permaculture

[mIEKAL aND <dtv@mwt.net>]

Begin forwarded message:

> From: "Hal Love" <lovehd@comcast.net>
> Date: Mon May 17, 2004  10:48:34 AM US/Central
> To: <nafex@lists.ibiblio.org>
> Subject: [NAFEX] revised cold hardiness zones
> Reply-To: North American Fruit Explorers <nafex@lists.ibiblio.org>
>
> Just took a look at the draft of the 2003 USDA Plant Hardiness Zone 
> Map.
> Seems a little behind schedule getting out, since its now 2004, but 
> since I
> did not see any mention of this in the archives, I thought it would be 
> of
> interest to this group.
>
> Descriptions of the new map can be found here,
> http://www.ahs.org/publications/usda_hardiness_zone_map.htm.
>
> Here is a portion of the information from the link above.
> "The updated USDA hardiness map shows in detail the lowest 
> temperatures that
> can be expected each year in the United States. These 
> temperatures-referred
> to as "average annual minimum temperatures"-are based on the lowest 
> average
> temperatures recorded for each of the winter seasons from 1987 to 2001.
>
> The 2003 edition of the USDA hardiness map has 15 zones (four more 
> than the
> 1990 version of the map), each of which represents a 10 degree 
> Fahrenheit
> (F) difference in average annual minimum temperature. The expansion of 
> the
> map to 15 zones is making it possible for the first time to assign 
> hardiness
> codes to sub-tropical and tropical plants, which previously had to be 
> listed
> by the minimum temperatures at which they would survive.
>
> The "a" and "b" intra-zone divisions used on the 1990 map have been
> dropped.......".
>
> ".....Unlike previous maps, the 2003 map was created digitally. "It 
> has a
> higher level of resolution and shows smaller areas of change called
> microclimates," says AHS President Emeritus Dr. H. Marc Cathey, who
> coordinated development of the updated map. "These microclimates 
> include
> warmer areas around major cities, which tend to hold more heat because 
> they
> have a high density of buildings and large areas of concrete and 
> blacktop.
> You can also see cooler areas that may indicate higher elevations."
>
> The new map reflects the current warming trend and there is significant
> northward drift of the zones from the 1990 map. Based on the new map, 
> I am
> now right in the middle of zone 7 (The "Rose Zone"), whereas before, I 
> was
> in zone 6b. Here is a direct link to the pdf version of the map (5.57 
> mb).
>
> http://www.ahs.org/pdfs/USDA_Map_3.03.pdf
>
> Hal