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Archive for December, 2007

Mariton – Freezing or Melting?

Here is a little pet peeve of mine.  Liquid water freezes (becomes a solid) at 32 degrees Fahrenheit.  Likewise, solid water (ice) melts at 32 degrees (given the usual disclaimers about air pressure, etc.).

Have you ever noticed that TV meteorologists never use the term "melting point"?  If it is 20 degrees outside and the temperature is expected to rise to 32 or above, the meteorologist will say:  "We expect temperatures to reach the freezing point later today."  When things are already frozen reaching the freezing point is a moot point isn’t it?  If you move ice cubes from your deep freeze to your refrigerator’s freezer, it is still ice.  So, technically they should say:  "We expect temperatures to reach the melting point for part of the day."

You might say that I am just nit-picking, but it is much different than pronouncing the word "tomato" with a "long a" versus a "short a".  This is about water completing a physical reaction.  When ice melts (i.e. solid water becomes liquid water), heat is absorbed from the surroundings.  When water freezes, heat is released.  When ice goes from 20 to 31 degrees, no heat is absorbed.  So, the act of melting and freezing has a direct effect on air temperatures and thus weather and weather prediction.  What’s more, every meteorologist learned this in several different freshman science classes.

I don’t really expect forecasters to change their terminology.  But now you can listen to your favorite meteorologist and see if they get it right.  Or listen and find just one more thing that they get wrong.  (Now, that is nit-picking.)

Mariton – Hermit Thrush Singing

I walked out the driveway for the paper at dawn and suddenly felt a wisp of spring.  Funny, because we just celebrated the Winter Solstice, and it was 20 degrees out.  But I heard a phrase of a bird song and it instantly warmed me.  I stopped to listen, and the bird sang another short phrase.  I realized I was listening to a Hermit Thrush (Catharus guttatus) as it sang its full song.  This is one of the most melodic and ethereal bird songs I know.  While it winters here, it breeds further north.  So, we rarely hear its beautiful song at Mariton.  It sang its song once and was done for the day, but I was warmed. 

Crow’s Nest: Re-Route of the Horse-Shoe Trail

Woods1If you hike the Horse-Shoe Trail in Warwick Township, you now pass through a part of Crow’s Nest Preserve. A short re-route has moved the trail from a muddy section just outside the preserve to higher ground just inside the preserve.

The Horse-Shoe Trail runs about 135 miles from Valley Forge to the Appalachian Trail near Harrisburg. Though officially founded in 1935, parts of the trail had been in use for hundreds of years. A few sections are relocated each year, usually when a property it passes through is sold and developed into house lots, necessitating a move onto public roads or nearby open space. The Horse-Shoe Trail Club maintains the trail, organizes hikes throughout the region, and publishes a detailed guide to following the trail.

In our neck of the woods the trail gradually climbs up the gorge at the falls of French Creek, passes scenic St. Peter’s Village, and then heads west on the right-of-way of the former Wilmington & Northern rail line. After it crosses Trythall Road and passes Warwick Woods Campground you start to see the the deep woods portion of Crow’s Nest Preserve on the right.

While the rail bed continues on to Warwick Village and Elverson the trail turns right into the woods, crosses a small stream called Mine Run, and enters Crow’s Nest for a short bit. Then the trail is located in State Game Lands #43 for a while before it heads on to Hopewell Furnace National Historic Site and French Creek State Park.

Crow’s Nest: Recycling

We have been fortunate to be able to reduce our footprint of managing the preserve by recycling stuff at Recycling Services, Inc., a nonprofit organization in Pottstown.

RSI is one of the oldest and most comprehensive recycling centers in the country. They caution that recycling is the last resort—after reducing consumption and reusing what can be reused. But they recycle a lot of different things and have a re-use-it store with lots of interesting items. RSI’s director Jim Crater has helped with our summer camp when the theme was Cycles in Nature.

We’re thankful that they’re nearby and so helpful.

