<PAGE>

                                                                     EXHIBIT 4.1

                          PLUM CREEK TIMBERLANDS, L.P.
                          999 Third Avenue, Suite 2300
                            Seattle, Washington 98104

                                                         As of December 19, 2002

To each of the Noteholders listed on the signature pages attached hereto

Dear Noteholder:

         Plum Creek Timberlands, L.P., (together with any Person who succeeds to
all or substantially all of Plum Creek Timberlands, L.P.'s assets and business,
herein called the "Company"), a Delaware limited partnership has heretofore
entered into that certain Senior Note Agreement, dated as of October 9, 2001
(the "Senior Note Agreements"), pursuant to which the Company issued its senior
notes in the aggregate principal amount of $500,000,000 ($55,000,000 of 6.96%
Series H Senior Notes due 2006, $75,000,000 of 7.25% Series I Senior Notes due
2008, $295,000,000 of 7.66% Series J Senior Notes due 2011 and $75,000,000 of
7.76% Series K Senior Notes due 2013, all of which remain outstanding and are
held by the institutions (individually a "Noteholder" and collectively the
"Noteholders") listed on the signature pages attached hereto (the "Notes").
Terms used herein which are not otherwise defined herein have the meanings
ascribed to them in the Senior Note Agreements, as amended by this Agreement.

         The Company and the Noteholders wish to enter into this agreement (this
"Agreement") in order to amend certain provisions of the Senior Note Agreements.
Accordingly, the Company hereby agrees with the Noteholder as follows:

         1.                AMENDMENTS TO SENIOR NOTE AGREEMENTS.

                  (a)               Clause (ix) of paragraph 6B(3) of the Senior
         Note Agreements is hereby amended to read in its entirety as follows:

                           (ix)     make Investments not otherwise permitted by
                  this paragraph 6B(3) in entities engaged solely in a Permitted
                  Business or Permitted Ancillary Business, provided that the
                  cumulative aggregate amount of such Investments, (calculated
                  at original cost and including (A) the fair market value of
                  property (other than cash invested as of the date of the
                  Investment) as reasonably determined in good faith by the
                  Responsible Representatives at the time such Investment was
                  made and (B) the principal amount of any obligations
                  guaranteed to the extent such guarantees are not otherwise
                  permitted by this paragraph 6B(3)) outstanding from time to
                  time made pursuant to this clause (ix) between the date of
                  closing and any date thereafter shall not exceed the greater
                  of $300,000,000 or 60% of the average annual Pro Forma Free
                  Cash Flow for the two fiscal years preceding such date;

                  (b)               A new clause (x) is added at the end of
         paragraph 6B(3) of the Senior Note Agreements as follows:

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        1

<PAGE>

                           and; (x) make contributions of property to the
                  capital of Persons in which the Company directly or indirectly
                  holds an equity or other ownership interest to the extent that
                  such contributions constitute Investments that are permitted
                  by the provisions of clause (ix) above;

                  (c)               Clause (iii) of paragraph 6B(5) of the
         Senior Note Agreements is hereby amended by adding the phrase "or a
         Permitted Ancillary Business" after the phrase "Permitted Business" in
         the seventh line thereof.

                  (d)               Clause (iv) of paragraph 6B(5) of the Senior
         Note Agreements is hereby amended by adding the phrase "or a Permitted
         Ancillary Business" after the phrase "Permitted Business" in the
         eighteenth line thereof.

                  (e)               Clause (viii) of paragraph 6B(5) of the
         Senior Note Agreements is hereby amended to read in its entirety as
         follows:

                           (viii)   the Company and its Restricted Subsidiaries
                  may otherwise sell for cash properties in an amount not less
                  than the fair value thereof as determined in good faith by the
                  Responsible Representatives, if and only if (a) immediately
                  after giving effect to such proposed sale, no condition or
                  event shall exist which constitutes an Event of Default or
                  Material Default, (b) not less than 50% of the Net Proceeds of
                  any such sale (x) are applied, within one year after such
                  sale, to the repayment of Qualified Debt selected by the
                  Company, which, in the case of the Notes, shall be a
                  prepayment pursuant to paragraph 4B, or (y) are applied,
                  within one year after such sale, to the purchase of productive
                  assets in the same line of business, and (c) immediately after
                  giving effect to such sale (giving effect on a pro forma basis
                  to any proposed retirement of Qualified Debt out of the
                  proceeds thereof), the Company could incur $1 of additional
                  Funded Debt or Current Debt pursuant to paragraph 6B(2)(ix);
                  provided that, if any such sale constitutes a sale of more
                  than 15% of the Company's Tangible Assets as of the end of the
                  Company's most recently ended fiscal quarter, all the
                  unapplied Net Proceeds of such sale less the amount, if any,
                  of such Net Proceeds to be included in clause (a)(vii) of the
                  definition of "Available Cash" in the calculation thereof for
                  the calendar quarter of the Company in which the sale occurs
                  shall be placed immediately in an escrow or cash collateral
                  account or accounts, pursuant to an agreement or agreements in
                  form and substance reasonably satisfactory to the holders of
                  greater than 50% of the outstanding principal amount of
                  Qualified Debt (which escrow agreement or agreements shall
                  provide for a release from escrow of an amount equal to any
                  additions to Available Cash pursuant to clause (a)(vii) of the
                  definition of "Available Cash" with respect to such sale in
                  calendar quarters of the Company subsequent to the calendar
                  quarter in which such sale occurs), for the purpose of
                  application in accordance with clause (b) above, and

