(As filed on June 12, 2003)
                                                             File No. 70-[_____]


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM U-1
                           APPLICATION OR DECLARATION
                                    UNDER THE
                   PUBLIC UTILITY HOLDING COMPANY ACT OF 1935

                               AMEREN CORPORATION
                              1901 Chouteau Avenue
                            St. Louis, Missouri 63103


             (Names of companies filing this statement and addresses
                        of principal executive offices)
             -------------------------------------------------------

                                      NONE

                 (Name of top registered holding company parent
                        of each applicant or declarant)
             -------------------------------------------------------


              Steven R. Sullivan, Vice President Regulatory Policy,
                          General Counsel and Secretary
                             Ameren Services Company
                              1901 Chouteau Avenue
                            St. Louis, Missouri 63103

                     (Name and address of agent for service)
             -------------------------------------------------------


The Commission is requested to mail copies of all orders, notices and other
communications to:

Ronald K. Evans,                                 William T. Baker, Jr., Esq.
Managing Associate General Counsel               Thelen Reid & Priest LLP
Ameren Services Company                          875 Third Avenue
1901 Chouteau Avenue                             New York, New York 10022
St. Louis, Missouri 63103





ITEM 1.   DESCRIPTION OF PROPOSED TRANSACTION.
          -----------------------------------

          A. Background.
             ----------

          Ameren Corporation, a registered holding company (the "Applicant"),
herein requests approval from the Commission pursuant to Sections 9(a)(1) and 10
of the Public Utility Holding Company Act of 1935, as amended (the "Act") to
acquire a membership interest in PowerTree Carbon Company, LLC (the "Company"),
a Delaware limited liability company formed to facilitate investments by the
Applicant and other energy companies in forestation projects in the Lower
Mississippi River Valley, and possibly other sites, as a means for removing
carbon dioxide (CO2) from the atmosphere. The Applicant proposes to acquire such
membership interest either directly or indirectly through one or more
subsidiaries, including a new subsidiary formed exclusively for the purpose of
acquiring and holding the membership interest.

          The Applicant directly or indirectly owns all of the outstanding
common stock of Union Electric Company d/b/a AmerenUE ("AmerenUE"), Central
Illinois Public Service Company d/b/a AmerenCIPS ("AmerenCIPS"), and Central
Illinois Light Company, d/b/a AmerenCILCO ("AmerenCILCO," and together with
AmerenUE and AmerenCIPS, the "Utility Subsidiaries"). Together, the Utility
Subsidiaries provide retail and wholesale electric service to approximately 1.7
million customers and retail natural gas service to approximately 500,000
customers in parts of Missouri and Illinois. The Utility Subsidiaries and other
non-regulated generating subsidiaries of the Applicant own all or portions of
electric generating plants in the United States having a combined generating
capability of approximately 14,500 megawatts (MW).

          The Company has been formed under the sponsorship of the electric
utility sector in cooperation with the Department of Energy ("DOE"). The Company
is part of an industry-wide effort to voluntarily address climate change through
measures designed to reduce greenhouse gas emissions in response to President
Bush's recent "Climate VISION" plan, or Climate, Voluntary Innovative Sector
Initiatives: Opportunities Now. Climate VISION is the first step in the
President's policy of encouraging industry to produce voluntary cuts in
greenhouse gas emissions. One proven means for reducing greenhouse gases is to
use trees to remove CO2 from the atmosphere and store it in tree biomass and
roots and soil. The Bush Administration has also proposed, as part of its Global
Climate Change program, the creation of transferable credits for measures which
reduce greenhouse gas emissions.

          The Company has obtained commitments totaling approximately $3.5
million from approximately 25 electric utilities, electric utility holding
companies and other energy concerns that will be used to fund six forestation
projects located in Louisiana, Mississippi and Arkansas. These projects will
provide multiple environmental benefits, including removing from the atmosphere
and storing over 2 million tons of CO2 over the projects' 100-year lifetimes.
Other benefits will include: restoring habitat for birds and animals; reducing
fertilizer inputs to waters; and stabilizing soils. Two of the projects will
involve purchase and donation of land to the U.S. Fish & Wildlife Service, while
other projects will involve obtaining easements for tree planting on private
land. The contributions of the members to the Company will be utilized for land
acquisition and to pay the cost of planting tree seedlings. It is estimated that


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these projects will provide carbon benefits of more than 400 and 450 tons of CO2
per acre by years 70 and 100, respectively, at a cost of less that $2.00 per
ton.

