**EXHIBIT 31.2****CERTIFICATION OF PERIODIC REPORT**I, David M. Gandossi, certify that:1. I have reviewed this annual report on Form 10-K of Mercer International Inc. (the“Registrant”); 2. Based on my knowledge, this annual report does not contain any untrue statement of a materialfact or omit to state a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading with respect to the periodcovered by this annual report; 3. Based on my knowledge, the financial statements, and other financial information included inthis annual report, fairly present in all material respects the financial condition, resultsof operations and cash flows of the Registrant as of, and for, the periods presented in thisannual report; 4. The Registrant’s other certifying officers and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d — 15(f)) for the Registrant and have: a) Designed such disclosure controls and procedures, or caused such disclosurecontrols and procedures to be designed under our supervision, to ensure that materialinformation relating to the Registrant, including its consolidated subsidiaries, ismade known to us by others with those entities, particularly during the period in whichthis annual report is being prepared;  b) Designed such internal control over financial reporting, or caused suchinternal control over financial reporting to be designed under our supervision, toprovide reasonable assurance regarding the reliability of financial reporting and thepreparation of financial statements for external purposes in accordance with generallyaccepted accounting principles;  c) Evaluated the effectiveness of the Registrant’s disclosure controls andprocedures and presented in this annual report our conclusions about the effectivenessof the disclosure controls and procedures, as of the end of the period covered by thisannual report based on such evaluation; and  d) Disclosed in this annual report any change in the Registrant’s internal controlover financial reporting that occurred during the Registrant’s most recent fiscalquarter (the Registrant’s fourth fiscal quarter in the case of this annual report) thathas materially affected, or is reasonably likely to materially affect, the Registrant’sinternal control over financial reporting; and5. The Registrant’s other certifying officer and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the Registrant’s auditors and theaudit committee of the Registrant’s board of directors (or persons performing the equivalentfunctions): a) All significant deficiencies and material weaknesses in the design or operationof internal control over financial reporting which are reasonably likely to adverselyaffect the Registrant’s ability to record, process, summarize and report financialinformation; and  b) Any fraud, whether or not material, that involves management or other employeeswho have a significant role in the Registrant’s internal control over financialreporting.Date:February 22, 2008                                                         /s/ David M. Gandossi   David M. Gandossi   Chief Financial Officer