Subject: Plant Geography Question

From: D Hayman <[email-masked]>
Date: 4 Apr 1996 21:37:32 GMT

Could someone please provide an explanation of why the eastern
N.A.forest is predominately deciduous yet the forest which 
develops west of the plains is predominately coniferous.  Is 
it not actually a question of rainfall regimen, that areas 
which recieve enough yearly ppt., but concentrated in the 
spring, favors trees which grow in the spring and have evolved 
leaves to withstand a more arid summer "growing" season?  This 
would also consider the high eastern humidities.

---

From: [email-masked]
Date: Mon, 08 Apr 96 22:24:17 PDT

:> From: D Hayman <[email-masked]>
 
:> Could someone please provide an explanation of why the eastern
:> N.A.forest is predominately deciduous yet the forest which 
:> develops west of the plains is predominately coniferous.

[From Northern PA]  This area was originally white pine and hemlock. 
Around 1900 it was timbered big time, large tracts subdivided and sold to 
farmers...many moving down from VT and NH.  I don't know why the 
deciduous trees prevailed after cutting; perhaps coniferous seed trees 
weren't left.

afs

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From: [email-masked] (Una Smith)
Date: 11 Apr 1996 21:11:55 GMT

D Hayman <[email-masked]> wrote:
 
>> develops west of the plains is predominately coniferous.

Eastern forests, whether or not second growth, have on average a
larger fraction of angiosperms than western forests do.  What else
is different about them?  The western forests are on average at
far higher altitude, which has several impacts on local climate.

I leave it to you to work out the probable casual relationships.

>[From Northern PA]  This area was originally white pine and hemlock. 

Yep.  Many parts of the northeast were covered in gymnosperms in
colonial times.

>Around 1900 it was timbered big time, large tracts subdivided and sold 
>to farmers...many moving down from VT and NH.  I don't know why the 

Read up on the topic of forest succession.  Among them, one of the 
very best historical treatments is:

Whitney, G. G.  (1994)  From coastal wilderness to fruited plain:
    A history of environmental change in temperate North America,
    1500 to the present.  Cambridge University Press.  ISBN 0-521-
    39452-X.

	Una Smith

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From: [email-masked] (rick strimbeck)
Date: Fri, 12 Apr 1996 14:24:26 -0600

> deciduous trees prevailed after cutting; perhaps coniferous seed trees 

Try this: get world maps showing the distribution  of biomes and
distribution of major climate types. Deciduous forests grow in areas of
cold temperate continental climates - mainly the eastern region of north
america, central Europe, and eastern asia. There are essentially no
(cold-season) deciduous forests in the S. hemisphere, presumably because
the S.Hemisphere has more water, less land, and climates are overall
milder. The cold-season deciduous habit seemes to work well in certain
climatic regions. Some of this is admittedly speculation, but seems to
fit.

Western conif forests (south of Canada) fall into two types, coastal and
montane. The coniferous needle-leaved habit seems to work well in boreal
climates, as are found at elevation in the mtns as well as all across much
of Canad and Siberia. The coastal forests may be more like rain or cloud
forests, with mild winter temperatures, plenty of moisture, maybe some
nutrient limitation problems in the soil? The needle-leaved habit may not
be necessary here, but nutrient limitation seems to lead to long leaf life
spans (among other things) so conifers are well suited. In NZ areas with a
climate similar to the Pacific NW have forests of S. conifers (Podocarps),
but also include S. beeches with small, dark green, long-lived leaves,
similar in some ways to conifer leaves (?). Chile, too.

The ecophysiology of all this is even more speculative... I for one would
be interested in more discussion.

-- 
Rick Strimbeck
University of Vermont
School of Natural Resources
Burlington, VT

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From: [email-masked] (m.lee)
Date: Tue, 16 Apr 1996 02:58:48 GMT

rick strimbeck ([email-masked]) wrote:
: In article <[email-masked]>, [email-masked]
: wrote:

: > :> From: D Hayman <[email-masked]>
: >  
: > :> Could someone please provide an explanation of why the eastern
: > :> N.A.forest is predominately deciduous yet the forest which 
: > :> develops west of the plains is predominately coniferous.
: > 
: > [From Northern PA]  This area was originally white pine and hemlock. 
: > Around 1900 it was timbered big time, large tracts subdivided and sold to 
: > farmers...many moving down from VT and NH.  I don't know why the 
: > deciduous trees prevailed after cutting; perhaps coniferous seed trees 
: > weren't left.
: > 
: > afs  

: Try this: get world maps showing the distribution  of biomes and
: distribution of major climate types. Deciduous forests grow in areas of
: cold temperate continental climates - mainly the eastern region of north
: america, central Europe, and eastern asia. There are essentially no
: (cold-season) deciduous forests in the S. hemisphere, presumably because
: the S.Hemisphere has more water, less land, and climates are overall
: milder. The cold-season deciduous habit seemes to work well in certain
: climatic regions. Some of this is admittedly speculation, but seems to
: fit.

: Western conif forests (south of Canada) fall into two types, coastal and
: montane. The coniferous needle-leaved habit seems to work well in boreal
: climates, as are found at elevation in the mtns as well as all across much
: of Canad and Siberia. The coastal forests may be more like rain or cloud
: forests, with mild winter temperatures, plenty of moisture, maybe some
: nutrient limitation problems in the soil? The needle-leaved habit may not
: be necessary here, but nutrient limitation seems to lead to long leaf life
: spans (among other things) so conifers are well suited. In NZ areas with a
: climate similar to the Pacific NW have forests of S. conifers (Podocarps),
: but also include S. beeches with small, dark green, long-lived leaves,
: similar in some ways to conifer leaves (?). Chile, too.

: The ecophysiology of all this is even more speculative... I for one would
: be interested in more discussion.

: -- 
: Rick Strimbeck
: University of Vermont
: School of Natural Resources
: Burlington, VT

I don't have my Esau here, but there was a list of stress reactions and 
responses that may in part fill this bill.  We have to remember that many 
of these plants evolved when the continental landmasses were configured 
differently and the climates have changed as well.  Talk to you next week :)

ml - [email-masked]