Arboriculture & Urban Forestry 37(3): May 2011 cut or collected from home into the states, respectively, while other state proportions ranged from only 9% to 15% (Table 4). Campers brought wood from the dead or dying tree in their yard at home in several instances. When the transport is long distance, homeowners are potentially transporting common ur- ban pests to new areas and states, especially if the wood is not properly seasoned. While the study authors did not determine the age of the wood in the surveys, other firewood surveys in the Midwest have shown that campers do move green fire- wood. Of the firewood pieces confiscated as noted in Michigan surveys, 47% appeared to have been cut from live trees in the previous year, a surprising result since older wood is drier and generally burns easier, cleaner, and hotter (Haack et al. 2010). There was no determination if live insects occurred in or on firewood, but most firewood observed showed evidence of previ- ous insect or fungal infestation (Table 6). While most Ceramby- cid species complete their life cycle in one year, some species (including Prionus and some Goes species) may take two to five years to fully develop and emerge (Craighead 1923). Petrice and Haack (2006; 2007) observed various stages of EAB larval de- velopment when infested wood was cut and dissected and de- termined it could take two summers for all the adults to emerge. Since fungi can remain viable for several years in bark and wood (Koski and Jacobi 2004), the presence of previous infestation in- dicates the firewood may still be infested and act as a source of viable inoculum. There are also several examples of relationships between pathogens, insects, and parasites that could increase the risk of spread of fungi in western states. These include the moun- tain pine beetle (Dendroctonus ponderosae) and blue stain fungi complex; pine wilt disease, where nematodes are vectored by longhorned beetles; and thousand cankers disease of black wal- nut, where the fungus (Geosmithia morbida sp. nov) is vectored by a twig beetle (Robinson 1962; Linit 1988; Kolarik et al. 2010). Research is underway at Colorado State University to quantify the number and genera of live insect infestations in untreated, com- mercially available firewood in the southern Rocky Mountains. To successfully establish or cause any risk, a receptive host needs to be present nearby when the transported fungus or insect moves from firewood. It is believed that suitable hosts are nearby given the proximity of large National and State Parks to urban or natural forests. For example, several State Park campgrounds sur- round reservoirs within the suburbs of Denver, Colorado, and the main visitor center at Rocky Mountain National Park is 4 km from downtown Estes Park, Colorado, a popular city for park visitors and other tourists. Boulder City, a suburb of Las Vegas, Nevada, is 6.4 km from Lake Mead NRA, which received more than 300,000 campers in 2008 (NPS Statistics 2008). Exotic organisms are likely to become pests when introduced into new areas, and urban forests are usually the first to be invaded (Liebhold 1995). Notable past introductions of highly destructive exotic organisms, includ- ing chestnut blight, gypsy moth, and EAB, were all introduced or discovered in urban or suburban areas (Liebhold 1995; Haack et al. 2002). While ash species are not common in the native conifer forests of the western U.S., green ash (Fraxinus pennsylvanica) is present in urban areas throughout the west and has naturalized in many riparian areas in the plains of Colorado and Wyoming. Many Colorado State Park campgrounds are surrounded by east- ern or plains cottonwoods (Populus deltoides) and most National Park campgrounds in the west have an aspen component. There are also some regions in the western U.S. without high popula- 135 tions of mountain pine beetle, and campers who move infested wood from home or other campgrounds may transport primary or secondary bark beetles if the wood is not properly seasoned. Reducing the Risk of Native or Exotic Pests in Firewood The potential for campers to transport firewood in the South- ern Rocky Mountains was quantified based on surveys from 13 National and seven Colorado State Parks. Although the number of campers transporting firewood in these 20 parks was under 0.5 million per year, the probable risk is increased by millions per year based on other popular travel destinations in the west. The probability of destructive insects or pathogens being pres- ent in firewood is apparent since the origin is generally that of dead trees. The federal, state, and county quarantines of firewood movement from infested areas also recognize the risk of mov- ing various pests via firewood (USDA APHIS 2010). Because campers are transporting firewood to parks from nonwestern origins and even from EAB infested states, and State and Na- tional Parks, urban communities and tree health professionals should be discouraging the movement of untreated firewood from state to state and not relying entirely on commercial or federal quarantines, especially given the current knowledge of EAB movement via firewood. The National Firewood Task Force recommends that all federal, state, and private parks, forests, and campgrounds encourage the use of local wood and institute policies to discourage campers from moving wood out of the lo- cal area (NPB 2010). These entities are encouraged to sell lo- cal or treated firewood on site, make available a list of nearby retailers selling local or treated wood, and to institute a firewood exchange program (NPB 2010). Neither agencies nor forest health professionals can always predict the next major forest pest introduction or foretell the pest’s native range or preferred hosts, therefore the movement of all species of firewood should be discouraged, not just those associated with known pests. Impacts to forest resources may be reduced if public education on the potential dangers of long-distance movement of firewood is increased, and if industry professionals learn how to manage and restrict the movement of infested wood (Lawrence 2006, NPB 2010). Firewood consumers were often unaware of the risks involved in moving infested firewood. These surveys offered op- portunities to inform and educate campers. In many cases, camp- ers were completely unaware of the risks and were very receptive to the educational opportunity. The National Firewood Task Force recommends that agencies should form a communication steering committee, develop online hubs of firewood outreach materials, and prioritize outreach activities that can be reasonably accom- plished for educational purposes (NPB 2010). Directing educa- tional efforts to specific target groups is one way to minimize risks of firewood movement. State Parks throughout the west should target all out-of-state visitors, especially those from nonwestern states, by providing information on of the dangers of transporting firewood when making reservations or prior to arriving at camp- grounds. This could be accomplished by mailing literature to those who reserve campsites or on park websites so future visitors see the information while planning trips. Education at National Parks should also be aimed towards out-of-state visitors during the reservation process or prior to arrival. Eighty-three percent of the 47,350 campers with firewood from nonwestern state origins ©2011 International Society of Arboriculture
May 2011
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
