Thursday, January 28, 2010

LOOK FOR: Rock Tripe, Fungi That Have Discovered Agriculture

"No one truly knows the woods," argued illustrator and naturalist Ernest Thompson Seton (1860-1946), author of early Boy Scout handbooks, "until he can find with certainty a number of wild plants that furnish good food for man in the season when food is scarce; that is, in the winter or early spring."

rock tripe, Umbilicaria mammulata
Photo credit: Paul J. Morris
And Seton's favorite wild edible at this famine time of year? Rock tripe. Which tells you something about the availability of wild foods in winter. I've never eaten tripe (cow intestines), so I'll have to leave it to others to say whether it's an apt description. But I suspect this cardboardy lichen got its common name because it's pretty low on the food totem pole. Rock tripe, Seton wrote, "is not delicious food, nor is it highly nutritious, but it will sustain life, and every traveler should know what it is like and how to use it."

Rock tripe grows in ragged pieces that people describe as looking like lettuce leaves or dried orange peels. They can grow up to 8 inches across, but most are probably in the 2 to 4 inch range. Each piece is anchored to the rock at a small spot in the middle, giving the lichen its Latin name: Umbilicaria. The top can vary in color from brown to grey, and the underside is darker -- often black. You'll often see it growing in clusters, covering the surface of a large boulder. Keep an eye out when you're walking in a rocky place, like the parks along the Potomac.

To me, the most interesting thing about rock tripe is the fact that it is not actually one organism, but two. Lichens, as you may recall from biology class, consist of a fungus living in a symbiotic relationship with algae. Or, as lichenologist Trevor Goward puts it, "lichens are fungi that have discovered agriculture." The fungus provides a structure that retains water and captures minerals; the algae photosynthesizes to provide sugars that are also food for the fungus. Together, they can colonize areas where neither fungi nor algae would otherwise survive.

rock tripe, Umbilicaria mammulata
Photo credit: Paul J. Morris
Unlike most mushrooms and plants, lichens persist year-round. And, rock tripe has been shown to contain one-third more calories than equal amounts of honey or corn flakes. Perhaps this is why rock tripe has been eaten for centuries, at least as a survival food. The Cree apparently included it regularly in soups as a thickener; other Native American tribes used it as a food of last resort. And it was from the tribes that European settlers learned the value of this strange food. Washington's troops are said to have used it to help them survive the winter at Valley Forge.

Should you eat rock tripe? We've been known to nibble on a piece now and then, just because we can. We just break a small piece off and chew (and chew, and chew). Folks who've had more experience with the stuff say that if you're going to eat a lot, it's best to dry it, then boil it for about an hour, which will soften it up considerably.  As with all wild foods, check your identification and be sure of what you're working with. And, start with a small quantity until you have a sense of how your body is going to react.

Here's hoping you're never in a situation when you're eating rock tripe out of anything more than curiosity. 

Tuesday, January 26, 2010

Rainy Day Nature: Planetariums in the DC Area

Some friends of ours are making an effort to learn a little astronomy, since their four year old seems to be taking a natural interest in the stars and planets (hi Solomon!). But it's awfully chilly to be outside at night right now, even if the darkness does start nice and early. Which led us to say, hey, aren't there a couple of planetariums around DC? Turns out, there's more than a couple.

illustration outside the Rock Creek Park planetariumWe've been to the one in the Rock Creek Nature Center (5200 Glover Road, NW; 202-895-6070). It's a small 75-seat space but the rangers do a nice job of putting together a variety of programs. In general, they have the following schedule of 45-60 minute, age-rated shows (check this week's exact topics here):

  • Saturdays and Sundays at 1:00: ages 5+
  • Saturdays and Sundays at 4:00: ages 7+
  • Wednesday afternoons at 4:00: ages 4+
Tickets to Rock Creek Planetarium shows are free and can be picked up at the information desk in the Nature Center a half hour before the show.

einstein planetarium ticketsThere's also the Einstein Planetarium at the Air and Space Museum (1-877-932-4629). With a 70-foot dome and 233 seats, it's a totally different experience from the planetarium at Rock Creek Park. Their website touts that "you'll feel the sensation of zooming through the cosmos, enveloped in color saturated moving images and spine-tingling sound." They offer 25 minute shows every half hour, from 11:00 to 5:00.  Tickets for these shows are $8.75 for adults, $7.25 for youth. But there are also FREE shows at 10:30 AM on selected days, including Saturdays (see schedule).

In addition to the two planetariums we knew about, we were surprised to discover that several local school systems have planetariums. These are used primarily for school groups, but also offer programs for the public. 

