Phoenix ARCS members who traveled to Flagstaff in early October were rewarded with a crisp, sunny day in the woods and several thought-provoking presentations. The Arboretum at Flagstaff had officially closed for the season, but staff members opened especially for the ARCS group and helped NAU representatives host the visitors. 

Dr. Kris Haskins, Director of the Arboretum and former ARCS scholar, led a walking tour of the grounds, pointing out the many experimental projects underway there.  In 2011 NAU received an award of $2.5 million for four years from the NSF (plus a $1 million match) for experimental garden sites. Three different types of natural water sources are currently studied, and there are experiments testing solar panels, new designs in micro-converters and drought-resistant genotypes, all underway on the 200 acre grounds.   It is a beautiful, wooded setting, the Naval Observatory visible on a nearby mountain and the San Francisco Peaks in the distance. 

The Horticultural Center is a research greenhouse, where endangered plants are grown to find the best for relocation and restoration projects.  Tall columns filled with water are heated by solar heat during the day so that the greenhouse is warmed at night and the heating stove is stoked with wood pellets made from the small diameter wood branches cut on the grounds.  A specially designed fence keeps the forest animals away from the gardens.

Dr. Margaret Moore of the NAU School of Forestry spoke of the need to protect the Ponderosa pine forests in the Southwest, the largest in the world.  She explained that the density of trees is now three to four times greater than it once was, and this makes them vulnerable to fire and insect damage.  Scientists can identify the age of a tree as the bark coloration changes, developing an orange layer visible between ridges in the bark at 120 to 180 years of age.  These Ponderosa pines can grow to 300 to 400 years, perhaps even 500 years of age or more.

Biodiversity in the forest is healthy, allowing a mix of plant life and permitting more moisture to reach the soil.  How can this be done?  Thinning out the smaller, younger “under-story” trees that crowd the older trees and permit the spread of fire through the crowns will help.  Tree density was once 30 – 40 trees per acre; now it is 300 – 400.  Reduction of standing trees opens up the canopy, increasing available moisture and decreasing fire risk.  It also helps them resist damage from bark beetles.

Kris Haskins spoke to the group of concerns related to climate change . . . warming temperatures, decreasing arctic summer ice, rising sea levels, loss of rain, more forest fires.  All are serious issues.  She pointed out that the drought of 1996 was a record; the drought of 2002 was worse. Evidence of the persistent drought are the fungus infections that make trees more vulnerable to bark beetles. Aspen stands are declining as are the Pinyons and the Junipers.  In some areas, the Pinyons are almost gone, and it is predicted that they’ll be lost by 2090.

What can we do?  Reduce greenhouse gas emissions?  Provide opportunity for adaptation? We could put them into an artificial world (greenhouses) but then, are they forever in captivity? And it is not possible to collect all genetic varieties; some would be left out.

Dr. Haskins explained that managed relocation has been attempted, moving plants across state boundaries to find a place where they might better survive.  Can we identify drought-resistant genotypes?  Should we restore for today or work toward what will be needed in the future – i.e. what vegetation might do well if (when) change happens?  As the land warms, we can move the plants higher on the mountain.  But what do we do after we reach the top?  All these are difficult questions!