From wmp@gaia.esd.ornl.gov Fri Aug 25 09:41:08 2000
Date: Fri, 25 Aug 2000 09:22:55 -0400 (EDT)
From: W. M. Post <wmp@gaia.esd.ornl.gov>
To: Gail Chmura <chmura@felix.geog.mcgill.ca>
Subject: Re: soil carbon error

Dear Gail Chmura:

Thank you for your interest in my paper.  You are correct - this is really
a pasture, not the first stages of a woodland.  I classified the plots
based on Holdridge life-zones and this one is cool temperate wet forest
based on climate and so it inadvertantly got left on the wrong table. I
waivered about putting this one in because of the initial conditions (same
from the mine soil bank plots) and was suprised to see how much C
accumulated.

There is another mistake in this table as well so if you are going through
the table you may be perplexed by this as well.  I attach below a reply to
another keen observer of our calculations.  I guess I need to construct an
errata page.

I would be interested in hearing more about the manuscript you are
preparing.

Mac Post
--------------
Environmental Sciences Division             865-576-3431
Oak Ridge National Laboratory               865-574-2232 (fax)
P.O. Box 2008, Bldg. 1509                   http://www.esd.ornl.gov/~wmp
Oak Ridge, TN 37831-6335                    wmp@ornl.gov

(Replace P.O. Box 2008 with "Bethel Valley Road" for express mail)

On Thu, 24 Aug 2000, Gail Chmura wrote:

> Dear Dr. Post,
> I have been using estimates from your recent paper in Global 
> Change Biology  "Soil carbon sequestration and land-use change: 
> processes and potential" in a paper which I am preparing.  I very 
> much appreciate this summary and analysis.
> 
> However, in going over some of you table entries I noticed a 
> mistake in table 1 - rates of soil C accumulating during forest 
> establishment after agricultural use.  There is an entry "constructed 
> dike to forest, reference source Beke 1990".  I have this paper 
> before me and note that the dike was composed of sediments from 
> tidal flats - and as a dike was an engineering structure rather than 
> an agricultural land.  On page 684 of his article Beke states "The 
> vegetation on the dike consisted of pasture grasses and forbs."  He 
> does report an increase of carbon in this small bit of soil, but it is a 
> transition from low to sub-tidal sediments to pasture - not pasture 
> to forest.  Thus, this more appropriately belongs in table 2 of your 
> article - and the calculations derived from that.
> 
> It may not change any of your calculations - but the cite did throw 
> me off, as I was keen to get such data on the Fundy dikelands and 
> dissappointed when I realized what the real focus of the study was.
> 
> Cheers,
> Gail Chmura
> 
> 
> Gail Chmura
> Associate Professor
> Department of Geography       phone (514)398-4958
> McGill University               FAX (514)398-7437
> 805 Sherbrooke St., W        chmura@geog.mcgill.ca
> Montreal, QC  H3A 2K6
> 

>From wmp@gaia.esd.ornl.gov Fri Aug 25 09:05:02 2000
Date: Tue, 9 May 2000 09:38:08 -0400 (EDT)
From: W. M. Post <wmp@gaia.esd.ornl.gov>
To: "Paul, Keryn (FFP, Yarralumla)" <Keryn.Paul@ffp.csiro.au>
Subject: Re: Global change Biology paper

Keryn

Sorry - this is embarrasing.  Something got shifted in my table somewhere
along the long trajectory of the manuscript.  The 310 value should be for
a 10 year old pine plantation (CF2) with 9.3 kgC/m2.  For the starting
point I averaged CA2 and CA3 for a value of 6.2 kgC/m2.

The 51 year old Mahogany (LF6 - 11.4 kgC/m2) should have been 102 gC/m2/y
[1000(11.4-6.2/51)].  This seems to be missing from my table.  The
difference between this and yours is that I decided to average CA2 and CA3
for the initial condition here as well.  I averaged things
together in this paper in an attempt to cut down on the effect of various
sources of variation involved in soil carbon measurements.  We will also
differ in just transcribing bar charts into numerical values.

Thanks for your interest in our paper.  I do have a couple of more recent
papers.  I'll send the cites along shortly.

Mac Post
--------------
Environmental Sciences Division             865-576-3431
Oak Ridge National Laboratory               865-574-2232 (fax)
P.O. Box 2008, Bldg. 1509                   http://www.esd.ornl.gov/~wmp
Oak Ridge, TN 37831-6335                    wmp@ornl.gov

(Replace P.O. Box 2008 with "Bethel Valley Road" for express mail)

On Tue, 9 May 2000, Paul, Keryn (FFP, Yarralumla) wrote:

> Dear W. M. Post,
> 
> CSIRO Forestry and Forest Products has been commissioned by the Australian
> Greenhouse Office to review the effects of afforestation on change in soil
> carbon.  The information is necessary for Australia to predict at the
> national level change in carbon stocks under plantation development during
> the commitment period of the Kyoto protocol (2008-2012). The area of new
> plantations is expanding rapidly in Australia  - 90,000 ha was planted in
> 1999 and by 2020 it is hoped that Australia will have about 2 mill ha of new
> plantations. It is expected these plantations will have a significant impact
> on national carbon budgets but measuring and predicting change in soil
> carbon under plantation establishment remains an area of some uncertainty.
> 
> I have read Post and Kwon (2000) in Global Change Biology. This is a
> fabulous review of soil C sequestration under different land-uses. However,
> I am pulling my hair out trying to work out why my calculations taken from
> Brown and Lugo (1990) differ from those in Table 1, Post and Kwon (2000).
> Taking  the subtropical wet forest, 10yr old crop fields to mahogany
> plantation, as an example (Table 1, Post and Kwon 2000), I calculated the
> change in C content (i.e. difference between CA2 and LF6) to 50 cm depth as
> 4.5 kg C/m2 (Fig 4a, Brown and Lugo 1990). I then multiplied this by 1000
> (to get g C/m2) and divided by the age of the forest (51 years, Table 1,
> Brown and Lugo 1990) to come up with a rate of C change of 88 g C/m2/y. But
> you have 310 g C/m2/y. Do you know what I am doing wrong?
> 
> Also, have you come across any other studies which have shown rates of soil
> C change under afforestation since Post and Kwon (2000) was published?
> 
> Hope you can help,
> 
> Keryn
> 
> 
> __________________________________________________
> 
> Dr Keryn Paul                  
> CSIRO Forestry and Forest Products       
> PO Box E4008  Kingston  ACT 2604  Australia            
> ph. +61_2_6281 8269; fax +61_2_6281 8312     
> Keryn.Paul@ffp.csiro.au  
> http://www.ffp.csiro.au    
> __________________________________________________
> 
>