Monday, March 2, 2015

Frigid Field Trip


I'm teaching two Landscape Restoration classes on Fridays this term, first for 10 graduate-level landscape architecture students, and then for 27 undergraduate landscape architecture and horticulture students.  I escorted the two classes on a field trip at my preserve last Friday (February 27).

The trails in the preserve were (and still are) very icy.  Three of the graduate students slipped; none of the undergrads did, perhaps because by the time the undergrads showed up the sun had warmed the snow and ice a bit.

It was in the mid-teens F when we started out in the morning, but it was sunny and not too windy.  I had considered postponing the trip, but then decided to proceed as planned.  If I had postponed, who knows what the weather would have been like on the next scheduled date.

The last two weeks of February were the two coldest weeks ever recorded in Philadelphia - not just for February, but for any two-week period since records have been kept (1841).  February 2015 was also the fifth coldest February on record.

My Stewardship Assistant, Chris, explaining how he manages our native prairie
Yours truly in the midst of our oldest reforestation project (25 years this year)
The undergrads examining a lesion caused by the chestnut blight fungus on one of our American chestnut trees

Thursday, February 26, 2015

Winter Weeds in Snow


On Sunday morning, February 22, 2015, the northern Piedmont received two inches of snow followed by a bit of freezing rain that left a glaze over everything outdoors.  As I walked to open the driveway gate to my preserve, some of the winter weeds slightly encased in ice struck me as having a particularly "Japanese" gestalt.  I hope you agree (and enjoy)!  The images are better enlarged.



Wednesday, February 25, 2015

Bad Timing


My staff and I spotted the "first" groundhog of the year today.  The groundhog's right on schedule for leaving its winter burrow, but the weather is hardly cooperating.  We had temperatures in the upper 30s F this afternoon (the high temperature "should" be in the mid-40s), but it's been so cold for so long that the ground is frozen solid to a depth of at least six inches, and there is absolutely nothing green for the poor groundhog to eat.  And, we're not going to get above freezing for at least another two days, so there's not much green on this poor woodchuck's horizon.  Maybe it'll find some of the birdseed we distribute so liberally.

Monday, February 16, 2015

A Ray of Hope

On Friday morning, February 13, I joined my landscape restoration students for tours of an urban oasis featuring the latest stormwater management and native gardening concepts.  My graduate students gathered for their tour at 8:30 a.m., and then my undergraduates met at 11:00 a.m. for a second tour.  When we got to the site, the temperature was 8 degrees F, and the wind was blowing strongly.  To say it was cold was an understatement, and the temperature had only risen to about 18 when the undergraduates convened for the second tour.

The site was the Salvation Army's Ray and Joan Kroc Community Center in Philadelphia.  Ray Kroc, founder of McDonald's restaurants, and his wife, Joan, gave the Salvation Army over $1 billion to build community centers in severely disadvantaged urban neighborhoods across the country.  I'm not much of a fan of the Salvation Army (because of their discriminatory practices) and everyone has an opinion about McDonald's.  Our tour leader, Chris, shared my opinions about both organizations, but he conceded that the community center was a godsend for the impoverished neighborhood in which it was located and he commended the Salvation Army for its good deeds here.

The site had been a lightly-contaminated brownfield associated with the Budd Manufacturing Company, one of Philadelphia's largest employers when manufacturing was king.  Budd's thousands of workers built zeppelin gondolas, railroad cars, and airplane parts.  Today, the factory buildings are vacant, derelict and marred by graffiti.  The 13-acre Kroc site had been a parking lot for Budd's workers.

When the Salvation Army decided to locate the community center on the site, they hired the local but widely-renowned landscape architecture firm Andropogon (named for a genus of native grasses) to design the landscape.  With Philadelphia's extremely strict  stormwater management regulations, the Salvation Army insisted that the designed landscape capture, retain, and infiltrate as much water as possible.  Andropogon's designers also decided to make the project "zero waste" - no material would be removed from the site.

