US lumber futures are on another wild ride, but trading them has gotten pretty boring.  In 25 of this year’s 35 trading sessions, prices of the leading lumber futures contract have moved so sharply that they have ended the Friday stuck at limits designed to ensure an orderly market. Some mornings, trading has opened at the limit and remained there. On those days, trading in lumber futures basically ends before it begins.  The condition is called “lock limit.” Traders compare it to squeezing through a keyhole. Trading doesn’t officially halt, but once the price ...