<PAGE>

                                                                   Exhibit 10.15

                             CABOT INDUSTRIAL TRUST
                          1999 LONG-TERM INCENTIVE PLAN
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                             CABOT INDUSTRIAL TRUST
                          1999 LONG-TERM INCENTIVE PLAN

                                TABLE OF CONTENTS

SECTION 1       GENERAL......................................................1

         1.1.  Purpose.......................................................1
         1.2.  Participation.................................................1

SECTION 2       OPTIONS......................................................2

         2.1.  Definition....................................................2
         2.2.  Eligibility...................................................2
         2.3.  Price.........................................................2
         2.4.  Exercise......................................................3
         2.5.  Post-Exercise Limitations.....................................4
         2.6.  Expiration Date...............................................4

SECTION 3       DIVIDEND AND DISTRIBUTION EQUIVALENT UNITS...................4

         3.1.  Award of Dividend and Distribution Equivalent Units...........4
         3.2.  Terms and Conditions of Dividend and Distribution
               Equivalent Units..............................................5

SECTION 4       SHARE AWARDS.................................................6

         4.1.  Definition....................................................6
         4.2.  Eligibility...................................................6
         4.3.  Terms and Conditions of Awards................................6

SECTION 5       OPERATION AND ADMINISTRATION.................................7

         5.1.  Effective Date................................................7
         5.2.  Shares and Units Subject to Plan..............................7
         5.3.  Reservation of Shares.........................................8
         5.4.  Adjustment....................................................8
         5.5.  Individual Limits on Awards...................................8
         5.6.  Limitation on Grant of Awards.................................9
         5.7.  Change in Control.............................................9
         5.8.  Limit on Distribution........................................10
         5.9.  Performance-Based Compensation...............................10
         5.10.  Withholding.................................................11
         5.11.  Transferability.............................................11
         5.12.  Notices.....................................................11
         5.13.  Form and Time of Elections..................................11
         5.14.  Agreement with REIT or Related Company......................11
         5.15.  Limitation of Implied Rights................................12
         5.16.  Evidence....................................................12
         5.17.  Action by REIT or Related Company...........................12
         5.18.  Gender and Number...........................................12
<PAGE>

SECTION 6       COMMITTEES..................................................13

         6.1.  Administration...............................................13
         6.2.  Selection of REIT Committee..................................13
         6.3.  Powers of Committee..........................................13
         6.4.  Delegation by Committee......................................14
         6.5.  Information to be Furnished to Committees....................14
         6.6.  Liability and Indemnification of Committees..................14

SECTION 7       AMENDMENT AND TERMINATION...................................15
<PAGE>

                             CABOT INDUSTRIAL TRUST
                          1999 LONG-TERM INCENTIVE PLAN

                                    SECTION 1
                                     GENERAL

      1.1. Purpose. The Cabot Industrial Trust 1999 Long-Term Incentive Plan
(the "Plan") has been established effective December 22, 1999 (the "Effective
Date") by Cabot Industrial Trust, a Maryland real estate investment trust (the
"REIT") to:

      (a)   attract and retain employees and other persons providing services to
            the REIT and the Related Companies (as defined below);

      (b)   motivate Participants (as defined in subsection 1.2), by means of
            appropriate incentives, to achieve long-range goals;

      (c)   provide incentive compensation opportunities that are competitive
            with those of other corporations and real estate investment trusts;
            and

      (d)   further identify Participants' interests with those of the REIT's
            other shareholders through compensation that is based on the value
            of the REIT's common shares;

and thereby promote the long-term financial interest of the REIT and the Related
Companies, including the growth in value of the REIT's equity and enhancement of
long-term shareholder return. The term "Related Company" means any company
during any period in which it is a "subsidiary corporation" (as that term is
defined in section 424(f) of the Internal Revenue Code of 1986, as amended (the
"Code")), with respect to the REIT or any affiliate of the REIT which is
designated as a Related Company by the REIT Committee (as defined in subsection
6.1 below), including Cabot Industrial Properties, L.P. (the "Partnership") and
Cabot Advisors, Inc. (the "Management Company"). The Plan is intended to be a
broadly-based plan within the meaning of the shareholder approval policy of the
New York Stock Exchange listing requirements in which all employees of the REIT
and the Related Companies shall be eligible to participate.

