Surprise!! Trees Grow

I am a fan of Sherlock Holmes, having read and reread all the Conan Doyle stories many times.  Conan Doyle was indisputably a very intelligent man and his stories are real lessons in the power of deductive reasoning.  However, even a learned man such as he suffers from some common misperceptions about trees as living, growing, changing things.  In the story "The Musgrave Ritual" Holmes is attempting to solve a riddle (written 200 years prior) that he thinks will lead to some sort of hidden treasure.  One of the clues in the riddle involves the shadow cast by an old elm tree.  Even though the poor tree was struck by lightning and died a few years earlier, the owner of the estate recalls that as a child he was required as part of his math lessons to calculate the height of all the trees around the house.  He tells Holmes that the tree was 64 feet tall.  With this information Holmes calculates the length of the shadow that would have been cast by the tree at a certain time if it had still been standing. From this he locates the "treasure" and solves the mystery.  Pretty clever.  

Except,  that  this would only work if trees did not grow.  Holmes (or rather Conan Doyle) was like many people and their perceptions of trees as something more akin to a statue or large lawn ornament than a living thing. We remember those big, old trees from our youth that we can go back to as adults and still see standing there like "sentinels" guarding the past. In some cases they may seem to have not changed much since we have grown too.  I recall a woman when I worked on the Prescott National Forest whose family had operated a youth camp south of Prescott for many decades.  She grew up there and when we proposed a thinning to reduce fire hazard and improve the health of the pine forest she was skeptical.  She had lived there all her life and she did not want us to change her beloved forest.  At the time she must have been in her 50's and the trees she was discussing were mostly about 70 to 90 years old.  When she was a child, say 45 years ago then, these same trees would have been only 30 to 40 years old, probably 20 to 30 feet shorter and much smaller in diameter. The forest would have been much denser in terms of numbers of trees per acre.  So, just from the natural growth of individual trees and the natural thinning from competition the forest she was in as an adult was quite a different thing than she would have experienced in her youth. 

You can get a general idea of the age of a young pine tree by counting the "whorls" of branches from bottom to top.  Each year a pine tree grows a central leader branch vertically, surrounded by a layer of horizontal branches.  One layer of horizontal branches per year.  Once trees get very old (say 30 to 50 years) the lower branches begin to die off and eventually even the dead branches drop and any remnant is covered up by wood and bark as the tree grows in thickness. Up until then you can look at the tree and do a quick count of branch layers (whorls) and see how old the tree is.  One thing that is very interesting to do is to count back from the top of the tree to estimate the height of that tree at a point of time in the past.  I first came to the Kaibab National Forest in 1975, nearly 42 years ago.  I have what I think are vivid memories of my first years here.  When I count backward as I have described, I find how much shorter the forest was when I came. In fact, though I discuss tree growth a lot in my profession, I am surprised at not only the height change but the fact that many trees I am looking at now where not even here or were very small seedlings back then.  

So what do we make of this natural change in things.  Well, for one thing, it teaches us the futility of expecting that somehow we can "preserve" nature.  Prevent change.  And that change in the natural world is a very bad thing.  I see this in the discussion of the repercussions of climate change.  I will not discuss the merits of the arguments for and against human influence being the main factor behind recent measured changes in climate.  I do, however, take exception to the idea that whatever changes have a occurred or will occur will invariably result in something bad. Maybe like that woman in Prescott we are afraid to lose what we think we had in our youth.  But we must realize that what we think we had and could keep "preserved" is an illusion.  Nature will change things. Nature has changed things.  Just look around. Take a lesson from the trees. 

Rare But Extremely Common

Rare But Extremely Common

There are plants that are extremely rare in every sense of the word.  They only grow in a few places.  Maybe you have to travel to the ends of the earth to catch sight of them.  However, every plant has its range. When you are on the edge of its range it can become very rare indeed.  Most of us live in one place at a time.  Sometimes for a very long time.  And we have a range within which we normally work and play.  If we are interested in plants or trees or birds or insects the intersection of our normal range and the ranges of all these things define what we think is common.  So when we only rarely happen on a certain plant, for example, it can become (or at least it does for me) something kind of exciting.  

In my long career with the U.S. Forest Service on the Kaibab National Forest I have ended up walking a lot of it.  Walking as the job of a forester is a passionate belief of mine and perhaps another blog post.  But, at any rate, I know much about the Williams Ranger District where I worked for 24 years.  I have been known to get excited about seeing a certain tree or shrub someplace I didn't expect or growing to a size I didn't expect.  Most of these plants are very common in the national or worldwide sense but rare enough within my home range to catch my eye such that I will note and remember their location. 