All of the existing parking lot pavement was either recycled to be reused for porous pavement on the new parking lot or was spread to level the site.  Slightly contaminated soil was buried deep under the site and encased in compacted soil.
Bioswale
The new porous pavement parking lot was divided into sections separated by bioswales.  Any stormwater which does not drain through the porous pavement runs into the bioswales planted exclusively with native species.  Stormwater which fails to infiltrate in the bioswales is gathered into one location and diverted to an extended detention and infiltration basin called Rain Garden B.
Roof stormwater management system
The community center building covers two acres.  The architects determined that installing a green roof would have been prohibitively expensive.  So, instead, they worked with Andropogon on an alternative.  Rain falling on the roof collects in three locations and spills into downspouts integrated into the building's design.  The spouts discharge into decorative runnels, which direct the water into one of two cisterns buried in the center of the site.  The cisterns were designed to supply water to the property's landscape irrigation system but, unfortunately, the irrigation system failed soon after it was completed and now the cisterns simply discharge into Rain Garden A when they are full.
Cleverly disguised downspouts and decorative runnels
Tour leader Chris demonstrating the capacity of the runnels
Small rain events fill just the central sculpted channel in the runnels, while larger events fill the broader channel.
Sculpted runnel designed to look like flowing water

Students standing at he edge of Rain Garden A that receives the discharge from the roof cisterns
All three of the rain gardens on the site were dry when we visited..  If Rain Garden A fails to infiltrate all of the stormwater it receives from the roofs, the excess water can flow into Rain Garden B, which collects water from the parking lots.  And, if Rain Garden B cannot infiltrate all of the water, the excess flows to Rain Garden C, which also includes a structural outlet to the city's stormwater sewers - a "fail safe" in the event of a major flood.  Chris emphasized that Rain Garden C had never spilled any water into the city's sewers since it had been built (though he admitted that we hadn't had a hurricane yet, either).
Rain Garden B on right of path
Last stop.  Rain Garden C, which can handle the overflow from A and B, if necessary.
The plantings in Rain Garden C included some bald cypress trees in the bottom of the basin.  Bald cypresses will survive this far north, but they are not part of the native flora.  I didn't challenge Chris on the issue, so I can't explain the reasoning behind planting cypress (versus a more northern species that could also tolerate wet feet like swamp white oak, pin oak, or sycamore).  With global warming, the cypresses may be very happy in the near future, but there was no evidence of global warming on the morning we visited!

Monday, February 2, 2015

A Century Later: Snowy Serenity

My county is creating a recreational trail on the unused rail line running through the middle of my preserve.  Full completion is scheduled for late summer 2015, but significant portions of the trail are in place and in use.

Kali and I have already developed a favorite loop hike that incorporates a section of county trail and the trails in my preserve.  We've walked it quite a few times.

Last Saturday was crystal clear but cold.  I suggested that we walk the loop, but Kali demurred because of the low temperatures.  So, I went out alone with my camera.  After I took the single image above, the camera's battery was fully discharged and I couldn't take any more images.  (Don't you hate when that happens?)
Sunday was warmer by about 15 degrees, but the sky was overcast.  Nevertheless, Kali agreed to walk the loop.  So, I took the same image in a horizontal orientation on Sunday.

This rock cut along the rail line right-of-way is of significance because this cut was the site of a horrific train accident on December 5, 1921.  Two passenger trains traveling in opposite directions collided head-on and the passenger cars caught fire.  Many passengers were injured and 16 were killed.  This accident was the "straw that broke the camel's back" with regard to wooden passenger cars; they were banned soon afterward.

Below are two historic images of the accident in the rock cut, which is now known as Death Gulch. 

Sunday, February 1, 2015

A Real Coup!

 
We've managed to attract a nesting pair of Bald Eagles to my preserve.  The nest is two miles from the Philadelphia city line in the most densely populated portion of the third most populous county in Pennsylvania.

