1025 See, e.g., Mt. St. Helens National Volcanic Monument Act, Pub. L. No. 97-243, 96 Stat. 301 (1982), 16 U.S.C. § 431 note (1982) (repealed 2014).Federal land exchanges are subject to the same valuation requirements as other types of federal acquisitions. In fact, federal regulations specifically require appraisals in many federal land exchanges to comply with these Standards. 1026 But special legal instructionsmay be necessary due to statutory or regulatory requirements for land exchanges. Special rules commonly dictate the larger parcel determination, reflecting federal statutes and agency regulations. 1027 The appraiser must also obtain instructions regarding the appropriate date of valuation, 1028 which may be negotiated by the parties involved in the exchange in accordance with agency regulations 1029 or dictated by statute. 1030 For example, following the volcanic eruption at Mount St. Helens in 1980, Congress authorized the acquisition of lands by donation or exchange in what is now the Mount St. Helens National Volcanic Monument. 1031 Most of these acquisitions required appraisal of the properties’ current market value, but the statute expressly provided for timber acquisitions to be valued as of July 1, 1982, in recognition of rapid deterioration of timber in the area. 1032