by John Schwartzer


Winter is a wonderful time to get out and identify Pennsylvania’s forest trees but can present some challenges. For instance, one of the easiest ways to tell a red oak from a red maple is leaf shape, but autumn has stolen that “easy button” from would-be tree detectives. There are still plenty of large clues to narrow down the list of 134 possible native trees to just a few. Subtle clues can help determine the exact species, and a good field guide can be very handy.

Branch Arrangement

There are three main arrangements in which branches grow. Buds will be arranged the same as the leaves and branches follow the same pattern. Look at a few branches just to make sure a branch wasn’t lost and healed over when the tree was young.


This arrangement would appear similar to your arms/shoulders. Two branches will leave the main stem at the same location directly across from each other. Maples, ash, and dogwoods are the only native opposite trees (see the red maple pictured).


An alternately arranged tree will have buds and branches with a staggered arrangement. Oak, cherry, hickory, walnut, and blackgum are examples (see the oak example pictured).


Whorled arrangement means that the tree has buds and branches circling the main stem. This is the least common arrangement for PA trees. Catalpa is a good example.


Bark can be another big clue as to what tree is found. Smooth (note beech bark pictured), rough, furrowed, streaked, and color are all indicators of a tree’s species.


The fruits of many trees fall to the ground during the summer, but some linger into and even through winter. Fruits are not just things we eat but anything that holds the genetic material for the next generation: nuts(walnut), samaras (maple), drupes (cherry), pomes (apple), berries (persimmon)… all trees have fruits; the list is long. A dried-up apple hanging on a tree is a good clue that you’re looking at an apple tree. The fruits don’t even have to be on the tree. Walnut husks and shells laying under a tree might show the location of a walnut tree.

Identification of trees can be more challenging in the winter, but with a little practice using the tips above, anyone can become an advanced tree ID sleuth.



A great resource for identifying common trees in PA is the DCNR publication “Common Trees of Pennsylvania.”

Forest Fridays are published weekly by the PA Bureau of Forestry,
Department of Conservation and Natural Resources (DCNR).