      1.2. Participation. Subject to the terms and conditions of the Plan, the
Committees (as described in Section 6) shall determine and designate, from time
to time, from among the Eligible Individuals (as defined below), those persons
who will be granted one or more awards under Sections 2, 3 or 4 of the Plan (an
"Award"), and thereby become "Participants" in the Plan. In the discretion of
the granting Committee, and subject to the terms of the Plan, a Participant may
be granted any Award permitted under the provisions of the Plan, and more than
one Award may be granted to a Participant. Except as otherwise agreed by the
REIT and the Participant, or except as otherwise provided in the Plan, an Award
under the Plan shall not affect any previous Award under the Plan or an award
under any other plan maintained by the REIT or the Related Companies. For
purposes of the Plan, the term "Eligible Individual" shall mean any employee,
officer, consultant, adviser or member of the Board of the REIT or a Related
Company; provided, however, that a member
<PAGE>

                                    SECTION 2

                                     OPTIONS

of the Board of Trustees of the REIT (the "Board") who is not an employee of the
REIT or a Related Company shall not be an Eligible Individual.

      2.1. Definitions. The grant of an "Option" under this Section 2 entitles
the Participant to purchase common shares of beneficial interest of the REIT
("Shares") or units of interest in the Partnership ("Units") at a price fixed at
the time the Option is granted, subject to the terms of this Section. Share
Options granted under this Section will be Share Options that are Non-Qualified
Options. A "Non-Qualified Option" is an Option that is not intended to satisfy
the requirements of an "incentive stock option" described in section 422 of the
Code.

      2.2. Eligibility. Each Committee shall designate the Participants to whom
Options are to be granted under this Section and shall determine the number of
Shares or Units, as applicable, subject to each such Option.

      2.3. Price. The determination and payment of the purchase price of a Share
or Unit under each other Option granted under this Section shall be subject to
the following:

      (a)   The purchase price shall be established by the granting Committee at
            the time the Option is granted; provided, however, that in no event
            shall the price of a Share Option be less than the par value of a
            Share on such date.

      (b)   Subject to the following provisions of this subsection, the full
            purchase price of each Share or Unit purchased upon the exercise of
            any Option shall be paid at the time of such exercise (or such later
            date as may be permitted by the Committee in the case of a cashless
            exercise) and, as soon as practicable thereafter, a certificate
            representing the Shares or Units so purchased shall be delivered to
            the person entitled thereto.

      (c)   The purchase price of a Share Option shall be payable in cash or in
            Shares (valued at Fair Market Value as of the day of exercise) that
            have been held by the Participant at least six months, or in any
            combination thereof, as determined by the REIT Committee. The
            purchase price of a Unit Option shall be payable in cash or in Units
            (valued at Fair Market Value as of the day of exercise) that have
            been held by the Participant at least six months, or in any
            combination thereof, as determined by the REIT Committee.

      (d)   The "Fair Market Value" of a Share or Unit as of any date shall be
            determined in accordance with the following rules:


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            (i)   If the Shares are at the time listed or admitted to trading on
                  any stock exchange, then the Fair Market Value of a Share
                  shall be the average of the highest and lowest sales price per
                  Share on such date on the principal exchange on which the
                  Shares are then listed or admitted to trading or, if no such
                  sale is reported on that date, on the last preceding date on
                  which a sale was so reported.

            (ii)  If the Shares are not at the time listed or admitted to
                  trading on a stock exchange, the Fair Market Value of a Share
                  shall be the average of the lowest reported bid price and
                  highest reported asked price of the Shares on the date in
                  question in the over-the-counter market, as such prices are
                  reported in a publication of general circulation selected by
                  the REIT Committee and regularly reporting the market price of
                  Shares in such market.

            (iii) If the Shares are not listed or admitted to trading on any
                  stock exchange or traded in the over-the-counter market, the
                  Fair Market Value of a Share shall be as determined by the
                  REIT Committee in good faith.

            (iv)  For purposes of determining the Fair Market Value of Shares
                  that are sold pursuant to a cashless exercise program, Fair
                  Market Value shall be the price at which such Shares are sold.

            (v)   As of any date, the Fair Market Value of a Unit shall equal
                  the Fair Market Value of a Share on such date.

      2.4. Exercise. Except as otherwise expressly provided in the Plan, an
Option granted under this Section shall be exercisable in accordance with the
following terms of this subsection:

      (a)   The terms and conditions relating to exercise of an Option shall be
            established by the granting Committee, and may include, without
            limitation, conditions relating to completion of a specified period
            of service (subject to paragraph (b) below), achievement of
            performance standards prior to exercise of the Option or the
            achievement of Share ownership objectives by the Participant. The
            granting Committee, in its sole discretion, may accelerate the
            vesting of any Option under circumstances designated by it at the
            time the Option is granted or thereafter.

