post I came across.  I personally believe landscapes are meant to be productive elements of our lives, and this requires maintenance.   This maintenance, and the products of the landscape, benefit us in innumerable ways.  From: Grounded Design

grounded design by Thomas Rainer: Why I Don't Believe in Low Maintenance Landscapes: The American obsession with low maintenance landscapes is a problem. Here’s why. There are several phrases I’ve learned to dread from clients. “I want to swim by Memorial Day,” is always a heart-stopper, particularly when you were hired in March to design a swimming pool and garden. “I want this garden to look perfect for my daughter’s wedding,” is perhaps the most dreaded phrase of all. If you ever hear that one, run far away. But the phrase that makes me cringe the most is a phrase I hear all the time: “I want this to be low maintenance.”

A low maintenance landscape is a rather innocuous request. It is also, of course, an absolutely sensible one. After all, who has the time or resources to pour endless hours into a landscape? Plus, traditional maintenance often focuses on chemical inputs and gas-powered machinery, all of which are bad for the environment. Perhaps low maintenance landscapes are both good for people and the environment, right?

Yes and no. “Low maintenance” is not just an idea, it is an ideology. It is the promise of more for less. As Americans, we still believe cheap, fertile land is our manifest destiny. We deserve bounty without labor, satisfaction without commitment.

The ideology of low maintenance has received new fervor from advocates of sustainable landscapes. In eco-speak, maintenance is a dirty word. Maintenance means gas-powered machinery, irrigation systems, and petro-chemicals. A low maintenance landscape is natural.

The promise of low maintenance landscapes is an empty one. The very idea that you can do less and have more is a mythology. Landscapes constantly change and require input—lots of it—to look the way we want them to. Lines blur, plants suffer without water, and weeds move in. Nothing stays the same. Even naturalistic and native landscapes require heavy interventions to look natural. In nature, thousands of years of natural selection create relatively stable environments. In our yards, our active engagement is the sine qua non of a garden. The less we do, the worse our yards look. 

Read the rest here:  Why I Don't Believe in Low Maintenance Landscapes