By Rebecca Shankland
What is all the commotion around the Diamond/San Ildefonso roundabout at the Bayo Canyon trailhead?
PEEC (the Pajarito Environmental Education Center) sponsored a hike with Tom Jervis on a September Saturday to find out the answer to this and other questions about forest thinning, fires, and bark beetles.
As we set off along the Bayo Canyon Trail, we got a history of New Mexico climate. Using statistics from a recent thesis and his own core samples of these ponderosas, Jervis explained the current situation. Wet and dry cycles occur throughout documented history, but we are now experiencing a drought that follows the wettest period on record. In addition, since the advent of the railroad and its encouragement of sheep grazing, the usual natural cycles of low-intensity grass and underbrush fires have been interrupted (the sheep eat the grass that fuels grass fires). Hence we see a few widely spaced ancient ponderosas with fire scars showing that they have survived numerous fires in their two-hundred-year lifetimes—but we also see that these old grandfathers are surrounded by thick dog-hair stands of trees that have flourished without the natural fire cycle.
Well, maybe not flourished—we looked at the tree rings and discovered that as the forest became crowded, the trees grew more slowly as they competed with each other for water and sun. This is the overcrowded forest situation that led to the Cerro Grande Fire and that we must now remedy by thinning the forest artificially—the so-called Fuel Mitigation Project now taking place in Los Alamos.
But just at that point we heard the sounds of the huge machines called forwarders lurching from the end of the Bayo bench to the open area by the roundabout, loaded with thinned trees. We cringed—but despite their size and power, they do little damage because they ride on giant flotation tires.
Now we looked at the area that had already been thinned and saw the results: open vistas with
scarlet gilia, lavender dotted gayfeather, purple nodding onion, rich yellow goldenrod, and red-berried currant bushes. The dog-hair forest looks barren and claustrophobic by comparison. We preferred the ponderosa meadow at 20-75 trees per acre to the stifling 2000 per acre of the unthinned woods.
As we walked on through the area being thinned, we followed the historic homestead road with deep ruts cut into the rock by old wagon wheels. The huge thinning machines were required by their contract with the county to avoid these relics of history. Of course, to do this they had to follow other paths or create new ones, but with the flotation tires and the restoration of disturbed areas, the problem should be solved in an environmentally and historically friendly way.
What about the bark beetle damage evident here? Jervis pointed out that because of 100 years of overcrowding followed by the current drought, the trees are stressed. Bark beetles are always present, but they multiply rapidly when the trees lack moisture to fight them off. Ponderosas, growing here at the limit of their range, are especially vulnerable. So the dead and dying are among those being thinned. However, strict rules in the fuel mitigation contract require that trees over 19 inches in diameter must be left. The large dead snags will benefit wildlife such as the acorn woodpeckers, who use them as granary trees to store their acorn supply.
Drought, years of mismanagement, and the bark beetle are taking their toll on our beloved forests, but they will survive. Instead of the thick stands of trees to which we’ve become accustomed, we’ll see more natural forests of scattered giants accompanied by oaks, junipers, grasses, shrubs, and wildflowers. Be patient. As the saying goes, fifty years is nothing in the life of a tree.