(NBBJ) - Growing global interest in North Coast wines has uncorked fast price escalation for the vineyards they come from, particularly in Napa Valley, but forecasts about bursting asset bubbles and crashing vineyard values may be getting ahead of reality, according to a closely followed agribusiness analyst.

Vineyard valuations for prime Napa Valley acreage are topping $400,000 an acre, but this reflects prices being paid for its choicest fruit, said Stephen Rannekleiv, global beverages strategist ­for Rabobank, in a recent wine industry briefing. Similar price inflation also is being seen in other premium California winegrowing regions.

“There’s a declining availability of reasonably priced fruit and increasing number of tons being sold for $10,000, $15,000 and even $50,000 a ton,” Rannekleiv said. “Obviously, that’s having an impact on driving vineyard valuations.”

A price per ton that would work into a valuation of $400,000 an acre would be a little over $10,000, based on production costs and the historical yield of roughly 3 tons an acre from top Napa Valley vines, Rannekleiv said.