Sunday, July 31, 2016

Delight and Tragedy in a Summer's Downpour

Water's capacity for delight and destruction was on full display yesterday during an extraordinary downpour. It provided definitive proof, as if any more were needed, that we must work with nature rather than against it.

When the rains began, I was just finishing an enjoyable tour of my friend Suzy's garden in Lawrenceville. She brought me in to consult on what plants to keep and which to remove. Suzy was one of the founders of the Whole Earth Center, nearly 50 years ago. The rain provided a chance to see how her roadside garden captures and channels runoff from the street.

Using stones to manipulate the water's flow, her gardener Andrew Thornton has created whimsical, Inca-like channels for the water to follow, feeding the native sedges, ferns and wildflowers as it heads down the slope.

The rain got very dense, and I retreated to my car to drive home to Princeton. Coming up 206, the street had already become a river, even though I knew the worst of the storm was yet to come. I began to think of places to go to see what the water was doing. The middle of a storm, if there's no lightning, is the best time to check out Princeton's water works, or water wrecks, depending.

Then I remembered the high school, and had a sense of foreboding. The school had flooded in 2009, due to poor design of an addition along Walnut Street. The basement, cafeteria, hallways and offices were flooded, and the performing arts stage had to be replaced. I had repeatedly warned the various powers that be that a repeat was very likely, and had offered a solution, but no action had been taken in all of those years. This storm felt very much like 2009's.

I arrived to find Walnut Street completely flooded. When the underlying stormdrains are overwhelmed, the street becomes a river that actually flows towards the school. That's the performing arts wing on the right, and the detention basin/wetland on the left. People have tried to blame the wetland plantings in the basin, but we have shown that the real problem is that Walnut Street is higher than the school. 

Water flows downhill, and went straight from the street down into the school's basement. In the past, the facilities crew has placed sandbags here to block the water, but staff probably live too far from Princeton to respond in time to a sudden storm. And it was only a matter of time before that bandaid approach would fail.

Some of the water from Walnut Street seeped under doorways and into the bandrooms and hallways.

Here, I found, was an entrance on the north side of the performing arts wing that led directly to the wooden stage. The drain that would normally take this water away was overwhelmed and useless. Will the stage be warped by the moisture, and have to be replaced yet again?

In the middle of this photo, taken nearby at the entryway to the performing arts center, you can see water coming out of the drain, rather than disappearing into it. Overwhelmed, the drains actually begin contributing to the flooding.

The wetland is in full bloom, and the plants should be fine. Despite their seeming mass, they do little if anything to affect the capacity of the basin, which was not designed to hold water coming in from the street.

What prevented even worse flooding was the driveway across the street leading into the Westminster property. A PHS science teacher, Tim Anderson, and I had recommended to the school that the curb on the Westminster side of Walnut Street be lowered, so that water, instead of flowing into the high school, could be channeled safely away,

into the Westminster's big field. That field, too, could be planted with beautiful sedges and wildflowers, like the PHS basin/wetland. The field is a designated wetland and cannot be developed, and Westminster Choir College would be motivated to assist, given its periodic use of the high school performing arts stage.

I hope our proposal will now be taken seriously. Risks of PHS flooding would be greatly reduced, and the neighborhood would become even more attractive and colorful. Big storms will bring not emergency workers but neighbors out to see water working its wonders in nature's garden. Work with gravity, work with nature. Please!

Update: The high school's wooden stage did in fact sustain water damage and had to be replaced--for the second time in five years. Here's a widely viewed video of floodwater cascading down into the high school basement.

Wednesday, July 27, 2016

Changing of the Guard in the Backyard

There's a changing of the guard in the garden, that is, the guardians of nectar. Flowers of July--Culver's Root, beebalm and tall meadowrue--are yielding to some of the flowers of August--rose mallow hibiscus,

cutleaf coneflower,

and Joe-Pye-Weed.

Meanwhile, a young American elm, so appealing in its shape and ambitions, has designs on the sunlight the flowers have had up to now. This is a guardian of a different sort, a guardian of shade, which means there's a decision to be made, sooner or later, between one and the other, by the guardian of balance.

