From the Field - Crow's Nest Preserve

A gardening warning

It is a beautiful day outside, and I know what you gardeners are thinking. You want to be out there in the yard, cleaning up and maybe turning over the soil.

Don't. It's too wet. The ground is still frozen a couple inches down and the surface is sticky. Manipulating soil while it's this wet will cause it to lose its structure—the arrangement of soil particles and air space. Plant growth will suffer.

Spring will be along soon. Start seeds indoors or go out for a hike—just be sure to wear boots.

More from the tractor seat

Farmers all know this, but perhaps other people don’t: John Deere (the person) never built a tractor. He lived from 1804 to 1886, before the motorized farming age. Nevertheless he arguably was a key figure in farming mechanization, since his company first manufactured self-scouring cast-steel plows, originally horse-drawn, that till and turn the soil. This was an early part of a transition from pastoral farming techniques to modern mechanized farming, with all of its simultaneous benefits and problems.

Even though our tractor (which we use for mowing, not plowing) can take a much sharper turn than a car, our four-wheel drive tractor doesn’t turn quite as easily as the old narrow-wheel row-crop tractors. Ours does has the right- and left-hand brakes that help the tractor pivot, but this is more effective on plowed soil than on the wildflower meadows we mow—the pivot can “turf” the vegetation down to bare soil.

So the pattern I choose when I mow meadows minimizes the turns the tractor has to make. Sometimes this pattern is a series of ever-narrowing concentric circles around the field, spiraling down until just the middle is left. This is the way we mow the lawn here, but that is with a zero-turn walk-behind mower. With the tractor those last few stripes require a series of three-point turns, or backing up over some distance.

With some of the fields I instead apply a lesson I learned from watching a Zamboni (tm) dress ice at a rink. The first pass goes up the center then loops around one side, and then the oval loops—each is the same size—keep moving across the rink until all the ground is covered. At either end the ground is mowed multiple times, but the tractor never needs to stop, reverse, or do a three-point turn.

From the tractor seat

Our tractors have come a long way in the fifteen years I’ve worked for Natural Lands Trust. In the “old days” we were using old two-wheel drive tractors that lacked rollover protection—often what came with a farm when we protected the property. The tractors lacked power brakes so it was essential to choose the correct low-enough gear when mowing down a hill. Too high a gear and the tractor would run away with you. We still use gears to determine working speed, but it’s nice to know modern brakes could stop you if you need to.

Four-wheel drive also offers a major safety advantage: most tractors are safer when they are pointing face-front down a hill; they are far less likely to flip over forward than backward (or sideways). But a two-wheel drive tractor cannot back up a steep hill easily, for example when you meet an obstacle ahead, or you’re mowing a slope above a pond, or you need to get to the top of the hill again to mow the next strip of field. The vehicle weight transfers to the front wheels backing up a slope and two-wheel drive tractors, even with ballast, may just spin their rear wheels. Four-wheel drive allows you to use the vehicle in the safer face-downhill orientation.

Our tractor is twelve years old, and yet has just 1,200 hours on it. That’s not a lot compared to a farmer’s, but we get a lot of utility out of it. In addition to mowing meadows and trails with it, we move loads of wood chips for the trails, haul logs from hazard trees and load them on the sawmill, rip out old fences, and use it to lift other things too heavy to lift by hand.

Yesterday I spent a few hours on the tractor: one job was one where I would rather drive over the hard snowpack than sensitive turf: I moved six loads of horse manure from our neighbors’ barnyard to our compost pile.

Then a delivery of recycled plastic landscape timbers arrived and I used forks on the tractor’s loader to help get them off the tractor-trailer. We’re going to use these timbers to build raised beds for the teaching garden. Raised beds offer many advantages to garden plants and the recycled plastic lumber should last a very long time and won’t leach toxic chemicals into the soil.

Each landscape timber contains 350 recycled milk jugs. So that stack contains 13,500.

I finished the morning by mowing a little more meadow. It felt like very productive time spent.

Regional Cooperation

Over the weekend I met with the board and volunteers from the Open Land Conservancy of Chester County to discuss management strategies for invasive plants on their lands.

This has to be one of the oldest land trusts in the country—it was founded in 1939 and protects hundreds of acres on their preserves and through easements in the Great Valley in Chester County.

If you'd like more information about the Open Land Conservancy please give me a call, 610-286-7955.

Winter Mowing

The thermometer read 7 degrees this morning when I got up. And the forecast called for a high of 18 in Philadelphia (we are usually a few degrees cooler here).

