Crocuses and daffodils began pushing up as early as mid-February – more than a month early. What does this mean for the forests?
"This has been an unusual winter," explained Jim Finley, professor of forest resources at Penn State University, "According to the Heating Degree Days, a measure used by oil companies to decide how much product to deliver to your home, we are running about 28 percent behind. That means that this winter was considerably warmer than normal.
"Across the state, we've not only been considerably warmer than normal, we've been a little dryer than normal, and by being a little dryer and a little warmer, we've had more sunshine. This all conspires to make plants to do some crazy things.
"One of them is to wake up earlier in the spring," he continued. "That can be a bad thing."
If a tree wakens early from its dormant state and begins to bud, the emerging flowers could be frozen by a late frost. If the flower is damaged, it doesn't fruit or produce a seed. This has an impact on both the tree, which is therefore unable to reproduce that year, and the wildlife that depend upon its fruit and seeds.
In particular, Finley has been focusing on the oaks. Although the red and white oaks are the 10th and 12th most common tree in Pennsylvania, the acorns that they produce form the principal food for most of the state's wildlife – from chipmunks to squirrels to turkey, deer and bear – while more common tree species like red maple and black birch do not provide a seed that is nearly as high in protein and fat as the oak's acorn.
If Pennsylvania doesn't have a late frost, then the productivity of the forest and the fields will depend on the amount of moisture. Currently, the ground is wet, which is a positive sign.
Another weather-related factor that may affect the forests this season is the relationship between the emergence of the flowers on trees and the emergence of the bugs that attack them.
"If the flowers come out earlier than the insects do, they may not do the damage they normally do if they emerged at the same time the flowers emerged," Finley noted.
"We saw this with an insect, called the peathrips, that emerges in the early spring just as the sugar maple buds are expanding," he explained. "As the buds expand, it enters the bud and lays eggs in the expanding leaf, and causes the leaves to fall from the tree.
"That synchronization between bud and bug is critical. For instance, when we set a small fire in a sugar maple stand, it will cause the peathrips to emerge too early and not be able to oviposit in the expanding buds."
In response to the warm winter weather, the bugs may also be coming out early.
The silver maples and red maples began to flower in late February. Sugar maple is a later flower, and has managed to remain dormant. Finley has checked with maple syrup farmers and they report that they have had good flows, which have not yet stopped, only the maple sap has a lower than typical percentage of sugar, which requires additional time and fuel to concentrate.
"I'm planning to watch and see what this past winter's weather does to things growing later this summer," Finley said. "Am I going to see a bumper crop, or not see any flowers or fruits at all in some species?"