We have picked three pies worth of cherries from our two backyard trees, and more are ripening every day. The birds and the squirrels are taking their share, but so far their depredations are nowhere near as bad as I had expected them to be. I had fantasies of sitting on the back porch with a .410 shotgun in a futile attempt to defend our crops from clouds of starlings darkening the skies. More rationally, I looked into the possibility of draping netting over the trees to keep the birds off. In my wildest dreams I imagined a pair of Cooper's hawks building a nest in one of the many tall trees in our neighborhood and patrolling our backyard for us.
Our cherry trees are feeding a nice selection of neighborhood birds, including starlings, house sparrows, robins, cardinals, blue jays, and grackles. The regular grackle flock includes a bird just out of the nest that perches with dozens of ripe cherries in easy reach and begs its mama to feed it. She of course obliges. For all this activity, our trees appear to be just one of the stops on the birds' daily round, not the focus of all their efforts. Our neighborhood seems to be a rich environment, and that allows the birds to spread their demands. Also they mostly take the fruit at the very tops of the trees, and we can't reach them anyway.
Our harvesting equipment consists of an ancient wooden stepladder left behind by the previous owners of our house. It is eight feet tall and weighs--I would estimate--about 700 pounds. Despite its weight, it is very rickety. Climbing above the fourth rung is terrifying, so fear effectively sets the altitude limit on our cherry collecting.
Sour cherry trees bring back all sorts of happy childhood memories for me. We had a tree in our backyard, and my grandparents had a really large tree next to their farmhouse. When the cherries ripened I used to climb the trees and eat the fruit right off the branches. A cherry plucked from the stem and popped into your mouth is about as fresh as fruit can get. And then there is the challenge involved in seeing how far you can spit the stone.
When I talk about my childhood cherry eating, some people wrinkle their noses. They take the name of the fruit too seriously. The cherries are actually tart rather than sour, and when they are fresh they are wonderfully flavorful. And every once in a while you come across one that is really sweet.
Sour cherries were domesticated in Asia and brought here via Europe. They are Prunus cerasus. The genus Prunus also includes sweet cherries, plums, and peaches. The fruits of all these are classified as drupes, which means they have a fleshy outer layer surrounding a very hard inner layer, the stone. If the hardness of the stone does not deter animals from eating it, the prussic acid that many Prunus stones contain is a very good way to ensure that nobody eats more than one.
Plants of the Chicago Region by Floyd Swink and Gerould Wilhelm lists nine species of the genus Prunus that have been introduced into this area. Seven of these are from the Old World, and two are from elsewhere in North America. None of these is at all common in the wild, so if you come across a Prunus in the forest preserves the odds are that you will be looking at one of our six native species.
Wild plums--Prunus americana--are tall shrubs that were a major presence in native savannas and shrub lands. They are still around, but probably less common than they were in presettlement times. Native shrub lands have become one of the rarest natural communities in our area. We have lands that are structurally similar--that is, they contain a mixture of shrubs, grasses, and scattered, usually small trees. But the precise species mix--wild plum, hazel, scarlet oak--of the old shrub lands is very hard to find.
Shrub lands have become a conservation concern in the midwest. Shrub-land birds such as loggerhead shrikes, blue-winged warblers, and yellow-breasted chats are declining. The loggerhead is already listed as threatened in Illinois and is a candidate for listing at the federal level. The removal of fire from the landscape is at the heart of this problem. Without fire, midwestern shrub lands rather quickly become woodlands; the invading trees alter the habitat enough to drive out the shrub-land species. But in the fragmented conditions of the contemporary landscape most woodland species cannot get to the newly created woodland habitat, so what we have is a weedy, impoverished community with a superficial resemblance to a woodland replacing both native shrub land and the structurally similar simulacra of recent times.
Just a few decades ago shrub-land species seemed to have all the habitat they could use. As conservation agencies took over old fields and turned them into forest preserves, state parks, and national forests, shrubs invaded the old croplands, opening up vast realms for chats, blue-wings, shrikes, and other shrub-land species. However, the days of large-scale land acquisition are mostly over, and the shrub lands are passing away.
One of the common trees in the new young woodlands is Prunus serotina, the black cherry. Black cherry fruits are clustered in long, slender bunches that hang from the tips of twigs. The drupes are small; a large one might be a half inch in diameter. These fruits really are sour, but the birds seem to like them--and that is the secret to the black cherry's ability to invade young woodlands. Many plants have evolved seeds that can pass through the digestive tracts of animals without damage. Sprouting tomatoes are a fairly common sight on sludge farms. Some seeds even require exposure to digestive acids to soften their seed coats enough to allow germination.
In a fragmented landscape black cherries are as mobile as birds, a fact that gives them a competitive edge over many other species. Our drastic alteration of the landscape produces some changes that are immediately obvious. Others are more subtle and may not reveal themselves for many decades. When we alter the competitive balance among various trees in a woodland we can change everything from the soil chemistry to the amount of light that reaches the ground. These changes in turn can produce population increases for some species and declines, even extirpation, for others. The changes happen in ecological time, and by the time the results are known it may be impossible for us to trace them back to their original cause.
Gastronomically speaking, the best of our local wild cherries is Prunus pumila, the sand cherry. This is a low shrub rather than a tree, and in suitable habitat it can form substantial thickets. Sand cherries are very common on the dunes along the shores of Lake Michigan. They sometimes actually invade the beach, but their more usual haunts are on the low dunes dominated by shrubs like bearberry or juniper. You can find them at both the Indiana Dunes and Illinois Beach State Park. Doubtless they were once common along the Chicago lakefront as well.
You can also find them inland on sand prairies and savannas. The Braidwood Dunes Nature Preserve in Will County has lots of sand cherries.
The fruits of sand cherries are large, succulent, and sweet. When ripe, their skin is darker than a Bing cherry. Unlike our sour cherries, they mature in late summer. I have a happy memory of a visit to Sleeping Bear Dunes National Lakeshore in Michigan when my daughter was six. We wandered over the high dunes on a sunlit day, cooled by a breeze from the lake and gobbling sand cherries until our hands were purple with the juice.
One of the best things about eating cherries fresh is that you can just spit out the stones. Cherries in pies have to be pitted, and this is a tedious process. We have a cherry stoner--also left by the previous owners--but I have to say that the design needs some work. It uses a plunger to poke the stone from the cherry, but often the stone does not fully detach, so I have to pull it off by hand. We are going to freeze most of these cherries in pie-sized batches for use this winter. We are not looking to add a chipped tooth to our memories of cherries.