Wissahickon Part 2: Forbidden Drive

Bell's Mill Road Bridge, viewed upstream

After Kali and I finished exploring Houston Meadows (previous post), which is located on a high, flat bluff above Wissahickon Creek, we descended the steep valley slope to the stream.  An old carriage road parallels the western bank of the creek for seven miles.  Because vehicles are prohibited from using the old road, it is called Forbidden Drive.  Forbidden Drive is one of the most heavily used recreational amenities in the city, with walkers, runners, equestrians, and bicyclists all mixed together in a generally congenial stew. 

Wissahickon Creek downstream of Bell's Mill Bridge

The land that is now Wissahickon Valley Park was a colonial industrial valley with mills and roads throughout.  The city bought the land in the late 19th century because Wissahickon Creek empties into the Schuylkill River just upstream of the city's drinking water intake, so the city wanted to try to preserve water quality in the Wissahickon and the receiving stream.  Nearly all vestiges of the industrial heritage are gone, but many of the stone ruins and the bridges that bore roads over the creek remain.

Blue wood aster (Aster cordifolius) and Wreath goldenrod (Solidago caesia) on the wooded streambank

Forested slope with denuded understory

White-tailed deer have been very abundant in the park.  As a result, nearly all of the forest understory is gone, and few sapling tress are growing to replace the old trees when they die.  For the last decade, the city has hired sharpshooters from the U.S. Department of Agriculture to cull the herd.  The sharpshooters hunt at night over bait, and the venison is donated to local food banks.  Nevertheless, animal rights group protests are a constant thorn in the city's side over this issue.  The culling has significantly reduced the number of deer, and the forest has begun to recover in places.

Parasitic beech-drops (Epifagus virginiana) in a patch of sunlight

One of the reasons that the Wissahickon is so popular is because it is very scenic.  The creek has cut a deep gorge though very hard rock, so the valley slopes are steep with lots of scenic boulders and bedrock exposed.  Because of the steepness, only one old road crosses the valley directly (Bell's Mill Road, the picture at the head of this post), and few roads penetrate down to Forbidden Drive.  Rex Avenue (image below) is one of those roads that descends from the eastern side of the valley and terminates at Forbidden Drive.

Rex Avenue Bridge

Old park guardhouse along Forbidden Drive

Covered bridge, the only one in Philadelphia

Invasive Japanese angelica-tree (Aralia elata), left, and Japanese knotweed (Fallopia japonica)

Wissahickon Creek rapid

Forbidden Drive

Forbidden Drive is not one of Kali's favorite walks because it is dark and claustrophobic; she much prefers the sun and openness of Houston Meadows.  However, I like the views of the creek and the general sense of community among the users.

Turf War

Like so many lawns in the Mid-Atlantic, my back yard has become a war zone - albeit an aesthetically pleasing one.  Some previous occupant of my house planted spring bulbs years ago, and Kali and I continue to enjoy the vernal exuberance of grape hyacinths, daffodils, crocuses, and the delicate blue flowers picture above, chionodoxa or glory-of-the-snow (Chionodoxa siehei).

More recently, the extremely aggressive non-native buttercup lesser celandine (Ficaria verna) managed to get a foothold in the lawn.  Lesser celandine prefers moist riparian areas, but once it gets established, it will grow in just about any situation.  (Naive visitors used to ask me if they could dig up a few plants to add to their garden; I assented, but always warned the folks that the plant would take over anywhere it was planted.  I suspect that most people now recognize the plant's aggressiveness because I almost never get such requests any more.)

It will be interesting to see if one or the other of these plants will win this slow-motion combat.  I once asked Pennsylvania's premier botanist if celandine really does exclude other plants because it is only a obvious player on the ecological stage for about a month, after which it disappears until next spring.  The botanist assured me that celandine definitely excludes other plants.  Perhaps there's an unseen, subsurface front in this war as well. 

Arboreal and Spiritual Rescue

Protecting a tree sapling in a wire cage

We've had perfect autumn weather this year in the northern Piedmont, and today was no exception.  So, I decided to "fly the coop" for an hour or so this morning to take care of two trees in serious need of attention.

I've got five guys on my stewardship (i.e., maintenance) staff who should be doing this kind of job. However, because the weather was so nice, and because it would have been harder to tell the guys where the trees were located than to just do the job myself, I went out in the field.

The first tree, a linden (or basswood) with a diameter of about 8 inches, was being rubbed by white-tailed deer bucks almost to death.  When rutting season comes around, the deer rub their antlers against trees they find suitable and, in the process, scrape off the bark.  If they scrape the bark all the way around the tree, it will kill the tree.  For some reason, the deer seem to find basswoods irresistible, and they will savage any specimen that is not adequately protected.  My staff either encloses the trees in wire cages or they wrap large trees with burlap sacks.  In the case of the basswood tree I went out to rescue, the burlap bag had slipped down and the trunk was exposed.  So, I firmly reattached the bag and I enclosed the tree in a wire mesh cage.