      (b)   No Option may be exercised by a Participant after the Expiration
            Date (as defined in subsection 2.6) applicable to that Option.

      2.5. Post-Exercise Limitations. The REIT Committee, in its discretion, may
impose such restrictions on Shares acquired pursuant to the exercise of a Share
Option or delivered in connection with the right described in Section


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4.2(e) of the Agreement of Limited Partnership of Cabot Industrial Properties,
L.P. providing for the exchange of Units for Shares (the "Conversion Right") as
it determines to be desirable, including, without limitation, restrictions
relating to disposition of the Shares and forfeiture restrictions based on
service, performance, Share ownership by the Participant and such other factors
as the REIT Committee determines to be appropriate.

      2.6. Expiration Date. The "Expiration Date" with respect to an Option
means the date established as the Expiration Date by the granting Committee at
the time of the grant; provided, however, that unless determined otherwise by
the Committee, the Expiration Date with respect to any Option shall not be later
than the earliest to occur of:

      (a)   the ten-year anniversary of the date on which the Option is granted;

      (b)   if the Participant's Date of Termination occurs by reason of death
            or Disability, the one-year anniversary of such Date of Termination;
            or

      (c)   if the Participant's Date of Termination occurs for reasons other
            than death or Disability, the three-month anniversary of such Date
            of Termination.

For purposes of the Plan, a Participant's "Date of Termination" shall be the
date on which he both ceases to be an employee of the REIT and the Related
Companies and ceases to perform material services for the REIT and the Related
Companies, regardless of the reason for the cessation; provided that a "Date of
Termination" shall not be considered to have occurred during the period in which
the reason for the cessation of services is a leave of absence approved by the
REIT or the Related Company which was the recipient of the Participant's
services. Except as otherwise provided by the Committee, a Participant shall be
considered to have a "Disability" during the period in which he is unable, by
reason of a medically determinable physical or mental impairment, to engage in
the material and substantial duties of his regular occupation, which condition
is expected to be permanent.

                                    SECTION 3

                   DIVIDEND AND DISTRIBUTION EQUIVALENT UNITS

      3.1. Award of Dividend and Distribution Equivalent Units. To the extent
determined by an affirmative action of the granting Committee at the time an
Option is awarded, a Participant who is awarded an Option under the Plan shall
also be entitled to receive "Dividend Equivalent Units" with respect to a Share
Option and "Distribution Equivalent Units" with respect to a Unit Option, as
applicable.

      (a)   Crediting of Dividend Equivalent Units. Except to the extent


                                       4
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            provided otherwise in a Participant's Option agreement, as of the
            last day of each calendar year, each Participant who has been
            awarded Dividend Equivalent Units with respect to a Share Option
            shall be credited with a number of Dividend Equivalent Units equal
            to (i) the amount the REIT Committee determines to be the average
            dividend yield per Share for such calendar year, reduced by the
            amount that the REIT Committee determines to be the S&P 500 average
            dividend yield for such year, multiplied by (ii) the number of
            Shares underlying the Participant's outstanding Share Option that
            are entitled to Awards under this Section 3 during such calendar
            year (reduced pro rata to reflect Shares underlying such Share
            Option that were not outstanding on the record date with respect to
            each dividend payment date during such year).

      (b)   Crediting of Distribution Equivalent Units. Except to the extent
            provided otherwise in a Participant's Option agreement, as of the
            last day of each calendar year, each Participant who has been
            awarded Distribution Equivalent Units with respect to a Unit Option
            shall be credited with a number of Distribution Equivalent Units
            equal to (i) the amount the REIT Committee determines to be the
            average distribution per Unit for such calendar year, reduced by the
            amount that the REIT Committee determines to be the S&P 500 average
            distribution yield for such year, multiplied by (ii) the number of
            Units underlying the Participant's outstanding Unit Option that are
            entitled to Awards under this Section 3 during such calendar year
            (reduced pro rata to reflect Units underlying such Unit Option that
            were not outstanding on the date each distribution was paid during
            such year).

      3.2.  Terms and Conditions of Dividend and Distribution Equivalent Units.

      (a)   The granting Committee shall determine whether a Dividend Equivalent
            Unit or a Distribution Equivalent Unit credited pursuant to
            subsection 3.1 shall vest over such period as may be designated by
            the Committee or only upon a Change in Control (as defined in
            subsection 5.7).