Mariton – Trail Conditions

I closed several of the trails today because of the ice.  In particular, the Fox Trails, the River Lookout Trail, and part of the Chimney Rock Trail are now closed.  These trails are impassable, especially in the mornings, without crampons.  Even with crampons, these trails are dangerous.

Trail_workRyan Hopkins, NLT’s Stewardship Assistant, and I put chains on the tractor this morning.  During mid-day, we broke trails with the tractor when the ice was a little softer.  These trails are still slippery, but the tire tracks provide areas where one can get some traction.  Fortunately, there weren’t any trees blocking the trails we were able to access.  Use caution if you come to walk the trails, and please honor the trail closings.

Mariton – Footwear Accessories Part II

I took a walk to see if I needed to clear any downed trees or limbs off of trails.  I figured I would wait until afternoon when the ice crust would be softest.  My boot studs worked well on the flat trails.  On inclined trails, however, I found myself slipping and falling.  This ice crust is still very thick and very slick.  In most places I could not kick my boot through the crust to get footing.  So, while I still like my creepers, they definitely have limitations.  I needed crampons to walk the trails.

I was unable to climb the Spruce or Main Trails.  I regret starting down the River Lookout Trail.  Thus, I recommend you don’t come out to walk the trails until conditions are safer.  I can’t imagine how the wildlife is faring.  It must be perilous for deer to walk in such icy conditions.  Finding food must be difficult for turkeys.  There are places where the crust is soft, and I am sure that the wildlife is staying in those areas.

Crow’s Nest: Fierce Weather

We’ve had some strong weather lately, now tempered to a sunny and calm cool day. We had only rain here in the valley on Sunday, but there was a distinct line above which the hills were coated with ice.

The preserve is situated between 436 and 680 feet above sea level. The low number is where French Creek leaves the downstream end of the preserve, the high is on the hilltop across the road from the visitor center. At the visitor center itself we’re at about 480 (looking at the U.S.G.S. map, Elverson Quadrangle). The surrounding ridges in French Creek State Park are just over 900 feet. I’d say the ice line was at about 700 feet elevation.

Nonetheless we had a surprising amount of damage to trees, mostly branches down. Everyone around was in the same boat. The power was out for a few hours, and now we have no shortage of holiday greens. (White pine, like tulip poplar, is sometimes called a self-pruner, since weak branches break off, sparing the rest of the tree.) The trees were no match for the wind in addition to the ice damage from the previous weekend.

FailureThis big old red maple was one casualty; it had insufficient roots on one side, probably the result of the roadside drainage ditch and macadam preventing rooting there.

Remember that most trees in our region do not have tap roots. Most of the roots grow within the first couple feet of the surface, where they can reach the air in porous soil and water and organic nutrients. The image I use to describe the shape of a tree and its roots is that of a wineglass on a dinner plate. (I’m not sure where I first heard the metaphor; it might have been Bill Graham’s Arboriculture classes at Morris Arboretum.) The roots extend well beyond the “drip line” of the canopy, and if growing in the forest tree roots from many trees intertwine.

Since having a drainage ditch on one side of the tree means there’s no soil to grow roots, and because roots may grow poorly under macadam (soil compaction and/or lack of water percolation) the tree grows its roots elsewhere. But that leaves the tree vulnerable to winds from that direction.

We’ve watched this tree over the years, pruned some branches and cut vines off of it, but I was never worried that it would fall toward the road, since it was likely well rooted on the far side. Since this one is in a very visible location we’ll cut it up and make room to plant a new tree, further from the road in a spot that has more soil in which to spread its roots.

Mariton: Footwear Accessories

Yesterday’s rain froze as a sheet of ice on Saturday night’s sleet/snow mixture.  The ice crust was too thick to punch through until the sun softened it.  This morning, the trails were like a skating rink as the sun came up.  Yet, I confidently strode out to the bird blind to fill feeders.

