Yellow, orange, red and purple leaves will soon scatter the ground of Penn State's campus.

Leaves in Happy Valley are turning colors early this year, and Mother Nature is responsible, said Marc Abrams, professor of forest ecology and physiology.

"We had a very severe drought during the first three weeks of August," he said. "This is followed by the first half of September being unusually cold."

The drought in August left State College with about two inches of rain less than normal, and September brought temperatures averaging nearly six degrees below normal, Abrams said. These abnormal climatic patterns, drought and cool temperatures can stimulate a change into early fall colors, he said.

Do not fear, foliage seekers, even though the trees are turning early, the vast majority of trees have yet to change, Abrams said.

"We will still have many trees turning color at the normal time, with a peak in mid-October," he said.

Other stresses like pollution, limited water, and pavement over root systems can cause leaves' colors to turn early as well, Bill Sharpe, professor of forest hydrology, said.

A honey locust outside Sharpe's window has roots that are covered by pavement and the leaves are yellow, he said. A honey locust 50 feet away, without pavement restricting its roots, is still green, he added.

Not all experts think the leaves have turned early this year, though.

Bill Elmendorf, assistant professor of community forestry, said he believes leaves are turning color normally.

"Different species color at different times," Elmendorf said. "Earlier fall color can be a sign of stress in the

tree, something is wrong or it is just getting older."

Elmendorf compared the black walnut tree to the ornamental pear tree, which lines Pugh Street.

"The black walnut tree loses its leaves early in the fall," he said. "The pear trees hold onto their leaves until very late into the fall season."

Elmendorf and Abrams both said they believe if there is warm weather in the coming weeks, it could produce a fall full of dull colors.

"If things were to get very warm at this time, it would keep the remaining trees green for a very long time," Abrams said. "We might enjoy Indian summers as people, but they are not the best for peak colors."

Cooler weather, especially cold nights that dip into the 30s will stimulate the most vibrant colors, Elmendorf said.

Elmendorf suggested students watch the color on Mount Nittany.

"The leaves will start to turn at the base of hill where cold air sinks and settles," he said. "The fall color will then move up and up until the top of the mountain turns."

Elmendorf has three tips for color lovers.

"Luck, being in the right spot at the right time, not a lot of wind because [leaves] get blown off, and clear sunny days will show fantastic color," he said.

For a bright, beautiful, yellow color, one should look for a gingko tree, one of the oldest species of trees, Elmendorf said. The sugar maple, one of the best-known trees around Penn State, is vibrant neon red, he added. Purple leaves can be found on the white ash and black gums, Elmendorf said.