      (b)   Each vested Dividend Equivalent Unit and Distribution Equivalent
            Unit shall entitle the holder thereof to a Share or Unit, as
            applicable, on the last day of the calendar year in which occurs the
            first of (i) the date the Participant exercises the Option with
            respect to which the Dividend or Distribution Equivalent Unit was
            awarded, (ii) the date such Option expires by reason of termination
            of employment, or (iii) the tenth anniversary of the date on which
            the Option was granted or, if later, the first anniversary of the
            date the Dividend or Distribution Equivalent Unit is fully vested if
            the holder is employed by the REIT or a Related Company on such
            date; provided, however, prior to the date the Shares or Units would
            otherwise be payable, to the extent


                                       5
<PAGE>

            permitted by the REIT Committee, a Participant may irrevocably elect
            to defer receipt of such Shares or Units until the last day of a
            later calendar year, but in no event later than the last day of the
            calendar year in which occurs the tenth anniversary of the grant of
            the underlying Option. Any such deferral election shall be made in
            such form and at such times as the Committee may determine and shall
            be subject to such other terms, conditions and limitations as the
            Committee may establish.

      (c)   All Dividend Equivalent Units and Distribution Equivalent Units
            which are not vested upon the Participant's Date of Termination
            shall be forfeited.

      (d)   Settlement of all Dividend and Distribution Equivalent Units shall
            be made in the form of whole Shares or Units, as applicable. Any
            fractional Shares or Units shall be settled in cash.

                                    SECTION 4

                                  SHARE AWARDS

      4.1. Definition. Subject to the terms of this Section, a Share Award under
the Plan is a grant of Shares to a Participant, the earning, vesting or
distribution of which is subject to one or more conditions established by the
REIT Committee. Such conditions may relate to events (such as performance or
continued employment) occurring before or after the date the Share Award is
granted, or the date the Shares are earned by, vested in or delivered to the
Participant. If the vesting of Share Awards is subject to conditions occurring
after the date of grant, the period beginning on the date of grant of a Share
Award and ending on the vesting or forfeiture of such Shares (as applicable) is
referred to as the "Restricted Period". Share Awards may provide for delivery of
the shares of Shares at the time of grant or may provide for a deferred delivery
date. A Share Award may, but need not, be made in conjunction with a cash-based
incentive compensation program maintained by the REIT and may, but need not, be
in lieu of cash otherwise awardable under such program.

      4.2. Eligibility. The REIT Committee shall designate the Participants to
whom Share Awards are to be granted and the number of Shares that are subject to
each such Award.

      4.3. Terms and Conditions of Awards. Share Awards granted to Participants
under the Plan shall be subject to the following terms and conditions:

      (a)   Beginning on the date of grant (or, if later, the date of
            distribution) of Shares comprising a Share Award, and including any
            applicable Restricted Period, the Participant as owner of such
            Shares shall have the right to vote such Shares.


                                       6
<PAGE>

      (b)   Payment of dividends with respect to Share Awards shall be subject
            to the following:

            (i)   On and after the date that a Participant has a fully earned
                  and vested right to the Shares comprising a Share Award and
                  the Shares have been distributed to the Participant, the
                  Participant shall have all dividend rights (and other rights)
                  of a shareholder with respect to such Shares.

            (ii)  Prior to the date that a Participant has a fully earned and
                  vested right to the shares comprising a Share Award, the REIT
                  Committee, in its sole discretion, may award Dividend Rights
                  with respect to such shares.

            (iii) On and after the date that a Participant has a fully earned
                  and vested right to the Shares comprising a Share Award, but
                  before the Shares have been distributed to the Participant,
                  the Participant shall be entitled to Dividend Rights with
                  respect to such Shares, at the time and in the form determined
                  by the REIT Committee.

            (iv)  A "Dividend Right" with respect to shares comprising a Share
                  Award shall entitle the Participant, as of each dividend
                  payment date, to an amount equal to the dividends payable with
                  respect to a Share multiplied by the number of such Shares.
                  Dividend Rights shall be settled in cash or in Shares valued
                  at Fair Market Value as of the date of settlement, as
                  determined by the REIT Committee, shall be payable at the time
                  determined by the REIT Committee and shall be subject to such
                  other terms and conditions as the REIT Committee may
                  determine.

                                   SECTION 5

                         OPERATION AND ADMINISTRATION

      5.1. Effective Date. The Plan shall be effective as of the date it was
adopted by the Board. The Plan shall be unlimited in duration and, in the event
of Plan termination, shall remain in effect as long as any Awards awarded under
it are outstanding and have not been exercised, terminated or expired; provided,
however, that no new Awards shall be made under the Plan on or after the tenth
anniversary of the date on which the Plan was originally adopted by the Board.