                  (f)               Paragraph 6C of the Senior Note Agreements
         is hereby amended by adding the phrase "or Permitted Ancillary
         Businesses" at the end of the first sentence thereof.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        2

<PAGE>

                  (g)               The following definitions set forth in
         paragraph 10B of the Senior Note Agreements are hereby amended to read
         in their entirety as follows:

                  "Assumption Agreements" shall mean those certain Assumption
         Agreements, dated as of October 9, 2001, executed as contemplated by
         (and in substantially the form designated as Exhibit 3H to) this
         Agreement, together with any Future Southern Timber Assumption
         Agreements or any Assumption Agreements executed by the Mississippi
         Subsidiary or any other Restricted Subsidiary in substantially the form
         of Exhibit 3H attached hereto.

                  "Available Cash" shall mean, with respect to any calendar
         quarter

                           (a) the sum of:
                                    (i)      the Company's net income (or net
                           loss) (excluding gain on the sale of any Capital
                           Asset) for such quarter,

                                    (ii)     the amount of depletion,
                           depreciation, amortization and other noncash charges
                           utilized in determining net income of the Company for
                           such quarter,

                                    (iii)    the amount of any reduction in
                           reserves of the Company of the types referred to in
                           clause (b)(iv) below,

                                    (iv)     proceeds received by the Company
                           from the sale of Designated Acres,

                                    (v)      any Cash from Capital Transactions
                           received by the Company during such quarter in
                           specific contemplation that such Cash from Capital
                           Transactions will be used to refund or refinance any
                           payment of Debt of the type specified in clause
                           (b)(i) below which was made in either of the two
                           immediately preceding quarters,

                                    (vi)     (A) with respect to the calendar
                           quarter ended September 30, 2001 only, $140,000,000
                           and (B) other Cash from Capital Transactions received
                           by the Company during the relevant quarter up to an
                           aggregate amount equal to $200,000,000 for all
                           calendar quarters, commencing with the calendar
                           quarter that ended March 31, 2002, less the aggregate
                           of other amounts of such $200,000,000 utilized in the
                           calculation of Available Cash for previous calendar
                           quarters, and

                                    (vii)    without duplication in respect of
                           clauses (a)(v) and (a)(vi) above, in the event of any
                           Asset Sale, an amount equal to that portion of the
                           Net Proceeds received from such sale that was applied
                           to the repayment of the Qualified Debt in accordance
                           with paragraph 6B(5)(viii) but not to exceed an
                           amount equal to 50% of the Net Proceeds received from
                           such sale; provided, that, the cumulative increase to
                           Available Cash pursuant to this clause (a)(vii)
                           (after giving effect to any current increase

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       3

<PAGE>

                           in respect thereof) with respect to any Asset Sale
                           shall not exceed, in any event, an amount equal to
                           the Net Proceeds from such Asset Sale less the
                           cumulative amount of such Net Proceeds applied to the
                           repayment of Qualified Debt and to the purchase of
                           productive assets in accordance with paragraph
                           6B(5)(viii);

                  less (b) the sum of:

                           (i)      all payments of principal on Debt made by
                  the Company in such quarter (excluding any payments of
                  principal on Debt made with Cash from Capital Transactions
                  received by the Company during such quarter or, to the extent
                  such Cash from Capital Transactions remains available,
                  received by the Company during the four immediately preceding
                  quarters),

                           (ii)     capital expenditures made by the Company
                  during such quarter (excluding any capital expenditures for
                  such quarter made with Cash from Capital Transactions received
                  by the Company during such quarter or, to the extent such Cash
                  from Capital Transactions remains available, received by the
                  Company during the four immediately preceding quarters, and
                  capital expenditures which the General Partner reasonably
                  anticipates will be financed with Cash from Capital
                  Transactions within 90 days from the end of such quarter),

                           (iii)    the amount of any capital expenditures made
                  by the Company in a prior quarter which was anticipated would
                  be financed from Cash from Capital Transactions but which have
                  not been financed from such source within 90 days from the end
                  of such quarter,

                           (iv)     the amount of any reserves of the Company
                  established during such quarter which are necessary or
                  appropriate (A) to provide funds for the future payment of
                  items of the types specified in clauses (b)(i) and (b)(ii)
                  above, (B) to provide additional working capital, (C) to
                  provide funds for cash distributions with respect to any one
                  or more of the next four quarters, or (D) to provide funds for
                  the future payment of interest in an amount equal to the
                  interest to be accrued in the next quarter,

