As sort of a postscript to my previous post on the Glendora Ridge Road, I wanted to mention what's visible to our Other California explorers if they look south from the highway. There is a deep dark valley down there...and it's a forbidden valley.
When I was a young man living in the valley below the San Gabriel Mountains, I studied maps of Angeles National Forest obsessively, and I climbed nearly every named mountain peak in the vicinity (with the prominent exception of Iron Peak, aka Sheep Mountain). But there was a blank spot on the map south of Glendora Ridge Road. It was labeled "San Dimas Experimental Forest - No Entry". And that was it. No explanation. In those pre-internet days, there wasn't much I could do to find out what secret and nefarious experiments were being carried out in that valley. To me, it was sort of a national forest "Area 51". And of course, it seemed so unfair that we couldn't explore the area, with the meadows, waterfalls and creeks that must be hidden in the folds of the valley.
When I returned to the region a few weeks ago after a long absence, I found it was not nearly so hard to find out what the experimental forest was all about (the internet is kind of nice that way). It was originally established in the 1930s to study ways of increasing water yields in the lower canyons. The role of the experimental forest evolved over time to become an important baseline region to study the vegetation, soils, slopes, water, air, and fauna of the chaparral plant communities of Southern California. Most of Angeles National Forest has been developed for a variety of uses (the "multiple-use" conundrum), and there are few areas that have not been severely influenced by human activities. The canyon is truly an open-air laboratory, and although it is not open for recreational use, it isn't that difficult to arrange educational tours, or conduct original research using the lab facilities in the lower canyons (with a database of more than 70 years of measurements and observations) .
The San Dimas Experimental Forest is now part of the Pacific Southwest Research Station, which consists of more than a dozen such areas in California and Hawaii. It is also recognized as a Biosphere Reserve by UNESCO's Man and the Biosphere program. For the mysterious forbidden valley of my youthful days, that's pretty cool! But darnit, where is the UFO landing pad?
Overview of research (from 1988, 8 mb download): http://www.fs.fed.us/psw/publications/documents/psw_misc078/psw_misc078.pdf
A vision statement from the National Forest Service concerning the experimental service: http://www.fs.fed.us/psw/publications/documents/psw_gtr104/psw_gtr104.pdf
Pacific Southwest Research Station: http://www.fs.fed.us/psw/