      5.2. Shares and Units Subject to Plan. The Shares with respect to which
Awards may be made under the Plan, including Shares delivered in connection with
the Conversion Right, shall be Shares currently authorized but unissued or
currently held or subsequently acquired by the REIT as treasury


                                       7
<PAGE>

shares, including Shares purchased in the open market or in private
transactions. Subject to the provisions of subsection 5.4, the number of Shares
and Units which may be issued with respect to Awards under the Plan shall not
exceed 2,000,000 Shares or Units in the aggregate. Except as otherwise provided
herein, any Shares or Units subject to an Award which for any reason expires or
is terminated without issuance of Shares or Units (including Shares reserved in
connection with the Conversion Rights of the Units and Shares or Units that are
not issued because they are withheld to satisfy tax withholding) shall again be
available under the Plan.

      5.3. Reservation of Shares. There shall be reserved by the REIT at all
times for sale under the Plan and for exchange pursuant to a Conversion Right
for a Unit received upon the exercise of a Unit Option an aggregate number of
Shares equal to the maximum number of Shares and Units which may be subject to
the granting of Awards under subsection 5.2.

      5.4. Adjustment. In the event the REIT Committee shall determine that any
extraordinary dividend or other distribution (whether in the form of cash,
Shares, Units, other securities or other property), recapitalization, stock
split, reverse stock split, reorganization, merger, consolidation, split-up,
spin-off, combination, repurchase or exchange of Shares, Units or other
securities, the issuance of warrants or other rights to purchase Shares, Units
or other securities, or other similar corporate, trust or partnership
transaction or event affects the Shares or Units with respect to which Awards
have been or may be issued under the Plan, such that an adjustment is determined
by the REIT Committee to be appropriate in order to prevent dilution or
enlargement of the benefits or potential benefits intended to be made available
under the Plan, then the REIT Committee shall, in such manner as it may deem
equitable, adjust any or all of (i) the number and type of Shares and Units that
thereafter may be made the subject of Awards, (ii) the number and type of Shares
and Units subject to outstanding Awards, and (iii) the grant or exercise price
with respect to any Option, or, if deemed appropriate, make provisions for a
cash payment to the holder of any outstanding Award; provided, that:

      (a)   the number of Shares or Units subject to any Award shall always be a
            whole number; and

      (b)   in the event of a merger or sale of substantially all of the assets
            of the REIT, the Board, in its sole discretion, may substitute
            awards of equal value for Awards under the Plan or cancel
            outstanding Awards, provided that the Participant receives an amount
            that the Board believes is reasonable payment therefor.

      5.5. Individual Limits on Awards. Notwithstanding any other provision of
the Plan to the contrary, no Participant shall receive any Award of an Option
under the Plan to the extent that the sum of:

      (a)   the number of Shares and Units subject to such Award;


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<PAGE>

      (b)   the number of Shares and Units subject to all other prior Awards of
            Options under the Plan during the one-year period ending on the date
            of the Award; and

      (c)   the number of Shares and Units subject to all other prior awards of
            options granted to the Participant under other plans or arrangements
            of the REIT or the Partnership during the one-year period ending on
            the date of the award;

would exceed the Participant's Individual Limit under the Plan. The
determination made under the foregoing provisions of this subsection shall be
based on the Shares and Units subject to the Awards at the time of grant,
regardless of when the Awards become exercisable. Subject to the provisions of
subsection 5.4, a Participant's "Individual Limit" shall be 500,000 Shares or
500,000 Units, or any combination of the foregoing.

      5.6. Limitation on Grant of Awards. Notwithstanding any provision of the
Plan to the contrary, in no event shall an Award be granted under the Plan if
the granting of such Award may, in the determination of the REIT Committee,
cause the REIT to lose its status as a real estate investment trust under
section 856 of the Code and applicable regulations thereunder.

