Tyler Durden 01/21/2015 While Crude Oil and Dr. Copper are often cited as economic indicators, as @Not_Jim_Cramer notes, in fact Lumber prices are the most correlated with ISM and GDP of all industrial commodities. That is a problem. Lumber prices are tumbling and are breaking the 6-year up-trend that has 'proved' the recovery. With no CCFD manipulation and less financialization than crude, perhaps Lumber is the real canary in the economic collapse coalmine... Lumber is the most correlated to ISM and GDP of all the industrial commodities... and that is not good for the US economy...