Thursday, July 21, 2016

When a Leaf Is Not a Leaf, and a Grass Is Not a Grass

The kids were having a gas, literally and figuratively, up at Hilltop Park last week when I went to lead a nature walk for Stone Hill Church's annual summercamp. Our Friends of Herrontown Woods nonprofit has been partnering now and then with Stone Hill Church, which borders Herrontown Woods up on Bunn Drive. Not easy to compete with bubbles on a summer's day, but even in a park that's mostly turf and trees, there's always some aspect of nature to point out. One of the counselors noticed large dragonflies cruising above the lawn, probably munching on tiny insects as the campers paused to eat their own snacks. I showed the campers how to identify a white pine (needles in clusters of five, just like the number of letters clustered in "white"), and how to tell that what looked like seven leaves on an ash tree was really only one compound leaf made up of seven leaflets. Tricky stuff.

A closer look at the ballfield revealed that what looked like grass wasn't necessarily grass. If you see light-green splotches in lawn this time of year, chances are you're looking at nutsedge, which looks grass-like but is actually a sedge. And how do you tell a sedge from a grass?

Pull one up, look at the stem and you'll see it's triangular. Roll the stem between your fingers and you'll see and feel that "sedges have edges"--the three edges of a triangle. Most sedges are native perennials typically found growing in wet ground, but the nutsedge is a nonnative that spreads quickly through gardens. Chances are, the kids could go home and find nutsedge invading their parents' garden. (see last photo in this post)

Another weedy plant flourishing in the ballfield was a round-leaved creeper named ground ivy or gill-over-the-ground.

Here's how it spreads, by sending out shoots above ground that make new plants. This weed too is common in gardens. If you want to prevent it from coating the ground, it's easier if you pull out the new extensions before their roots get too established. One could say its presence in the field is good news, in that it indicates that broadleaf herbicides aren't being sprayed on the grass.

Here's the typical look of nutsedge spreading through a garden. It lifts pretty yellowish seedheads to the sky while sabotaging the intended neat formality of a row of Liriope.

Later on, the campers got to appreciate nature in another way, sitting in the comforting shade of an ash tree while listening to a fireman talk about safety in the home.

Wednesday, July 13, 2016

Why the Native/Non-native Distinction Matters

Here are two examples of leaves being stripped by insects in the backyard. One example is likely harmless, and actually shows that there's a functional foodchain in this backyard habitat. The other signals the arrival of yet another severe blow to our local ecology.

Most people recognize jewelweed, the annual with tubular orange flower that feeds hummingbirds, and has a fleshy stem that some use to rub on poison ivy skin rash. The flowers hang like earrings, and turn into spring-loaded seedpods that are fun to put in the palm of the hand and explode. Used to seeing it grow robustly in low wet areas, I was surprised this morning to find one defoliated.

A few new leaves had sprouted from stems made bare by a caterpillar.

Closer inspection showed a busy caterpillar on the underside of new leaves. Some internet research (here and here) suggests there are several species of moth that feed upon it.

Though this one plant was defoliated, others in the garden are prospering. If the caterpillar is native, one can assume it's been consuming jewelweed for thousands of years, and so poses no threat to its favored plant species' survival.

Here is a much different situation--an arrowwood Viburnum showing signs of insect damage. Chances are good that this native Viburnum, which has flourished for a decade in our backyard, is not being eaten by a native insect with which it has coexisted for millenia. More likely the hungry caterpillar is the Viburnum Leaf Beetle. Imported from Europe, it has been spreading across the eastern U.S. Since it did not evolve here, the native Viburnums have had no chance to develop defenses to limit its consumption. As with the Emerald Ash Borer that is beginning to devastate our ash trees, the introduced Viburnum Leaf Beetle will likely cause radical changes, not only in our forests but in backyards as well.

Local nature, in effect, is sustaining one body blow after another, due to the introduction of non-native species, some of which unleash radical change. It's important to note how our world is being transformed by unintended acts while the news media focus on intentional acts of destruction. If a rogue arborist began randomly cutting down people's trees and shrubs, there'd be a great outcry and the destruction stopped. But if an accidentally introduced insect does the same, causing millions of dollars in damage, its accepted with a shrug and a sigh. Add the collateral damage known as climate change into the mix, and you see how profoundly vulnerable is our world, no matter how big the military or well trained the police force.

