Chicago Mercantile Exchange March lumber futures surged the $10.00 per thousand board feet daily limit Thursday, sparked by reports that a major retailer started buying wood from Eastern Canadian mills, traders said. Lumber futures closed unchanged to $10.00 per tbf higher, with March limit up at $244.60 and May up $7.90 at $252.90 per tbf. March has turned up sharply since setting a two-week low of $231.30 early Wednesday. Cash sources cited buying by Home Depot Inc. (HD.N) of spruce studs from Eastern Canadian mills as the reason for futures trading limit up most of the session. Home Depot had been buying 2X4 studs from European lumber producers but turned to Canadian producers when the rise in the euro currency prompted European mills to put a floor on prices. "Over the last year they (Home Depot) have been bringing in some European lumber; but with the rally in the euro against the dollar and our depressed prices, the Europeans aren't willing to renew supply for another year for them," said Curt Cunningham, president of Pacific Futures Trading. "So it appears they are going to be buying more (Canadian) spruce." Home Depot, the largest U.S. retailer of lumber, said through a spokesman late Thursday that it has not recently changed the percentage of wood it buys from Europe or Canada. Futures have turned up sharply after slipping early in the week following the recent weak tone to cash lumber. Private sources said cash prices are firming after spruce traded down in the $202 and $204 per tbf area Wednesday. Canfor Corp. (CFP.TO) announcing the closing of two mills also had an effect on the market initially. Rumors of the closures hit the pits at the start and sparked buying, before some traders sold when informed the closings would actually take place in the third quarter. Prices surged again when word of Home Depot buying Canadian spruce circulated in the market, traders said.