In this picture we have a large Smoketree on the left and a fairly large desert Willow on the right.

The way of the Smoketree

Apr 20, 2013
By knowing a little bit about the Smoketree one can learn a lot about the desert. This tree marks out many unique environmental features in the desert.
The first thing one wants to understand about the Smoketree is that it's name refers to the way the tree looks rather than the way it burns. While this tree is relatively small and irregular shaped it can usually be seen from a very long distance, partly because it grows in the very visible main channel of the wash.
One of the most important things we must understand about the Smoketree is it's unique relationship to geology. To start with, it can only grow in the main and active channel of an alluvial fan or a Canyon. By growing in the main channel it helps to move the main channel back-and-forth across the alluvial fan. It does this by stopping rocks and boulders, thereby diverting the force of the water during a flash flood. One can often see this in the Smoketrees themselves, as they quickly die when the channel moves away from them and they no longer get water from the summer thunderstorms. It is here that you can also see do to the design of their root system and the attributes of the soil they grow in. The soft winter rains do not help them much. The Smoketree can only sprout after a summer thunderstorm in a rough gravelly soil that can grind open the seed, and then bury it deep in the ground. This must be deeper than what most seeds need to be buried. The reason for this is that this water from a flash flood can pour straight through this mixture of rock and gravel and reached down as much as 20 feet or more, where this damp, humid mixture of rock and dirt can last for perhaps 2 to 3 years. At the same time this loose gravel allows for the top foot or two to dry out relatively fast, preventing most other plants growing near it. If we look at a typical stand of Smoketrees, we will find that the largest ones are typically half way to three quarters of the way up on the alluvial fan. The reason for this is that the trees above this point get more water but the soil condition is very poor, and the trees below this point have much better soil, but they don't get as much water, because the floodwaters don't always reach all of the alluvial fan. So there is a sweet spot of sorts for these trees. Many times this sweet spot that has the largest smoke trees also has desert Willows. This zone that has both smoke trees and desert Willows often marks the place with the widest margin for life in the desert for miles around. One of the most common ways a person experiences the Smoketree is by starting at the bottom of the alluvial fan and working their way up to the foot of the mountain.
Let us take this classic desert journey to discover the ways of the Smoketree. Often times at the bottom of the alluvial fan there is no distinct main channel, however we can look up and see a line of Smoketree's. This tells us exactly where the main channel is. At the bottom of the alluvial fan the soil is different than the rest of the main channel. It is very fine and absorbent and works well with the softer winter rains. Here we have a very different plant community along the bottom of this alluvial fan. If we are driving in a vehicle we always want to steer for the largest and closest Smoketree's because they mark out the smoothest and easiest way to drive up the wash and there we will do the least amount of damage to the environment. Due to the fact that this is the flood channel it will change dramatically every four or five years. When we get to the first Smoketree we know that there's been a flash flood that made it this far down the alluvial fan in the last 50 to 100 years and we know this because that's as long as a Smoketree tends to live.
Then as we move further up the wash will come to a place where Smoketrees look a little greener or perhaps are in the bloom. This marks the place where the waters from the last flash flood ended, perhaps two or three years ago. There may be other signs of this, such as a debris line and the condition of other plants.
Now, if we are on foot, rather than driving, there are some things that will want to consider. Walking through the center of the wash is the route that most people take. There are some disadvantages to this. Typically you do not have a very good view of the surrounding area and at the same time walking in this part of the wash one tends to make a lot of noise because of the gravel. The other option is to walk on top of the bank and looked down into the wash. While this provides a better view of the wash it also allows the wildlife to see you as well. In either position a good set of binoculars can be used to great advantage.
As we move further up the wash will begin to notice that there are more jackrabbits here. One of the major reasons for this is the Smoketree. The trees provide shade and this is a crucial element in the survival of the jackrabbits. In the relatively cool shade a jack rabbit can conserve his body's moisture and survive. Jack rabbits that live beyond the smoketrees have little or no shade, so during a dry spell these jackrabbits sit in the sun and literally dry out and die.
Moving up the wash little further we enter an area that has smoke trees and desert Willow's. Here you'll find a concentration of insects and birds. While the reasons for this are many the major ones are that the Willow tree provides shade with a very different characteristic than the Smoketree, as well as food for many of the insects, and is the best place for the birds to roost for miles around.
Now as we move further up the wash we eventually move into an area beyond the Smoke trees and the Willows, into an environment that is very steep and Rocky and this of course is the end of the Smoketrees environment.