                           (v)      the amount of any noncash items of income
                  utilized in determining net income of the Company for such
                  quarter,

                           (vi)     the amount of any Investments in the form of
                  cash or cash equivalents (other than guarantees, contingent
                  liabilities or endorsements, except to the extent payments are
                  actually made under such guarantees, contingent liabilities or
                  endorsements) made by the Company during such quarter pursuant
                  to clause (i), (viii) or (ix) of paragraph 6B(3) (or in the
                  case of any Subsidiary, Investments in the form of cash or
                  cash equivalents (other than guarantees, contingent
                  liabilities or endorsements, except to the extent payments are
                  actually made under such guarantees, contingent liabilities or
                  endorsements) of similar

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        4

<PAGE>

                  type) to the extent not included in capital expenditures or
                  payments on principal on Debt made by the Company during such
                  quarter (excluding (A) any such Investments for such quarter
                  made with Cash from Capital Transactions received by the
                  Company during such quarter or, to the extent such Cash from
                  Capital Transactions remains available, received by the
                  Company during the four immediately preceding quarters, and
                  Investments which the General Partner reasonably anticipates
                  will be financed with Cash from Capital Transactions within 90
                  days from the end of such quarter and (B) the Investments made
                  pursuant to the Merger-Related Contributions), and

                           (vii)    the amount of any Investments (other than
                  guarantees, contingent liabilities or endorsements, except to
                  the extent payments are actually made under such guarantees,
                  contingent liabilities or endorsements) made by the Company in
                  a prior quarter pursuant to clause (i), (viii) or (ix) of
                  paragraph 6B(3) (or in the case of any Subsidiary, Investments
                  (other than guarantees, contingent liabilities or
                  endorsements, except to the extent payments are actually made
                  under such guarantees, contingent liabilities or endorsements)
                  of similar type) to the extent not included in capital
                  expenditures made by the Company during such quarter which was
                  anticipated would be financed from Cash from Capital
                  Transactions but which have not been financed from such source
                  within 90 days from the end of such quarter, other than any
                  Investments made pursuant to the Merger-Related Contributions.

                           Notwithstanding the foregoing, "Available Cash" shall
                  not take into account any reductions in reserves or
                  disbursements made or reserves established after commencement
                  of the dissolution and liquidation of the Company. In
                  determining "Available Cash", (i) all items under clauses
                  (a)(i), (ii), (iii), (iv), (v), (vi) and (vii) above and all
                  items under clauses (b)(i), (ii), (iii), (iv), (v), (vi) and
                  (vii) above shall be (A) calculated on a consolidated basis
                  with any Subsidiary of the Company whose income is accounted
                  for on a consolidated basis with the Company and (B)
                  calculated on a consolidated basis with any other Person in
                  which the Company directly or indirectly holds an equity or
                  other ownership interest, and, in accordance therewith,
                  "Available Cash" shall include a percentage of each such item
                  of each such Subsidiary or such other Person equal to the
                  Company's percentage ownership interest in such Subsidiary or
                  such other Person, provided, however, that the items under
                  clauses (a)(i), (ii), (iii), (iv), (v), (vi) and (vii) above
                  shall only be included in Available Cash to the extent that
                  the General Partner determines such amount to be legally
                  available for dividends or distributions to the Company or a
                  Subsidiary by such Subsidiary, and with respect to dividends
                  or distributions to the Company or a Subsidiary by such other
                  Person, that such dividends or distributions have been paid to
                  the Company or such Subsidiary; (ii) the amount of net income
                  and the amount of depletion, depreciation, amortization and
                  other noncash charges, utilized in determining net income
                  shall be determined, with respect to the Company, by the
                  General Partner in accordance with generally accepted
                  accounting principles and, with respect to any Subsidiary or
                  such other Person in which the Company directly or indirectly
                  holds an equity or other ownership interest, by its Board of
                  Directors (or by such

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        5
<PAGE>

                  other body or Person which has the ultimate management
                  authority of such Subsidiary or such other Person) in
                  accordance with generally accepted accounting principles;
                  (iii) the net income of any Subsidiary or other Person in
                  which the Company directly or indirectly holds an equity or
                  other ownership interest shall be determined on an after-tax
                  basis; (iv) the amount of any reductions in, or additions to,
                  reserves for purposes of clauses (a)(iii) and (b)(iv) above
                  shall be determined, with respect to the Company, by the
                  General Partner in its reasonable good faith judgment and,
                  with respect to any Subsidiary or other Person in which the
                  Company directly or indirectly holds an equity or other
                  ownership interest, by its Board of Directors (or by such
                  other body or Person which has the ultimate management
                  authority of such Subsidiary or such Person) in its reasonable
                  good faith judgment; and (v) any determination of whether any
                  capital expenditures or investments are financed, or
                  anticipated to be financed, with Cash from Capital
                  Transactions for purposes of clause (b)(ii) or (b)(vi) above
                  shall be made, with respect to the Company, by the General
                  Partner in its reasonable good faith judgment and, with
                  respect to any Subsidiary or other Person in which the Company
                  directly or indirectly holds an equity or other ownership
                  interest, by its Board of Directors (or by such other body or
                  Person which has the ultimate management authority of such
                  Subsidiary or such Person) in its reasonable good faith
                  judgment.

