The Pine Forests of Mexico's Trans-volcanic Belt

My first non-aerial experience of the higher elevations of central Mexico was one of surprise.  I did not really know what to expect from the peaks that lay between Mexico City and Cuernavaca, but I figured that even relatively high elevations south of the Tropic of Cancer would be nothing like those further north.  It turns out that the treeline in Central Mexico generally falls at 13,300 to 13,700 feet, which when compared to a much further north Colorado's treeline of 11,500 feet is not really that high.  Mexico City itself rests in a valley surrounded by volcanic ranges that are snow-capped year round, and boasts a really pleasant climate that stays fairly consistent due to its location both in the tropics and at a height of around 7,000-8,000 feet.

The cultivated plant life is not that different from what usually gets planted in the more inland parts of southern California, with Italian Cypresses, Canary Island Date Palms, and even various manzanitas being popular landscaping choices.  Outside of the developed city, however, in some of the last remaining wild land, are expanses of the southernmost sputterings of the Chihuahuan desert which stretches far to the north in Texas and New Mexico, mixed together with remnants of once-extensive wetlands lined with the lovely Montezuma Baldcypress (Taxodium Mucronatum), some of the hardier tropical species that creep in among the lower passes into the central valley, and... pines!  Many pines!  Mexico boasts more native species of pines than any other country in the world, including isolated populations of species that occur far away, like the Eastern White Pine.  Some botanists think that Mexico is the genetic center of pine diversity and the original habitat of the very first pines.

So what does a Mexican pine forest look like?  I suppose it can look like many different pine forests that we have further north, but I was only able to catch some time in the forests of Hartweg's Pine (Pinus Hartwegii), which I encountered about 10,500 feet up in the mountains off of Mexican highway 95.

Source: http://www.geographylists.com/nevado_de_toluca.html, taken by Brandt Maxwell, who has a site that is really worth checking out if you want to see more of this part of Mexico (and many others).  This was actually taken a bit west in the mountains closer to Toluca, but the forest I explored was nearly identical.

As you can see, this forest is a bit more of a closed-canopy savanna, but there are areas that are thick forests of both pines and firs that can put your average stretch of Oregon to shame, with so many different species that identification proved something of a chore.  In addition to this are other shrubs, cacti, and yuccas.  I had initially assumed that heavy grazing was responsible for the meadows, but I saw little in the way of grazing herds anywhere, and did see plenty of healthy saplings in the area.  Fire apparently plays a significant role around here, and it has not been suppressed to the same degree that it is in the United States, apparently because people knew about the benefit it could play for potential grazing.  Regardless of the motives for the slightly open canopy, the same dried up yellow grass we see here continues on past the treeline, which this far south does not always indicate the presence of glaciers and snowfields, but rather that trees cannot necessarily cope with the intensity of solar radiation at this altitude within the tropics.  Then again, I am not really sure, because these forests, like much of Mexico, remain a botanical land of mystery and discovery, at least for me.