Lumber prices notched a record on Thursday but are likely to fall back to earth.  September lumber futures closed at $939 per thousand board feet, eclipsing the previous high mark set on Sept. 1 and pushing to 47% its climb above the commodity’s prepandemic high.  There are a few more days for prices to push farther into record territory before that futures contract expires on Sept. 15 and prices make their seasonal step down.  Most trading has moved to November futures, which closed Thursday at $611.40. Lower prices for autumn ...