                           Subject to the immediately succeeding sentence, any
                  increase to Available Cash pursuant to clause (a)(vii) above
                  shall be made in the calendar quarter in which Qualified Debt
                  is repaid in accordance with such clause (irrespective of the
                  calendar quarter in which the Asset Sale occurred).
                  Notwithstanding the foregoing, the item under clause (a)(vii)
                  above shall only be included in the calculation of Available
                  Cash if (A) the Company has delivered to the Noteholders an
                  Officers' Certificate demonstrating (with computations in
                  reasonable detail) compliance by the Company with the
                  provisions of clause (B) below for the calendar quarter in
                  which the payment of Qualified Debt in accordance with clause
                  (a)(vii) above is made, and (B) the ratio of Pro Forma Free
                  Cash Flow to Maximum Pro Forma Annual Interest Charges as of
                  the last day of such calendar quarter is not less than
                  2.50:1.0.

                           "Designated Acres" shall mean up to an aggregate
                  800,000 acres owned by the Company which (based on the good
                  faith determination of the Responsible Representatives that
                  such acres have at the time such determination is made a
                  higher value as recreational, residential, grazing or
                  agricultural property than for timber production) may be
                  reasonably designated by the General Partner at the time of
                  the sale thereof as constituting Designated Acres (such
                  aggregate number of acres to be determined over the term of
                  existence of this Agreement). The maximum number of Designated
                  Acres as set forth above shall be adjusted from time to time
                  as follows: (i) upon any acquisition of Timberlands made after
                  September 30, 2002, the maximum number of Designated Acres
                  shall be increased by an amount equal to five percent (5%) of
                  the aggregate acreage of Timberlands so acquired, and (ii)
                  upon any disposition or sale of Timberlands (other than a sale
                  of Designated Acres) made after September 30, 2002, the

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       6

<PAGE>

                  maximum number of Designated Acres shall be decreased by an
                  amount equal to five percent (5%) of the aggregate acreage of
                  Timberlands so disposed or sold, provided, however, in no
                  event may the number of Designated Acres be decreased below
                  the number of Designated Acres previously sold as Designated
                  Acres.

                           "Other Senior Notes" shall mean the following
                  outstanding Senior Notes of the Company (other than the
                  "Notes" as defined herein) (a) 8.73% Senior Notes due August
                  1, 2009, (b) 11-1/8% Senior Notes due June 8, 2007, (c) Senior
                  Notes, Series A, B, C and D due November 13, 2006, 2008, 2011
                  and 2016, respectively, (d) Senior Notes, Series E, F and G
                  due February 12, 2007, 2009 and 2011, respectively, (e)
                  $20,000,000 Floating Rate Notes Series L due 2008, $47,000,000
                  4.96% Notes Series M due 2008, $55,000,000 5.48% Notes Series
                  N due 2010 and $178,000,000 6.18% Notes Series O due 2013 and
                  (f) 5.31% Senior Notes.

                  (h)               The following new defined terms are hereby
         added to paragraph 10B of the Senior Note Agreements in the proper
         alphabetical order:

                           "Asset Sales" means any sale or disposition of
                  properties (other than inventory in the ordinary course of
                  business) of the Company, any of its Subsidiaries or any other
                  Person in which the Company holds an equity or other ownership
                  interest, by the Company, such Subsidiary or such other
                  Person.

                           "5.31% Senior Notes" shall mean the Company's 5.31%
                  Senior Notes due September 17, 2007, in the original principal
                  amount of $25,000,000.

                           "Net Proceeds" means proceeds in cash as and when
                  received by the Person making a sale of property, net of: (a)
                  the direct costs relating to such sale excluding amounts
                  payable to the Company, any Affiliate of the Company or any
                  other Person in which the Company holds an equity or other
                  ownership interest, (b) sale, use or other transaction taxes
                  paid or payable as a result thereof, and (c) amounts required
                  to be applied to repay principal, interest and prepayment
                  premiums and penalties on Debt secured by a Lien on the asset
                  which is the subject of such disposition.

                           "Permitted Ancillary Business" means the ownership,
                  development, management and sale of property owned or
                  previously owned by the Company or a Restricted Subsidiary
                  that, based on the good faith determination of the Responsible
                  Representatives at the time of determination, has a higher
                  value as recreational, residential, grazing or agricultural
                  property than for timber production.

                  (i)               All references in the Senior Note Agreements
         to "net proceeds" shall be deemed to be references to "Net Proceeds."

