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Archive for December, 2006

Thinking about the garden

Now that seed catalogs are piling up in the mailbox and the days are getting imperceptibly longer you may be thinking of the flower garden, or perhaps about planning a bit of landscaping.

After you’ve done a soil test and determined how much sun the site receives and how well drained it is you will be able to research what plants will do well there.

SketchA good way to start planning an ornamental garden bed is to sketch the current appearance of the site. You don’t have to be a good artist (clearly I’m not). Then photocopy the sketch and use the copies to draw out what you’d like the area to look like when it’s completed.

Use those garden catalogs to get an idea of what each plant will look like, how tall it will be, and how much space needs to grow.

Choose some native plants and you will attract native bees and butterflies. Learn a few principles of landscape architecture: use odd numbers of plants to make it look more natural, use repetition as a way to impose order and variation to add interest. Think about what flower colors go together, but don’t forget about foliage color and texture: coarse-leafed plants look closer than they are and fine-textured ones look like they are farther away than they are—adding depth to shallow or small gardens. If a plant goes dormant after blooming you can plant a later-season plant next to it to automatically fill in the gap.

Or just plant what you like—that’s what’s most important.

DiagramDiagram those plants to scale on a piece of graph paper—a two-dimensional aerial view of the garden. This helps you get the spacing right. Don’t forget to place a few flat rocks in the garden to use as stepping stones when you weed; they create a space to put your foot and keep you from compacting the garden soil.

Gardenbeds_1Then, voila! Plant your garden and you’re finished!

I will happily present a slideshow of how I employed this process to plan and plant the native garden in the barnyard at Crow’s Nest. Just give me a call to set one up.

Two years!

It’s now been two years (!) that I have been writing this Crow’s Nest Preserve weblog. It remains a joy to write and is beginning to serve as a bit of an archive for the preserve.

If you meet me on the street and ask me what’s new at the preserve, and I give you a blank look, it’s because I must have “downloaded” all the recent activity into the weblog. (I should just refer people here.) There really is a lot going on at Crow’s Nest, and if you include all of Natural Lands Trust, there is really a lot to keep track of. I enjoy having a place to write down and share just a small part of it.

Thank you to everyone who has donated time, money, supplies or services to Natural Lands Trust this year.

Happy Holidays and Best Wishes for the New Year.


Memo to self: Never store mid-morning snacks in the desk drawer at the office. I should have known better. We’ve had mice in the barn before, but never have they eaten so well.

By the way, I highly recommend the following book for learning how to get rid of uninvited visitors—whether they be ants, moths, garden weeds, fleas, or um, mice: Common Sense Pest Control: Least-toxic solutions for your home, garden, pets and community by William Olkowski, Sheila Daar, and Helga Olkowski (The Taunton Press, 1991). The key to the methods of Integrated Pest Management they describe is to identify the pest and then remove the habitat and food source.

Winter Solstice

It seems appropriate as we mark our entrance into winter that I try to answer that age-old question: What do you [preserve managers] do in the winter? Aside from updating the preserve weblog?

You can read what I wrote on this topic in January 2005 here.

Or just know that we are doing almost everything we do in the summer except mow the lawns and trails. Lately we have been brushcutting multiflora rose, barberry, and bittersweet—and there is a lot more to do this season. In winter most plants are dormant; an exception is evergreen Japanese honeysuckle. On some of the warm days we’ve had we were able to apply an herbicide without affecting the deciduous plants honeysuckle is growing over.

I don’t do much leaf raking. Since the visitor center is at the base of an oak forest on a hill, we do get many oak leaves blowing into the lawn. But then most of them eventually blow away into other woods. I only need to rake, mow, or vacuum them out of window wells on the barn and away from the sides of buildings where they accumulate. This is ongoing—it will be spring when we finish.

We’ll continue to remove some hazard trees along the roads, supervise a managed deer hunt, patrol & post the boundary, work with college students doing research and with elementary school students at WebWalkers and Spiderlings. We’ll host several trail club hikes. And we’ll be planning summer camp activities and marketing.

We’ll do some building maintenance, service some equipment, and purchase necessary supplies for ongoing projects and programs. And we’ll start drawing up a budget for the following fiscal year. Field staff will also monitor the conservation easements Natural Lands Trust holds—currently 14,000 acres to walk around this winter.

We will review the preserve’s prescribed fire management plan and prepare the scheduled meadow “burn unit” for a safe burn this spring. We’ll also be building raised beds for the vegetable garden where the kids will be growing food this year.

If it snows we will plow the parking lot & driveways and shovel the walks. And we’ll play that roulette game of waiting as late in winter as we can (to keep brushy habitat for wildlife) but not so late that the ground thaws—to do the annual mowing of our meadows.

Talk about the weather

Frost_1Today we had a heavy frost. No surprise there; it was about 22 degrees this morning. But even though the temperature rose into the mid-40’s this afternoon, there were still pockets of frost in the shade that never melted by late this afternoon.

