Restoring Ponderosa Pine Forests

Brad Blake and Philip Patterson are Northern Arizona University’s own Johnny Appleseeds—but rather than dispersing non-native apple seeds, they are collecting local ponderosa pine seeds from high-risk wild fire communities and banking them until they’re needed to restore a tree or forest.

Besides the one housed by the USDA Forest Service, NAU’s ponderosa pine seed bank is the only one of its kind. And even there it has an edge: Unlike the USDA Forest Service, Blake and Patterson have the ability to distribute seeds directly to landowners thanks to the support of partners like the Arizona Community Tree Council and the Arizona State Forestry Division. 

A seed bank worth one million

Blake and Patterson, who run NAU’s eight research greenhouses, started the ponderosa pine seed bank in 2002. Since then, they have collected, processed, and banked 100 pounds of seed—an amount that has the potential to generate nearly one million trees if everything goes just right. The stored seeds can speed the return of lost trees and forests, which might normally take several generations—under ideal conditions—to regenerate.  

“Natural regeneration after a fire is not easy,” says Blake, the greenhouse manager. “A really hot fire will confound these conditions even more.” Banking source seeds is the secret to optimizing restoration because it allows the greenhouse staff to react quickly and plant seeds from the very region affected by a fire. Because these seeds come from trees that have adapted to local circumstances, the replanted seedlings should be able to more easily withstand weather fluctuations, poor soil conditions, insect infestations, and diseases they may encounter, thus increasing their survival rate. 

Gathering and growing seedlings

Seed collection is a labor-intensive process complicated by unpredictable seed availability. In October, during the harvesting season, it’s not uncommon for Blake or Patterson to travel hundreds of miles and only collect a few, seed-rich cones. One bushel of cones yields one pound of seeds if the cones are burgeoning with good seed, but most bushels yield only a quarter or half that amount. Sometimes the two foresters go harvesting with an arborist who climbs up a tree to capture cones that are beyond the reach of clippers that only go up 30 feet.   

Back in the greenhouse, the seeds are dried, dewinged, cleaned, and vacuum packed in heavy duty, one-pound freezer bags to prevent moisture loss.  Then the bags—each holding 11,000 seeds—are stored in a stainless steel freezer at minus 10 degrees Fahrenheit, where they can lay dormant for 20 years or more before planting. 

When ponderosa seeds are needed, the greenhouse staff, student workers, and volunteers follow a method inspired by the late Dr. Richard Tinus of the USDA Rocky Mountain Forest Experiment Station. The team mixes soil consisting of 2/3 vermiculite and 1/3 peat moss, fills ridged cells in book-style containers, and plants the seeds (minimum two per cell), toping them off with a half-inch of pearlite. It takes 120 days to nurture a seed to a seedling (watering, feeding, flushing, thinning, and weeding) and another 60 days to harden the bud nodes and acclimate a seedling to being outdoors. 

Luckily, they have many hands contributing hundreds of hours of labor each year to the cause. “Work/study students and volunteers are an essential part of this effort,” says Patterson, the greenhouse plant production manager. “We couldn’t complete our projects without them.” 

Helping to restore private lands

Blake and Patterson have already helped thousands of landowners restore scorched lands. For example, the greenhouse team has grown and distributed 300,000 tree and plant seedlings to landowners affected by the 2002 Rodeo-Chediski fire, which was the second largest wildfire in Arizona history, and they continue to provide seedlings to individuals whose lands burned during the highly destructive 2003 Aspen Fire on Mount Lemmon in Tucson. 

In addition to providing seedlings, Patterson and Blake educate landowners. This is a critical step to assuring the successful growth of the seedlings. Patterson has developed a plant care guide that teaches seedling recipients how to plant and take care of their trees. He and Blake also recommend  a fire-wise planting program that encourages people to plant ponderosa pines away from their homes and fruit tree and other deciduous trees closer in.

A model for future communities

During a time when wildfires have been a frequent threat in Arizona, NAU’S seed bank is an environmental boon. Not only can it speed the return of lost trees and forests, but Blake and Patterson’s model can also guide other communities to mitigate their own environmental disasters by planning ahead. “I think this is a program that can be used anywhere for restoration,” says Blake. “It can apply to other species.”