Exhibit 99.3

WEYERHAEUSER COMPANY

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The following unaudited pro forma condensed combined financial information is based on the historical consolidated financial information of Weyerhaeuser Company (referred to as “Weyerhaeuser”) and Plum Creek Timber Company, Inc. (referred to as “Plum Creek”) and has been prepared to reflect the following:

The unaudited pro forma condensed combined balance sheet as of December 31, 2015 is presented as if the Merger Transaction and the Capital Transaction were completed on that date. The unaudited pro forma condensed combined statement of operations for the year ended December 31, 2015, assumes that the Merger Transaction and Capital Transaction were completed on January 1, 2015. The historical consolidated financial information has been adjusted to give effect to estimated pro forma events that are (1) directly attributable to the Merger Transaction or the Capital Transaction, (2) factually supportable, and (3) with respect to the statement of operations, expected to have a continuing impact on the combined results of operations. The unaudited pro forma condensed combined financial information should be read in conjunction with the historical consolidated financial statements and accompanying notes of Weyerhaeuser and with the historical consolidated financial statements and accompanying notes of Plum Creek.

The unaudited pro forma condensed combined financial information is presented for illustrative purposes only, contains a variety of adjustments, assumptions and estimates, is subject to numerous other uncertainties, and does not reflect what the combined company’s financial position or results of operations would have been had the Merger Transaction and Capital Transaction been completed as of the dates assumed for purposes of that pro forma financial information, nor does it reflect the financial position or results of operations of the combined company following the Merger Transaction and Capital Transaction.

The pro forma adjustments are based on the information available at the time of the preparation of this financial information. For purposes of the unaudited pro forma condensed combined financial information, the value of the equity consideration issued by Weyerhaeuser in exchange for 100% of Plum Creek’s equity has been preliminarily allocated to the Plum Creek assets acquired and liabilities assumed based on an initial estimate of fair values.

Additionally, the unaudited pro forma condensed combined financial information does not reflect the cost of any integration activities or benefits from synergies or different asset management strategies that may be derived from any integration activities, nor does it include any items not expected to have a continuing impact on the consolidated results of operations of Weyerhaeuser.

On November 8, 2015 Weyerhaeuser announced that the Weyerhaeuser board authorized the exploration of strategic alternatives for Weyerhaeuser’s Cellulose Fibers business. The pro forma condensed combined financial information does not include any adjustments to reflect potential outcomes of the Weyerhaeuser board’s evaluation process.

Weyerhaeuser Company

Unaudited Pro Forma Condensed Combined Statement of Operations

For the year ended December 31, 2015

Weyerhaeuser Company

Unaudited Pro Forma Condensed Combined Balance Sheet

As of December 31, 2015

NOTES TO THE UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The unaudited pro forma condensed combined financial information is based upon the historical consolidated financial information of Weyerhaeuser and Plum Creek.

On February 19, 2016, pursuant to the Agreement and Plan of Merger (the “merger agreement”), dated as of November 6, 2015, between Weyerhaeuser and Plum Creek, Plum Creek merged with and into Weyerhaeuser. Each outstanding share of Plum Creek common stock (other than shares of Plum Creek common stock owned by Plum Creek as treasury stock, which were canceled) was automatically converted into the right to receive 1.60 Weyerhaeuser common shares, with cash paid in lieu of any fractional shares. Weyerhaeuser will account for the Merger Transaction as the acquirer in a business combination using the acquisition method in accordance with accounting principles generally accepted in the United States. Under the acquisition method, the assets acquired and liabilities assumed by Weyerhaeuser from Plum Creek will be recorded as of the date of the acquisition at their respective fair values. The pro forma financial information also reflects adjustments needed to conform Plum Creek’s historical financial information to Weyerhaeuser’s historical accounting policies and practices.

Weyerhaeuser also announced its intention to repurchase $2.5 billion of outstanding Weyerhaeuser common shares following the closing of the merger. Weyerhaeuser has entered into $2.5 billion of bank term loans to finance the repurchase.

