Thursday, October 18, 2018

Boogie-Woogie


It’s fall and beneath some of the smaller American beech in the Big Woods is a black or dark gray mess.



The mess is honeydew, the sugar-filled waste of insects. Large quantities of honeydew drip to the ground and provide food for a sooty mold fungus which covers the honeydew. 


That stuff is worth investigating, not necessarily by examining it closely, but by looking up. Above you will find small branches or twigs covered with what, at first glance, looks like snow.


But snow it’s not, instead that “snow” is actually a mass of insects, small white insects.



Those are beech blight aphids (Grylloprociphilus imbricator) that feed on the sap of American beech trees by piercing the thin bark on twigs and small branches with their piercing-sucking mouthparts. The common name of “beech blight aphid” is a poor choice of name; beech trees have been dying for decades from what some people call "beech blight" which is actually an insect/fungus combination – but not this one. The beech blight aphid does not kill trees, it doesn't even do significant damage to the trees.


The aphids exude long white waxy strands from their abdomens, those strands make a mass of these insects quite noticeable.



Whenever the aphids are threatened, either by a predator or a photographer, they raise their abdomens and wave from side to side, frequently quite rapidly, shaking the waxy strands. For that reason they’re often called the boogie-woogie aphid –


The aphids don’t rely on the waving to deter the threat, instead it’s used to disperse a warning scent to their fellow aphids. The aphids are quite aggressive, a number of them will swarm the threat and stab it with their piercing/sucking mouthparts which frequently drives off a potential predator.

Thursday, October 11, 2018

In Praise of the Hollow Tree


Foresters, loggers and sawmill owners are, in general, no fans of hollow trees. Hollow trees take up growing space that could be utilized by trees of greater economic value. Felling hollow trees is dangerous and takes the time and fuel that could be used to cut trees that are valued in terms of dollars.

However, hollow trees and even hollow branches on otherwise healthy trees have a value beyond dollars.



Not all hollow trees are created equal. There are, of course, trees large and small – there are trees whose trunks are hollow from top to bottom; trees whose trunks are only partially hollow; dead or decaying trees in which woodpeckers have chiseled cavities; fallen hollow trees. Everything said about hollow trees may also be said to apply to hollow limbs and branches.


We’ll leave how and why trees become hollow for another day and take a further look at the value of those hollows. 
    

Before European settlement of eastern North America when vast acreages were occupied by forests containing large trees, black bears spent the winter in trees like this one (they still do where such trees are available) –






And turkey vultures nest in some of those large hollow trees –



Smaller hollow trees are frequently used by smaller creatures: raccoons –



And squirrels of all species –

Red Squirrel

Southern Flying Squirrel

Eastern Chipmunk

The porcupines that leave a pile of droppings at the base of a hollow tree –



Have an impregnable fortress inside a hollow tree –



Woodpeckers frequently create their own hollows in trees with soft wood –

Yellow-shafted Flicker
Pileated Woodpecker

Those cavities are often used by other cavity-nesting or cavity-roosting birds that also frequently use natural hollows –

Black-capped Chickadee
White-breasted Nuthatch

Insects, spiders, mice, shrews, fishers and a lot of other animals use hollow trees, even snakes like this black rat snake –



Wildlife populations can utilize more than ten tree hollows of various sizes on every acre of woodland; so please, oh please, save that hollow tree.

Thursday, October 4, 2018

Falls in the Gorge


Northcentral Pennsylvania’s Pine Creek gorge was created when the stream, originally draining to the northeast, was dammed about 20,000 years ago by the most recent glacier, thus forming a lake which overtopped the high ground to the south and eroded a new channel draining the lake. Thus Pine Creek now flows south for over 50 miles through a gorge whose depth varies from 800 feet in the north to 1,400 feet further south.



In the 1880s a railroad was constructed through the gorge and heavy logging removed almost all of the old growth forests in the watershed. The forests have regrown albeit largely with different species; the railroad was abandoned in 1988 and the tracks removed. Most of the gorge and the surrounding uplands are now in the Tioga and Tiadaghton state forests.


Now a rail-trail occupies the old railroad grade and provides easy access to the streams flowing down the gorge’s steep sides from the surrounding Allegheny Plateau. Many of those streams flow over waterfalls of varying height and the heavy rainfall of the last few months has meant that the waterfalls are at their best.


A sampling of the waterfalls in one section of the Pine Creek Gorge Natural Area, first the waterfall on Stone Quarry Run –


Although I have a preference for photographs of waterfalls taken at ¼ of a second, H much prefers waterfall photographs taken at a higher shutter speed so, where available light allowed, there are photographs taken both ways –


A little further north in the gorge is Water Tank Hollow –



It’s easy to get to the base of this waterfall since there is no plunge pool, but the camera lens becomes coated with spray –



The next stream is Clay Mine Run –



Benjamin Hollow is steep with many mini-waterfalls and very slippery footing –



An old log slide climbs the hollow, however a portion has been washed out, crossing the wash-out involves a bit of slipping and sliding. A climbing rope that some kind predecessor had left in place makes it easier to get beyond the steepest and most slippery section which yields a sideways view of the highest waterfall in Benjamin Hollow –



Above that is another waterfall –



Further along is Pine Island Run, whose first tributary has a series of small waterfalls –



Pine Island Run is, in many ways, the prettiest of these four streams. It has several pools –



And a beautiful slide-type waterfall –



Some of the small cascades are especially appealing –



These aren’t the only waterfalls in the Pine Creek Gorge, some streams further north have even more spectacular waterfalls – but those will have to wait for another day.