Perhaps one of my most exciting finds is of a plant that has a worldwide range and even has "common" as part of its name.  This is a shrub known as common juniper or ground juniper (Juniperus communis).  Northern Arizona is at the very southern extent of its range in North America. At this latitude it would only be expected to be found on the highest mountain peaks.  I have found it in only three places on the Williams District in all my literally thousands of miles of walking over all those years.  (One of those lone patches, on Bull Basin Mesa, was burned and destroyed in the Wildhorse Fire in 2009.) As common as this plant is worldwide I cannot tell you how exciting it was to find these isolated clumps.  One group of plants is only 3 or 4 feet across.  This clump is separated from the nearest known clump by over 20 miles distance.  I won't say it couldn't occur at a few other spots but it is very uncommon.

Here is a photo of the group of plants near Sitgreaves mountain:

 You can see that its distinctive color and growth habit really make it stand out within the pine forest.

Closeup of Foliage of Ground Juniper

These plants are surely leftover from the days of much cooler climate after the last ice age.  Truly what can be called "relict".  In time they too will be gone.  But for now they are the kind of find that can really make my day in the woods one to remember.  

Deer's Ears and Beautiful Places 

There are places I love. I am thinking of a lovely little valley of green grass and bracken fern and aspen and large old tall oaks with scattered pine. At the right time of year a plant grows there that is totally imposing. It makes me think of the jungle or the lush northwest forest. It goes by two names Monument Plant or Deer's Ears. I used to think it was two different plants and perhaps it is. It grows as tall as me or taller maybe 6 feet with whorls of big green leaves which gives it its name. It starts out looking like this:

Deer's Ears

Later in the season it puts up the huge stalk. It should have at the end of the stock a large red or blue cluster of flowers. But it doesn't. Look close at the stock and there are the flowers green in whorls at the base of the leaves. Regular whorls as you follow up the stalk and clustering toward the top.

Monument Plant

This area  I am thinking of south of Williams, AZ on the Kaibab National Forest lies at the head of a draw in the closest thing to a “cove” you will find in the southwest pine forest. The cove I refer to is a term used in the east for those moist, deep-soiled sites that grow tall beautiful hardwoods like tulip poplar and walnut. This is a different type of cove but shares the moist deep-soiled character though in a relative way compared to other sites in the southwest.

There are other similar places that sit at the base of steep hills that mostly face north topped by basalt rimrock. Bracken fern grows from the base of the rocks and pines are tall and oaks are large and grass is lush and green in spring and late summer. Sometimes these are the places that grow aspen. But everything we see is compared to everything else and these green places stand out from their surrounding dry ridges above and dominating pine forest below and all around. And when we enter there we know we are in a different place than the average. Though I love the average, plain old, pine forest of average grass and pine needles and pine trees large and small on rocky rough soil of clay and silt.

 

I love most to descend into these areas from a hot ridge of struggling pines and even cactus. To enter the shade of a massive old oak and wade through the high grass and maybe see a monument plant. But then again there is something special early in the morning or later in the afternoon when the shadows are long and the light is subdued and maybe it rained and the air is thick and almost misty and it smells like the wet summer pine forest which you must experience to know. It's then that I like to enter these coves from below and ascend to the base of the surrounding slopes on three sides of me at the head of this like the apse of a cathedral. And like the apse would be appropriate for altar and sanctuary to worship the creator. I should kneel and pray here to Him who authored this beauty to draw us to heaven like the worship and sacrifice of the altar. Drawing us up to heaven. Like the trees who point the way upward to Him. Hints of paradise. 

 

And I miss these places right now in winter but know the bare oaks and pines heavy with snow must be buried right now so that we can see the green and smell the lush and know the smell all the rest of the time. But I am lonely, longing for it.

The Death of Pinyon Pine in Northern Arizona

At the turn of the 21st century the arid southwest experienced one of the worst droughts since the historic droughts of the 1930's and 1950's with accompanying high temperatures especially in the summer of 2002.  Also accompanying the drought was panic over anthropogenic global warming that was bringing disaster to the forests and woodlands of the southwest. One such proclamation was made by numerous academics concerning rapid changes in the range of pinyon pine in northern Arizona.  Changes that could eventually lead to the extirpation of the species over much of its range since the trees would not have time to extend there range upward and northward to cooler and wetter climates that were conducive to survival. Trees were dying by the millions all across Arizona and New Mexico.  The drought had lowered natural defenses the trees had to survive or limit bark beetle infestations from the pinyon ips beetle.  It was more than a little frightening to see.  We saw it everytime we stepped outside and looked at the south facing slope of Cedar Mountain.  Instead of green crowns of pinyon and juniper the dominant color was brown. 

