Subject: WANTED: Zone Information

From: [email-masked] (Kathleen Fischer)
Date: 26 Sep 1994 16:42:05 GMT

As several people have sent me email asking me to post the info when I got it. 
Here it is.  My thanks to Dewey Coffman for having it and Bill Pulliam
for writing
it (I think I go those names in the right order!

In article <[email-masked]> you write:
>A few months ago during the debate about splitting this group, someone
>posted a very
>detailed message pertaining to information that is far more useful for
>determining plant
>hardiness than just Zone number.
>
>It included things like Climate (ie, Mediterraining, Desert ... ), and
>rainfall, and a million other
>things that I can't remember. Unfortunatly, I didn't have the foresight
>to save it, and now
>I would really really *really *like that information again.
>
>If anyone has a copy (or knows of an archival site where I could do some
>searching), I
>would be very grateful.
>
>--
>Kathleen Fischer
>[email-masked]
>
>DISCLAIMER: Statements expressed here are mine, Mine, MINE!!!

Newsgroups: rec.gardens
From: [email-masked] (Bill Pulliam)
Subject: Re: Zones (was Re: Signatures) -- a suggestion
Date: Fri, 17 Jun 1994 18:40:48 GMT
Organization: Natural Resource Ecology Lab, Colo. State Univ.

In article <[email-masked]> [email-masked] (Donald
J. Collins) writes:
[discussion of geographical range of zones and differences between 
north Georgia and southeast Alaska trimmed]
[more discussion by previous posters on similar topic deleted]

The USDA Plant Hardiness Zones cover only one aspect of local climate,
the hardest freeze to be expected.  Gardeners/landscapers/ecologists
would mostly agree on the following as a minimum set of critical
climate variables:

Winter Minimum
Precipitation amount
Precipitation distribution
First/Last freeze dates
Summer maximum
Between-year variability in all the above.

Several other things that are very important to plants are 
corollaries to the above:

Depth of soil frost penetration (winter minimum, length of anti-
     growing season, precipitation)
Presence/absence of reliable winter snow cover (winter temps and precip)
Summertime drought stress (summer precip and temperatures)

Much of this could probably be captured by just adding a few extra
descriptors to your USDA classification, like:

Maritime:  Damp year-round, annual temperature range fairly small,
    places like Vancouver, Southeast Alaska, Britain, wet parts of
    other oceanic islands (Hawaii, Puerto Rico)
Humid:  Precip ample and spread throughout the year (droughts will
    happen, of course).  Has a substantial annual temperature range,
    often sultry summers and chilling damp winters.  Eastern North 
    America, much of Continental Europe, wet parts of the Rocky 
    Mountain region, etc., generally areas that are naturally 
    forested.
Subhumid:  Like humid but with drier spells, lower natural soil
    moisture.  In N. America the midwest, eastern Great Plains,
    much of the high country in the Rockies, drier parts of Canada,
    in Eurasia in the wetter parts of the Central Asian Steppes,
    much of the dry tropics.  Generally where natural vegetation
    would be open woods, savannah, tallgrass prairie.
Semiarid:  Quite dry in some parts of the year, but reasonably
    wet at other seasons.  Often in continental interiors with 
    large annual temperature ranges.  Western Great Plains, high
    deserts and foothills of western N. America, dry Asian Steppes,
    dry tropics, etc.  Generally places where native vegetation is
    shortgrass plains, shrublands, dry very open woodlands, etc.
Arid:  Dry nearly year round except for brief, usually variable
    rains.  The true deserts of the world, including the low 
    deserts of Mexico and the Southwestern U.S., N. Africa, the
    Middle East, etc.  Areas where the native vegetation is 
    succulents, very low-water tolerance shrubs, very short-lived
    rain annuals, etc.

To the last three of these, you might want to add a descriptor
about when the dry vs. wet periods are, since it makes a huge
difference whether the water comes in summer, winter, or all 
year:

Mediterranean:  Precip comes during the winter, summers are
    dry.  Pacific coast of U.S., Southern Europe, etc.
Monsoonal:  Precip comes during the summer, winters are dry.
    Parts of southwestern U.S., Great Plains, northern
    Mexico, much of the tropics, etc.
<no extra descriptor>:  Precip comes in summer and winter,
    dry spells come at either time also.  

And one final descriptor might be needed:

Tropical:  Very little annual temperature range (less than,
    say, 9 deg. F/ 5 deg. C between warmest and coolest month).
    This is independent of the hardiness zones; tropical
    highlands can be quite cold.  Some very cold oceanic
    islands might fit here, too  (the Aleutians tropical?
    maybe...)

So how this would work for some places I've spent time:

Eastern Colorado:  Zone 5 semiarid

Coastal South Carolina:  Zone 8 humid (and trust me, the biggest
    difference between South Carolina and Colorado is the switch 
    from humid to semiarid, NOT the move from zone 8 to zone 5!)

San Francisco Bay Area:  Zone 9 semiarid (dry parts) / subhumid 
    (wet parts) mediterranean (all parts).

Northern Rockies:  Zone 3 humid or subhumid

Southeast Alaska:  Zone 7 maritime

Interior Alaska:  Zone 1 semiarid

Eastern Puerto Rico:  Zone 10 maritime tropical

Western Puerto Rico:  Zone 10 subhumid tropical

Sonora desert:  Zone 9 arid monsoonal

South Florida:  Zone 10 humid (not tropical, too big a range
    between January and July)

So, does anyone find this useful?  

Bill Pulliam
Natural Resource Ecology Laboratory
Colorado State University
Fort Collins  CO  80523
(303) 491-1919 / FAX (303) 491-1965
E-mail: [email-masked]

-- 
Dewey Coffman   [email-masked]   [email-masked]   [email-masked]
USDA Zone 8, CST6CDT, 78759, 30 20 30N/97 44 05W, 10th Congressional District
Travis County, Austin, Texas, USA, North American, Earth, Milky-Way Galaxy
"Not for publication in newsprint or broadcast media." [\]

--
Kathleen Fischer
[email-masked]

DISCLAIMER: Statements expressed here are mine, Mine, MINE!!!