         2.                CONDITIONS TO EFFECTIVENESS.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        7

<PAGE>

         The amendments set forth in paragraph 1 shall become effective (the
"EFFECTIVE DATE") concurrently with the issuance of the Company's $20,000,000
Floating Rate Notes Series L due 2008, $47,000,000 4.96% Notes Series M due
2008, $55,000,000 5.48% Notes Series N due 2010 and $178,000,000 6.18% Notes
Series O due 2013 (collectively, the "NEW NOTES"), subject to the satisfaction
(or waiver) by the Required Holders of the following conditions:

                  (a)               REPRESENTATIONS AND WARRANTIES; NO DEFAULT.
         The representations and warranties contained in paragraph 3 hereof
         shall be true in all material respects on and as of the Effective Date;
         there shall exist on the Effective Date no Event of Default or Default;
         and the Company shall have delivered to you an Officer's Certificate,
         dated as of the Effective Date, to both such effects.

                  (b)               PROCEEDINGS. All proceedings taken or to be
         taken in connection with the transactions contemplated hereby and all
         documents incident thereto shall be satisfactory in substance and form
         to you, and you shall have received all such counterpart originals or
         certified or other copies of such documents as you may reasonably
         request.

                  (c)               NOTEHOLDER CONSENT. The Company shall have
         received executed counterparts of this Agreement from the Required
         Holders.

                  (d)               AMENDMENT OF AGREEMENTS. The amendment of
         even date herewith of the agreements pursuant to which the Other Senior
         Notes were issued and the amendment of even date herewith of the
         Mortgage Note Agreements shall have been approved by the Required
         Holders in each such agreement.

         3.                REPRESENTATIONS AND WARRANTIES.

         The Company represents and warrants as follows:

                  (a)               NO DEFAULT. No Default or Event of Default
         has occurred and is continuing, and, after giving effect to the
         amendments contemplated hereby, no Default or Event of Default will
         exist.

                  (b)               ORGANIZATION. The Company is a limited
         partnership, duly organized, validly existing and in good standing
         under the Delaware Revised Uniform Limited Partnership Act and has all
         requisite partnership power and authority to own and operate its
         properties, to conduct its business as currently conducted, to enter
         into this Agreement and to carry out the terms of this Agreement and
         after giving effect to the amendments contemplated hereby, the Senior
         Note Agreements and the Notes. The Restricted Subsidiaries,
         Manufacturing and the Facilities Operating Subsidiaries are each a duly
         organized and validly existing corporation, limited partnership or
         limited liability company, as applicable, and in good standing under
         its jurisdiction of incorporation or formation, as applicable, with all
         requisite corporate, partnership or limited liability company power and
         authority, as applicable, to own and operate its properties, to conduct
         its business as proposed to be conducted.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        8

<PAGE>

                  (c)               GENERAL PARTNER NET WORTH. As of the
         Effective Date, the General Partner will have a net worth (excluding
         its interest in the Company and any notes receivable from or payable to
         the Company) at least equal to the amount sufficient to meet the tax
         requirements, if any, for a general partner of a Delaware limited
         partnership (based on the fair market value of its assets).

                  (d)               OWNERSHIP AND SUBSIDIARIES. The Corporation
         owns 100% of the membership interests in the General Partner. The
         General Partner owns the 1% general partnership interest in the Company
         and the Corporation owns the 99% limited partnership interest in the
         Company. The Company owns directly or indirectly, all of the issued and
         outstanding equity interests of all of its Subsidiaries, which
         interests will have been duly authorized and validly issued, fully paid
         and non-assessable and be owned free and clear of any Liens. There are
         no outstanding warrants or options to acquire, or instruments
         convertible into or exchangeable for, any equity interest in any such
         Subsidiary. As of the Effective Date, the Company will have no
         Subsidiaries other than the Subsidiaries listed on Exhibit A. The only
         general partner of the Company is the General Partner, which as of the
         Effective Date owns a 1% interest in the Company.

                  (e)               CORPORATION. The Corporation is a
         corporation, duly formed, validly existing and in good standing under
         the laws of Delaware and has all requisite corporate power and
         authority to own and operate its properties, and to conduct its
         business as currently conducted. The Corporation is organized in
         conformity with the requirements for qualification as a real estate
         investment trust under the Code and its ownership and method of
         operation since July 1, 1999 has enabled it to meet the requirements
         for taxation as a real estate investment trust under the Code.

                  (f)               QUALIFICATION. The Company and each of its
         Subsidiaries is duly qualified or registered for the transaction of
         business and in good standing as a foreign partnership, corporation or
         limited liability company, as the case may be, in each jurisdiction in
         which the failure to so qualify or be registered would have a Material
         Adverse Effect.

