Friday, March 16, 2012

White Tank Mountains: Mesquite Canyon Trail Part 2

Barrel cacti.
The trail continues upslope until it comes to a fork in an area of the mountain that broadens and levels out.  Here you have the choice to head to the right on the Willow Canyon Trail or continue to the left on the Mesquite Canyon Trail.  For our purposes we will continue on the Mesquite Canyon Trail.  At this point the elevation has increased to about 2,400 feet and as a result temperature and precipitation also increase in this area.  Average annual temperature is about 2 degrees cooler at this elevation and precipitation about 2 inches more.  At this elevation the Sonoran Desert begins to transition into desert grasslands.  Cooler temperatures prevent cacti from establishing and increased precipitation begins favoring grasses.  In this flatter basin like area of the mountains there still are a lot of Saguaro cacti.  Something interesting I noticed was that Saguaros were smaller and had fewer arms here than Saguaros at the base of the mountain.  While this may indicate the Saguaro population grows slower here, I suspect it is because they are actually younger in age.  This means the population is much healthier and more actively reproducing at this higher elevation.
Saguaro Cacti along the Mesquite Canyon Trail.
Continuing on the trail, by the time the trail hits about 3,000 feet, close to the Ford Canyon Trail, Saguaros are extremely rare.  The Ford Canyon Trail reaches slightly over 3,000 feet, here average temperature has decreased to about 70 degrees (4 degrees cooler than the base of the mountain) and precipitation increased to about 11 inches (about 3 inches greater than the mountain base).  At this elevation there are far more grasses.  Also, if you look closely at the ground often charred sticks and stumps can be found.  Anytime there is an increase in grasses there is also an increase in the presence of fire.  Charred sticks and stumps indicate the historical presence of fire at this elevation.  It seems that charred wood increases right around 3,000 feet near and along the Ford Canyon trail.  With fire and freezing temperatures more frequent at this elevation, cacti, and especially saguaros, are much rarer.

Hiking through this higher elevation area there are two main vegetation types, areas dominated by brittle  bush and areas dominated by grass.  Brittle bush generally occupies ridge tops where the soil is extremely rocky and loose.  These areas are extremely well drained and therefore very dry.  Lower on the hill or mountain sides through soil becomes more stable and better developed.  Red coloration of this soil is an indicator of its stability and anywhere there is reddish soil there is an abundance of grasses.  Likely, water runs off higher slopes where brittle bush is present into areas where grass dominates, making grass dominated areas generally wetter.  And when I say wetter I mean that in a desert sense, where wet is still very dry.  These grasses are quite interesting, they are almost bushy and semi-woody.  Most of the year they are a drab tan color but in spring after winter rains and late summer after monsoon storms they will green up considerably.  The higher elevations of the White Tanks are blanketed with rolling hill and mountainsides of these two or three foot high grasses; quite a different sight from the desert shrubs and cacti of lower elevations.  There are three different grasses that dominate here: three-awn, tobosa, and big galleta.  Tobosa and big galleta look almost identical and are almost bush like.  Three-awn is more grassy standing more up-right.
Desert grasslands found at the upper elevations of the White Tank Mountains.
Taking the Willow Canyon Trail where it intersects with the Ford Canyon Trail, will return back to Mesquite Canyon trail.  From here it is a generally down slope hike.  With the lower elevations down slope and corresponding lower rainfall and higher annual temperatures, the desert vegetation returns. 
This concludes the Mesquite Canyon-Ford Canyon-Willow Canyon trail loop in the White Tank Mountain Park.  Currently I am 59 miles towards my goal of 150 miles of hiking this year.  I have two other nature hike posts ready to go for the near future.  I am wanting to get all my hiking in prior to the scorching heat of summer that starts in June.  I am really enjoying this hiking goal.  So far I can tell there have been huge benefits in the way I feel and the strength of my body.  When I started an eight mile hike would leave me tired and soar.  Now though, an eight mile hike is easy.  In the very near future I will be doing a 13 mile hike, hopefully my body will hold-up without problem.

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