¶ 1. This property tax appeal concerns the valuation of five electrical substations, seven transmission lines, a fiber-optic fine, land, and utility easements located within the Town of Vernon. Taxpayer Vermont Transco LLC challenges a decision of the state appraiser fixing the 2011 listed value of taxpayer’s utility property in the Town at $92 million. We reverse *587and remand for further findings regarding the lifespan of the property to be used in calculating depreciation, and whether to depreciate the assets in the first year of service.
¶ 2. The equipment at issue in this case was designed and installed to handle the transmission of electric power generated by the Vermont Yankee Nuclear Power Plant and the Vernon Hydroelectric Station. Taxpayer is the successor to Vermont Electric Power Company, Inc. (VELCO), which operates Vermont’s electric transmission system.
¶ 3. The town listers set a value of $92,023,693 on the property effective April 1, 2011. This value was upheld by the Town of Vernon Board of Civil Authority. Taxpayer appealed to the state appraiser pursuant to 32 V.S.A. §§ 4461-4467.
¶ 4. On appeal to the state appraiser, the principal issue was the correct method of calculating depreciation with respect to the electrical equipment that comprises almost the entire value of the property. In addition, taxpayer and the Town disagreed about whether the valuation should include the value of utility easements and rights of way held by taxpayer, estimated by the Town’s appraiser at $277,100. Finally, the parties disagreed about whether to apply depreciation for certain equipment’s first year of life.
¶ 5. In May 2013, the state appraiser issued a ruling setting the total value of the property at $92,023,700. The state appraiser agreed with the Town and its appraiser that an appraisal based on replacement cost new, depreciated in a straight line, provided the most accurate basis for estimating the value of the improvements. The state appraiser did not address taxpayer’s arguments that easements cannot be taxed and that depreciation should have been taken for 2010, the first year of service. This appeal followed.
¶ 6. Taxpayer raises four issues on appeal. First, it argues that the state appraiser should have used an alternative nonlinear depreciation schedule — the “Iowa Curve” method — because that method was previously approved by this Court in reviewing the method of property tax appraisal in Vermont Electric Power Co. v. Town of Vernon, 174 Vt. 471, 807 A.2d 430 (2002) (mem.). Second, taxpayer contends that the state appraiser’s decision on fair market value is not supported by a sufficient analysis of the “core factual issues, including whether fair market value is best estimated by the economic or physical life of the assets, and what those lives are.” Third, taxpayer contends that the state appraiser failed to explain its decisions not to depreciate assets during their *588first year of service. Finally, taxpayer challenges the state appraiser’s decision to include an appraised value for the utility easements.
¶ 7. In an appeal to the state appraiser, a town’s property appraisal is presumed to be valid and legal. City of Barre v. Town of Orange, 152 Vt. 442, 444, 566 A.2d 951, 952 (1989). If the taxpayer introduces evidence that his or her property was assessed above fair market value, the presumption disappears. Vanderminden v. Town of Wells, 2013 VT 49, ¶ 8, 194 Vt. 96, 75 A.3d 598. It is then up to the town to introduce evidence showing “either that it substantially complied with the relevant statutory and constitutional requirements or that its valuation was supported by independent evidence of fair market value.” Id. ¶8 (quotation omitted). The taxpayer has the ultimate burden of proving that the appraisal was incorrect. Adams v. Town of West Haven, 147 Vt. 618, 620 n.*, 523 A.2d 1244, 1245 n.* (1987).
¶ 8. We will not disturb the state appraiser’s findings of fact unless they are clearly erroneous. Vanderminden, 2013 VT 49, ¶ 9. “Our review of legal conclusions, by contrast, is nondeferential and plenary.” Barnett v. Town of Wolcott, 2009 VT 32, ¶ 5, 185 Vt. 627, 970 A.2d 1281 (mem.).
