Back to List View Text Only

Updated Hardiness Zones Offer Latest Tree Selection Advice

date 04/19/04

For more information, contact

Arbor Day Foundation
Danny Cohn

Nebraska City, Neb., April 19, 2004 -- Choosing the right tree for your location is key to successful tree planting. And thanks to The National Arbor Day Foundation`s updated Hardiness Zones map, making the right choice is easier than ever.

Tree planters and gardeners can now find pinpoint information for their location by going to the 2004 Hardiness Zones map and entering their zip code. The map/Web site combination offers up-to-date and precise information on cold-hardiness zones, a key factor in selecting trees for planting. A hardiness zone is the area defined by a 10-degree range of average annual minimum temperatures.

The Hardiness Zones map is based on the most recent 15 year`s data available from more than 5,000 National Climatic Data Center cooperative stations across the United States. Visitors to simply enter their five-digit zip code to learn their specific hardiness zone and choose a suitable tree for their growing conditions.

"The Arbor Day Foundation exists to help people plant and care for trees," said Foundation President John Rosenow. "Providing the hardiness zone for individual zip codes at is an important part of that goal, by giving tree planters the most complete data available."

Rosenow added that once the Foundation analyzed the new data, hardiness zones were revised, generally reflecting warmer recent temperatures in many parts of the country. The need to reflect climatic change was one of the reasons given by the U.S. Department of Agriculture for the 1990 revision of its original hardiness zone map, first introduced in 1960. The Arbor Day Foundation used the updated versions of the same sources of data as had been utilized by the U.S. Department of Agriculture in the creation of its hardiness zone maps.

"We`re pleased to offer the Hardiness Zones map as a useful guide for selecting and planting trees," Rosenow said. "While the map is especially important in finding a tree suitable for your area`s temperature extremes, other factors must also be considered -- including moisture, soil, and sun requirements, as well as microclimates within a hardiness zone. At, we offer advice on all of these requirements, to make tree planting a successful experience."

The National Arbor Day Foundation is a million-member, nonprofit education organization dedicated to tree planting and environmental stewardship.