Boots_001Boots_006I wore a pair of creepers pulled over my boots.  Maureen and I own different types, and I am sure they have different brand names.  One set has little steel studs.  (You would not think the studs were long enough to do any good, but they work great.)  Another set has little chains that criss-cross the bottom of your boots.  Another kind has wire-wrapped cable instead of chains.  (I personally prefer the studs, because I worry about the chains catching a branch if I am walking in the woods.)  The common thread is that they are mounted on a rubber base that slips over your shoes, just like old-fashioned rubbers.  They come off, even more easily. 

For me, it is simple choice it allows me to work and enjoy the outdoors safely.  But, I think they would be just as useful for people that walk in town, where one has to cross patches of ice and frozen slush.  I have slipped and fallen on my tail-bone and elbow enough to believe that an ounce of prevention is worth a pound of cure. 

Mariton – Bois d’Arc

My collegue, Dan Barringer, at Crows Nest recently wrote a wonderful post on Osage-Orange.  (See that post here:  I have no intention of hi-jacking that post, but I wanted to add something to it.  Another common name for osage-orange is bois d’arc or French for "wood of the bow." 

Dan mentions that osage orange was used as a bow wood.  It was so important to the Native Americans, that the wood was an valuable trade item.  The Indians of Pennsylvania’s forests used local woods such hickory, elm, ash and maple for their bows.  But those bows have to be constructed longer and wider than osage bows of the same draw weight.  So, like chert, flint, obsidian, copper and other materials that were only found in certain geographical areas Native Americans traded for pieces of osage orange to make their bows.  The wood was highly prized.  The fact that a common name bois d’arc indicates its use, implies the importance of osage-orange.

Copy_of_bow_wood_011One of my hobbies is traditional archery (or BC "Before Compound" bows).  I have a few bows that are built with osage.  One of the neat things about the wood is that it turns darker with exposure to sunlight.  These are two very different types of bows, but both are of osage.  The bow on the top doesn’t get a lot of sunshine.  It really illustrates both the light as well as the dark colors of osage-orange.  The bottom bow has received lots of sunshine and you can see the rich color of the wood.

Mariton doesn’t have any osage-orange growing on the property.  But nearby, in Riegelsville, it was planted along the canal and can be easily seen from either the towpath, or the street along the canal.  As Dan indicates it is a loveable tree.

Mariton – Great-horned owls

Saturday morning, I walked out to the bird blind early to make sure all the feeders were full.  The birds usually prepare for a storm by feasting, and I wanted to make sure there would be lots of food available to them.  As I reached up to hang one of the feeders, I saw a Great-horned Owl fly from a tree top to another tree across the trail. 

Chances are good, that the owl was also preparing for the storm by looking for unwary birds at the feeders.  This mortifies some people, but not me.  Mariton has wonderful habitat for song birds, as well as their predators.  I find that the owls and hawks rarely hunt at the bird blind, except in cases like approaching storms, or times of scarcity.  Besides there is plenty of escape cover provided at the bird blind for the birds.  Which may be another reason the owls seldom hunt there.

In the afternoon, I was checking trails and picking up sticks from the last bit of ice and wind.  The frozen snow was crunchy.  When I stopped to pick up a branch, I heard the sharp raspy whistle of a Great-horned Owl.  I glanced up to see two owls leap-frogging through the trees.  This was near the Dark Habitat on the Spruce Trail, an area where I often see owls as I walk the trails.

The Great-horned Owl (Bubo virginianus) is so named because of the feather tufts that resemble horns on its head.  It is funny, but I rarely see the tufts on the birds in the forest.  Usually I see their round heads and know that they are owls and not hawks.  It would be easy for one to see the round head and assume that they are looking at a Barred Owl (Strix varia) which is near the same size as the Great-horned but lacks the tufts.  The fact that Barred Owls are a little more active during the day is another thing that would tend to point one in that identification.  I have never heard a barred owl at Mariton, although I am always listening for the possibility.  Great-horneds have several characteristic vocalizations, and it is usually the sound that leads me to the sighting.  So, it is the combination of several clues (jiz) that I use in identifying Great-horned Owls.


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