It's tough to create a new Silicon Valley. Despite all the talk of "smart growth" and "knowledge cities" and the "creative class," tech hubs are hard to plant and grow.

Margaret Pugh O'Mara, a University of Washington professor, wrote a book on the subject. She was schooled and taught at Stanford University in Palo Alto and knows the landscape first-hand. In her book Cities of Knowledge: Cold War Science and the Search for the Next Silicon Valley, she says that the formula for tech towns is tough to successfully replicate. 

For one thing, in the U.S. they are largely the creation of massive federal (especially Cold War) spending. They don't simply grow along highway corridors (like Boston's Route 128), they sprout where big research dollars are funneled, where major universities like Stanford, Harvard, and MIT devote enormous resources to basic research. It helps if the results of that research get to market fast. The hubs thrive on publicly funded initiatives plus private entrepreneurism, both the grant and the garage.

Silicon Valleys or Alleys have roots in military and defense work, and they tend to generate suburban sprawl. One reason was that there were federal incentives to scatter talent across the countryside so it couldn't be taken out all at once by a Soviet nuke. Another was a desire to provide campus conditions once thought essential to the deep thinking and interdisciplinary play necessary for innovation.

Those tastes can shift: A younger generation is turning to renewed inner cities for techie-friendly lifestyles (think Amazon at South Lake Union instead of Microsoft in Redmond). But there are other conditions too. To grow a Silicon Valley you have to have a location that's going to appeal to "knowledge workers" in terms of amenities, climate, setting, and lifestyle.

There's also an element of dumb luck. Here in the Silicon Forest — still small potatoes compared to Silicon Valley — there was good fortune in the fact that Bill Boeing decided to build planes here, thus launching an aerospace empire that in turn helped Seattle become a fit place for the dreams of another Bill who decided to dominate the world of personal computers.

The thing is, the ecosystem is complicated and can't be taken for granted. Tending, mending, and adjusting are required. In the face of the state and federal budget crisis, the slashing of research grants and elimination of defense programs, the slicing and dicing of institutions like the University of Washington and higher ed generally, and increased competition from overseas, there is nothing inevitable about keeping a Silicon Valley or Forest or any other tech center going once its rooted.

It's not simply a matter of making a locality more tax-friendly for tech companies. The multiple components all need funding and feeding, and much comes from the public trough, though libertarian techies in the private sector might be loath to admit it. 

High-tech clusters are vulnerable even where they have flourished. Even the  Silicon Valley isn't taking anything for granted, and while they're relatively healthy compared to other parts of California, there is concern over how to stay globally innovative. I recently visited and looked more closely at the concept (which I've previously written about here) to host a Silicon Valley World's Fair in 2020. The fair as currently conceived could leave the legacy of a new mini-Silicon Valley right in the heart of the Valley itself, recapitulating the ingredients every Valley needs.

When you drive south on Highway 101 from San Francisco toward San Jose, it's likely that you've noticed a strange, metallic structure rising on your left between the freeway and the Bay as you near Santa Clara. Glinting in the sun, the silvery structure looks like an alien mother ship has landed, but it arrived well before Roswell. It's Hangar One, the historic airship shed that once housed part of the U.S. Navy's fleet of dirigibles in the 1930s.

The former Naval base, Moffett Field, is now mostly owned by NASA, whose Ames Research Center is there. The California Air National Guard still flies out of Moffett and so do Google executives. Google is on part of the site and it pays to use the massive runways that are largely idle these days.

Nearby are big-name technology companies in addition to Google: Yahoo, Microsoft (their largest campus outside of Redmond), Juniper Networks, Lockeed-Martin. Moffett Field is sandwiched between Sunnyvale and Mountain View. There are over 1,000 acres there, much of it unused or still in transition from one era to the next.

It's like Seattle's Magnuson Park (formerly Sand Point Naval Air Station, and just recently landmarked) on steroids. There is the giant airship shed, plus two companion hangars, and a historic district of old base buildings, some of which are occupied by academic programs from major universities like Carnegie-Mellon. Some 77 acres are leased from NASA by University Associates-Silicon Valley LLC, a public-private partnership of the University of California, Santa Cruz, and Foothill-De Anza College and developers TMG and Related Companies. The hope is to create a Silicon Valley academic presence for the University of California and bring housing (up to 1,900 units) and new commercial development to the site. 

The University Associates project is stalled by the recession. But Bill Berry, a former NASA administrator and president of the group, hopes that the world's fair idea can jump-start the project. The Expo idea is being backed by the powerful Bay Area Council, a business group. The notion is to mount a bid for a major world's fair in 2020. It would be privately funded and sited at Moffett Field under a lease from NASA.

The fair, it is hoped, would get the UC campus off the ground because that part of the site could be developed as the Expo Village, which would remain afterwards to house students, staff, tech workers, research facilities, and private tech companies along 101. The fair would mostly take place on the vast stretches of runways that once accommodated massive airships. Imagine an array of temporary, high-tech, green pavilions sprawling over 450 acres or more.

A legacy of the fair would be transportation and utility improvements. When I visited Moffett recently, I was warned that AT&T mobile coverage might be spotty. Not that unusual, but it struck me as funny: You still can't get reliable cell service in the heart of the Silicon Valley? Turns out that isn't the only challenge. The site needs new electrical, water, sewer, and IT upgrades.

There's also a pollution issue, with an underground plume of toxics working their way slowly toward the Bay — residue from the base dry cleaner and nearby semi-conductor manufacturers. Even the iconic Hangar One is toxic, a veritable layer of asbestos, PCBs, and lead paint. It needs to be restored and cleaned up. During a fair, the airship hangars would make great (and vast) exhibition spaces, and Hangar One has been touted by some as a possible USA pavilion. It certainly offers the Expo a pre-existing landmark.

The advantages of Moffett seem strong. It's hard to find huge chunks of developable land in the heart of the Valley (or any urban center). The fair could result in environmental improvements. The site is easily connected with heavy rail (a dormant Caltrain freight spur could bring commuter rail right there), and there's light rail to the site from San Jose. Passenger ferry/hovercraft service could be added on the Bay.