                  (g)               BUSINESS; FINANCIAL STATEMENTS. The Company
         and its Subsidiaries have not engaged in any business or activities
         prior to the Effective Date other than (i) owning, acquiring and
         disposing of Timber and Timberlands, and (ii) owning and operating
         lumber mills, plywood and fiberboard manufacturing plants, wood chip
         plants and natural resource assets. The Company and its Subsidiaries do
         not have any significant assets other than Timber, Timberlands and the
         facilities described in clause (ii) above, cash and cash equivalents
         and general intangibles acquired, used or useful in connection with its
         Permitted Business, and as of the Effective Date will not have any
         significant liabilities other than the Notes, the Other Senior Notes,
         the Guarantee, the Mortgage Notes, indebtedness under the Bank of
         America Revolving Credit Agreement and the Company's 364-Day Revolving
         Credit Agreement dated as of November 26, 2002, as it may be amended,
         amended and restated, supplemented, modified, renewed or refinanced
         from time to time, and liabilities incurred in the ordinary course of
         business.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                        9

<PAGE>

                  (h)               CHANGES, ETC. Except as contemplated by this
         Agreement, subsequent to December 31, 2001, (a) neither the Company nor
         the Facilities Subsidiary has incurred any material liabilities or
         obligations, direct or contingent, or entered into any material
         transactions not in the ordinary course of business, except (i) the
         Company's 364-Day Revolving Credit Agreement dated as of November 26,
         2002, as it may be amended, amended and restated, supplemented,
         modified, renewed or refinanced from time to time, (ii) the Purchase
         and Sale Agreement dated as of September 17, 2002 governing the terms
         of acquisition by the Company of approximately 309,000 acres of
         Timberlands from Stora Enso North America Corp. for the purchase price
         of $142,000,000 and (iii) the Company's 5.31% $25,000,000 Senior Notes
         due September 17, 2007; and (b) there has not been (i) any material
         adverse change in the condition (financial or other) or operations of
         the Company or the Facilities Subsidiary or (ii) any Restricted Payment
         of any kind declared, paid or made by the Company in violation of
         paragraph 6A of the Senior Note Agreements.

                  (i)               ACTIONS PENDING. Except as set forth in
         Exhibit B attached hereto, there is no action, suit, investigation or
         proceeding pending or, to the Company's Knowledge, threatened against
         the Company, or any properties or rights of the Company, by or before
         any court, arbitrator or administrative or governmental body which
         questions the validity of this Agreement, the Senior Note Agreements or
         the Notes or any action taken or to be taken pursuant to this
         Agreement, the Senior Note Agreements or the Notes or which would be
         reasonably likely to result in any material adverse change in the
         business, property or assets, condition (financial or other) or
         operations of the Company, or in the inability of the Company to
         perform its obligations hereunder, under the Senior Note Agreements or
         under the Notes.

                  (j)               COMPLIANCE WITH OTHER INSTRUMENTS, ETC.
         Neither the Company nor any Subsidiary of the Company is in violation
         of any term of the Partnership Agreement or of any term of any other
         agreement or instrument to which it is a party or by which it or any of
         its properties is bound or any term of any applicable law, ordinance,
         rule or regulation of any governmental authority or any term of any
         applicable order, judgment or decree of any court, arbitrator or
         governmental authority, the consequences of which violation would be
         reasonably likely to have a Material Adverse Effect, and the execution,
         delivery and performance by the Company of this Agreement, the Senior
         Note Agreements and the Notes will not result in any violation of or be
         in conflict with or constitute a default under any such term or result
         in the creation of (or impose any obligation on the Company to create)
         any Lien (other than the Liens contemplated by this Agreement) upon any
         of the properties or assets of the Company, pursuant to any such term
         except for Liens permitted by paragraph 6B(1) of the Senior Note
         Agreements; and there is no such term which materially adversely
         affects or in the future would be likely to materially adversely affect
         the business, property or assets, condition (financial or other) or
         operations of the Company, or the ability of the Company to perform its
         obligations under this Agreement, the Senior Note Agreements or the
         Notes.

                  (k)               GOVERNMENTAL CONSENT. No consent, approval
         or authorization of, or declaration or filing with, any governmental
         authority is required for the valid execution, delivery and performance
         by the Company of this Agreement.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       10

<PAGE>

                  (l)               DISCLOSURE. Neither this Agreement nor any
         other document, certificate or statement furnished to the Noteholders
         by or on behalf of the Company in writing, in connection herewith
         contains any untrue statement of a material fact or omits to state a
         material fact, in each case, as it relates to the Corporation, the
         Company or its Subsidiaries, necessary in order to make the statements
         contained herein and therein not misleading. There is no fact peculiar
         to the Company which materially adversely affects, or in the future may
         (so far as the Company can now reasonably foresee) materially adversely
         affect, the business, property or assets, condition or results of
         operations of the Company and which has not been set forth in this
         Agreement, the Corporation's periodic reports filed with the Securities
         and Exchange Commission under the Securities Exchange Act of 1934, as
         amended, or in the other documents, certificates and statements in
         writing furnished to the holders of the Notes by or on behalf of the
         Company prior to the date hereof in connection with the transactions
         contemplated hereby.