Prince George's Howard B. Owens Science Center in Lanham (9601 Greenbelt Road; 301-918-8750) has a 55-foot dome with 174 seats -- the largest planetarium in Maryland. Public programs are on the first Friday of every month during the school year. Tickets are $4 for adults and $2 for students and seniors. (Power Point slide of this spring's programs here.)

Arlington's 70-seat David M. Brown Planetarium (1426 N. Quincy St.) offers a kid-oriented public program on Friday and Saturday evenings and Sunday afternoons during the school year (it appears to be the same show every time; see schedule).  They also hold a program on the first Monday of the month that focuses on the current night sky and includes an interactive talk with the planetarium director, followed by the opportunity to use outdoor telescopes if weather permits. Tickets for all events are $3 for adults, $2 for children and seniors.

At 24 feet wide and just 42 seats, the Montgomery College planetarium (about 7651 Fenton Street; see directions) is pretty tiny. But it was an exciting find, since it's right down the street from us! It's open to the public for free shows once a month or so during the academic year, on Saturday nights at 7:00 (see schedule). Compared to several other planetariums, the show topics appear to be more adult-oriented (Space-Time Invariance and Quantum Gravity, anyone?). Shows are followed by the opportunity to use telescopes outdoors, weather permitting.

Even smaller, the Alexandria planetarium at TC Williams High School (3330 King St., 703-824-6805) has just 35 seats available, so they require advance registration for their monthly hour-long shows (see schedule).

Have you been to any of the shows at these planetariums? Leave a review in the comments section -- it'll take us a while before we make it to all of them!

Like the photos in this post? Mouse over for credits; a click takes you to the photographer on Flickr.

Saturday, January 23, 2010

Links: Back from Costa Rica Edition

We've been back from Costa Rica for a week and a half, but it feels like we're just now adjusting back to being home. It was beautiful -- there was ocean, there were mountains, there were waterfalls, and there were lots and lots of critters. We sat for hours and watched monkeys swing through trees. We tromped around in the rain and looked for quetzals. And we couldn't walk long distances because we kept stopping to look at birds. And that's the way we like it. Costa Rica doesn't have the same edge as some other places in Latin America that we've travelled to -- there's no "if I eat this, will I be puking my guts out tomorrow?" and a lot less visible poverty. Sometimes it feels a little like Disneyworld, full of tourists. But it's no Disneyworld -- that beauty is real, and they've done a great job of protecting it. Our pictures are here.

Have you taken our survey yet? We'd love your feedback on the Natural Capital. This is your chance to tell us what you missed -- and what you didn't -- while we were gone. And you can win some of our favorite native plant seeds for filling it out!

Other things that caught our eye this week:

And a quote for your week:
"In wilderness I sense the miracle of life, & behind it our scientific accomplishments fade to trivia." - Charles Lindbergh
See you out there!

Thursday, January 21, 2010

LOOK FOR: Squirrels (It's Squirrel Appreciation Day!)

squirrel in DC
Photo credit: Vicki's Pics
I'll admit it: we here at Natural Capital headquarters have a love-hate relationship with squirrels. They're fun to watch, chasing each other around our yard -- especially when they leap heroically from tree to tree. It's adorable when they squat on their hind legs to nibble on a tasty morsel. It's not so adorable when that tasty morsel is a tomato from our garden, somehow lugged all the way across our yard and nibbled on in front of our sliding glass door, seemingly just to taunt us. And it's been years since we've attempted to keep a birdfeeder -- the birds don't have a chance against our squirrels (and the English sparrows, but that's a complaint for another day).

squirrel on tree
Photo credit: Bob Travis
But today is Squirrel Appreciation Day, or at least, wildlife rehabilitator Christy Hargrove of Asheville, NC, thinks it should be. It seemed like a fitting time to reflect a little on these furry sometimes-friends.

The squirrels you see running around in woods and yards in the DC are generally Eastern gray squirrels (Sciurus carolinensis). They've got brownish grey fur with white-tipped hairs, and lighter grey bellies.

Except when they don't have grey fur at all: the Washington, DC, area has a unique genetic diversity amongst its Eastern grey squirrels. In the early 1900's, several Canadian squirrels were released on the grounds of the National Zoo, probably in an effort to boost the local population (which had been depleted from hunting).

black squirrel
Photo credit: ehpien
Those Canadian squirrels were the same species as our locals, but they looked different -- they were all black, not grey, possibly as an adaptation to gather a little extra heat in the winter. These black squirrels have integrated with our local squirrel population, and slowly increased their range -- you can now see their offspring throughout the area.

soundboard.com
soundboard.com
It's easy to see squirrels, and everyone knows what they look like. But do you know what they sound like? Listen to these clips -- they're probably familiar sounds. But you may have thought the chirps and chatters were birds when you heard them. Keep an eye out the next time you hear one of these noises in the woods -- you'll probably be able to find a squirrel perched in a branch, unhappy about your presence or some other happening in the area.

