Lumber prices plunged 66% last year as the once red-hot US housing market faltered – and the commodity's troubles will likely continue in 2023, according to experts.    The Federal Reserve's campaign to quell inflation fueled an unprecedented surge in mortgage rates in the past year, which weighed on homebuilding and the demand for lumber. Average 30-year mortgage rates more than doubled in 2022 to 6.42%, before extending the climb to 6.59% this week.    Westline Capital Strategies president Greg Kuta sees a "treacherous" first half for the lumber ...