I. Depreciation Method
¶ 9. This is the second time in less than fifteen years that the state appraiser and this Court have considered the depreciation schedule and appraised value. of taxpayer’s transmission equipment and realty within the Town. See Town of Vernon, 174 Vt. 471, 807 A.2d 430 (affirming Town’s valuation of taxpayer’s utility property). In 1999, the Town conducted a town-wide reappraisal. VELCO, taxpayer’s predecessor in interest, appealed the Town’s valuation to the state appraiser. Although VELCO owned less property than taxpayer in this case (only one substation and four parcels containing transmission lines), the issues resolved by the state appraiser then were similar to the issues raised before the state appraiser in this case. In particular, the parties and their expert appraisers disagreed about the appropriate depreciation methodology for the electrical equipment. The state appraiser accepted the methodology used by VELCO’s expert, including the *589application of the Iowa Curve method to the useful life of the equipment.2 Id. at 472, 807 A.2d at 433.
¶ 10. We affirmed the state appraiser on the ground that as the factfinder the state appraiser exercised his discretion appropriately in choosing the Iowa Curve method over straight-line depreciation. Id. at 473-74, 807 A.2d at 434-35. We noted that the Iowa Curve method had been employed in a previous tax appeal, Vermont Electric Power Co. v. Town of Cavendish, 158 Vt. 369, 611 A.2d 389 (1992). 174 Vt. at 473, 807 A.2d at 435. We ruled that the state appraiser’s decision to use the Iowa Curve method was supported at the hearing below by “testimony indicating that [this method was] standard practice in Vermont, endorsed by the State Department of Taxes, and most appropriate for use with transmission lines.” Id. at 473-74, 807 A.2d at 435. We further noted that “[t]he unswerving goal of the statute is fair market valuation, but there is no single pathway to that goal.” Id. at 474, 807 A.2d at 435 (quotation omitted).
¶ 11. In this appeal, taxpayer claims that the state appraiser erred in failing to adopt the Iowa Curve method as a matter of law on the basis of this Court’s decisions in Town of Vernon and Town of Cavendish.
¶ 12. At the hearing before the state appraiser in this matter, an accountant employed by taxpayer, Sharon Tucker, testified that in the valuation taxpayer submitted to the Town it used the Iowa Curve method to calculate depreciation. Ms. Tucker testified that taxpayer adjusted the value of all equipment owned by taxpayer through the use of the Handy-Whitman Index of Public Utility Construction Costs to determine its “trended” or “replacement *590cost new” value.3 Taxpayer assigned each piece of equipment to a thirty- or forty-year curve and calculated a depreciated value on that basis. If a piece of equipment had been owned for longer than the depreciation schedule, taxpayer assigned a fixed value of 24.745%. This calculation resulted in a value of $80,950,830 for the equipment alone. Ms. Tucker testified that taxpayer used the Iowa Curve method because the method had been approved by the state and this Court in Town of Vernon.
¶ 13. Taxpayer also presented expert testimony from a professional appraiser, George Silver. Mr. Silver testified that he employed three appraisal methods (comparable sales, cost, and income-based) to determine fair market value, and determined that the cost approach was most appropriate. Depreciation was relevant to his cost analysis. He employed straight-line depreciation over periods ranging from forty-seven-and-a-half to sixty years for different classes of equipment. He calculated a total value of $83,100,000, of which $79,775,250 was attributed to depreciable equipment. The remainder is land or improvements to land not subject to depreciation. Mr. Silver testified that he did not use the Iowa Curve method of depreciation for calculating the fair market value of taxpayer’s equipment because he “ha[d] not seen the Iowa Curve being used in market transaction^], period.”
¶ 14. George Sansoucy, an appraiser retained by the Town as an expert witness, employed the same three appraisal methods as Mr. Silver, and also concluded that the cost approach was the best method for valuing taxpayer’s property. He also used a straight-line depreciation method in applying the cost approach. He used longer periods of estimated future life for the equipment, ranging from sixty-five to ninety years. He calculated a total value of $92,023,700, of which $91,028,800 was attributed to depreciable equipment. Mr. Sansoucy was critical of the Iowa Curve method, noting that the curves had not been updated since 1942, and that they were not developed for high-voltage transmission lines, such as taxpayer’s, which have a relatively long useful life and are not retired in the same fashion as other industrial equipment. He testified that the trend in the utility industry was to move away from the Iowa Curve method because it depreciates property too quickly. He further noted that the Iowa Curve method is typically *591used for book value analysis but not for appraising property for ad valorem tax purposes. The state appraiser found the Town’s depreciation method persuasive and adopted its valuation.