                  (m)               INCORPORATED REPRESENTATIONS AND WARRANTIES.
         All of the representations and warranties made in the Amendment to
         Mortgage Note Agreements dated of even date herewith are true and
         correct and are incorporated herein by reference with the same effect
         as if set forth at length herein.

         4.                EXPENSES; INDEMNIFICATION.

         The Company shall, whether or not the transactions contemplated hereby
are consummated, save each holder of the Notes harmless for all out-of-pocket
expenses arising in connection with the execution and delivery or performance of
this Agreement or any Assumption Agreement, including the reasonable fees and
expenses of special counsel for the holders of the Notes but not any other legal
fees incurred by any holder of the Notes. The Company shall also indemnify and
save each holder of the Notes harmless from and against all liabilities,
obligations, losses, damages, penalties, actions, judgments, suits, costs,
expenses or disbursements of any kind whatsoever (including, without limitation,
any taxes, and any additional taxes imposed on any amounts payable pursuant to
this paragraph 4) which may at any time be imposed on, incurred by or asserted
against any holder of the Notes in any way arising out of, relating to or
resulting from this Agreement or the transactions contemplated hereby. The
obligations of the Company under this paragraph 4 shall survive the transfer of
any Note or portion thereof or interest therein by a holder of the Notes or any
transferee and the payment of any Note.

         5.                MISCELLANEOUS.

                  (a)               CONTINUITY AND INTEGRATION OF AGREEMENTS.
         The Senior Note Agreements, as supplemented and amended by this
         Agreement, shall remain in full force and effect and are hereby
         ratified and confirmed, and the Senior Note Agreements and this
         Agreement shall be deemed to be and construed as a single agreement.
         Without limitation of the foregoing, or any provision of the Senior
         Note Agreements, all

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       11

<PAGE>

         representations and warranties made herein or in any certificate or
         document delivered in connection herewith shall for all purposes be
         deemed made by the Company on, and delivered by the Company pursuant to
         and in connection with, the Senior Note Agreements.

                  (b)               SURVIVAL OF REPRESENTATIONS AND WARRANTIES.
         All representations and warranties contained herein shall survive the
         execution and delivery of this Agreement, and the transfer of any Note
         by a holder thereof. Such representations and warranties may be relied
         upon by any transferee of a Note from a holder thereof.

                  (c)               SUCCESSORS AND ASSIGNS. All covenants and
         agreements in this Agreement contained by or on behalf of any of the
         parties hereto shall bind and inure to the benefit of the respective
         successors and assigns of the parties hereto whether so expressed or
         not.

                  (d)               DESCRIPTIVE HEADINGS. The descriptive
         headings of the several paragraphs of this Agreement are inserted for
         convenience only and do not constitute a part of this Agreement.

                  (e)               COUNTERPARTS. This Agreement may be executed
         in any number of counterparts and by different parties hereto in
         separate counterparts, each of which when so executed and delivered
         shall be deemed to be an original and all of which taken together shall
         constitute but one and the same instrument.

                  (f)               THIS AGREEMENT SHALL BE CONSTRUED AND
         ENFORCED IN ACCORDANCE WITH, AND THE RIGHTS OF THE PARTIES SHALL BE
         GOVERNED BY, THE LAWS OF THE STATE OF NEW YORK.

                        [Signatures Appear on Next Page]

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       12
<PAGE>

If you are in agreement with the foregoing, please sign the form of acceptance
on the enclosed counterpart of this letter and return the same to the Company
whereupon this letter shall become a binding agreement among us.

Very truly yours,

PLUM CREEK TIMBERLANDS, L.P., a
Delaware limited partnership

By:  Plum Creek Timber I, L.L.C., a Delaware
     limited liability company,
     its General Partner

     By: Plum Creek Timber Company, Inc., a
         Delaware corporation, its sole
         member

         By:________________________________
         Name:  William R. Brown
         Title: Executive Vice President and
                Chief Financial Officer

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-1

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

MINNESOTA LIFE INSURANCE COMPANY

By:  Advantus Capital Management, Inc.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

AMERICAN FIDELITY ASSURANCE COMPANY

By:  Advantus Capital Management, Inc.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

FARM BUREAU LIFE INSURANCE COMPANY
OF MICHIGAN

By:  Advantus Capital Management, Inc.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

MTL INSURANCE COMPANY

By:  Advantus Capital Management, Inc.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-2

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

AIG LIFE INSURANCE COMPANY

By:  AIG Global Investment Corp., as investment adviser
By:  _____________________________
     Name:  Gerald F. Herman

SUNAMERICA LIFE INSURANCE COMPANY

By:    _____________________________
Name:  Gerald F. Herman
Title: Authorized Signatory

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       S-3

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

ALLIANCE CAPITAL MANAGEMENT CORPORATION

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-4

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE HANOVER INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-5

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

ALLSTATE LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

By:    _______________________________
Name:  _______________________________
Title: _______________________________

