Photo by Corey Husic

Sunday, September 4, 2011

Meteorological Fall

In case you missed it, we slipped into meteorological fall this past week.  As humans, we know the signs (at least in the more northern latitudes):  school starts for many, pools and beaches close after Labor Day, and if you are an early riser, you likely have already noticed that it is a bit darker in the morning than it was just a few weeks ago.  In Kunkletown, PA, our latitude is around 40.8 to 40.9° (vs. about 40.7° at the Lehigh Valley Airport between Bethlehem and Allentown).  On September 1st, our day length is 13 hours and 6 minutes.  By September 30th, it decreases to 11hours and 48 minutes.  I won’t even mention (for now) how much shorter the days get by the end of October.  The average high for September 1st for this area is 80°F and the average low being 58°F.  By the end of the month, the average high will be 70 and the low 47 -- so 10 degrees cooler.

But how do things in nature sense that the seasons are changing?  They certainly don’t look at the calendar on the wall!  Instead, there are a number of factors including changes in temperature or amounts of precipitation, or changes in the availability and types of food.  But the shortening of day lengths of fall (meaning the time from sunrise to sunset; we still have 24-hour days) is likely the principal trigger that sets into motion changes in plants and animal behavior.  For birds and migrating butterflies, it is a signal that it is time to fatten up with fuel stores in preparation for their upcoming journey.  Less sunlight alters the rates of synthesis and breakdown of chlorophyll (the green pigment responsible for much of the light absorption needed for photosynthesis).  The decreasing levels of this green pigment in leaves not only allows the colors of other pigments to increasingly show through, but also triggers a number of molecular and physiological events in plants preparing them for dormancy or the end of their life span for annuals

Over the past week, I noticed a yellowish tinge on the slopes of the Kittatinny Ridge.  Our field is filled with Goldenrod (Solidago sp.) looking quite lovely. 

The KIttatinny Ridge is in the background but the high humidity
causes a haze that really reduced visibility over the past two days.

Yellow is also showing up in the greenbrier (Smilax sp.) and silver maple (Acer saccharinum) leaves.  Reds are showing up in burning bush (Euonymus alata which is beautiful in fall, but invasive), Tupelo or Black gum trees (Nyssa sylvatica), and sumacs (Rhus sp.).  Today, I noticed seeds on the Little Bluestem (Schizachyrium scoparium).

Above and below - the first hints of color in the leaves of Silver Maple.

Burning bush starting to live up to its name

Hints of red along the roadside (above) and in a
young Dogwood below

The berries have appeared on the Oriental Bittersweet (Celastrus orbiculatus) and some are beginning to change from green to orange.  I used to think that this was an attractive plant in fall, but then learned that it is an invasive species.  No wonder I saw so much of it.  And over the past two years, this rapidly growing vine has crept into our property and become a major problem.  The weight of the vegetation can damage the shrubs and trees that the vine climbs up and over.

Oriental Bittersweet berries
The pears on our two trees are ripe and falling faster than I can use them.  As they begin to rot on the ground, the yellow jackets become quite numerous.  And our dog begins his own fuel storage gobbling up as many of the sweet pomes as he can before we pull him away!  A futile effort on our part since when we pull him away from one tree, he runs to the other in a different part of our yard.  I am always amazed that he doesn’t get stung by the yellow jackets or if he does, he doesn’t seem to be phased by it.

I am seeing fewer Milkweed Tussock Moth caterpillars, but finding a number of Monarch chrysalides and fall webworm nests.  Monarchs are nectaring in the habitat garden; some look as though they have started to migrate as they fly as if they are "on a mission".

Around mid-August, the last of the barn swallows fledged from their nests in our barn.  We still saw large mixed flocks of swallows flying around, but it appeared that they were gathering up with friends.  Sometime over the past week or so, they seem to have disappeared.  A sure sign of fall coming at our farm.

Raptors are migrating; you can follow the reports from the various Pennsylvania Hawk Watch (count) sites at the Hawk Migration Association of North America (HMANA) website:

The last two days, I saw groups (a coronation or tyranny) of Eastern Kingbirds sitting on the tops of some dead trees.  One day, they were joined by a Yellow-bellied Sapsucker and a Pileated Woodpecker.  Odd to see those three species in a tree together.  Each day in the same location on our property, a family of the large Pileateds flys around making a lot of noise, either sounding off their alarm or showing of their children.  Several times over the last week, I have heard Eastern Wood-peewees in the forest.  They don't breed here, so must be passing through.  A few weeks ago, I heard the Eastern Towhees after a hiatus, but this past week I haven’t heard any.  Have they moved on already or just become silent again?

The Ruby-throated Hummingbirds and Gray Catbirds have been quite active.  I was being yelled at by the latter this morning as I picked the last of the blackberries and the “hummers” were dive bombing me!

The passing of Hurricane Irene last weekend took a toll on some of my gardens, but I will end this post with a series of pictures from my habitat garden which is still full of bee, butterfly, and hummingbird activity.  What is happening in your backyard that lets you know that fall is here?
Caryopteris sp. (Blue Mist Shrub - love the color and this plant
really attracts bees)
As seen below, the Autumn Joy Sedum is not yet quite in full color.
This was an accidental pairing, but I love the combination of colors.

Winterberry (Ilex verticillata) - the berries  have recently appeared

Crape Myrtle (Lagerstroemia sp.)
It is surprising that this species grows in our yard (technically
zone 6a, behaving like 6b) -- at least to this height. 
In front is a Spirea shrub.

This Crape Myrtle tends to die back more over the winter than the one
in the previous photo, so stays about 3 feet high but blooms perfusely in
late summer.

Grapeleaf Skeletonizer
You can Google this insect to see the beautiful caterpillars.

Despite the hurrican there is still a lot of color (even if many plants
are more horizontal than normal) and a lot of insect and bird activity.
In other gardens, the groundhogs are causing problems but they
leave this one alone.

The Turtlehead  (Chelone glabra) seemed to flower late this year.

1 comment:

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