The second tree I went to rescue was a red oak sapling whose protective wire cage had been completely overwhelmed by the insidious invasive vine porcelain-berry.  Imagine the tree being planted in the image at the head of the post completely blanketed by a mass of vines and you get the idea.  I cut away and uprooted the vines, replaced the wooden stakes supporting the cage, and generally tidied up the planting spot - I'm an "anal" neat freak.

While I was working, a man stopped to tell me that there was a sizable snapping turtle alongside the trail about 50 feet away.  I had just walked the trail to get to the tree and hadn't even noticed the turtle, which looked like a big, gray rock when I went up to see it.  Cool!  Then, when I went back to the tree to finish up, a woman walked by and thanked me for saving the tree.

She went on to say that my preserve is the one thing in life that keeps her sane and she didn't know what she would do if she couldn't walk the trails and rejuvenate her psyche.  She knew my name (though I didn't recognize her), and she concluded by thanking me profusely for being the heart and soul of the preserve.  She told me that she had so much gratitude and appreciation for me and and my commitment to the natural world.

Deferential type that I am, I sorta' gave her an "Aw, shucks" response.  But, you know what?  She really did lift my spirits.

Invasive Aliens and Alien UFO

A splendid late summer view of my preserve's meadows

A former member of my land stewardship staff, Mike, moved on five years ago to become the land manager at a preserve owned by another land conservancy in our area.  I consider Mike a colleague, and I contacted him when Temple University (where I am an adjunct faculty member) needed an individual to teach a class on invasive organisms.  It was a match made in heaven (both for Mike and Temple), and Mike is now teaching the class for a second year.

Mike (second from right) holding forth on restoration strategies

On Thursday, September 17, Mike brought his students to my preserve to examine invasive plants (no shortage of them here, unfortunately) and our organization's restoration projects.  I spent the morning outside (a rarity for me) accompanying the class as we walked about three miles through the preserve.

Handling (carefully!) an American chestnut burr

One of our stops was a reforestation area planted in 1994.  We incorporated pure American chestnut trees into the reforestation project, and now the trees are 30 feet tall and producing fruits (more appropriately called burrs).  The trees are all infected with the non-native chestnut blight fungus, but they are pumping out burrs like crazy nonetheless.  The burrs are really prickly and painful to hold; I don't know how squirrels manage to get them open.

Preparing for liftoff

After the walk, Mike brought out his drone to show the students how these devices can be useful for examining the landscape from the air.  He flew the drone about one mile away and returned it to the launch site, a tour that took 9 minutes.  The drone has the capacity to fly for about 18 minutes on one battery charge.

UFO spotted over the preserve

Mike remotely piloted the drone to fly over the meadows and woodlands of the preserve, and then to circle the tower on the right (one mile distant) in the image above.  All the while, the drone was sending back remarkably clear video that Mike recorded on his iPad.  He promised to share the video with me; if he does so, I will post it later.

Late Summer on the Trail

Japanese angelica-tree (Aralia elata) seeds

It's been a while since I've posted (mostly because Kali's broken foot kept me from getting out much during her four-week convalescence), but her cast came off last Tuesday, the crutches are stored in the attic, and Kali is, once again, driving herself to and from work.  On Saturday afternoon, we took advantage of her new-found freedom and nice weather to walk on the level, even-surfaced rail-to-trail pathway in the county park downstream of my preserve.  It was the longest walk Kali had taken in five weeks, so we started out slowly; she was only able to walk a mile before her foot began to hurt and we turned around, but in that distance I got some late summer images.

Kali on the trail

One long section of the trail is bordered by dense growth of non-native, invasive Japanese angelica-tree (Aralia elata).  This plant is closely related to native Aralia spinosa, which is also known commonly as Hercules'-club or devil's walking stick. 

Aralia alongside the trail

Aralia branch and flower/seed stalk from below

Angelica-tree and Hercules'-club have the largest leaves of any plant in the mid-Atlantic.  Each leaf is pinnately compound, with a dozen or so leaflets strung along a central rachis.  The tree produces tiny white flowers on feathery pink flower stalks, giving the plant an interesting and unmistakable appearance.

Aralia leaves and flower stalks from above

Aralia gets its common name of devil's walking stick because the stem and even the leaves are liberally  festooned with defensive thorns.

Aralia stem

There were lots of weedy late-summer native plants producing seeds and fruits along the route...

False climbing buckwheat (Polygonum scandens)

Bur-cucumber (Sicyos angulatus)

The trail heading north along the west bank of the creek flowing about 20 feet below.

The creek photographed downstream

...and there was no shortage of non-native invasive plants, too, in addition to the Aralia.

Mile-a-minute weed (Polygonum perfoliatum) with blue seeds favored (and spread) by birds

Japanese knotweed (Fallopia japonica)

Porcelain-berry (Ampelopsis brevipedunculata) - the bane of my professional existence

Autumn was just beginning to make its advent apparent in the trailside foliage.

