Tumamoc Hill, Ariz. - When the Carnegie Institution established its desert laboratory on this stony, black basalt hill 94 years ago, some 12,000 residents lived in the small town of Tucson two miles to the east. Today Tucson has grown to almost half a million people, and Sunbelt sprawl threatens the future of one of the nation's oldest continuously operated biological field stations.


The Desert Laboratory, operated by the University of Arizona, encompasses 869 acres of Sonoran desert scrub that has remained relatively pristine since livestock grazing was halted in 1907. The surrounding area is awash in new housing and resort development.


The university owns part of Tumamoc Hill, including the laboratory's historic stone buildings. But 320 acres of the total are owned by the Arizona State Land Department.


The land department is currently considering whether to renew the permit that allows the university to use 320 acres of state trust land as part of the laboratory, raising fears that the state might opt to sell the land to deep-pocketed developers. If that happens, the laboratory would lose some of its long-term monitoring plots, where slow-paced changes in vegetation have been watched for nearly a century.


"It wouldn't shut down the research projects here, but it would mutilate them," says Paul Martin, a geosciences researcher who has been stationed at the laboratory since 1957. "We have time on our side here. After collecting almost 100 years of data you can really start cashing in on how the desert works."


Early laboratory researchers were meticulous in counting and mapping plants on the site. By looking at their data, botanists in recent decades have been able to document the spread of non-native species - more than 50 at last count - as well as ups and downs in the populations of saguaros, creosote bushes and other desert perennials. They have learned volumes not only about how individual plant species adapt to the desert, but how species interact.


"All of the research conducted here revolves around the changes that happen over time," says Raymond Turner, a Desert Laboratory botanist who has devoted much of his career to monitoring long-term vegetation changes in the Southwest. "Some of the vegetation plots here were first mapped in 1906. They are the oldest plots in the world on which individual plants have been censused."


They are also very cheap plots. The university currently pays the state land department a bargain fee of $4,199 a year to use the land. The land department, which is charged with making a maximum profit on its land to support public schools, could make a lot more money than that if it sold to a developer. Construction of new homes and resort facilities around Tumamoc Hill has raised estimates of the value of those 320 acres to as high as several million dollars, according to state officials.


Charles Geoffrion, associate vice president for research at the University of Arizona, says the university, which has faced significant budget cuts in recent years, probably can't afford the land if the state puts it up for sale.


But, the rapidly escalating land values around Tumamoc Hill, ironically, may buy its defenders some time. Dennis Cady of the state land department says that even if approached by a developer, the department might decide not to sell the land now.


"We look at when the best time is to sell the land, when revenues will be highest," he says. "That may not be until more development has occurred in the area."


In the meantime, some land department officials have begun exploring other ways to preserve the laboratory. Last year, state legislators passed a law that allows the department to designate state land near towns and cities for conservation. The land would still be auctioned or leased to the highest bidder, but with the stipulation that it remain undeveloped.


Last fall, the university submitted a formal proposal asking that the department dedicate the land for conservation. Officials say the land department will likely decide on the university's application by late spring, after a public comment period. If its request is approved, the university will have from three to eight years to raise money to buy the land at market value. Anticipating such a possibility, the Pima County Board of Supervisors is considering a bond package - which voters would decide in May - that would include funds for that purpose.


Voters may not be thrilled about that. But at a time when urban sprawl confronts residents throughout the Tucson area, there will likely be considerable support for preserving Tumamoc Hill as open space, as a research facility, and as a hitherto underappreciated local landmark.


"We're getting the pulse of the desert here," says the laboratory's Paul Martin. "In the future, if all goes well here, Tucson will be known as a community with unusual access to how the desert works."





* Peter Friederici





The Arizona State Land Department will hold a public hearing in Tucson on the university's application at 1:30 p.m. on April 3, at 400 W. Congress, room 5.