          Unlike some earlier forestation projects that U.S. electricity
generators have supported in the past, the Company is being formed as a
for-profit limited liability company ("LLC"), which it is believed will allow
carbon or CO2 reduction credits, if and when they become available, to be more
readily transferred. The LLC structure will also allow the members of the
Company to take advantage of tax benefits of land donation. Nevertheless,
although formed as a for-profit LLC, the Company is essentially a passive medium
for making investments in projects that are not expected to have any operating
revenues, and will not engage in any active business operations.

          To the extent not exempt under Rule 43, the Applicant is also
requesting authorization pursuant to Section 12(f) of the Act to sell all or a
portion of its membership interest in the Company at any time to any of its
associate companies. Any sale by the Applicant of its membership interest in the
Company to an associate company shall be for an amount equal to the Applicant's
investment or pro rata share thereof in the case of a sale of a portion of the
Applicant's membership interest. No sale to an associate company that requires
approval by any other regulatory commission shall take place until such approval
has been obtained.

          B. Capital Contribution Commitments of Initial Members.
             ---------------------------------------------------

          The Applicant is one of eleven registered holding companies that have
committed, either directly or through subsidiaries, to make capital
contributions to the Company. The others are American Electric Power Company,
Inc., Cinergy Corp., Dominion Resources, Inc., Entergy Corporation, Exelon
Corporation, FirstEnergy Corp., Great Plains Energy Incorporated, PEPCO
Holdings, Inc., Progress Energy, Inc., and Xcel Energy, Inc. Other energy
companies that have committed to make capital contributions are: CLECO
Corporation, The Detroit Edison Company, Duke Energy Corporation, Minnesota
Power (a division of ALLETE, Inc.), OGE Energy Corp., Oglethorpe Power
Corporation, Peabody Energy Corporation, Pinnacle West Capital Corporation,
Public Service Electric and Gas Company, Public Service Company of New Mexico,
Reliant Resources, Inc., Tennessee Valley Authority, TXU Corp., We Energies (the
trade name of Wisconsin Electric Power Company and Wisconsin Gas Company), and
Wisconsin Public Service Corporation. The amount of the commitments of the
eleven registered holding companies is as follows:

          -------------------------------------- -------------------------------
          Name of Registered Holding Company     Total Capital Contribution
                                                 Commitment
          -------------------------------------- -------------------------------
          Ameren Corp.                           $100,000
          -------------------------------------- -------------------------------
          American Electric Power Co.            $300,000
          -------------------------------------- -------------------------------
          Cinergy Corp.                          $100,000
          -------------------------------------- -------------------------------
          Dominion Resources, Inc.               $100,000
          -------------------------------------- -------------------------------
          Entergy Corp.                          $100,000
          -------------------------------------- -------------------------------
          Exelon Corp.                           $100,000
          -------------------------------------- -------------------------------
          FirstEnergy Corp.                      $100,000
          -------------------------------------- -------------------------------
          Great Plains Energy Inc.               $  50,000
          -------------------------------------- -------------------------------


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          -------------------------------------- -------------------------------
          PEPCO Holdings, Inc.                   $  50,000
          -------------------------------------- -------------------------------
          Progress Energy, Inc.                  $100,000
          -------------------------------------- -------------------------------
          Xcel Energy, Inc.                      $100,000
          -------------------------------------- -------------------------------
                                          Total  $1,200,000
          -------------------------------------- -------------------------------

          In the aggregate, the capital contribution commitments of the eleven
registered holding companies represent approximately 35% of the commitments of
all of the initial members.

          C. Principal Terms of Operating Agreement.
             --------------------------------------

          Under the Company's Operating Agreement (Exhibit A hereto), the
business and affairs of the Company shall be managed by its Board of Managers.
Each member that commits to make a capital contribution of at least $100,000 is
entitled to appoint one representative to the Board of Managers. In general,
actions by the Board of Managers may be taken by a majority of the managers
present at a meeting. However, certain actions of the Board of Managers or of
any individual manager or any officer require authorization by a two-thirds vote
of the full board. These include, among others actions: the sale, exchange or
other disposition of any of the assets of the Company greater that $20,000 in
value; the commencement of a voluntary bankruptcy proceeding; the declaration or
making of any distributions to members; the incurrence of any indebtedness by
the Company; capital expenditures exceeding $20,000; and the acquisition or
lease of any real property and any sale of, donation, lease or sublease
affecting real property owned by the Company.

          New members may be admitted to the Company only upon the unanimous
approval of the then existing members. Upon admission of any new member, the
percentage interests of existing members shall be reduced accordingly. A member
may transfer all or a portion of its membership interest only upon receiving
approval of two-thirds of the existing members, except that, without the prior
approval of the other members, a member may transfer all or a part of its
membership interest to an affiliate of such member or to any other member. A
two-thirds vote of the members is also required for the election of officers of
the Company. The members have equal voting rights, regardless of their
percentage interests in the Company.

