Fall 2005

Fragmentation and Forest Health

by Bud Mayfield

Due to pressures of population growth, development, changing land use values, and other social and economic factors, private forestland in the United States is becoming increasingly fragmented. During each year between 1997 and 2001, more than a million acres of forests were converted to developed uses, nearly double the rate between 1982 and 1992. Forest landscapes are also becoming increasingly subdivided; average forest tract sizes are declining while numbers of landowners are increasing. Large tracts of forestland are routinely subdivided and sold to multiple owners who are not necessarily interested in managing or even retaining the forest cover. These pressures are likely to continue and intensify in the rapidly growing South.

Like wildfire prevention, watershed protection, or wildlife conservation, management for forest health (including keeping damaging insects and diseases at tolerable levels) frequently requires a broadscale or “landscape” approach to be most effective. Forest pest outbreaks can be precipitated by forest conditions that stretch across large geographic areas. When the landscape is a fragmented mix of multiple ownerships, reducing overall forest susceptibility or vulnerability to specific pests becomes extremely difficult. Differing landowner attitudes and objectives, lack of communication and cooperation among owners, and limitations to using traditional forest management practices on small tracts all contribute to the challenge.

The southern pine beetle is an excellent example of a pest that becomes more difficult to manage as forests become increasingly fragmented. Southern pine beetle outbreaks can occur at scales of hundreds of square miles, and individual infestations can expand rapidly to kill pines on multiple acres.

Promptly harvesting and removing infested pines is the best way to stop infestations from expanding, and thinning helps reduce stand susceptibility, and prevent infestations from becoming established. On large forested tracts, both of these management techniques can usually be accomplished as commercial harvests that bring revenue to the landowner. On small, isolated tracts or wildland-urban interface lots, however, the value of harvested wood is usually not enough to offset logging costs, and it may not be possible to use traditional harvesting operations in residential settings. On these small parcels, prevention or control treatments usually come at a net expense to the landowner, with tree removals potentially costing hundreds to thousands of dollars.

Furthermore, when forests are subdivided into numerous small and adjacent ownerships, pest infestations (like those of the southern pine beetle) can easily spread across property boundaries and become the problem of multiple owners. Without careful and purposeful cooperation among neighbors, poor management or inaction can lead to hostile accusations and even litigation.

As the momentum toward increased forest fragmentation builds, forestry professionals and agencies need to find ways to encourage and enable practical forest management on small tracts. Many private landowners of small forest parcels do not attend traditional forestry workshops. Direct mailings, mass media, or presentations through nonforestry venues should be used more frequently to disseminate forest management information. Owners of small tracts can be encouraged to cooperate with adjacent owners and jointly contract for management services such as thinning. Economic incentives for managing small woodlots and wildland-urban interface forests should be developed and promoted. In addition, the need to prevent or control specific pests should not be presented in isolation, but within the broader context of improving forest health and with appeals to other compatible benefits such as improved timber value, wildfire risk reduction, and wildlife habitat enhancement.

Above all, coordinated economic and social strategies that promote the retention of forests on private property are needed in the face of competing development interests and poorly planned urban sprawl. Without this, forest landscapes will only become increasingly fragmented and forest health more difficult to achieve.

Back to Rapid Changes In Forest Ownership Increase Fragmentation

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Bud Mayfield is a forest entomologist with the Florida Division of Forestry, Forest Health Section located in Gainesville, FL.