Signs of Spring 12: The Forest and the Trees!

Photo by D. Sillman

The woods around us are changing almost daily due to their relative abundances and leafing orders of their trees. These passing days let us see the trees for the forests! They also remind us of a century and a half of ecological history!

A month ago the ridges throughout Western Pennsylvania had a reddish glow from all of the flowers of the incredibly abundant red maple trees. Those flowers have now faded and fallen, and the leaf buds of all of the species of maples are opening up. The red maple’ new leaves will live up to their common name and have, initially, a distinctly reddish tint. This red, though, will be quickly covered up by the deepening green of their rapidly synthesizing chlorophyll molecules. We won’t see their red color again until fall.

Photo by D. Sillman

The red maples next to my house started to leaf out a few days ago, and the silver maple at the bottom of my field set its leaves last week. I have seen sugar maples all over the area that are already covered with large, deep green leaves. I have seen some others, though, that are still mostly bare. There is a lot of individual variation in sugar maples as to when they unfurl (or when they shed) their leaves!

Along Roaring Run the yellow poplars started to leaf out a couple of weeks ago and are now covered in their distinctive, tulip-shaped leaves. The abundance of poplars on the hillsides is really apparent now, too, as Deborah’s picture (at the top of page) of the hillside on the south bank of the Kiski River shows you. Most of the spaces in between the green of the poplars have a faint, reddish tint. These are all of those red maples just starting to roll out their leaves.

Photo by D. Sillman

The apple, crab apple, pear and cherry trees have all leafed out and are in or have been in flower. The grass beneath them has been speckled with shed, white flower petals. Fields, roadsides and hillsides are flushing green especially with the abundance of black cherry trees that characterize this southern edge of the “Allegheny Hardwood” forest mix. The sun-loving black cherries (along with all of those red maples and yellow poplars!) were among the first species to recolonize the clear-cut forest sites all across Western Pennsylvania in the early years of the Twentieth Century. This forest mix grew rapidly but is made up of relatively short-lived tree species. The first black cherries that grew in this forest succession sequence will be reaching the end of their expected life spans within the next couple of decades.

What will these forests look like when all of those trees are gone? The deer have eaten most of the seedlings that tried to grow under the mature canopy. The deer leave behind the ferns, of course, and the multiflora rose. Maybe all of these Pennsylvania forests will turn into vast fern and rose thickets.

Another major tree of our forests is the red oak. It responded to the clear-cut forest destruction by sprouting new trunks from the stumps and roots of the downed trees. Often the re-sprouting red oak trunks grow in pairs, so when you see a double trunked red oak you are looking at a tree that rebounded from the ecological devastation of the late nineteenth and early twentieth centuries, the devastation that Gifford Pinchot called “an orgy of forest destruction.”  Red oaks are just starting to unfold their leaves. Many are covered with tiny, light green versions of their familiar looking leves.

Photo by D. Sillman

The young red oaks in my back yard grew up protected from the deer under the cover of my now departed spruces. They are fine looking pole trees between twelve and twenty-five feet tall. The shorter trees, sheltered from the winter winds, held onto last year’s leaves until very recently. I wonder if these old leaves that cling on these trees help to protect the new leaf buds? Or, do these tough, old, oak leaves weather down a bit while they up hanging in the wind and weather and then decompose more rapidly when they finally get added to litter layer of the forest floor in the spring? Beech trees (another very tough leaved species!) keep their leaves through the winter, too. It would be interesting to look at this more closely!

That we have forests around us at all after that century-plus ago, uncontrolled assault on our ecosystems is a credit to the nutrient richness of our soils, the abundance of our rainfall, and to the ecological reservoirs of plant species (especially trees!) to fuel a robust successional recovery. The forest we see now, though, is very different than the forest that had evolved here over the millennia after the retreat of the last Ice Age’s glaciers. These forests are an unprecedented, broad scale experiment whose ultimate fate is not at all known.

And finally, along many waterways and in many tended yards, willow trees have been in light green leaf for a couple of weeks now. I have been watching set of willows that grow along my driving route to campus from my home. They are starting to fill in their dropping branches with denser and denser arrays of leaves, and are slowly becoming more and more solid to the eye.

Photo by D. Sillman

Looking out the window over my writing desk I still see the dark, bare branches of the black locust trees and the oaks. Spring is just getting started! Deborah saw a pair of pileated woodpeckers out on our old cherry stump this afternoon. They must have their nest somewhere close. I thought that I heard a Baltimore oriole down on Roaring Run this morning, and I did hear a wood thrush up on campus last week! The spring migrants are returning in numbers! The rose-breasted grosbeaks and scarlet tanagers should be filling in the forest gaps on the trails down along the river soon, and the indigo buntings should be flitting in and out of the shrubby cover further up river toward Edmund.  The whole summer ensemble will be here soon!

 

 

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