WEST FRASER TIMBER CO., LTD

Lumber Segment

1. This is a non-GAAP financial measure. Refer to the “Non-GAAP and Other Specified Financial Measures” section of this document for more information on this measure. 2023 Adjusted EBITDA was impacted by a one-time charge of $2 million related to inventory purchase price accounting related to the Spray Lake lumber mill acquisition.

Lumber sales decreased compared to 2022 due primarily to lower product pricing and, to a lesser extent, lower shipments. The price variance resulted in a decrease in operating earnings and Adjusted EBITDA of $1,588 million compared to 2022.

SPF shipment volumes were comparable versus 2022. SPF shipment volumes in Q1-23 increased year-over-year as Q1-22 was impacted by disruptions to rail and truck services resulting from severe weather and flooding in B.C. carried over from Q4-21. This increase was substantially offset by lower shipment volumes resulting from weaker demand during the balance of the year.

SYP shipment volumes decreased compared to 2022 due primarily to reductions in production volumes, discussed further in the section below.

The volume variance resulted in an increase in operating earnings and Adjusted EBITDA of $4 million compared to 2022.

• 5 -

We ship SPF to several export markets, while our SYP sales are almost entirely within the U.S. The relative proportion of shipments of SPF by destination was comparable versus prior year. Exports of SPF outside North America have declined in recent years due to reduced exports of low-grade lumber to China.

Wood chip and other residual sales decreased compared to 2022 due primarily to decreases in the pricing of chips and lower lumber production in the U.S. South. Logs and other sales were broadly comparable to prior year.

SPF production volumes were comparable versus 2022 due primarily to fewer reductions in operating schedules taken in the current year, offset in part by the impact of the previously announced permanent curtailment of one shift at our Fraser Lake and Williams Lake lumber mills and reduced production at certain of our lumber mills in Alberta in the summer due to wildfire evacuation impacts.

SYP production volumes decreased compared to 2022 due primarily to the curtailment of operations at our lumber mill in Perry, Florida and incremental production curtailments to manage inventory.

Cost inflation across a number of our inputs including supplies and materials, energy, labour costs, and transportation has moderated.

Costs of products sold decreased compared to 2022 due primarily to lower log and manufacturing costs in our Canadian operations, lower SYP shipment volumes, and a favourable $77 million variance relating to inventory write-downs. We recorded significant inventory valuation reserves in Q4-22 due to low product pricing at period-end. Required inventory valuation reserves were lower in 2023 due to decreases in inventory costs, primarily from lower log costs, and lower overall inventory levels. Log harvesting in Western Canada in Q4-23 has been slowed by warm weather.

Most of our SPF log requirements are harvested from crown lands owned by the provinces of B.C. or Alberta. B.C.’s stumpage system is tied to reported lumber prices, with a time lag, and publicly auctioned timber harvesting rights. Alberta’s stumpage system is correlated to published lumber prices with a shorter time lag.

SPF log costs decreased compared to 2022 due primarily to lower stumpage rates in Alberta and B.C. and lower purchased log costs.

SPF unit manufacturing costs decreased compared to 2022 due primarily to lower energy, supplies and materials, and labour costs. The weakening of the CAD against the USD was also a contributing factor.

SYP log costs decreased compared to 2022 as availability of logs improved. SYP unit manufacturing costs increased compared to 2022 due to higher maintenance and labour costs, offset by lower energy costs.

Freight and other distribution costs decreased compared to 2022 due primarily to lower trucking rates, favourable changes in customer geography mix, and lower shipment volumes.

Export duty expense decreased compared to 2022. As disclosed in the table below, prior to consideration of the impact of duty recoveries attributable to finalization of POIs, export duties for 2023 decreased compared to 2022 due primarily to lower pricing, and a lower CVD cash deposit rate, offset in part by a higher estimated ADD rate. Export duties in 2023

• 6 - included a recovery of $62 million related to the USDOC finalization of AR4 duty rates whereas export duties in 2022 included a recovery of $81 million related to the USDOC finalization of AR3 duty rates.

The following table reconciles our cash deposits paid during the year to the amount recorded in our statements of earnings:

1. Represents combined CVD and ADD cash deposit rate of 11.12% for January 1 to January 9, 2022, 11.14% for January 10 to August 8, 2022, and 8.25% from August 9, 2022 to July 31, 2023, and 9.25% from August 1 to December 31, 2023.

2. Represents adjustment to West Fraser Estimated ADD rate of 8.84%for 2023 and 4.52% for 2022.

3.$81 million represents the duty recovery attributable to the finalization of AR3 duty rates for the 2020 POI. The final CVD rate was 3.62% and the final ADD rate was 4.63% for AR3.

4.$62 million represents the duty recovery attributable to the finalization of AR4 duty rates for the 2021 POI. The final CVD rate was 2.19% and the final ADD rate was 7.06% for AR4.

Amortization expense was comparable versus 2022.

Restructuring and impairment charges of $137 million were recorded in 2023. Of this amount, $128 million related to facility closures and curtailments due to availability of economic fibre sources in the U.S. South and B.C. The remaining balance relates to impairment losses relating to an equity accounted investment that produces and distributes wood pellets and the closure of a regional corporate office.

Restructuring and impairment charges of $31 million were recorded in 2022 relating to the curtailment of operations at our lumber mill in Perry, Florida.

Operating earnings for the Lumber Segment decreased by $1,430 million compared to 2022 for the reasons explained above.

Adjusted EBITDA for the Lumber Segment decreased by $1,326 million compared to 2022. The following table shows the Adjusted EBITDA variance for the period. The impact of the contribution from our Spray Lake lumber mill from November 17, 2023, the date of acquisition, to December 31, 2023 is nominal and included under Other. This impact includes a one time charge of $2 million related to inventory purchase price accounting. The impact of changes in pricing, cost and volume for wood chip and other residuals is also included under Other. Energy revenues were also lower compared to the prior year.

• 7 -