A useful approach to defining "native": 
There's a lot of confusion about what the word "native" means, and why it's an important distinction in ecology. Some contend that all plants and animals are native to the planet, and so all species should be welcomed everywhere with open arms. That supposedly openminded point of view requires denying the reality of co-evolution. It's really quite simple. When plants and animals evolve together for thousands of years, they adapt to each other's presence. A balance develops, in which plants evolve chemical or physical defenses that discourage animals from eating them into oblivion. Animals, in turn, develop the capacity to crack those defenses sufficiently to get the food they need to survive. There's a balance of consumption.

Here's a well-written column explaining how differently a plant like garlic mustard behaves where it evolved, vs. after being introduced to a new continent.

Sunday, July 10, 2016

July Flowers

Purple coneflowers greet passing traffic on Harrison Street.

Backyard buttonbush thriving in the runoff from the neighbors' yards.

Some leaves on the buttonbush were fashioned into a webby tent for a clutch of baby spiders--by the spider, not by me.

Culvers root just beginning to open its long lines of flowers.

Towered over by a pokeweed (Phytolacca americana), which looks like it has aspirations to rival its tree-like relative in the pampas of South America called the Ombu (Phytolacca dioica). Flowers tba.

Clouds of tall meadow rue attract tiny bees.

A good year for elderberry, and just about everything else.

Sunday, July 03, 2016

Young Black Bear Spotted in Princeton

Seen in Herrontown Woods yesterday, Saturday, July 2, the black bear was moving through town today, and was on Fisher Ave (near Harrison St and Hamilton Ave) around 8am. The police and animal control officer are aware, and say that the bear is not aggressive. The PlanetPrinceton facebook page is a good place to get updates.

It's a good time to brush up on etiquette for black bear encounters. How you should respond to a black bear is completely different from the recommended response when encountering a grizzly bear out west.

This is serious business, of course, but after reading the state's recommendations, which call upon us to exhibit considerable self-control and courage, you can find below a comic version customized for Princetonians, which I wrote in 2012 after a presentation on black bears at town hall.

At the presentation last month on black bears, given by state officials in township hall, I was astonished to learn that, in the very rare case that a black bear attacks, the best tactic is to fight back. Princetonians have not been called upon to display such courage since 1777, when we all could conveniently claim we had yet to be born. 
To bridge this gap between experience and expectation, I herein provide a translation of the wildlife officials’ instructions, customized to fit the Princetonian lifestyle:
Black bears are near-sighted, so make noise to avoid surprising it. If the bear stands up on its hind legs, don’t worry. It’s just trying to see you better. Make sure the bear has an escape route. For instance, if it is following you out of the public library, hold the door open and give it plenty of room. If you encounter the bear in the woods, or on Nassau Street, you can back away slowly, but don't turn your back to the bear. In a calm, assertive voice, put the bear on notice that you are a Princetonian fully armed with opinions, and will not hesitate to express them. 
Avoid eye contact. If it doesn't run away right off, bang the pot you happen to be carrying with you, or download a "kitchenware noise" app on your iphone. Bears hate to cook, which explains their interest in garbage. Otherwise, clap your hands, raise your arms over your head, wave a jacket, all of which should make you look large and impressive.
On rare occasions, the bear will do a bluff charge, at speeds up to 35 mph. If a cafe is close by, this is a good time to duck in for a double latte. If that option is not available, then you'll need to dig deep. Fleeing will only make you appear weak. Perhaps the stirring words of a high school football coach will come to mind. In any case, stand your ground, wave your arms and shout. Pretend you're in front of town council, venting your outrage over moving the Dinky. The bear should veer away from you at the last moment, providing a bigger thrill than any 3D movie at the mall. 
If the bear actually attacks, which is extremely rare, it's time to drop all remaining pretense of civility. Fight back. Don't worry about the bear's lack of access to dental care. Without asking permission, bop it on the nose. Bears' noses are 100 times more sensitive than ours. Use this sensitivity to your advantage, all the while reveling in what a great story this will make to tell the grandkids.
In case you surf the internet for more info, don't be confused by accounts of how to behave when encountering a grizzly bear out west, where the protocol is completely different and not nearly so gallant.July, 2012