¶ 15. “It is within the discretion of the state appraiser to determine the most appropriate method for arriving at fair market value,” including the method of depreciation. Town of Vernon, 174 Vt. at 473, 807 A.2d at 434. Taxpayer argues, however, that principles of finality preclude the Town and the state appraiser from using a different method of depreciation for taxpayer’s property than has been approved in prior cases.
¶ 16. “To properly preserve an issue for appeal a party must present the issue with specificity and clarity in a manner which gives the trial court a fair opportunity to rule on it.” State v. Ben-Mont Corp., 163 Vt. 53, 61, 652 A.2d 1004, 1009 (1994). The same principle applies to appeals from administrative agencies. In re Green Mountain Power Corp., 2012 VT 89, ¶ 73 n.7, 192 Vt. 429, 60 A.3d 654.
¶ 17. At no point did taxpayer argue below that the state appraiser was required to use the Iowa Curve method, or that the Town was precluded or estopped from arguing for the use of a different depreciation method than the Iowa Curves. At the hearing, taxpayer’s accountant stated only that taxpayer used the Iowa Curve method because that is the method it had used in the past, and its use was approved in Town of Vernon. In the proposed findings of fact and conclusions of law that taxpayer submitted to the state appraiser after the hearing, taxpayer stated that the Iowa Curve method “has been preferred and recommended by the Vermont Department of Taxes Division of Property Valuation and Review” and that the method “was specifically approved by the Vermont Supreme Court in the Town of Vernon case.” Taxpayer did not argue, however, that the Town could not present an alternative method of depreciation. Nor did taxpayer argue that the state appraiser had to use the Iowa Curve method. Indeed, taxpayer’s own appraiser used the straight-line method of depreciation, undermining its argument that no other method was acceptable. Not until this appeal did taxpayer argue that the state appraiser was barred by principles of issue preclusion from using another method. Taxpayer therefore failed to preserve this issue, and we will not address it here.
*592II. Lifespan of the Equipment
¶ 18. Taxpayer’s second point of error is that the state appraiser accepted the Town’s valuation without making specific findings concerning the lifespans of the equipment to be used in depreciation or addressing the proper approach for estimating those lifespans. In its prior decision, the state appraiser set the useful life of taxpayer’s transmission lines at forty years and the substation at thirty years. Town of Vernon, 174 Vt. at 472, 807 A.2d at 433. In the course of testimony in this case, taxpayer’s accountant set the average life of the transmission equipment at thirty to forty years. Taxpayer’s appraiser used an “economic life” approach, resulting in estimated lifespans of fifty to sixty years for the equipment. The Town’s appraiser employed a “useful life” approach, resulting in estimated lifespans of sixty-five to ninety years.
¶ 19. Because there have been great changes in the quantity and value of taxpayer’s assets, the state appraiser was not bound by the lifespan figures employed in the 1999 tax year. Taxpayer does not make this argument either. Instead, the state appraiser was obligated to make findings concerning the lifespan of the equipment that are sufficiently detailed for us to determine whether they have support in the record. See id. at 474, 807 A.2d at 435 (“The state appraiser has a duty to make clear findings and state how his decision was reached. A mere recitation of the contentions of the parties is not sufficient to support the judgment.” (citation omitted)). We agree with taxpayer that although the state appraiser accepted the Town’s estimates of useful life as part of a general approval of its methodology, few reasons are provided. The state appraiser’s decision states only that “I am persuaded that the town’s approach to depreciation is more appropriate than that advanced by Transco. The evidence supports the belief that a 65 year useful life span as advocated by the Town more accurately reflects Transco’s assets in this appeal.” This finding is insufficient. It is beyond the scope of a state appraiser decision to calculate the depreciated value of each stick of furniture, but it is necessary to a fair process that the basis for accepting the Town’s depreciation figures receive a more complete explanation. See Kachadorian v. Town of Woodstock, 144 Vt. 348, 351, 477 A.2d 965, 967 (1984) (explaining that state appraiser’s “[fjindings of fact must state clearly what was decided and how *593the decision was reached” (quotation omitted)). We therefore remand for further findings on lifespans to be used for calculating depreciation.
