Dying pinon pines indicate 'beyond dry' conditions

For thousands of years, American Indians carefully tended stands of pinon pines in Nevada. The Washoe people would gather nuts in the Pine Nut Mountains and use them throughout the year to toast and make powder, stews and salves.

Surviving climate changes and a small ice age, stands of the odd-looking trees with twisting branches and stiff needles spread through the West. But a recent phenomenon has scientists concerned.

A few years ago, researchers in several Western states started noticing shorter needles on the pines and black-powdery substances around them.

Then the trees started dying.

"When you see those start dying, they're beyond just dry," said Kelly Redmond, climatologist with the Western Regional Climate Center in Reno. "They belong here. They're adapted to dry conditions. When they start showing stress, they're telling you there's more stress than usual."

Tree experts are now trying to figure out what is killing off hundreds of pinons, the state tree of Nevada. Scientists are also concerned the dead trees could add to fire danger and destroy the habitat of native wildlife.

"People are starting to very much watch these patterns of mortality," said Connie Millar, research geneticist at the Institute of Forest Genetics for the U.S. Forest Service's Pacific Southwest Research Station. "We're looking at a regionwide phenomenon."

In one grove south of Gardnerville along Highway 395, as many as 20 percent of the trees have died in the past few years - likely because of ongoing cold winters and drier-than-normal summers.

Scientists investigating the tree deaths are focusing on the effects of a four-year drought that has gripped Northern Nevada and neighboring states.

With a decent snowpack and recent wet storms, the area could finally see some relief this year, experts say, but that could easily turn around.

"We're off to a good start here," said Douglas LeComte, drought specialist with the National Oceanic and Atmospheric Association Climate Prediction Center in Washington, D.C. "If it continues, it will make a significant difference."

Snow water-content readings in the mountains around the Carson region are showing 125 to 150 percent of normal, LeComte said. The area could still take a turn and end up like the past four years, though, with warmer weather and below-normal precipitation predicted for the next few weeks.

The region has seen the same pattern in the last few years with decent storms easing the drought, only to be thwarted by the heat and dryness of late spring and summer. If the pattern locks in, the area could see another year of drought, LeComte said.

The Yerington area has been hard hit by the drought. It has received only 12 inches of rain in the past five years, averaging 2 1/2 inches per year. It would normally get 26 inches in the same period.

The pinon pine population has also fluctuated because of human and climatic conditions. The species is something of a newcomer to Northern Nevada, reaching the Carson and Reno area about 400 years ago.

Scientists can track the tree's presence in central Nevada as far back as 5,000 years. Research indicates it reached its northernmost limit at Pyramid Lake only 200 years ago.

Ideal climate conditions of summer moisture and warmer winters allowed the climate-sensitive pinons to flourish in the dry, rocky soils of the northern parts of the state for 200 years. Eighty-five percent of the trees in this area began growing between 1825 and 1850, researchers in Reno estimate.

Scientists with the U.S. Forest Service in Reno will monitor pinons south of Gardnerville to determine the long-term effects of changes in climate on tree mortality of both single-needle pinon and Utah junipers.

Peter Wigand, a professor of geography and researcher in Reno, said the tree deaths may be cyclical for a species still trying to establish itself in the north. One of the problems is finding out whether global warming is adding to the problems, Wigand said.

"What we're seeing with all this die-off is cyclical adjustment," he said. "We're looking at a species at its northernmost boundary. We could turn around; the summer should get wetter and warmer. With that, it could just as easily re-expand."

Contact Jill Lufrano at jlufrano@nevadaappeal.com or 881-1217.