      5.7. Change in Control. In the event of a Change in Control of the REIT
(as defined below), all Options and related Awards which have not otherwise
expired shall become immediately exercisable and all other Awards shall become
fully vested. For purposes of the Plan, a "Change in Control" means the
happening of any of the following:

      (a)   the shareholders of the REIT approve a definitive agreement to merge
            the REIT into or consolidate the REIT with another entity, sell or
            otherwise dispose of all or substantially all of its assets or adopt
            a plan of liquidation, provided, however, that a Change in Control
            shall not be deemed to have occurred by reason of a transaction, or
            a substantially concurrent or otherwise related series of
            transactions, upon the completion of which 50% or more of the
            beneficial ownership of the voting power of the REIT, the surviving
            corporation or corporation directly or indirectly controlling the
            REIT or the surviving corporation, as the case may be, is held by
            the same persons (as defined below) (although not necessarily in the
            same proportion) as held the beneficial ownership of the voting
            power of the REIT immediately prior to the transaction or the
            substantially concurrent or otherwise related series of
            transactions, except that upon the completion thereof, employees or
            employee benefit plans of the REIT may be a new holder of such
            beneficial ownership; provided, further, that any transaction
            described in this paragraph (a) with an "Affiliate" of the REIT (as
            defined in the Securities Exchange Act of 1934, as amended (the
            "Exchange Act")) shall not be treated as a Change in Control; or


                                       9
<PAGE>

      (b)   the "beneficial ownership" (as defined in Rule 13d-3 under the
            Exchange Act) of securities representing 25% or more of the combined
            voting power of the REIT is acquired, other than from the REIT, by
            any "person" as defined in Sections 13(d) and 14(d) of the Exchange
            Act (other than any trustee or other fiduciary holding securities
            under an employee benefit or other similar stock plan of the REIT);
            or

      (c)   at any time during any period of two consecutive years, individuals
            who at the beginning of such period were members of the Board cease
            for any reason to constitute at least a majority thereof (unless the
            election, or the nomination for election by the REIT's shareholders,
            of each new trustee was approved by a vote of at least two-thirds of
            the trustees still in office at the time of such election or
            nomination who were trustees at the beginning of such period).

      5.8. Limit on Distribution. Distribution of Shares or Units under the Plan
shall be subject to the following:

      (a)   Notwithstanding any other provision of the Plan, the REIT shall have
            no liability to deliver any Shares or Units under the Plan unless
            such delivery would comply with all applicable laws and the
            applicable requirements of any securities exchange or similar
            entity.

      (b)   In the case of a Participant who is subject to Section 16(a) and
            16(b) of the Exchange Act, the REIT Committee may, at any time, add
            such conditions and limitations to any Award to such Participant, or
            any feature of any such Award, as the REIT Committee, in its sole
            discretion, deems necessary or desirable to comply with Section
            16(a) or 16(b) and the rules and regulations thereunder or to obtain
            any exemption therefrom.

      (c)   To the extent that the Plan provides for issuance of certificates to
            reflect the transfer of Shares or Units, the transfer of such Shares
            or Units may be effected on a non-certificated basis, to the extent
            not prohibited by applicable law or the rules of any stock exchange.

      5.9. Performance-Based Compensation. To the extent that the REIT Committee
determines that it is necessary or desirable to conform any Awards under the
Plan with the requirements applicable to "Performance-Based Compensation", as
that term is used in Code section 162(m)(4)(C), it may, at or prior to the time
an Award is granted, take such steps and impose such restrictions with respect
to such Award as it determines to be necessary to satisfy such requirements
including, without limitation:

      (a)   The establishment of performance goals that must be satisfied prior
            to the payment or distribution of benefits under such


                                       10
<PAGE>

            Awards.

      (b)   The submission of such Awards and performance goals to the REIT's
            shareholders for approval and making the receipt of benefits under
            such Awards contingent on receipt of such approval.

      (c)   Providing that no payment or distribution be made under such Awards
            unless the REIT Committee certifies that the goals and the
            applicable terms of the Plan and Agreement reflecting the Awards
            have been satisfied.

To the extent that the REIT Committee determines that the foregoing requirements
relating to Performance-Based Compensation do not apply to Awards under the Plan
because the Awards constitute Options, the REIT Committee may, at the time the
Award is granted, conform the Awards to alternative methods of satisfying the
requirements applicable to Performance-Based Compensation.

      5.10. Withholding. All Awards and other payments under the Plan are
subject to withholding of all applicable taxes, which withholding obligations
may be satisfied, with the consent of the REIT Committee, through the surrender
of Shares which the Participant already owns or to which a Participant is
otherwise entitled under the Plan; provided, however, previously-owned Shares
that have been held by the Participant less than six months or Shares to which
the Participant is entitled under the Plan may only be used to satisfy the
minimum tax withholding required by applicable law.

