Trees signal autumn's early arrival Trees' colors herald autumn's early arrival in California Carl Nolte, Chronicle Staff Writer Thursday, September 6, 2001 ©2001 San Francisco Chronicle

URL: http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2001/09/07/MNTREES.TMP&nl=top

The calendar says it is still summer, but some scientists and a lot of ordinary observers think autumn has come early this year.

For example, University of California resource specialists noticed that many species of oak trees in the Sierra foothills have changed color or shed their leaves entirely months early this year.

Some of the evidence of an early change in seasons is anecdotal: Many of the trees such as elms and maples that line streets on the Peninsula and in the East Bay have started to turn color weeks ahead of time.

Even the somewhat battered Japanese locust trees that grow in Hallidie Plaza at Powell and Market streets in downtown San Francisco lost most of their leaves by Labor Day.

Susan Smith, former president of the San Francisco chapter of the California Native Plant Society, says she and others interested in plants have noticed the shift to autumn "is about two weeks early this year."

She thinks the reason is a drought -- but the state Department of Water Resources says there is no drought. Rain and snowfall last winter was average or a little above.

There are also reports of the return of El Nino the weather pattern in the central Pacific Ocean that set off flooding three winters ago. But, meteorologists say, it's too soon to tell whether this has any effect.

But something is up.

The buckeye trees in the foothills and on the coast have also lost all their leaves, and the aspens that turn the eastern face of the Sierra Nevada into a riot of gold and sometimes red have started to turn, weeks ahead of time.

There are other signs: The September full moon, traditionally called the Harvest Moon, occurred on Sept. 2 this year. And for the past couple of weeks, the lowest temperature readings in the country have been in Bodie and Bridgeport, in the eastern Sierra region.

Is it an early autumn, as in the old Johnny Mercer song? "Yes, I'd say so," said Doug McCreary, a natural research specialist at the UC Cooperative Extension station. "It's autumn if you associate the season with leaves dropping."

McCreary, who studies native blue oak, black oak and valley oak trees from a base at the Sierra Foothill Research and Extension center near Marysville, began to notice the changes in the oaks in midsummer.

He and his colleagues found that these trees were turning brown and losing all their leaves, a process that McCreary said normally does not happen until around Thanksgiving.

The UC agriculture stations began getting a lot of calls from foothill residents, who thought the trees were dead, victims of the malady called sudden oak death syndrome, which affects oaks on the coast. But this was different.

For one thing, the trees weren't dead, only dormant. They had responded to natural signals -- lack of water, cooler weather -- by shutting down early, as if September had come in July.

The reasons are a bit of a mystery, but the changes probably are connected to an unusually warm May, which caused an early melt in the Sierra snowpack. That was followed by a fairly cool summer. There were only a few Sierra thunderstorms. The cool weather, particularly in Southern California, saved the state from the worst effects of an energy crisis, but it brought about other changes.

"As usual with natural systems, this is probably caused by a combination of things," said Pierre Stephens, a hydrologist with the California Department of Water Resources. He noted that when the snows melted early, the streams dropped -- to only 20 percent of a normal July on the San Joaquin River system -- which sent signals out over the Sierra drainage.

"Trees are really very smart," said LeRoy Johnson, a retired forestry geneticist, "The drying out is a way to handle the stress. They take evasive measures."

One of them is to shut down, go dormant.

Johnson noticed that the buckeye trees, among to first to lose their leaves, lost them much earlier this year. He saw this happening in July.

Although most of coastal California -- where the bulk of the population lives, is not known for colorful autumn weather -- the eastern part of the state, along the Sierra, has a different climate.

"In the eastern Sierra, autumn is the most beautiful time of the year," said Johnson, who lives in an area called Sierra Paradise, near Bishop. "I look forward to it."

-- Anonymous, September 07, 2001

Answers

Animal kingdom predicting snowy forecast for Northwest

By SKIP CARD Scripps-McClatchy Western Service September 06, 2001

TACOMA, Wash. - Autumn hasn't even officially arrived yet, but the buzz around the ski slopes is that the coming winter will be snowier than normal.

That buzz is coming from the insect world.

"The bees have been out early, and they have been very aggressive for this time of year," said Stacy Schuster, marketing director for Crystal Mountain Ski Area. "A lot of mountain folk contend that's a big sign that something's coming."

The bug-based winter wisdom is echoed by the observations of Mike McFarland, a forecaster with the National Weather Service's Seattle office. McFarland said woolly bear caterpillars in his driveway have thick orange and black coats with wide bands.

"The first two I saw, they were definitely suited up for some snowy, cold weather," McFarland said. "I saw those guys and, boy, right away I knew."

If the bees' and caterpillars' subtle predictions prove correct, it will be welcome news for skiers, snowboarders and resort operators. Last year's dry skies left many ski resorts with thinly blanketed slopes that scratched skis and dented profits.

But if the bugs believe a big winter is looming, the National Weather Service doesn't officially agree.

McFarland said the long-range computer forecast for November through January doesn't indicate anything particularly out of the ordinary for temperatures or precipitation in the Northwest.

That doesn't mean forecasters are predicting an average winter, McFarland explained.

Instead, it means observable data and trends aren't strong enough to skew the safe bets.

The problem for forecasters is a lack of significant El Nino or La Nina events near the equator and in the southern Pacific Ocean, McFarland said. Such weather patterns often have been linked to colder or milder winters in parts of the Northern Hemisphere.

When it comes to long-range winter predictions, "The only time we ever have anything intelligent to say is when there's a strong El Nino going, and we don't have one of those," McFarland said. "Unless there's an El Nino, any bet is foolish."

However, other forecasters see enough trends and patterns to make a prediction.

Tom Dunklee, chief meteorologist with the private Global Climate Center for the Washington Cascades, this week predicted above-average precipitation in September, October and November.

Rainfall totals should be 125 percent to 150 percent of average, particularly in October and November, Dunklee said.

"I look for a highly fluctuating snow line in November with above-average snow," he said.

November's heavier than normal rain coupled with fluctuating freezing levels should increase the chance of flooding, he said.

Freezing levels should stabilize by December, leading to above-average snowfall in the mountains, Dunklee predicted.

Dunklee bases his forecasts on factors such as sea surface temperatures and air flow in the upper atmosphere. His predictions rely in part on charting the pace of changes in sea temperature and matching current long- and short-term weather factors with past weather history.

Although he admitted he is no expert on insect behavior, Dunklee said he sees no correlation between busy bees, fuzzy caterpillars and severe winters.

"My philosophy is that the animals react to what the weather is doing or has done," he said. "Their bodies don't prepare for it before it has happened."

-- Anonymous, September 07, 2001

"My philosophy is that the animals react to what the weather is doing or has done," he said. "Their bodies don't prepare for it before it has happened."

Interesting philosophy. not.

-- Anonymous, September 07, 2001