Greedy Gardeners - NYTimes.com ROOFTOP vegetable gardens were one thing, but the urban agricultural movement has gone a step too far. A new brand of activists want to incorporate fruit trees into the fabric of city life by turning our limited green space into woody groves filled with apples, cherries and plums. One group, the Guerrilla Grafters, has gone so far as to graft the branches of fruit trees onto street-side ornamental trees in San Francisco. At first blush these campaigns appear well intentioned. The groups are planting trees in underserved neighborhoods to provide access to healthy foods. What could be wrong with that? Don't misunderstand me, I like fruit as much as the next person. It's not the orchards themselves that irk me - it's the shortsightedness they represent. By so narrowly defining useful landscapes, the craze to farmify our surroundings has made it all about humans. There's nothing wrong with a utilitarian view of nature. The problem is that we are ignoring the utility of plants like wildflowers and native ornamentals in favor of imported fruit trees. All around us, even in cities, there are natural processes at work that we depend on. Although largely overlooked, these "ecosystem services" are critical to the survival of our species. Pollination is one such service. The transformation from flower to fruit does not happen in a vacuum. Plant sex requires an intermediary, in this case, wild bees. They do the work of spreading pollen from flower to flower - a sperm delivery service. Though European honeybees were imported to pollinate our crops, our native wild bumblebees and other insects pollinate a significant portion, and may be more productive. The results help fill our produce aisles. One study placed the monetary value of pollinating the world's main food crops at over $200 billion in 2005. Though we pay these insects not a penny, we are deeply in their debt. A farm-filled landscape would undermine this critical ecological process. Bumblebees rely on wildflowers for a steady supply of pollen and nectar. But fruit trees bloom for only a few weeks a year. When forests and meadows are lost (to development or farming), places for bees to eat also disappear. These wild bees feed us, but we are not feeding them. The craze for farms has even reached our urban parks. When the High Line, the former railroad-turned-park, opened in Manhattan, the editor of the design magazine Dwell praised the park's success. But he said nothing about the wildflower beds weaving through the abandoned tracks, yearning instead for the addition of "vegetable gardens or chicken coops." Yet landscapes designed solely to put food into our mouths result in the further loss of winged wildlife. A better way to reimagine our public spaces is through the multifaceted eyes of insects, the original locavores. The foodies among us will note that sassafras, a local woodland tree, is the source of root beer. But its true gift to us is the gorgeous spicebush swallowtail. The caterpillars of this native butterfly are picky eaters. They feed on the leaves of sassafras, spicebush and closely related woody plants. This butterfly, which is also a pollinator, is not able to survive on cultivated plants like peaches and cherries. Most commercial fruit trees, and food crops for that matter, hail from other ports of call. A monoculture of exotic imports offers little nourishment for our wild neighbors. But plants that have been here for thousands of years are in constant communication with insects. A chemical cue here, a flash of color there, so goes the ecological dance in which native pollinators and other insects participate. A study published early this year in the Proceedings of the National Academy of Sciences found that bumblebees preferred to forage at sites with a greater variety of plants and more floral choices. They would like our landscapes to look more like diverse natural meadows than single-species farm fields. Such considerations are paramount in cities, where open space is in short supply. Urban activists should celebrate the indigenous wildflowers that sustain our pollinators beyond the short life span of fruit tree blossoms. In addition, we should incorporate native edibles into the planting palette. Blueberries, Juneberries and beach plums feed more species than just us humans. Here is what you will not see in a vista full of fruit trees: a surge of migrating monarchs, a dizzying constellation of wild bees, the swoop of songbirds that feed on them. These natural phenomena still occur in cities, but have been marginalized. They should be reclaimed and put center stage in our public spaces. To do this, we need urban oases filled with native plants. With all we are continually discovering about the world around us, let's not limit ourselves to supporting only what directly fills our stomachs. A rich natural environment also provides what is on our plates, while nurturing our heads and our hearts, too. Mariellé Anzelone, an urban conservation biologist, is the executive director of NYC Wildflower Week.