You can certainly feel cold pockets as you walk around the valley that is Crow’s Nest. Cold air pours off the surrounding hills and collects in the hollows. The sun will do a better job of warming the ground in February—when it climbs higher—than it does now.

Wind Power and Bird Fatalities

"Nocturnal Bird Migration Over an Appalachian Ridge at a Proposed Wind Power Project" is a research paper published in The Wildlife Society Bulletin October 2006.  The authors (Mabee et. al.) studied night migration along an Allegheny Frontline in West Virginia in the fall of 2003.  They used an equipment van with a roof-mounted marine radar antenna to monitor flight direction, altitude, passage rates and groundspeeds.

I was interested by several things in this paper.  For instance, I learned that resident raptors were the main fatalities at older wind powered units in the U.S.  Because of this, most modern facilities study the behavior of diurnal species when planning the layout of the windmills.  This is great.

However, there are all sorts of other birds (and bats) that use the same ridgelines at night and at different seasons of the year.  In fact, more birds migrate at night than during the day.  The authors point out that much more research needs to be done in the planning of wind powered units.  For instance, this study was conducted for 6 weeks in the fall, during peak passerine (songbird) migration, however, "most bat fatalities at wind power developments appear to occur between approximately mid-July and late September (Johnson 2004)."  I also learned that songbirds migrate at much lower altitudes than waterfowl or shorebirds.  Their research corresponded with previous research that most songbirds migrate below 600 meters (above ground level).

A few more interesting points:  Most of nocturnal use occurred from an hour after sunlight until 2:00 a.m.  They observed relatively large flights of birds on about a quarter of the nights monitored.  The mean flight altitudes were above the proposed turbine heights, however, there were 5 nights when the mean flight altitudes fell to 200-300 meters.  Birds did not seem to use the Allegheny Frontline to migrate along; rather most of their observations had birds flying across instead of parallel to the ridgeline.  The authors felt nightly variations would be explained by weather and even the species of birds migrating.  Obviously, spring migrations weren’t studied in this research, but should be in the future.

I think the important point made by this research is that this equipment is capable of detecting night bird migration; and that with more baseline data humans will be able to predict where most bird strikes are likely to occur before the wind turbines are constructed.

Holly greens

HollyConsider the American holly (Ilex opaca). This one species illustrates one aspect of the complexity of conservation. Marlin Corn, Naturalist at the Churchville Nature Center (Bucks County), wrote about American holly—the conundrum of its being both threatened yet occasionally common—in his "Through the Eye of the Dragonfly" column in this month’s CNC newsletter, which prompts me to write about the holly here at Crow’s Nest.

American holly is both listed as a threatened species in Pennsylvania and yet is common locally. There are two simple reasons—and one complex one—why it is listed as threatened in this state. First, its native habitat is mostly in the Coastal Plain physiographic provence in Pennsylvania, most of which is the heavily urbanized Philadelphia metropolitan area. So habitat loss is one simple reason there’s not as much native holly here as there might be.

The second simple reason is that the political boundary of Pennsylvania is arbitrary with respect to plant ranges. There are more American hollies growing in other states, but Pennsylvania has only a little bit of what is thought to be the tree’s native range within its boundaries.

And the complex reason—a social factor—is that the greens are used for decorations. You can help protect American holly by asking for holiday decorations that are nursery-grown.

Yet holly is not entirely uncommon in our region. It is widely planted as an ornamental tree in our yards and—since birds eat and pass the red fruit—holly can spread and "escape" in nearby woods (Rhoads & Block, 2000. The Plants of Pennsylvania, University of Pennsylvania Press, p. 151). Holly has spread beyond the Coastal Plain by this partnership of humans planting trees and birds planting the berries.

For example, Crow’s Nest is located in the Piedmont physiographic provence—a more upland habitat that usually hosts a somewhat different community of plants than the Coastal Plain. But American holly appears here and there throughout the preserve, on the wooded floodplain of French Creek, and they are probably descendants of hollies planted in neighborhood yards.

But there is no guarantee that our "escaped" hollies are the same genotype (genetic variety) of holly that naturally occurrs in Pennsylvania—in fact it is likely they are not. Many hollies sold for landscaping are grown in nurseries in New Jersey and North Carolina and could represent genetically distinct, disjunct populations.

Ann Rhoads, the chief botanist at Morris Arboretum of the University of Pennsylvania, expressed concern about hollies she saw growing at Crow’s Nest some years ago. There is a continuum between the subset of garden plants that escape cultivation and the subset of those that naturalize (establish self-replicating populations in the wild) and then the subset of those that are invasive (grow aggressively and displace other plants to the detriment of these other species). A tree that is threatened in its native habitat can be a pest in another habitat. Wouldn’t it be amazing that a single species could be both threatened and invasive in different habitats within the same region or state?

