area in determining that the proposed sale includes no old growth forest. AR Tab 59, pp. 13, 44. Using a different definition of old growth forest, the Virginia Department of Conservation Resources identified ten acres of the sale as old growth. The Forest Service argues that the state agency’s definition of old growth is more simplistic and produces less representative stand ages because it uses a single age cutoff for all. species, focuses on the older trees in a stand, and considers no factors other than age. The court need not concern itself with the merits of the competing methodologies, however, because the Forest Service is entitled to substantial deference on scientific questions within its area of technical expertise. Sierra Club v. Marita, 46 F.3d 606, 621 (7th Cir.1995) (<HOLDING>); Inland Empire Public Lands Council v.
holding that an agencys interpretation of its own regulations is entitled to deference holding the agency is entitled to use its own methodology unless it is irrational holding that agency interpretation which is reasonable is entitled to deference holding that as a general rule the prosecution is entitled to prove its case by evidence of its own choice holding deference to agency methodology appropriate unless agency failed to address an essential factor