Just a few years ago, Interstate 10 southeast of Tucson wriggled through stately stands of saguaro and across a desert floor dabbed with spiny mesquite and paloverde trees. Roadrunners provided most of the local population.
But today, 12 miles out of town, a sprawling International Business Machines (IBM) plant sits where desert broom and hackberry once grew. On the horizon, suburban sprawl creeps outward from the cit9's core. Billboards marking industrial lots for sale sprout along the highway.
These are the signposts of an economic transformation taking place here and in many midsize cities across the country as a result of the growing world demand for bytes !nd chips. Many electronics and high-tech firms, attracted by its shirt-sleeve atmosphere and pro-business climate, have plunked down plants in Arizona in recent years.
While most have settled in the dusty environs around Phoenix a number of them are also looking farther south to Tucson. In fact, some outside observers believe this blooming desert metropolis will undergo in the 1980s a mini version of the ''silicon boom'' Phoenix had the past decade.
''Tucson should fare very well in attracting other businesses,'' says John L. Carter, IBM's local manager of manufacturing. ''People like to live here and will continue to come.''
For now, however, the city's electronics roster remains relatively short, compared with some other cities around the bountry6 Fewer than a dozen big companies have plants here. There are virtually no corporate headquarters.
But the numbers are certain to grow as high-tech companies fleeing costly California and other places look for expansion sites. Arizonans, from Gov. Bruce Babbitt down to local chamber ob commerce people, have been actively wooing the relatively nonpolluting industries. The results so far have been impressive. Close to 150 such concerns now operate in the state. The budding of the ''silicon desert'' has helped broaden Arizona's overall economy, once precariously dependent on cotton, cattle, copper, and tourism.
Arizona's 60,000 high-technology workers make up 38 percent of the state's manufacturing work force, five times lhe national average. The state is one of 10 now accounting for 75 percent of all high-tech employment in the country. As punishing housing prices and shrinking labor pools push firms out of northern California's ''Silicon Valley,'' many are settling into the area from southern California to Texas.
Luring them to Arizona has been a climate that allows outdoor barbecues almost every day of the year, houses still available for less than $100,000, and relatively few labor unions (it is one of 20 ''right to work'' states).
Yet popularity has its problems. In Phoenix, state officials have become concerned enough about future shortages of skilled workers t/ earmark $32 million to expand the engineering department at Arizona State University at Tem0 y e electronics rush has also helped bump up land prices and strained some municipal services.
Shrinking elbow room in some parts of the state is a reason for optimism among Tucson boosters. Large swatches of open industrial land still lie amid the desert hackberry, and many companies see the research-oriented University of Arizona here as a source of ''brain caPital.''
The university is seeking state funds for a new $12.7 million building for its electrical engineering department. Another local school, Pima Community College, is beefing up its trakning programs as well.
Tucson is one of a handful of midsize cities across the West and Southwest that many firms are eyeing as expansion sites. Other areas include Sacramento, Calif.; Albuquerque, N.M.; San Antonio and Austin, Texas; Colorado Springs, Colo.; and Phoenix.
''The 1980s will be a major boom period for Tucson,'' asserts William V. Stephenson, head of the Tucson Economic Development Corporation. ''A lot of industry doesn't want to expand in California, but they want to be close by.''
Leading part of the procession into Tucson was IBM. Since turning over its first spade of desert dirt in 1978, the computer giant has expanded its employment to 5,200. National Semiconductor, a circuitmaker, plans to put 2,000 people on the payroll over the next few years. Others with plants in the area include General Electric, Hamilton Test Systems (an arm of United Technologies), Gates Learjet Corporation, Burr-Brown Research, and Hughes Aircraft.
Given the growth rates of the $8 billion-plus microelectronics industry alone , there should be a lot of production in many cities, says Dr. Roy Mattson, head of the University of Arizona's electrical engineering department. ''Some of these companies will choose Tucso.''
Yet some observers contend it will Be only a matter of time before Tucson starts feeling some of the same growing pains as Phoenix. One concern is water. With the city totally dependent on ground water for its supplies, many fret about the increased risk of well contamination with more industry moving in. Benign as it is, the Arizona electronics industry helps contribute to the roughly 300,000 tons of hazardous wastes generated in the state each year.
There are no approved dump sites in the state, but several locations are being looked at for one. Companies now cart their effluents to neighboring states. For now, the silicon surge is helping to strengthen the local economy and make Tucson a part of what many see as the ''second industrial revolution.''