The ranks of the appraisal profession are shrinking fast. For home lenders, that spells higher costs, longer turnaround times and poorer appraisal quality in future years. While there's less appraisal work to go around these days than there was a few years ago at the height of the housing market boom, lenders fear that when the market does rebound, there won't be enough qualified appraisers available to do the job for them. A dwindling appraiser population would lead to an "absence of local expertise," said Kurt Noyce, the chief executive of the Providence, R.I., lender Embrace Home Loans.