“It’s a perfect morning for mowing meadows,” I announced.

On the preserves we try to mow the meadows as late as we can in winter and yet while the ground is still frozen to minimize damage to the fields and soils. We’re also trying to keep the tall grasses up as late as we can for winter cover for wildlife and because they are beautiful.

The tractor has four-wheel drive, so it isn’t likely to get too stuck in thawing mud, but ruts would compact the soil and alter surface hydrology by collecting water and either creating a wet spot or draining an existing wet spot. And I abide by the saying, “Having four-wheel drive just means you’ll be farther from the road when you get stuck.”

So we mow when the ground is frozen. It’s best when it is below 20, and preferable before the sun has warmed the ground. Even then you have to keep an eye out since Crow’s Nest’s fields have a number of surface springs with groundwater flowing that never substantially freeze.

If we can’t finish the fields in winter we wait until mid-summer after ground-nesting songbirds would have fledged.

How cold was it today? There was ice on the inside of the barn windows. The camera stopped working after a few minutes outside.

I mowed for over four hours at a rate of about an acre an hour. We have been spreading out the mowing over the course of a couple weeks to minimize the impact on wildlife. Today’s mowing represents a small but substantial part of our remaining meadows.

I mowed a strip that buffers a wooded spring, the perimeter of a field we will burn this spring, and half of the field around the Chief’s Grove.

A personal aesthetic preference for neatness, and my work ethic (to do a thorough job) tries to compel me to mow the entire field to an even height. But I know that it is better to create a patchy meadow, leaving some areas unmowed, to leave a more varied and diverse habitat (much as a prescribed fire does). I cut most of the woody plants that would otherwise invade the meadow, but I left patches of grasses standing here and there.

It was pretty uncomfortable to sit mostly still (just steering, occasionally braking or shifting gears) on this winter morning (by midday the temperature rose to 15). But the results should be worth it.

Research & land management

This past semester students enrolled in Patty Zaradic’s Senior Seminar in Ecology at Bryn Mawr College prepared papers on research they conducted at Crow’s Nest Preserve.

The themes were based on evaluating the ecosystem services of various aspects of the preserve. Topics included the value of native bees at the preserve in pollinating local crops, the values (and strategies for conserving) native plants, the value of carbon sequestration in the preserve’s trees, the economic value of deer management, and the ecosystem services performed by beavers.

The students visited the preserve and in some cases laid out study plots. In other cases the preserve was compared with data collected elsewhere. We scoured our records for plant lists and poured over maps (ground-truthing the data on the maps with current land use conditions). We surveyed hunters and compared the data with statewide trends.

The projects pointed out a need for more raw data from the preserve: we haven’t done a blooming calendar in several years and we can always use more baseline species and natural community lists.

And the projects also pointed out some ways we might adapt our management of the preserve: for example, leaving more areas in a 2 – 3 year rotation of succession (rather than annual mowing of meadows) conserves habitat for a greater diversity of native bee species.

Over the next few weeks I will write a short description of the projects on the weblog and some of their implications.

This week I am cutting multiflora rose and vines with a hand held brushcutter, selectively cutting back the undesirable species while preserving as much as possible of the native vegetation. Some of the areas I am working in have been cut and sprayed before so I am just doing a very precise follow-up to the earlier work and it is progressing more quickly than the original management. Other places I am just getting to for the first time and I am using a power-pole pruner (a chainsaw on a pole) to cut the thick bases of the invasive species.

Continuous improvement

I try to manage the preserve using a principle of continuous improvement. Each year, things get a little closer to ideal: the trails become a little more visitor-friendly, the habitat improves, and we expand our programs.

This means that when the boardwalk gets rebuilt, it has to be better than the one I built before (not necessarily a tall order for some potential Eagle Scout). Each year when I repost a section of the property boundary I try to have it be more accurate. Our resource inventories gradually become more complete, the hazard trees reduced, the buildings in better repair. And although invasive plants are increasing everywhere, I hope to manage them in a new section of the preserve each year, or get to a project that I never was able to before.

These are not small tasks in the face of the entropy that happens everywhere around us: rust, rot and gravity rule as a part of the cycles of life.

Of course the ideal of continuous improvement doesn't apply everywhere. For example, when I put up the Christmas lights at home, I don't try to make the display bigger and better each year. If I had, by now the house would be visible from outer space...

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.

A 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.

Diagram 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.

Then, 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.

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.

Trash Surfacing

You 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.

The 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.