      5.11. Transferability. Awards under the Plan are not transferable except
as designated by the Participant by will or by the laws of descent and
distribution. To the extent that the Participant who receives an Award under the
Plan has the right to exercise such Award, the Award may be exercised during the
lifetime of the Participant only by the Participant. Notwithstanding the
foregoing provisions of this subsection, the REIT Committee may permit Awards
under the Plan to be transferred to or for the benefit of the Participant's
family (including, without limitation, to a trust or partnership for the benefit
of a Participant's family), subject to such limits as the REIT Committee may
establish.

      5.12. Notices. Any notice or document required to be filed with the
granting Committee under the Plan will be properly filed if delivered or mailed
by registered mail, postage prepaid, to such Committee, in care of the REIT or
the Management Company, as applicable, at its principal executive offices. Each
Committee may, by advance written notice to affected persons, revise such notice
procedure from time to time. Any notice required under the Plan (other than a
notice of election) may be waived by the person entitled to notice.

      5.13. Form and Time of Elections. Unless otherwise specified herein, each
election required or permitted to be made by any Participant or other person
entitled to benefits under the Plan, and any permitted modification or
revocation thereof, shall be in writing filed with the applicable Committee at


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such times, in such form, and subject to such restrictions and limitations, not
inconsistent with the terms of the Plan, as the Committee shall require.

      5.14. Agreement with REIT or Related Company. At the time of an Award to a
Participant under the Plan, the granting Committee may require a Participant to
enter into an agreement with the REIT or the Management Company, as applicable
(the "Agreement"), in a form specified by the granting Committee, agreeing to
the terms and conditions of the Plan and to such additional terms and
conditions, not inconsistent with the Plan, as the granting Committee may, in
its sole discretion, prescribe.

      5.15. Limitation of Implied Rights.

      (a)   Neither a Participant nor any other person shall, by reason of the
            Plan, acquire any right in or title to any assets, funds or property
            of the REIT or any Related Company whatsoever, including, without
            limitation, any specific funds, assets, or other property which the
            REIT or any Related Company, in its sole discretion, may set aside
            in anticipation of a liability under the Plan. A Participant shall
            have only a contractual right to the amounts, if any, payable under
            the Plan, unsecured by any assets of the REIT and any Related
            Company. Nothing contained in the Plan shall constitute a guarantee
            by the REIT or any Related Company that the assets of such companies
            shall be sufficient to pay any benefits to any person.

      (b)   The Plan does not constitute a contract of employment, and selection
            as a Participant will not give any employee the right to be retained
            in the employ of the REIT or any Related Company, nor any right or
            claim to any benefit under the Plan, unless such right or claim has
            specifically accrued under the terms of the Plan. Except as
            otherwise provided in the Plan, no Award under the Plan shall confer
            upon the holder thereof any right as a shareholder of the REIT or as
            a holder of interests in the Partnership prior to the date on which
            he fulfills all service requirements and other conditions for
            receipt of such rights and Shares or Units are registered in his
            name.

      5.16. Evidence. Evidence required of anyone under the Plan may be by
certificate, affidavit, document or other information which the person acting on
it considers pertinent and reliable, and signed, made or presented by the proper
party or parties.

      5.17. Action by REIT or Related Company. Any action required or permitted
to be taken by the REIT or any Related Company shall be by resolution of its
board of trustees or directors, as applicable, or by action of one or more
members of the board (including a committee of the board) who are duly
authorized to act for the board or (except to the extent prohibited by
applicable law or the rules of any stock exchange) by a duly authorized officer
of the REIT.


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<PAGE>

      5.18. Gender and Number. Where the context admits, words in any gender
shall include any other gender, words in the singular shall include the plural
and the plural shall include the singular.

      5.19. Applicable Law. The provisions of the Plan shall be construed in
accordance with the laws of the State of Maryland, without giving effect to
choice of law principles.

                                    SECTION 6

                                   COMMITTEES

      6.1. Administration. The authority to control and manage the operation and
administration of the Plan shall be vested in a REIT Committee and a Management
Company Committee (the "Committees") in accordance with this Section 6.

      6.2. Selection of REIT Committee. So long as the REIT is subject to
Section 16 of the Exchange Act, the REIT Committee shall be selected by the
Board and shall consist of not fewer than two members of the Board or such
greater number as may be required for compliance with Rule 16b-3 issued under
the Exchange Act.