Flowering dogwood leaves (Cornus florida) on the woodland edge are turning maroon

Great Blue Heron fishing the creek's shallows

Several groups of skittish Wood Ducks in autumn eclipse plumage were cruising the creek.  I captured the image below with my telephoto lens extended to its maximum, and then I further enlarged and sharpened the image digitally, so the quality is not great, but it was the best I could get.  When enlarged, I think the image looks a little Impressionistic as a result of my manipulations.  Wishful thinking...?  What do you think?

Wood Ducks on the creek

The creek at the north end of our walk

Invasives Dystopia

I've been asked to give the keynote address to a regional gathering of Garden Club of America clubs in October.  The theme that the organizers chose for the gathering is "invasive plants," which gives me a lot of leeway for my talk.  I'm going to focus on introduced ornamentals that have escaped and become invasive pests.

One of the organizers wants to create a poster board of "bad actors," and she wants to include Japanese knotweed (Fallopia japonica) among the plants.  I needed to find images of knotweed for her, and on the way back from the grocery store yesterday I saw a perfect patch just begging for a photograph.  So, I parked and walked over to get some shots.

The area is on the floodplain of a small tributary to my creek just upstream of my preserve.  It is - to put it bluntly - an invasives hell.  An ecological nightmare.  A complete write-off.

The floodplain is an impenetrable thicket of Japanese knotweed.  It's 10-feet tall - the tallest knotweed I've ever seen.  But wait, there's more!  The knotweed is being over-topped by porcelain-berry (Ampelopsis brevipedunculata).  And, just outside the area where the knotweed is so thick, there's a thriving stand of purple loosestrife (Lythra salicaria).  About the only plant I didn't notice was mile-a-minute weed (Persicaria perfoliata), but it certainly could have been there amid the green chaos.

I will admit that bees were enjoying the scene - and not just non-native honeybees, but native bumblebees, too, so I guess the site is not a complete write-off.

Invasive Gulch

Knotweed in flower

Porecelain-berry is rapidly engulfing the trees in the background

The land is owned and managed by the municipal wastewater authority.  Although the site is at the intersection of two fairly significant roads, the wastewater authority doesn't do much to maintain the property.  They probably don't know what to do (repeated herbicide applications would be appropriate), but they do try to mow it down occasionally.  I've tried to talk to them about management, but they're in the wastewater treatment business, not invasive plant control, and I've gotten nowhere with them.

Knotweed (background) and purple loosestrife

Purple loosestrife (mostly) with a little porcelain-berry in the foreground

Of course, since the stream is a tributary to my creek and is upstream of my preserve, all of the propagules produced by these noxious weeds flow downstream and end up you-know-where.

The knotweed in the foreground is being over-topped by porcelain-berry

Summer Snowstorm

Look carefully for the "snowflakes" against the dark trees in the background

We're experiencing a "snowstorm" in my preserve this month.  Non-native Canada thistle (Cirsium arvense) (a real misnomer and a "slight" to Canada since this thistle is actually a native of Eurasia) has exploded in our grasslands.

The culprit in flower

All stages -  from flower to fluff

The incredible infestation is the result of a perfect storm of unfortunate events.  First, our boom sprayer was out of commission in the spring so our land manager couldn't spray the thistle when it was most susceptible.  Second, the herbicide we've been using to try to control the thistle, Transline, seems to be losing its effectiveness, so we're going to have to find an alternative.  And third, by the time we realized the mess we were going to be in, migratory birds and rabbits had begun to nest in the fields, so we couldn't mow the thistle to prevent it from going to seed.

A patch with countless seeds

Non-native wineberry (Rubus phoenicolasis) cloaked in thistledown

Everything in the fields that's not green is thistle

One silver lining to these thistledown clouds: the American Goldfinches (Carduelis tristis) are having a field day (so to speak) feasting on the abundance.

Down to Seeds and Stems

We've had generous numbers of American Robins (Turdus migratorius) around my preserve all winter.  There are always robins here during the winter, but we seem to have more than the typical number this winter - despite the fact that there's more snow and longer-lasting snow cover than usual.

Because the snow has lasted so long, I (and other birders) have been wondering what the robins have been eating.  Though they are insectivores and carnivores during the growing season, they rely on fruits and berries during the winter.  However, they long ago stripped all the crabapple trees and holly shrubs of their berries.  What's left?

When Kali and I took a walk on Sunday afternoon, I noticed a small group of robins perched in a tree, flitting from branch to branch.  When I pulled up my camera with the telephoto lens, it became clear what was happening: the robins were eating fruits of invasive alien Asian bittersweet.

I knew that robins ate bittersweet arils (along with the berries of invasive Japanese honeysuckle and the hips of alien multiflora rose), which helps to spread the plants, but this is the first time I had seen them in action.  In addition, one of our strategies for managing our preserve is to try to eliminate as many of these alien plants as possible, so I feel a little guilty about reducing the winter birds' food sources.  On the other hand, the birds can always seek food in warmer climes, can't they...

The image above depicts an Eastern Bluebird (Sialia sialis) nesting box adorned with an icicle.  Bluebirds, also thrushes like robins, switch their diet in winter, too, and we host many bluebirds in the preserve as well.