The pro forma financial statements have been derived from the historical consolidated financial statements of Weyerhaeuser and Plum Creek. Assumptions and estimates underlying the pro forma adjustments are described in these notes, which should be read in conjunction with the pro forma financial statements. Since the pro forma financial statements have been prepared based upon preliminary estimates and assumptions, the final amounts recorded may differ materially from the information presented.

The pro forma statement of operations for the year ended December 31, 2015, gives effect to the Merger Transaction and the Capital Transaction as if they were consummated on January 1, 2015. The pro forma balance sheet as of December 31, 2015, gives effect to the Merger Transaction and the Capital Transaction as if they were consummated on December 31, 2015.

The pro forma financial statements do not reflect any cost savings or associated costs to achieve such savings from operating efficiencies, synergies, debt refinancing or other restructuring that may result from the Merger Transaction except for the pro forma adjustments related to the Capital Transaction.

On November 8, 2015, Weyerhaeuser announced that the Weyerhaeuser board authorized the exploration of strategic alternatives for its Cellulose Fibers business. The pro forma condensed combined financial information does not include any adjustments to reflect potential outcomes of the Weyerhaeuser board’s evaluation process. See discussion and summary historical segment financial information in Note 4. Strategic Evaluation of Weyerhaeuser’s Cellulose Fibers Business for more information.

NOTE 2: MERGER TRANSACTION BUSINESS COMBINATION AND PURCHASE PRICE ALLOCATION

Calculation of Preliminary Purchase Consideration

The preliminary purchase price reflects the market value of Weyerhaeuser’s common shares issued in connection with the Merger Transaction. For pro forma purposes, the fair value of the consideration given and thus the preliminary purchase price was determined primarily based on the $22.87 per share closing price of Weyerhaeuser common shares on February 19, 2016. Additionally, the preliminary purchase price includes additional consideration related to converted Plum Creek stock options.

The following table summarizes the estimated purchase price for accounting purposes (dollars in millions, except per share amounts):

Preliminary Purchase Price Allocation

Under the acquisition method of accounting, the identifiable assets acquired and liabilities assumed of Plum Creek are recorded at the acquisition date fair values and added to those of Weyerhaeuser. The pro forma adjustments are preliminary and based on estimates of the fair value and useful lives of the assets acquired and liabilities assumed as of December 31, 2015 and have been prepared to illustrate the estimated effect of the Merger Transaction.

For the purpose of measuring the estimated fair value of the assets acquired and liabilities assumed, Weyerhaeuser has applied the accounting guidance for fair value measurements in Accounting Standards Codification Topic 820, Fair Value Measurement. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date, which, in this case, will be the date of the merger. This is an exit price concept for the valuation of the asset or liability. In addition, market participants are assumed to be buyers and sellers in the principal (or the most advantageous) market for the asset or liability. Fair value measurements for an asset assume the highest and best use by these market participants. As a result, the pro forma financial statements may record assets at fair value measures that do not reflect Weyerhaeuser’s intended use of those assets. Many fair value measurements can be highly subjective, and it is possible that others applying reasonable judgment to the same facts and circumstances could develop and support a range of alternative estimated amounts.

The purchase price allocation and underlying valuations may change materially based on the receipt of more detailed information. Furthermore, the actual allocations will differ from the pro forma adjustments presented. There can be no assurances that these additional analyses and final valuations will not result in significant changes to the estimates of fair value set forth below.

The following table presents the general assumptions reflected in the pro forma balance sheet for the assets acquired and liabilities assumed from Plum Creek:

For pro forma purposes we have assumed that the combined company incurred certain non-recurring expenses directly attributable to the Merger Transaction, including termination benefits for certain Plum Creek executives, investment banking fees, legal fees, accounting and appraisal fees, and other costs related to filing the joint proxy statement/prospectus for the Merger Transaction. As described in H. and S. in Note 3. Pro Forma Adjustments, these amounts are excluded from the unaudited pro forma condensed combined statement of operations because they are charges directly attributable to the merger, factually supportable, and will not have a continuing impact on Weyerhaeuser’s operations; however, these amounts are reflected in the unaudited pro forma condensed combined balance sheet.