Do you have any good squirrel stories? Post them as a comment for Squirrel Appreciation Day!

Tuesday, January 19, 2010

Enter to win seeds from some of our favorite native plants!

As we enter a new year, we'd love to get your feedback on how we're doing here at the Natural Capital. As a little incentive, we'll select three responses at random to receive some seeds from some of our favorite native plants: cardinal flower, rose mallow, and Joe Pye weed. Start them in your yard, or scatter them in a wild place you visit. Just answer the 7 questions below, and be sure to click the "done" button when you're done. (If you don't see a survey below, click here.)

Thursday, January 14, 2010

LOOK FOR: Hemlock Trees (While You Still Can)

Eastern hemlock, tsuga canadensis
Photo credit: lumierefl
Eastern Hemlock (Tsuga canadensis) is a majestic tree sometimes called the "redwood of the East." They can form tranquil evergreen groves in the understory, but really, they're just waiting for their big break. When a tree falls and opens a spot in the canopy, hemlocks will shoot up -- eventually reaching heights of 80 or even 100 feet over their 350 year lifespan. In the second-growth forests of the DC area, though, you'll see only scattered trees, and they're rarely taller than 15 or 20 feet tall.

Because they're evergreen, this is a great time of year to look for hemlocks, when other trees have lost their leaves. The needles of hemlock will help you distinguish this tree from other evergreens in our area: they are flat, about 3/4 of an inch long, and grow in a plane off the twigs. The overall form of hemlocks can also be distinctive:  branches grow horizontally from the trunk, but are floppy on the ends as the twigs haven't hardened up yet. Up close, you may notice very small cones on the trees -- they look like pine cones, but much smaller.

cones on eastern hemlock (Tsuga canadensis)
Photo credit: DaveSF
The genus name, Tsuga, is a Japanese word supposedly meaning "mother tree." Unfortunately the relationship between North American and Japanese hemlocks is not so nurturing. Around 1911, some imported hemlocks bound for a Japanese garden in Richmond came bearing an insect known as the hemlock woolly adelgid (uh-DELL-jid). This relative of the aphid is just a minor pest in Japan, where it's got several predators and the trees have some natural resistance. For our local Tsuga canadensis, though, infestation by the woolly adelgid is usually fatal within 4 to 10 years.

It wasn't until the 1980's that people started noticing that the adelgid had spread from ornamental plantings in Richmond to native trees in York River State Park and Shenandoah National Park. By the mid-90's, the adelgid had spread to Connecticut and Massachusetts, and it is now considered established throughout the hemlock's eastern range, from Maine to Alabama. Experiments are being done with the release of adelgid-eating beetles from Japan, but results don't seem very promising, and many stands of hemlock have already been lost. (To see some of the destruction to old growth hemlock groves, see this video from the Charlotte Observer.)

eastern hemlock (Tsuga canadensis) at Scott's Run Nature Preserve
Hemlock at Scott's Run by the Natural Capital
There are two morals to this story. First, garden with native plants, so that you don't unwittingly import a pest that will devastate an entire species. Second, get out there and appreciate what we've got, while you can.

In the wild: We're not aware of any really large hemlocks in the DC area (do let us know!) but there are still some small hemlocks scattered in our local forests. The most we've noticed are at Scott's Run Nature Preserve in McLean -- they grow right along several of the trails there (like the one shown here).

In your yard: It's probably better not to bother planting hemlocks unless and until someone figures out how to control the adelgids. Too bad, because they're beautiful trees.

Tuesday, January 12, 2010

Keep Winter Cold - CCAN's Polar Bear Plunge

On the morning of January 23, at least 350 people will jump into the Chesapeake Bay in Annapolis to raise money and awareness for the need to stop global climate change. The Polar Bear Plunge Team asks:

What if winter were no longer cold?  What if there was little or no snow for skiing, no hard frosts to kill off insect pests or bring out the sap of a maple tree to make that delicious syrup?  How would polar bears and other animals that need the cold survive?
With climate change legislation pending in the Senate, this is an important opportunity to draw attention to alarming signs of global warming. Climate scientists report that arctic sea ice is melting faster than predicted, and that the top of the world could be free or nearly free of summer sea ice by 2013 or even earlier. This would mean almost certain extinction for polar bears - and a potentially catastrophic jolt for global climate patterns.

And so, once a year, we take this chance to get up close and personal with what winter feels like -- while we still can. Matt's taking the plunge. Will you join him, or sponsor him? The polar bears could use your help.

Need more inspiration? Check out this video from last year's plunge: