The Pinon Die-out in Northern New Mexico

An overview of the ecology of the pinon/juniper habitat.


Item # 99590 		'The Western Trails' Wildflower Seed Mix

each $11.95
  • Topic: Trees & Shrubs
  • Author: David Salman
  • Keywords: habitat, pinon, juniper, ecology, Trees, NM
  • Date: October 2002

© All articles are copyrighted by High Country Gardens. Republication is prohibited without Permission.

The Ecology of Pinon/Juniper Habitat

As a result of the drought conditions of the past seven years, we’re seeing many pinons dying across the northern parts of our state. To better understand what is happening, it is important to now a little about the ecology of Northern New Mexico and the place of conifers in it.

Pinon and junipers are actually invaders in our high dry grassland terrain. Before man disrupted the natural competition between trees and grasslands, low intensity lightning-caused grass fires periodically swept through pinon/juniper areas. These fires killed the smaller trees and seedlings, while renewing and revitalizing the grasslands.

The larger trees that survived the fires were widely spaced. Through the centuries the range of these conifers would ebb and flow back and forth across the terrain in response to moisture levels. Historically many areas around Santa Fe have been too dry for pinon.

Because the combination of intensive livestock grazing in the later half of the 19th and early 20th centuries, that destroyed or damaged much of the grass, and intensive fire suppression efforts, the pinon and juniper began to overtake the grasslands. An extreme example of this is on the plains and foothills around Pecos.

Because the latter half of the 20th century has also been a wetter period, the pinon, juniper and Ponderosa pine began moving more aggressively into grassland and foothill areas that were previously too dry for them to grow.

Now, with the persistent drought conditions of these past few years, we are witnessing the die-off of pinon. In some areas only the weaker trees are dying, which thins the population leaving more moisture for the stronger surviving trees. In other areas entire populations are dying as the pinon retreats from areas that have become too dry. This is happening all across northcentral and northwestern New Mexico. In general, junipers and the Ponderosa pines are more drought resistant; and though recently stressed, they have not started to die in significant numbers.

What to Do with Diseased Trees

Many trees have died as a result of bark beetle attack and the blue stain fungus carried by the beetle. Once the pinon canopy has faded to gray-green or is completely brown, the tree should be cut down to prevent the spread of bark beetles. No amount of spraying or other pesticide treatments will bring these trees back to life. The branches and wood can be buried or chipped and hauled away or cut as firewood.

When used as firewood the wood must be “solarized” to kill the beetles, their larvae and to prevent more infestation. Cover the pile of brush and logs with clear plastic and bury the edges with dirt. Leave covered for six weeks. The plastic traps the sun’s heat, creating fatal heat for the beetles.

Next spring, seed the new sunny spaces created by the removal of the dead trees with blue grama or other native grass and wildflower mixes suitable for the pinon/juniper region. Notice also the many pinon seedlings that have escaped attack are growing to replace many of the larger, dead trees.