 Now it is 14 years later.  Is pinyon pine gone?  Has its range in this part of the world been reduced?  What actually has been the result of all this tree mortality?  
Before I try to answer these questions we have to look at what happened in light of the history of these woodlands and all the many factors that effect the survival or not of all these individual pinyon pines. In other words the results of this bug infestation cannot be boiled down to one single factor (climate change).  This simple-minded approach to explaining change in forest communities was astounding to hear.  Not least because the catastrophic pronouncements of the doom facing pinyon were coming from "experts" with PhD's in ecology, botany, and forestry.   

History and Dynamics of Pinyon-Juniper Woodlands in Northern AZ

So where to begin.  Let's go back to the 1870's and the introduction of grazing livestock to the region. Prior to the introduction of grazing the pinyon-juniper woodland was dominated by groups of large old pinyon pine and juniper.  In the Cedar Mountain area the juniper was mostly one-seed with areas on more favorable sites of alligator and Utah junipers. The majority of the area within these stands was open area occupied by grasses, shrubs, and forbs.  The species composition of grasses was likely very different than the current one which is dominated by blue grama and other hardy, grazing tolerant or increasing species.  The original mixture was no doubt taller, thicker, and well-established and maintained by frequent fire which easily killed invading trees.  
Cattle and sheep grazing had a huge effect on grass composition and abundance.  The numbers of livestock put on these lands can hardly be imagined these days.  Literally millions of head beat much of this land down to dirt and trees.  Fire became non-existent and trees began to occupy most of the space formerly occupied by grasses.  By the end of the 20th century tree density increased to levels never previously found on these sites.  
So what? Trees are good.  The more the merrier.  However, without the check on tree growth from natural fire, trees became so thick that individual tree vigor (the health of each tree) was getting worse and worse.  Warnings of impending problems were evident.  For example, clumps of bark beetle mortality were becoming more frequent in pinyon pine.  This was in spite of extremely wet conditions that were prevalent throughout most of the 1980's and 1990's. Something wasn't right.  It was obvious that should we enter a dry, hot period similar to those that occurred in the 1930's and 1950's mortality from bark beetles would be epidemic.  Between 1999 and 2003 we experience drought and heat on par with those of the 1930's.  The result was predictable and in fact had been expected by those of us familiar with the changes that had been occurring throughout the region in pinyon-juniper woodlands as well as the ponderosa pine forest.  I remember having numerous discussions at work expressing the expectation that these epidemics were imminent. 
You should notice that in this discussion above the impact of climate change was not considered.  And though the actual influence of climate change on the drought has yet to be determined, it is almost irrelevant to the discussion. Much more important was the fact that these systems were way out of there natural range of variability in terms of species composition, tree density, and fire frequency.  It was and accident waiting to happen. 

Results of the Bark Beetle Epidemic and Tree Mortality

So what was the overall effect of all this pinyon pine mortality?  Well, as in most things dealing with complex natural systems the effects are a mixed bag of positive and negative.  And we must view this reduction in overall tree density as an adjustment back towards a more sustainable condition.  A crude, somewhat haphazard adjustment, but a generally positive one in terms of sustainability.  So let's look at some of these effects.  I will categorize them as "good" or "bad" based on a somewhat subjective analysis blending effects on plant and animal diversity, watershed condition, and tree health both as individuals and as tree communities. 

Negative Effects

• Many large old trees that had existed for centuries succumbed to bark beetle attack because of their weakened condition due to competion with the many younger trees established post-grazing, as well as, the large buildup of bark beetle populations in these young trees that overwhelmed the natural defenses of the old trees. These trees had obviously survived many previous droughts but they had never entered one in such a poor state due to unnaturally high tree densities.  Densities which had never existed prior to this. 

• Due to all this dead material suddenly present on these sites the risk of a possibly catastrophic wildfire fueled by this material was increased temporarily. 

Positive Effects

• Large numbers of pine snags have provided increased habitat for snag dependent birds and other wildlife.  This is a temporary effect which is now decreasing as snags rot and fall over in great numbers (though they still provide benefits as downed logs)
• Watershed condition has improved greatly due to a huge increase in grasses, forbs, and shrubs which have much better soil holding and nutrient recycling characteristics than the previous tree-dominated landscape. 
• This same increase in ground vegetation area over treed area has been beneficial to overall wildlife habitat diversity and no doubt has improved species richness and overall species diversity. 
• Horizontal diversity of tree cover has been moved toward a more historical, pre-grazing structure that may favor the reintroduction of natural fire to these landscapes. 

