Whether a proposal to guide development at Lake Tahoe for years to come goes far enough to protect the area's natural environment continues to be a concern for area conservationists.Laurel Ames, with the Tahoe Area Sierra Club, called the Tahoe Regional Planning Agency's Regional Plan Update "unfocused" at a joint meeting of the agency's Governing Board and Advisory Planning Commission at Harveys Lake Tahoe Thursday.The long-awaited plan contains few binding rules and there are "exemptions to everything," Ames added.The TRPA released final documents for the Regional Plan Update this week. The agency's Governing Board is expected to vote on the …