III. First Year of Life
' ¶ 20. Taxpayer next argues that the state appraiser failed to address its argument that equipment acquired during calendar year 2010 should have been depreciated for a year as of April 2011 and simply accepted the Town’s decision not to depreciate the equipment without the necessary findings. The Town asserts that the state appraiser had discretion ‘ to accept the Town’s methodology and was not required to specifically address the issue.
¶21. In a property-tax appeal, the state appraiser is required to make findings to support its determination and in the face of conflicting evidence “must state clearly what evidence it credits and why, so that the parties and this Court will know how the decision was reached.” Beach Props., Inc. v. Town of Ferrisburg, 161 Vt. 368, 371, 640 A.2d 50, 51 (1994). This Court will not affirm a decision that is not supported by adequate findings. Id.
¶22. Here, the findings are insufficient because the state appraiser failed to explain how it resolved the conflicting testimony. Before the state appraiser, the parties disputed whether taxpayer’s property, which was put into service in 2010, should have been depreciated for a full year. There was conflicting testimony as to the appropriate accounting method for depreciating the assets. The state appraiser did not specifically address the issue, but simply stated generally that he was “persuaded that the town’s approach to depreciation is more appropriate than that advanced by Transco.” This general statement is insufficient for this Court to determine how the state appraiser evaluated the conflicting evidence and why it reached the decision it did. Therefore the matter is also remanded for further findings.
IV. Inclusion of Utility Easements
¶ 23. This Court has previously held that easements are not subject to Vermont’s municipal property tax. Vill. of Lyndonville v. Town of Burke, 146 Vt. 435, 438, 505 A.2d 1207, 1209 (1985). Although this principle was established in the special *594context of payment of property tax by one municipality to another, our decision reflected a broader underlying concern that it is impossible to identify, value and tax the multitude of easements in a reliable, efficient manner. See id. (“It appears unreasonable to conclude that the Legislature intended to cast upon the listers the burden of determining the nature of the titles of various owners of different interests in a piece of real estate.” (quotation omitted)). Instead, the value of the fee interest is taxed to the fee owner without setoffs for easements conveyed to third parties. The Town’s principal rationale for changing this rule in the case of utility easements is that they are large, obvious, and more valuable than an easement providing seasonal access to a landlocked wood lot. The statutory provisions which govern the real estate tax make no distinction between great and small easements, or between those which are used for the transmission of electricity and those which provide access or convey well rights. In the absence of a statute singling out utility easements for different treatment, we will continue to follow Village of Lyndonville in excluding easements from the grand list of properties subject to tax. The state appraiser therefore erred by including the value of the easements in its valuation.
Reversed and remanded for further proceedings consistent with this opinion.
The Iowa Curves were first published in 1935 and are based upon retirement patterns of 176 classes of industrial equipment. R. Winfrey, Iowa EngJg Experiment Station, Bulletin No. 125, Statistical Analyses of Industrial Pnperty Retirements 7-9 (1935). As the state appraiser explained in Town of Vernon-.
Essentially this statistical study asserts that depreciation is NOT straight lined, but curvilinear. This method acknowledges a schedule of 30 to 40 year economic life estimates but compensates for remaining functional utility (a factor other than age) by leveling off after accelerated depreciation thereby avoiding excessive depreciation by keeping the depreciation from going to zero.
174 Vt. at 475, 807 A.2d at 436.
Both parties used the Handy-Whitman Index for this purpose, and there was no dispute about the replacement cost new for the equipment.