ALLSTATE LIFE INSURANCE COMPANY OF NEW YORK

By:    _______________________________
Name:  _______________________________
Title: _______________________________

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-6

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

IDS LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-7

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE CANADA LIFE ASSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-8

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

CONNECTICUT GENERAL LIFE INSURANCE COMPANY

By:  CIGNA Investments, Inc. (authorized agent)

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                       S-9

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

CLARICA LIFE INSURANCE COMPANY - U.S.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                      S-10

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

GENERAL ELECTRIC CAPITAL ASSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

GE EDISON LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

FIRST COLONY LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

GE LIFE AND ANNUITY ASSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

GE GROUP ADMINISTRATORS, INC.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

GE GROUP LIFE ASSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                 Amendment to Series H, I, J & K
                                                          Senior Note Agreements

                                      S-11

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE GUARDIAN LIFE INSURANCE COMPANY OF AMERICA

By:    _______________________________
Name:  _______________________________
Title: _______________________________

BERKSHIRE LIFE INSURANCE COMPANY OF AMERICA

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-12

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

GOLDEN AMERICA LIFE INSURANCE COMPANY
By:  ING Investment Management LLC

By:    _______________________________
Name:  _______________________________
Title: _______________________________

NORTHERN LIFE INSURANCE COMPANY
By:  ING Investment Management LLC

By:    _______________________________
Name:  _______________________________
Title: _______________________________

RELIASTAR LIFE INSURANCE COMPANY
By:  ING Investment Management LLC

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-13

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

JEFFERSON PILOT FINANCIAL INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

JEFFERSON-PILOT LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-14

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

JOHN HANCOCK LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

JOHN HANCOCK VARIABLE LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

INVESTORS PARTNER LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

SIGNATURE 5 L.P.
By:  John Hancock Life Insurance Company,
     as Portfolio Advisor

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-15

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THRIVENT FINANCIAL FOR LUTHERANS

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-16

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

METROPOLITAN LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

METROPOLITAN INSURANCE AND ANNUITY COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-17

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

MODERN WOODMEN OF AMERICA

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-18

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

MONY LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-19

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

NATIONAL LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

LIFE INSURANCE COMPANY OF THE SOUTHWEST

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-20

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

NATIONWIDE LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

NATIONWIDE LIFE AND ANNUITY INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

NATIONWIDE MUTUAL INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                       S-21

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

NEW YORK LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-22

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE OHIO NATIONAL LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-23

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

PACIFIC LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-24

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

PRINCIPAL LIFE INSURANCE COMPANY,
an Iowa corporation

By:  Principal Capital Management, LLC
     a Delaware limited liability company,
     its authorized signatory

By:    _______________________________
Name:  _______________________________
Title: _______________________________

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-25

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

CGU LIFE INSURANCE COMPANY OF AMERICA,
a Delaware corporation

By:  Principal Capital Management, LLC
     a Delaware limited liability company,
     its attorney in fact

By:    _______________________________
Name:  _______________________________
Title: _______________________________

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-26

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

PROVIDENT MUTUAL LIFE INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-27

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE PRUDENTIAL INSURANCE COMPANY OF AMERICA

By:    _______________________________
Name:  _______________________________
Title: Vice President

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-28

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

SECURITY FINANCIAL LIFE INSURANCE CO.

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-29

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE UNION CENTRAL LIFE INSURANCE COMPANY

By:  Summit Investment Partners, LLC

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-30

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

TEACHERS INSURANCE AND ANNUITY ASSOCIATION OF AMERICA

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-31

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

THE TRAVELERS INSURANCE COMPANY

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-32

<PAGE>

The foregoing Agreement is accepted
as of the date first above written

UNUM LIFE INSURANCE COMPANY OF AMERICA

By:  Provident Investment Management, LLC
Its: Agent

By:    _______________________________
Name:  _______________________________
Title: _______________________________

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                      S-33

<PAGE>

                                    EXHIBIT A

                                  Subsidiaries

Plum Creek Timber II, L.L.C.
Plum Creek Maine Timberlands, L.L.C.
Plum Creek Southern Timber, L.L.C.
Plum Creek South Central Timberlands, L.L.C.
Plum Creek Manufacturing, L.P.
Plum Creek Manufacturing Holding Company, Inc.
Plum Creek Northwest Lumber, Inc.
Plum Creek Northwest Plywood, Inc.
Plum Creek MDF, Inc.
Plum Creek Southern Lumber, Inc.
Plum Creek Marketing, Inc.
Plum Creek Investment Company
Plum Creek Land Company
Plum Creek Maine Marketing, Inc.
Highland Resources Inc.
PC Timberland Investment Company

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                   Exhibit A-1

<PAGE>

                                    EXHIBIT B

                                 Pending Actions

None.

                                                   Amendment to Series H,I,J & K
                                                          Senior Note Agreements

                                   Exhibit B-1