      6.3. Powers of Committees. The authority to manage and control the
operation and administration of the Plan shall be vested in the Committees,
subject to the following:

      (a)   Subject to the provisions of the Plan, the REIT Committee will have
            the authority and discretion to grant Share Options and Unit Options
            and Dividend and Distribution Equivalent Unit rights to individuals
            who, at the time of grant, perform services for the REIT or the
            Partnership, or who are officers, trustees, directors or other
            persons subject to Section 16(a) of the Exchange Act with respect to
            the REIT. The Management Company Committee shall have sole and
            exclusive authority to grant Share Options and Unit Options and
            Dividend and Distribution Equivalent Unit rights to persons who, at
            the time of grant, perform services for the Management Company and
            are not officers, trustees, directors or other persons subject to
            Section 16(a) of the Exchange Act with respect to the REIT. Each
            Committee shall have the authority to determine the time or times of
            receipt, to determine the types of Awards and the number of Shares
            or Units covered by the Awards, to establish the terms, conditions,
            performance criteria, restrictions, and other provisions of such
            Awards, and to cancel or suspend Awards. In making such Award
            determinations, the granting Committee may take into account the
            nature of services rendered by the respective individual, the
            individual's present and potential contribution to the REIT's
            success and such other


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<PAGE>

            factors as the granting Committee deems relevant.

      (b)   Subject to the provisions of the Plan, the REIT Committee will have
            the authority and discretion to determine the extent to which Awards
            under the Plan will be structured to conform to the requirements
            applicable to Performance-Based Compensation, and to take such
            action, establish such procedures, and impose such restrictions at
            the time such Awards are granted as the REIT Committee determines to
            be necessary or appropriate to conform to such requirements.

      (c)   Subject to the provisions of the Plan, the REIT Committee will have
            the authority and discretion to interpret the Plan, to establish,
            amend and rescind any rules and regulations relating to the Plan, to
            determine the terms and provisions of any agreements made pursuant
            to the Plan and to make all other determinations that may be
            necessary or advisable for the administration of the Plan.

      (d)   Any interpretation of the Plan by a Committee and any decision made
            by it under the Plan is final and binding on all persons.

      (e)   Except as otherwise expressly provided in the Plan, where a
            Committee is authorized to make a determination with respect to any
            Award, such determination shall be made at the time the Award is
            made, except that the granting Committee may reserve the authority
            to have such determination made by the granting Committee in the
            future (but only if such reservation is made at the time the Award
            is granted and is expressly stated in the Agreement reflecting the
            Award).

      6.4. Delegation by Committee. Except to the extent prohibited by
applicable law or the rules of any stock exchange or NASDAQ (if appropriate), a
Committee may allocate all or any portion of its responsibilities and powers to
any one or more of its members and may delegate all or any part of its
responsibilities and powers to any person or persons selected by it. Any such
allocation or delegation may be revoked by the Committee at any time.

      6.5. Information to be Furnished to Committees. The REIT and Related
Companies shall furnish each Committee such data and information as may be
required for it to discharge its duties. The records of the REIT and Related
Companies as to an employee's or Participant's employment (or other provision of
services), termination of employment (or cessation of the provision of
services), leave of absence, reemployment and compensation shall be conclusive
on all persons unless determined to be incorrect. Participants and other persons
entitled to benefits under the Plan must furnish the Committees such evidence,
data or information as the Committees consider desirable to carry out the terms
of the Plan.

      6.6. Liability and Indemnification of Committees. No member or


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<PAGE>

authorized delegate of either Committee shall be liable to any person for any
action taken or omitted in connection with the administration of the Plan unless
attributable to his own fraud or willful misconduct; nor shall the REIT or any
Related Company be liable to any person for any such action unless attributable
to fraud or willful misconduct on the part of a trustee or employee of the REIT
or Related Company. Each Committee, the individual members thereof, and persons
acting as the authorized delegates of the Committee under the Plan, shall be
indemnified by the REIT against any and all liabilities, losses, costs and
expenses (including legal fees and expenses) of whatsoever kind and nature which
may be imposed on, incurred by or asserted against the Committee or its members
or authorized delegates by reason of the performance of a Committee function if
the Committee or its members or authorized delegates did not act dishonestly or
in willful violation of the law or regulation under which such liability, loss,
cost or expense arises. This indemnification shall not duplicate but may
supplement any coverage available under any applicable insurance.

                                    SECTION 7

                            AMENDMENT AND TERMINATION

      The Board may, at any time, amend or terminate the Plan, provided that,
subject to subsection 5.4 (relating to certain adjustments to shares), no
amendment or termination may materially adversely affect the rights of any
Participant or beneficiary under any Award made under the Plan prior to the date
such amendment is adopted by the Board.


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