would be consistent with the land resource management plan of the entire forest.” See Neighbors of Cuddy Mountain, 137 F.3d at 1377; 36 C.F.R. § 219.10(e). The For , the Forest Service admits that “soil porosity or compaction was not explicitly assessed in detail in the FEIS.” See Cook Decl. ¶ 18. In explanation, the Forest Service relies on the declaration of Cook, who states that the potential for compaction was not considered “significant” because “experience” indicated that the type of soil underlying most of the project area “do[es] not readily compact to the detriment of re-growth potential.” See id. The record, however, does not contain any data or analysis to support Cook’s opinion nor is the opinion disclosed within the EIS. See Idaho Sporting Congress, 137 F.3d at 1150 (<HOLDING>) The Forest Service may not cure deficiencies
recognizing that an advisory opinion is one that offers an opinion on a moot issue holding agency may not rely on expert opinion without disclosing hard data supporting opinion to the public holding that an expert opinion on a question of law is inadmissible recognizing district courts authority to exclude opinion evidence that is connected to existing data only by the ipse dixit of the expert should it conclude that there is simply too great an analytical gap between the data and the opinion proffered holding a medical opinion to be not significantly probative where the opinion was contrary to other substantial record evidence