(The tension here is perhaps in the definition of "species," since that term is a container that holds a variety of related individuals and populations, but sometimes so varied as to want to be split into different species.)

Another factor that could (in theory) threaten Pennsylvania’s native hollies is that their genetic distinctiveness could be lost by interbreeding with imported ones, creating yet other genotypes. This genetic "swamping" occurs with small remnant populations that become surrounded by a related but distinct population of the same species. I don’t know how likely this is to happen with holly, just that it has happened with other species.

One more piece of background is necessary to this story: American holly is diecious: there are male- and female-flowering trees. Only female trees produce the lovely red fruit, but to do this the female’s flowers need to be pollinated by an insect that also visited a tree (just one) with male flowers that are open at the same time.

So with the knowledge that I didn’t want to spread more holly through the preserve but wanting a holly for screening in the yard, a few years ago I bought a small American holly from a Pennsylvania nursery at a native plant conference. It was listed as a male tree—so no fruit—that would have been grown as a cutting from an open-pollinated native male tree. So this tree wouldn’t be setting seed, though of course it could be causing female trees in the same area (within the flight range of a bee, which can be considerable) to be more fruitful.

But look at the photo above. The "male" tree turns out to be bearing fruit! I don’t know much about holly, so I don’t know whether it was a simple mistake at the nursery or something else. There are plants and animals that change gender based on environmental conditions, a factor that can improve the population’s ability to sustain itself. Are these fruit viable? I haven’t experimented with them (yet).

I don’t plan to remove this holly in the near future, and I won’t discourage anyone from growing these beautiful trees, particularly if you can find a local nursery propagating Pennsylvania natives. But it does make you think about how a seemingly simple decision of what to plant could have wide-ranging consequences.

Winter Programs – January 2007

WebwalkersflyersIt won’t be long until our winter WebWalkers and Spiderlings programs start—Thursdays and Fridays beginning January 25 and 26. We’ll be mailing out these flyers right after the holidays.

We’ll be holding after-school sessions on Thursdays and Fridays and have added a daytime WebWalkers program for homeschooled kids on Friday mornings. The theme this time is "Things We Cannot See," which describes a lot of things at the preserve that are inside something, under something else, or are too small to immediately catch our attention.

We’ll be going outside for a hike during each session and will have time for games and indoor activities too. The fee for each six-week program is $25/child. For more information or to receive an application please call me at 610-286-7955.

Restoration Update

LukeblacksmithWe are very fortunate at Crow’s Nest to have very talented staff and contractors working on our building restorations. In between projects this morning I went over to see Luke DiBerardinis forging the hinges for the barn doors. If you want to see some great photos of Luke blacksmithing go to professional photographer Jared Castaldi’s website.

Barn_wingThen at lunchtime I went to take a photo of a set of Luke’s hinges just installed on a door on the wing of the barn. I caught the low winter sunlight reflecting off the driveway on the other side of the barn. Luke, his father Scott, and Steve Holmburg and Bob Johnson built everything you see in this photo except the 1915 silo on the left.

Oldbarn_4Then I dug through some older photos and found this photo of the barn and wing in December 2001, five years ago almost to the day. The before-and-after photos alone don’t tell the story of how much work this project has been. The interior workshops are nearing completion and will provide space for storing and maintaining equipment and woodworking.

Trash Surfacing

DumpYou might not believe this photo was taken at the preserve (it was). You might also not believe that the surface of this old bottle dump was entirely cleaned up a few years ago, but the volunteers who helped with project would again back me up. We pulled a whole truckload out of here, well, it’s been about five years.

It was once a common practice on old farms to throw trash away in a pit or over a bank behind the house, a practice that today is unacceptable.

By the same physical process that causes our farm fields to "grow" rocks—larger "particles" rise to the top with the freezing and thawing action of the soil and are exposed by erosion from rain—the dumps continually disgorge their contents. (Modern landfills are lined and capped to prevent this from happening.)

This dump, one of at least three at the preserve today, is currently yielding items from perhaps the 1960’s and ’70’s, sort of the end of the era when most household items were packaged in glass. (It is interesting to see familiar brands packaged in thick blue or brown glass instead of the plastic we’ve grown used to.) There are also children’s toys, leather shoe soles, and ceramic insulators for electric fencing.

CollectionThe more interesting stuff we find ends up on a shelf in the library at the visitors’ center. The rest ends up bagged and sent to another landfill. (I am aware of some irony in this, but figure it is better not to have the trash on the surface of the ground at a nature preserve.)

We don’t plan to excavate this dump, located along a spring that feeds a high-quality wetland. Digging causes too much erosion and creates the ideal condition for weeds. But we’ll continue to pick up what surfaces; I picked up the visible trash today and will be back with volunteers again in April.

It’s too bad we’ll never be able to bring the kids to this part of the preserve for nature programs. But I am interested in the history of what we find here.


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