Family Forests Are the Ties That Bind the Landscape

Family forests have an enormous capacity to provide ecosystem services such as clean air and water, timber and nontimber forest products, wildlife habitat, and scenic beauty and recreation — benefits that stretch far beyond property lines.

Riitters and Costanza studied changing landscape patterns over a 10-year period to assess threats to family forests. Photo by Larry Korhnak, Interface South.

According to USDA Forest Service research, sustaining these services depends on not only the condition of individual family forests but also the characteristics of bordering lands.

“If the expansion of an urban area results in the loss of forest or if forest land is converted to farm land, an adjacent family forest’s ability to sustain ecosystem services is threatened,” says Kurt Riitters, research ecologist with the Eastern Forest Environmental Threat Assessment Center and the lead author of a study published in the journal Landscape and Urban Planning. “The effects could even be felt across a regional area.”

Riitters and co-author Jennifer Costanza, a North Carolina State University landscape ecologist and Center cooperator, assessed the threats to family forests by measuring changes in the landscape around them over a 10-year period.

They focused on changes in interior forest (unfragmented areas that maintain critical habitat and ecological functions) and human interface zones — areas bordering family forests that comprise urban development and agricultural operations.

The researchers consulted 2005 data from the Forest Inventory and Analysis (FIA) program. For more than 132,000 FIA data collection plots, they categorized lands as family forests, non-family forests, and public forests.

They compared landscape patterns from 2001 and 2011 on lands surrounding these forests and determined the proportion and status of interior forest cover. They did the same for developed and agricultural surroundings.

Researchers mapped changes (in percent) in interior forest land between 2001 and 2011.

According to the 2005 FIA data, family forests covered 43 percent of total U.S. forest area, with more family forest area concentrated in the East. The researchers examined the patterns of areas around family forests. “Our results showed that landscapes containing family forests exhibited substantial changes over a relatively short period of time,” says Riitters.

By 2011, 46 percent of family forest land area was in a human interface zone, an increase of 1.5 percent since 2001. In comparison, 19 percent of non-family forest area and six percent of public forest area was in a human interface zone. Thirty-three percent of family forest area was in an agricultural interface, a zone that has been linked to ignition of wildland fires and the spread of exotic invasive plants.

Just 29 percent of family forest area was considered interior forest by 2011. Percentages of public interior forest and non-family interior forest were 48 percent and 36 percent, respectively, reflecting trends of a global loss of interior forest.

“While fragmentation rates are higher on private land than public land, most interior forest is still privately owned because most forest area in the U.S. is privately owned,” says Riitters.

When forest is lost due to urban expansion, an adjacent family forest’s ability to sustain ecosystem services is threatened. Photo by Larry Korhnak, Interface South.

Considering the amount and distribution of family-owned U.S. forest land (it exceeds corporately owned and public forest land in 27 of 50 states), the importance of conserving the family forest network should not be underestimated.

The study also identified broad areas where conservation of family forests and interior forest in particular could be targeted and leveraged to achieve far-reaching impacts. These areas include the eastern Great Plains steppe and parkland, Midwest broadleaf forest, and California coast, where interior forest is relatively rare, as well as most of the eastern U.S., where family forests dominate the landscape.

“Knowledge of landscape patterns is essential when assessing forest sustainability, because patterns create, mediate, facilitate, and impede ecosystem services that are essential for maintaining human well-being,” says Riitters. “This study can be a step toward assessing the sustainability of family forests and the ecosystem services they provide.”

Read the full text of the article.

For more information, email Kurt Riitters at

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