          The Operating Agreement provides that, so long as any member is a
registered holding company or subsidiary company thereof, any voting rights in
the Company received or otherwise obtained by such member equal to or exceeding
10% of the total outstanding voting rights in the Company shall be automatically
(and without any requirement for consent on the part of the affected member)
allocated to the other members in equal portions such that no registered holding
company member will hold 10% or more of voting rights in the Company. In
addition, any member may elect to limit its voting rights to less than 5% of the
total voting rights in the Company, in which case the voting rights of such
member or members equal to or exceeding 5% of the total voting rights in the
Company would be automatically allocated in equal portions to the other members.

          The Operating Agreement further provides that each member (or its
designee(s) or transferee(s)) shall be entitled to claim a pro rata share of all
carbon that is determined to be sequestered by the Company's efforts to which


                                       4



legal rights, if any, have been obtained ("Carbon Reductions") based on the
member's percentage interest in the Company. A member may generally utilize such
member's share of any Carbon Reductions in connection with its participation in
any greenhouse gas reporting or regulatory program or transfer or assign such
Carbon Reductions to one or more other persons.

ITEM 2.   FEES, COMMISSIONS AND EXPENSES.
          ------------------------------

          The fees, commissions and expenses incurred or to be incurred in
connection with the preparation and filing of this Application/Declaration are
estimated not to exceed $2,000.

ITEM 3.   APPLICABLE STATUTORY PROVISIONS.
          -------------------------------

          A. General.
             -------

          Sections 9(a)(1) and 10 of the Act are applicable to the proposed
acquisition of a membership interest in the Company, as well as to the
acquisition of the securities of any new subsidiary formed exclusively for the
purpose of acquiring and holding the membership interest. The subsequent sale of
all or a portion of the membership interest in the Company acquired by the
Applicant to any associate company thereof is subject to Section 12(f) of the
Act, but may be exempt under Rule 43.

          B. Standards of Sections 9(a) and 10.
             ---------------------------------

          The transaction proposed herein involves an acquisition of securities,
as well as an acquisition of an interest in an other (i.e., non-utility)
business, and is therefore subject to the approval of this Commission under
Section 10. The relevant standards for approval under Section 10 are set forth
in subsections (b), (c) and (f). As applied to interests in non-utility
businesses, Section 10(c)(1) of the Act provides that the Commission shall not
approve an acquisition that is "detrimental to the carrying out of the
provisions of section 11." Section 11(b)(1), in turn, directs the Commission to
limit the operations of a holding company system to a single integrated
public-utility system and such non-utility businesses as are "reasonably
incidental, or economically necessary or appropriate to the operations" of its
integrated system or systems. The Commission and the courts have interpreted
these provisions as expressing a Congressional policy against non-utility
activities that bear no operating or functional relationship to the utility
operations of the registered system.1

          The Commission has previously authorized new registered holding
companies to retain, under the standards of Section 11(b)(1), interests in
ventures formed to invest in start-up companies that offer products or services
that will generate greenhouse gas emission reductions for submission to the DOE
as "Climate Challenge" credits pursuant to Title XVI of the Energy Policy Act of


--------------------

1  See Michigan Consolidated Gas Co., 44  S.E.C. 361, 363-365 (1970),
   aff'd 444 F.2d 913 (D.C.Cir.1971).


                                       5



1992.2 Further, under Rule 58(b)(1)(ii), a registered holding company may,
without the need for prior approval by the Commission (subject to certain
investment limitations), acquire the securities of companies that engage in the
"development and commercialization of electrotechnologies related to energy
conservation, storage and conversion, energy efficiency, waste treatment,
greenhouse gas reduction, and similar innovations." (Emphasis supplied)

          The Applicant's proposed investment in the Company is intended to
contribute positively to the national goal of reducing greenhouse gases through
voluntary industry specific efforts. The forestation projects that the Company
will fund have received strong backing from the DOE, Department of Agriculture
and Department of Interior. Moreover, the proposed investment in the Company
will provide the Applicant with a means to obtain carbon or CO2 reduction
credits, if and when such credits become available.

          C. Compliance with Rule 54. The proposed transaction is also subject
to Rule 54. Rule 54 provides that, in determining whether to approve the issue
or sale of any securities for purposes other than the acquisition of any "exempt
wholesale generator" ("EWG") or "foreign utility company" ("FUCO") or other
transactions unrelated to EWGs or FUCOs, the Commission shall not consider the
effect of the capitalization or earnings of subsidiaries of a registered holding
company that are EWGs or FUCOs if the requirements of Rule 53(a), (b) and (c)
are satisfied. Under Rule 53(a), the Commission shall not make certain specified
findings under Sections 7 and 12 in connection with a proposal by a holding
company to issue securities for the purpose of acquiring the securities of or
other interest in an EWG, or to guarantee the securities of an EWG, if each of
the conditions in paragraphs (a)(1) through (a)(4) thereof are met, provided
that none of the conditions specified in paragraphs (b)(1) through (b)(3) of
Rule 53 exists.

