Both civilisations decamped to the valleys when the climate deteriorated. In the case of the abandonment of the MWP farmsteads in the 1350′s we know the names of the people, what crops were growing and details of converting their barns to take different crops as the cultivation level dropped from around 1500 feet to around 1050 feet. I shall be there tomorrow at Hound Tor (mentioned in Sherlock Holmes adventure Hound of the Baskervilles)where the building walls and the field systems are still clear to see.

Presumably you are after observations of tree line levels rather than crop height levels to pursue your research?

Tony B

Back on the topic of this thread, I was able to download a much better map of the White Wing Mountain area. The location is between Mammoth Mountain and June Lake. This area has relatively easy access from nearby roads.

The USGS map server is at http://nmviewogc.cr.usgs.gov/viewer.htm.

The location of White Wing Mountain is N 37 43.52′ W 119 3.71′

Nearby, Dead Vlei was originally part of the greater Sossusvlei, but was cut off from the course of the Tsauchab River around 500 years ago. The trees have long since died, but have remained due to the slow rate of decomposition in the dry, salty environment. The remaining camel thorn trees stand out in stark contrast to the white floor of the pan.

link

I know that the LIA in parts of Africa was very arid, but are you sure that this climate here?

Here are several links:
http://www.pbase.com/rhoover/namibia
http://www.slrobertson.com/namibia-namib-desert.htm
http://www.travelblog.org/Photos/62088.html
http://www.rosemarycalvert.com/id49.htm

The photos are labled “Dead Vlei Tree”. Several of these have comments that the trees have been dead for between 500 to 700 years.

Everyone, thanks for the various references. There’s a micro-survey by Graunlich and Lloyd which I’ll post up in a day or two. By a tree line graphic, I’m looking for somtething like the Shiyatov graphic for Polar Urals.