What Is Zone 7?
Zone 7 is considered to be one of the most extreme growing zones because it requires a great deal of water and nutrients. It’s very hot and dry, so plants cannot grow well there. Plants are able to survive in zone 6, but they will not thrive. Most people consider zone 5 to be the middle ground between these two extremes. Some experts say that even zone 4 isn’t safe from frost damage or severe drought conditions due to its mild climate.
The USDA Hardiness Zone Map shows the range of temperatures and precipitation that exist within each of the seven zones. These maps were developed based on data collected over many years by thousands of volunteers and scientists around the world. They’re updated every five years, and are used to determine which areas receive federal funding for conservation projects. The map was first published in 1990, when it covered only four states: Alaska, Hawaii, California and Nevada. Since then, it has been revised several times.
The latest version covers all 50 states and Washington D.C., with additional states added in the last few years.
In order to qualify for federal funding under the National Climate Change Adaptation Program (NCCAP), a state must meet certain criteria related to its vulnerability to climate change impacts such as sea level rise, droughts, heat waves and other weather events, wildfires and floods.
The most recent update to the map moved many states into a higher zone, including most of California, which suddenly jumped from zones 8-10 to zones 4 and 5. Other states that were previously classified as zone 4 have now been moved into zone 3.
Even in Tennessee, which was previously covered by just three zones, sweeping changes have been implemented. The entire state of Tennessee is now listed as zones 3-
6. Previously, West Tennessee was primarily zone 5.
The Tennessee counties of Hardin, Chester, most of McNairy and part of Henderson are now zone 6. The rest of the state, including East Tennessee, remains in zone 4.
The latest map also includes new zones for parts of New York state, with some areas dropping from zone 4 to zones 3 or 2. New zones have also been implemented in parts of North and South Carolina (zones 4-5), Alabama (zones 3-4), and several other states.
Why Are Changes Being Made?
With these sweeping changes, some people are wondering why the NCCAP is now considering many states to be at a higher risk of climate change effects when temperatures have actually been on a general downward trend over the past few years. Others are wondering why the changes aren’t even greater.
The answer is that these changes don’t necessarily reflect a change in the actual climate in these areas. Instead, they reflect changing real estate development patterns and increased awareness of how climate change will effect each area. For example, Tennessee was previously listed as zone 5, but it is now broken up into zones 4 and 6. Changes in land use and construction standards have caused more severe weather events to become more common and more damaging in the western part of the state.
The NCCAP’s goal is to help states prepare for the effects of climate change on agriculture, forestry, water supply and other industries that are vital to our nation’s economy. The new zone information will be used to develop new conservation plans and grant programs to help states, tribes and local governments adapt to a changing climate.
What Does This Mean for Tennessee Property Owners?
These changes to the NCCAP map won’t have much of an effect on most Tennessee property owners. If you are a farmer or own land that is at risk of flooding or other natural disasters, the new zone information may be helpful in applying for grants for conservation measures such as tree planting or construction of retention ponds.
For most people, the changes to the NCCAP map will be of interest mainly to those who are concerned about how climate change may affect them in years to come. If you are a homeowner in zones 4 or 5, you may want to consider buying flood insurance or making sure you aren’t located in a floodplain if you aren’t already required to have it. You may also want to consider the potential long-term effects of climate change on your home, such as the possible need for extra insulation or double-pane windows if winters get colder or summers get hotter.
Your Choice Tennessee is dedicated to helping you make informed decisions on issues that affect your life, like climate change and how it will affect Tennessee. We can help you find information about NCCAP updates and changes so you can better plan for the future.
Sources & references used in this article:
Development of hardwood seed zones for Tennessee using a geographic information system by SE Schlarbaum, LS Post, F van Manen… – Southern Journal of …, 2003 – academic.oup.com
Rangeland cover types of the United States by TN Shiflet – 1994 – fws.gov
Variation in Shortleaf Pine from Several Geograpbic Sources by OO Wells, PC Wakeley – Forest Science, 1970 – academic.oup.com
Can an ecoregion serve as a seed transfer zone? Evidence from a common garden study with five native species by …, M Gisler, K Ward, AS Young, TN Kaye – Restoration …, 2011 – Wiley Online Library