Sales of the Ram, Chevrolet Silverado, Ford F-150, and their peer group, were up almost 27% from a year ago, surely benefitting from a recovering housing market. Armies of plumbers, roofers, carpenters, and landscapers were working — a good reason to trade in their trucks, whose average age had reached more than 10 years, according to researcher R.L. Polk.

But the other big chunk of the pickup market — those who buy big pickups to make a fashion or lifestyle statement — may not be recovering so quickly. “Trucks lost ground in the recession and haven’t kept pace with the rest of the market,” wrote Lacey Plache, an economist for Edmunds.com in early March, comparing current sales numbers to 2007. According to Plache’s analysis, light-vehicle sales as a whole — cars, crossovers, pickups, etc. — have recovered to 90% of 2007 levels, while pickups on their own only returned to 76% of what they were.

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Driving big pickups for personal transportation might be construed as frivolous or wasteful. Schlepping plywood, pipe, or sod to a job site is, by contrast, its own justification. In any event, the U.S. is the only place in the world that sells large pickups, which means foreign automakers have never generated serious competition.

Housing starts, including single- and multi-family homes, advanced 7% in March from the prior month, to a 1.04 million annual rate, the highest since June 2008, the Commerce Department reported on April 16. Economists are cautioning that the housing recovery could be short-lived, for a number of reasons from rising interest rates to labor shortages.

The market leader, Ford’s (F) F-150 pickup surged almost 24% in the month to 40,594 deliveries. GM’s (GM) Chevrolet Silverado and GMC Sierra, more or less the same truck, totaled about 2,000 less. Chrysler’s Ram was just shy of 16,000, and the Toyota (TM) Tundra totaled more than 8,000.

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Recently, Ford said it was adding 2,000 jobs to its Kansas City truck plant, 900 of which will be to add a third work shift for building F-150s. The remaining 1,100 will assemble Ford Transit vans later in the year. GM, meanwhile, is beginning media test drives of its long-awaited replacements for the Silverado and Sierra, whose development and introduction have been delayed by the 2009 recession. GM filed for bankruptcy and was reorganized in mid-2009, which slowed new-model cadence. The current Silverado was introduced in 2007.

GM’s first-quarter profit was down 14% to $865 million. The reason for the drop was in part due to the slowdown of production of the current pickup model so assembly lines could tool up for the new model. GM said it also had to discount the old model to keep sales moving. The Ram is a new model and a mainstay for the Chrysler-Fiat venture, which posted disappointing earnings for the first quarter.

What remains clear is that large pickup trucks are the jewel in Detroit’s crown, even more valuable perhaps than a foothold in China and other developing markets. The mood of the Motor City, in other words, is definitely tied to pickups.