There are other nesting Bald Eagles in similar situations in Pennsylvania; in fact, eagles are nesting in areas even more urban than my preserve.  The difference is that those nests generally are along large rivers that can provide a reliable source of fish.  My creek is far too small to be a dependable food source, and the fish in my creek are too diminutive to feed eagles and their offspring.  Furthermore, the creek ices over if it's really cold.

No, the draw isn't fish.  It's roadkilled deer.  Our organization collects deer struck on the roads surrounding our preserve - both as a courtesy to the municipalities and as a way to get biological information about the deer herd.  Once my staff has collected the carcasses, we place them in a an open field where they are quickly devoured by coyotes, foxes, black and turkey vultures, crows, and (this year) ravens and eagles.  We've seen eagles availing themselves of deer carcasses in the past, but always individually and always for just a day or so.  This is the first time a pair has decided that there's enough food to sustain a family.

The eagles took over a Red-tailed Hawk nest in a huge white pine tree and augmented it significantly.  There's no evidence of eggs yet, but there's still time.  The Game Commission said that the birds may be a young pair constructing a "practice nest."  Naturally, we hope they use it to raise a brood.

The image above was taken by a photographer who only identified himself as Frank when he sent it to me in an email.  The nest and this dead tree are about a third-mile from the best location for photography, so it takes a photographer with good equipment to capture a decent image.

Thursday, November 13, 2014

Schuylkill Banks (Urban Hike)

Pierce Park skateboard daredevils  with Philadelphia Art Museum in background
Kali and I have walked the "natural areas" within easy striking distance of our house so many times we decided we needed a change of scenery.  So, last Sunday (November 9), I proposed an urban walk though central Philadelphia.  When I reminded Kali we could stop for a gelato midway through the walk, she was hooked.  (I got a double with grapefruit and dark chocolate, and Kali got chocolate and pistachio, by the way).

While I like our urban walks in general (I love to go downtown), I had an ulterior motive for this trek (other than gelato).  The city of Philadelphia is gradually constructing a recreational pathway alongside the Schuylkill River (the city's "western" river, as opposed to the much larger Delaware that flows along the city's east side).  The recreational path and associated green space is called the Schuylkill Banks and it is immensely popular with walkers, runners, bicyclists,  skaters, and skateboarders.

The easy parts of the trail have been built, but the city ran into a dilemma where a set of freight railroad tracks was located very close to the edge of the river.  The city's solution for continuing the trail in this location was to build the trail out into the river on concrete pylons anchored into the bedrock below the silt.  Because the Schuylkill is subject to flooding and bears lots of flood-borne debris, the structure had to be very sturdy but also aesthetically pleasing.  I think that the city and its design team succeeded masterfully.  The trail surface is poured concrete etched to look like wooden planks. 
Kali about to enter the over-water section of the trail
Detail of one of the handsome granite entrance posts to the over-water section
Another entrance post detail
The over-water trail at river level
The trail currently/temporarily ends at the South Street Bridge (yes, that South Street made famous in the pop song).  There were literally hordes of people on the bridge taking pictures very similar to the one below.  I had to jostle to the railing to get a shot.  The over-water section of the trail has only been open for about a month, so it's still drawing plenty of touristas - including Kali and me.  The view below filled me with civic pride and gratitude that we're living near a vibrant, exciting city.
View of the over-water trail and Philadelphia from the South Street Bridge
After we walked the Schuylkill Banks, we headed into the city for our gelato fix.  Our route back to our car took us past the Philadelphia Museum of Art, which has added a considerable number of contemporary sculptures to its grounds.  The piece on the left in the image below is called Symbiosis, and depicts (in gleaming stainless steel) a broken tree that has crashed into and is partially supported by a smaller neighboring tree.
Symbiosis (left) and another structure whose title I didn't notice