Lumber prices in the US went higher during last week, as buyers tried to cover pressing needs. Extended mill order files, rail and truck shortages, and pent-up seasonal demand generated a frenzied market tone.  Heavy substitution for limited supplies of Canadian S-P-F helped generate a surge of orders in western species and Southern Pine. Buyers often paid little heed to prices, and put the priority on finding the quickest shipments possible.  The Random Lengths Framing Lumber Composite Price skyrocketed to a record $543.     Week May ...