Within this area of generally abundant vegetation, there are a number of small (10 to 30 ft diameter) patches in which the vegetation is sparse or absent.  You can see from these photos that the patch boundary is quite distinct.

There is sometimes a crust layer (shown lower right) in some of these areas that forms on the surface.  Sometimes, plants or liches grown on top of this crust.

The hypothesis tested was that soil temperatures are limiting the plant growth.

Only the very preliminary results are reported here.

The ambient air temperature was recorded as about 64 F.

The thermometer was pushed into a number of places in this preliminary reconnaissance.  If possible, the probe was pushed approximately 2" into the material being measured.

Most of the places with abundant vegetation show temperatures less than 100 F, often less than 90 F.

These sparsely vegetated areas generally showed high temperatures.  However, the pattern was highly variable.  Here a reading of 122 F is taken near a xxx individual.  At the location of the plant, the temperature could be considerably lower, perhaps in the 105 F range.