Colorado ranchers say dead forests may boost runoff
Summit County, CO Colorado
SUMMIT COUNTY – Heavy rains in early June led to high stream flows in the local area – in some cases three to four times the historic average for this time of year, according to water commissioner Scott Hummer.
And there may be another factor in play. Vast areas of dead lodgepole pines could be boosting runoff. There’s no long-term research yet to quantify those anecdotal observations, but ranchers in the Lower Blue have been reporting unusual conditions in streams running through their properties.
“The best indicator might be how long these creeks are staying up in the fall,” said Grady Culbreath, who has been watching the ebb and flow of forests and streams on his spread for decades. In recent years, Culbreath said smaller streams that normally dry up by late summer have flowed well into autumn.
“We’ve seen more water later than we ever have,” Culbreath said. “Seeing this much water late in the year is wonderful. Of course, every winter is different,” he added.
Because conditions vary so much from year to year, it’s hard to say that the beetle-killed forests are boosting stream flows. The amount of winter snowpack, spring rains and temperatures are other important factors.
And any water boost from the dead forest could be short-lived. Thick grass and shrubs have quickly grown to fill in the forest floor among the dead trees, taking up some of the moisture, and a new forest is emerging.
“We’re seeing a lot of areas where the quakies are coming in like crazy,” Culbreath said, referring to the growth of aspen trees in beetle-killed areas.
“The ranchers often know what’s going on before anybody else,” said U.S. Forest Service ranger Kelly Elder, project leader and administrator for the Fraser Experimental Forest. “But there’s no statistically significant study that show (an increase in runoff),” Elder said. “It’s a really complicated system. We’re seeing a lot of climate variability. That’s another signal on top of the beetle kill,” Elder said.
Elder briefly explained both sides of the issue: “When the trees die, they stop intercepting snow. A healthy canopy catches snow and there’s more loss back to the atmosphere through sublimation (snow turning directly to water vapor without going through a water stage). So there’s more snow on the ground. And when the trees are dead, less of it gets used,” Elder said.
On the other hand, new grasses, shrubs and trees are springing up in the beetle-killed zones.
“We have a very healthy understory,” Elder said, explaining that young lodgepoles are growing at phenomenal rates now that they are getting plenty of sunlight and moisture. And like Culbreath, he also pointed to the growth of aspens in dead lodgepole areas, explaining that the new trees are using at least some of the water previously absorbed by the lodgepole forest.
Many of the ongoing studies at the Fraser Forest are aimed at answering these questions.
“We’re working on it 24-7,” Elder said.
June weather stats
For June, the National Weather Service site near Dillon Reservoir recorded 2.09 inches of rain, well above the historic average of 1.14 inches for the month.
June temperatures reflected the rainy conditions, with the average daily high temperature coming in at 63.6 degrees, more than 5 degrees below the historic norm. The average daily low temperature was 34 degrees, higher than the historic average 31.3 degrees.
The high reading for the month was 77 degrees on June 25. The coldest overnight low was 30 degrees on June 15.
In Breckenridge, weather watcher Rick Bly tallied the 12th-wettest June on record, with 2.27 inches of precipitation, 64 percent above average. Bly said the notable statistic was the number of rainy days in June – 22 – compared to an average of eight.
For the weather year-to-date (beginning Oct. 1), Bly said moisture is about 5.5 percent above average.
July is the wettest month in Summit County, when the monsoon brings 2.32 inches of moisture on average to Bly’s backyard weather gauge.
Summit County could be on track for plentiful summer moisture, with an emerging El Nino (warmer than average eastern Pacific) potentially boosting moisture late summer, according to Klaus Wolter, a climate researcher with the National Oceanic and Atmospheric Administration.
The cyclical variation in the Pacific doesn’t make a huge difference in terms of summer thunderstorms, but can push more moisture into the southern Rockies at the tail end of summer, he said.
” El Nino is on the march. In general, it’s kind of good for us,” Wolter said, explaining that, in the past 10 years, abundant moisture in September and October coincided with El Nino conditions.
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Are we seeing more bears because there are more bears on the valley floor, or because we’re all spending more time at home? It could be a bit of both.