Conclusion
 So now lets look again at the questions I posed concerning pinyon pine and what really happened here. 

Is pinyon pine gone?
Hardly.  Though some large old trees were lost, particularly from exposed south-facing slopes on cinder cones like Cedar Mountain, the species is certainly as abundant as ever and occurs still at higher numbers than it did historically. Most, if not all, of these trees had many established pine seedlings under them that were not effected by the beetle because of there small size.   In the following photo you can there are at least 8 seedlings that were under these two that died that have been released and are already 3 to 5 feet tall. 

Has the range of pinyon pine been reduced?  
Not in any noticeable way.  Pinyon pine remains abundant (maybe over-abundant) on the same areas it occupied before the beetle epidemic.  The panic over rapid change in suitable conditions for species growth due to climate change is not evident.  No doubt over the long term climate change (natural or man-influenced) will have an effect on the distribution of tree species in northern Arizona as it has since the last ice age.  

What actually has been the result of all this tree mortality?
The effects have been largely positive on balance.  Other than the loss of some old, large trees, this adjustment to the pinyon-juniper ecosystem brought on by the drought and resultant beetle epidemic has been beneficial to the system as a whole.  

Here is a photo of the the approximate area covered in the 2002 photos of dead trees as it appears now. 

Catastrophic and apocolyptic are not words that come to mind now when we see these landscapes.  Change in natural systems is natural. When we have forced these systems through our actions into a condition that is outside the area of historic variability, nature will eventually make adjustments.  Nature does not put a value on these as negative or positive but we have the responsibility as stewards of these lands to honestly evaluate the condition of them and manage them to improve their health.  This may mean action or no action as long as we are consciously choosing and evaluating what the future holds.  But we must understand all of the factors that are involved and consider them together.  When we go off the deep end and/or focus on one factor without considering what we are missing we run the risk of not making the correct decisions about these lands that we are responsible for.

Rattlesnake Weed

When we talk about beautiful flowers we can only express what appears so from our own limited perspective. Our eyes can see things that are only so small. We often describe those things that are small for our eyes as "diminutive". A relative term certainly. But by being so a thing falls out of those lists of objects, and here we are talking about flowers, that may or may not be beautiful but we just can't see them well enough to know.  "Its flowers are diminutive."  End of discussion. There is a plant that I have seen thousands of times as I walk the pinyon-juniper woodlands around here. I've stepped over it. I've no doubt stepped on it as well.  It grows along roadsides and in other disturbed areas throughout the woodlands and grasslands.  If you choose to one day look it up just for the heck of it you find that it is in the spurge family with the common name of rattlesnake weed.  When I first saw this name I assumed this low flat-growing plant had that name because it was close to the ground just like a rattlesnake.

The fact is though that the plant received its name because of the belief that it could be used to cure snake bite.  From what I understand the plant if ingested as a tea or just eaten acts as an emetic. This reaction was felt to have a curative benefit to the snakebite victim. I guess absent of any local emergency room with anti-venom this was at least doing something for the poor bitten person back in the old days.

Well here is a the normal view of rattlesnake weed taken as it appears to the unaided eye as you stroll through the countryside:

If those are flowers down there the certainly are diminutive.










Perhaps if we were to bend over a little to improve our view:

Well I guess they are flowers.   Still pretty small but not too noticeable.  However, if we get out our hand lense and really zoom in :

Perspective is everything. Diminutive, showy, beautiful, non-descript. How can you describe them? How should you describe them?  How do you see them?  The Grand Canyon is not far from here.  Are these flowers that should grace the Grand Canyon?  They do. How do they compare?  How do we see the small and the grand?  Should our response to this tiny blossom  be any less than the grandest canyon?  It is.  But maybe if we think on it. Ponder the reality of it. Maybe we'll see the universe in the flower as well.

Summer is here

Summer is here on Cedar Mountain. Hot and dry.  Where was spring. Do we even have spring around here.  It was only about a week ago that the morning low was 34 degrees.  Now we are in that hot spell that always precedes our summer rains of July and August.  Old-timers have told me "It has to get hot before it can rain." Actually there is some truth to this as the "heat low" that develops in the desert at this time of year is what draws the moisture in from the south to feed our summer rains.  This is when the newly sprouted plants in our garden are really tested. These tender domesticated things want to just shrivel up and blow away in the hot, dry wind. The native plants know what to do. They are still maintaining themselves on what's left of the spring moisture in the soil.  But they don't try to grow much. They are waiting.  Some like the globemallow have done a little flowering but the hot and dry have told them to wait.

