The notion that selecting the “no active management” option will perpetuate the status quo is wrong. When it comes to forested wildlife habitats, change is constant. It's automatic. As long as the sun shines and trees grow, habitat changes accompany a centuries-long continuum of forest succession.

An example: Hay meadows and livestock pastures quickly revert to rough weeds and small tree seedlings in the absence of active mowing or grazing. In a matter of months, coarse milkweed and thistle replace grasses. The next year, thorny shrubs and young tree saplings crowd out and shade all the sun-loving pioneers. Soon, the juniper, gray birch and poplar that colonized an open, sunny pasture are choking in the shade of oak and fast-growing white pine that eventually yield to shade-tolerant beech, maples, hemlock and spruce.

Successional changes to former farm fields and young forests have decreased a statewide abundance of avian habitat specialists. Whipoorwills and brown thrashers favor a mix of dry oak forests, open field edges and shrubs. Eastern rufous-sided towhees favor the dry blueberry and black huckleberry understory of once-bald mountains ringed by dry oak and pine forest. These dry heathlands develop beneath pitch pine and red pines on granite mountain tops prone to frequent lightning fires.

Old apple orchards interspersed with pasture and shrubs are favored by blue-winged warblers and Eastern bluebirds. More actively mowed fields and pastures in regions of dairy farming support bobolinks. Eastern meadowlarks need a threshold of no less than 400 acres of open pasture or mowed hay meadows.

Doing nothing does not maintain habitat or the views and blueberries which often compel people to climb hills in summer.

The state's forests are ever-changing — and they are aging. Like birds, some “specialist” trees might one day become less common, or eventually be counted among the missing. Foremost on the list is our state tree. White birch, a tree cloaking the White Mountains, as a legacy of turn-of-the-century logging and fires. Century-old paper birches are now declining throughout the White Mountains because of age-related effects.

The recent 10-year update to the U.S. Forest Service's “Forest Inventory and Analysis” data reveals New Hampshire now has a higher percentage of forest — 85 percent of the state now forested. Yet, more than half the timberland in New Hampshire — 57 percent — is older than 61 years of age.

As forests age, they change composition. A higher percentage of our state's forestland is now growing more shade-loving hemlock, beech, yellow birch and red or sugar maple. While many people think older forests and larger trees sound great, those species of wildlife and trees dependent on young forest conditions might disagree.

Only 13 percent of the state's forest is now less than 40 years old. Seedlings, saplings and small-diameter, brushy forests of sun-loving trees, such as paper birch, pin cherry and poplar, are less common. These “pioneer species” cannot establish in partial shade. They require larger cleared openings to regenerate and survive. Think “shopping mall parking lot” size without asphalt. Large clearings allowed to regrow new forest sustain hot, dry micro-climates that these trees need to establish, compete and thrive.

Healthy statewide forests communities include a range of different tree ages, sizes and species. In that sense, forests are analogous to healthy human communities with diverse age profiles.

Naturalist Dave Anderson is director of education and volunteer services for The Society for the Protection of New Hampshire Forests. His column appears once a month in the New Hampshire Sunday News. Email him at danderson@forestsociety.org or through the Forest Society Web site at forestsociety.org.