          Rule 53(a)(1): The Applicant's "aggregate investment" (as defined in
Rule 53(a)(1)) in EWGs as of March 31,2003 was $421,408,655, or approximately
23.8% of the Applicant's "consolidated retained earnings" (also as defined in
Rule 53(a)(1)) for the four quarters ended March 31, 2003 ($1,767,489,637). The
Applicant does not currently hold an interest in any FUCO.

          Rule 53(a)(2): The Applicant will maintain books and records enabling
it to identify investments in and earnings from each EWG and FUCO in which it
directly or indirectly acquires and holds an interest. The Applicant will cause
each domestic EWG in which it acquires and holds an interest, and each foreign
EWG and FUCO that is a majority-owned subsidiary, to maintain its books and
records and prepare its financial statements in conformity with U.S. generally
accepted accounting principles. All of such books and records and financial
statements will be made available to the Commission, in English, upon request.

          Rule 53(a)(3): No more than 2% of the employees of Applicant's
domestic utility subsidiaries will, at any one time, directly or indirectly,
render services to EWGs and FUCOs.


--------------------


2  See Exelon Corp., Holding Co. Act Release No. 27256 (Oct. 19, 2000);
   and CP&L Energy, Inc., Holding Co. Act Release No. 27284 (Nov. 27, 2000).


                                       6



          Rule 53(a)(4): The Applicant will submit a copy of each
Application/Declaration relating to investments in EWGs and FUCOs and copies of
any related Rule 24 certificates, as well as a copy of the Applicant's Form U5S,
to each of the public service commissions having jurisdiction over the retail
rates of the Applicant's domestic utility subsidiaries.

          In addition, the Applicant states that the provisions of Rule 53(a)
are not made inapplicable to the authorization herein requested by reason of the
occurrence or continuance of any of the circumstances specified in Rule 53(b).
Rule 53(c) is inapplicable by its terms.


ITEM 4.   REGULATORY APPROVAL.
          -------------------

          No state commission, and no federal commission, other than this
Commission, has jurisdiction over the proposed transaction.

ITEM 5.   PROCEDURE.
          ---------

          The Commission is requested to publish a notice under Rule 23 with
respect to the filing of this Application/Declaration as soon as practicable.
The Applicant requests that the Commission's order be issued as soon as
practicable after the notice period and in any event not later than July 31,
2003 in order to accommodate the initial call of capital contributions by the
Company. The Applicant further requests that there should not be a 30-day
waiting period between issuance of the Commission's order and the date on which
the order is to become effective, hereby waives a recommended decision by a
hearing officer or any other responsible officer of the Commission, and consents
to the assistance of the Division of Investment Management in the preparation of
the Commission's decision and/or order, unless the Division of Investment
Management opposes the matters proposed herein.


ITEM 6.   EXHIBITS AND FINANCIAL STATEMENTS.
          ---------------------------------

          A.   Exhibits.
               --------

               A     -   Draft of Operating Agreement of PowerTree Carbon
                         Company, LLC

               B     -   None

               C     -   Inapplicable

               D     -   None

               E     -   Inapplicable

               F-1   -   Opinion of Counsel for the Applicant.

               F-2   -   Opinion of Morris, James, Hitchens & Williams LLP.


                                       7



               G     -   Form of Federal Register Notice

          B.   Financial Statements.
               --------------------

               (Deemed unnecessary because of the de minimis nature of the
               proposed transaction)


ITEM 7.   INFORMATION AS TO ENVIRONMENTAL EFFECTS.
          ---------------------------------------

          None of the matters that are the subject of this
Application/Declaration involves a "major federal action" nor do such matters
"significantly affect the quality of the human environment" as those terms are
used in section 102(2)(C) of the National Environmental Policy Act. The
transaction that is the subject of this Application/Declaration will not result
in changes in the operation of the Applicant that will have an impact on the
environment. The Applicant is not aware of any federal agency that has prepared
or is preparing an environmental impact statement with respect to the
transaction that is the subject of this Application/Declaration.

                                     SIGNATURE

          Pursuant to the requirements of the Public Utility Holding Company Act
of 1935, the undersigned company has duly caused this statement to be signed on
its behalf by the undersigned thereunto duly authorized.

                                     AMEREN CORPORATION

                                     By: /s/  Steven R. Sullivan
                                              ------------------
                                     Name:    Steven R. Sullivan
                                     Title:   Vice President Regulatory Policy,
                                              General Counsel and Secretary



Date:  June 12, 2003


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