The following table summarizes the estimated purchase price for accounting purposes (in millions):

The following notes describe the adjustments presented on the unaudited pro forma condensed combined financial information.

Based on the amounts reported in the Weyerhaeuser consolidated balance sheet as of December 31, 2015 and the consolidated statement of operations for the year ended December 31, 2015, and the Plum Creek consolidated balance sheet as of December 31, 2015 and the consolidated statement of income for the year ended December 31, 2015, certain financial statement line items included in Plum Creek’s historical presentation have been reclassified to conform to corresponding financial statement line items included in Weyerhaeuser’s historical presentation. These reclassifications had no material impact on the historical operating earnings, earnings from continuing operations, total assets, liabilities or shareholders’ equity reported by Weyerhaeuser or Plum Creek.

Statement of operations

Presented for the year ended December 31, 2015.

Plum Creek capitalizes reforestation costs and other costs, such as site preparation, seedlings, planting, fertilization, herbicide application and the thinning of tree stands, to the depletable bases of Timber assets. Weyerhaeuser capitalizes only initial site preparation and planting costs to the depletable bases of Timber assets. Weyerhaeuser generally expenses costs after the first planting as incurred, with the exception of fertilization expense, which is capitalized and amortized on a straight-line basis over five years. This pro forma adjustment reflects the impact of applying Weyerhaeuser’s historical accounting practices to Plum Creek’s reforestation costs, resulting in additional pro forma amortization expense of $18 million for the year ended December 31, 2015.

To adjust depletion to reflect increasing the carrying value of Timber and Timberlands assets, Plum Creek depletion rates were revised to reflect the fair value estimated in the purchase price allocation excluding estimated future silviculture costs divided by historical estimated volume of timber to be available over the growth cycle. These adjusted depletion rates were applied to historical units of production for the year ended December 31, 2015 to estimate additional pro forma depletion expense of $20 million.

Plum Creek’s historical treatment of amortizing capital road costs was revised to conform with Weyerhaeuser’s historical treatment, resulting in decreased amortization expense of $8 million for the year ended December 31, 2015.

To adjust depletion to reflect the increase to the carrying value of Minerals and Mineral Rights assets, Plum Creek depletion rates were revised to reflect the fair value estimated in the purchase price allocation. For pro forma purposes these assets are amortized on a straight-line basis over an estimated economic life of 15 years, resulting in additional depletion expense for minerals and mineral rights of $3 million for the year ended December 31, 2015.

Additionally, pro forma weighted average shares outstanding used in calculating pro forma diluted earnings per share were adjusted to reflect the dilutive impact of Plum Creek options and restricted stock units outstanding by converting dilutive Plum Creek shares at a ratio of 1.60:1 in accordance with the Merger Agreement. Diluted pro forma combined weighted average shares outstanding is calculated as follows (shares in millions):

Balance Sheet

Presented as of December 31, 2015.

NOTE 4: STRATEGIC EVALUATION OF WEYERHAEUSER’S CELLULOSE FIBERS BUSINESS

On November 8, 2015, Weyerhaeuser announced that the Weyerhaeuser board authorized the exploration of strategic alternatives for its Cellulose Fibers business. At this time there can be no assurance that the board’s evaluation process will result in any transaction or that any transaction, if pursued, will be consummated. The pro forma condensed combined financial information does not include any adjustments to reflect potential outcomes of the board’s evaluation process.

The following table provides summary historical financial information of Weyerhaeuser’s Cellulose Fibers operating segment for the year ended December 31, 2015 (in millions):