Here's one that has a couple of flowers but if you look close you can see dozens of buds ready to open (or not) if and when we get the summer rains.

There's a common late summer blooming wildflower that the local rancher's call tallow-weed that sprouts in the spring if we have good spring moisture.  They will grow into June as long as the moisture holds up in the soil.  Then they stop.  Waiting for the summer rains. They can survive quite a few weeks of dry through June and into July.  If the rains come anywhere near on schedule (first half of July) they will have mostly survived and will continue to grow and bloom.  Otherwise, if the rains are late they start to die out.  The later the rains the fewer the blooming tallow-weed.  Here is how the tallow-weed look today baking in the hot June sun:

They can hang in like this for a long time once they have become established.  We have not had any moisture in about 4 weeks and as long as the summer rains come in the next 2 weeks most of these plants will make it.  But what would have happened if we had not gotten enough spring moisture to get them started?  Well back in the late 90's and early 00's we had a terrible drought.  We didn't have the right conditions for tallow-weed for many years.  But as soon as those conditions returned out popped the tallow-weed in abundance. Filling all the open spaces in the pinyon-juniper woodland with a carpet of sulphur-yellow blooms.

Our climate here is all about uncertainty.  Our native plants have adapted to it. We may not see them or not see their blooms every year but they have learned (or their genes have learned) what to do no matter what.  Our common cactus species are particularly well-adapted.  Take the pin-cushion cactus.  A common small round cactus which sets its flower buds in the spring if we get good snow that hangs around into April.  But the actual blooming doesn't occur until late June.

 Above is a pincushion I caught blooming yesterday and to the right is a prickly pear that's been blooming for a few days now.  It seems to have similar requirements as the pincushion and blooms about the same time.  Both species are adapted to long drought periods where they may not bloom at all. 





One of our local barberry species called aljerita has the same requirements for late spring snowmelt as the pincushion cactus.  The aljerita is blooming like crazy right now.  Here is recent picture:

What happens if we don't get our winter snow?  If we have a dry winter, the aljerita, which normally sheds a few leaves prior to adding new growth in the spring, will drop all of its leaves.  It looks dead. But when the rain finally comes, it resurrects itself. It has learned patience with our frustrating climate.

This is how you adapt to uncertainty.  This is how you survive in the Southwest.  You give something up one year or two years then you gain it back and then some in the good year. It's how we do it and coyotes do it and all opportunistic, adaptable species. As a last resort though, we can move. The plants are stuck and have learned to adapt to this extreme variability.  I am in awe at this.

Cedar Mountain

The focus of this blog is the tremendous diversity of this portion of the Colorado Plateau.  Grand Canyon to the north and the Mogollon Rim to the south with unsure boundaries east and west.  It's an area that gets millions of visitors every year but is only really explored by a few.  Almost everyone who comes here has one goal.  Get to the Grand Canyon.  This is a worthy goal. There is no place like Grand Canyon. I love it. But this highland area of forest, woodland, and prairie continues to astound me in what it reveals.  I have spent a lot of time out "in" it and I want to put some of those observations here. Hopefully, they will give a taste for this landscape and its beauty but mostly it's variety and what we can learn from it. On a recent walk on Cedar Mountain here are some things I encountered.

This is a banana yucca sending up a flower stock on the south slope of Cedar Mtn. The date is May 27.  A little later this year due to our cold winter and spring.  The number of yucca that bloom in a given year is related to the winter/spring moisture conditions. This year we had about average winter precip though maybe a little more in the form of snow but a somewhat dry spring.  Some yucca blooming but not a lot.

An aspen sprout emerges from a crack in these north-facing rocks on Cedar Mountain.  You would never expect to find aspen in these parts but there are two small clones that have hung on for thousands of years from when the climate was much cooler and aspen and other high mountain species were abundant.  What is called a 'relict' community.  During the severe drought of 1999 - 2002 I expected we had lost these clones.  Some of the individuals died off but in recent years they have been expanding again.

Living on the edge of things is exciting.  The rim of Grand Canyon is a perfect analogy but anywhere in this striking landscape you can find yourself on the knife's edge of change. Much like the abyss seen at the canyon's edge.  From dry, harsh to reassuring green.   Yucca to aspen.  All adapted to this erratic mix of factors. These plants are tested time and again when we go from 40" of precip a year to 11".  From 20 degrees below zero to 100 above.   It's truly astounding.