The tree streets and BYU have been neighbors since the university was established in 1875.

Most residents have liked having this option to live in the tree streets, said Ray Christensen, a homeowner in the tree streets and BYU political science professor. But concerns have risen about owners renting their houses without concurrently living in them.

When it was rumored that St. George developers Mervyn and Sue Cox filed a lawsuit challenging the constitutionality of the requirement for owner-occupancy in their home on 9th East, three homeowners intervened.

The homeowners filed to join Provo City in defending the owner-occupancy zoning requirement.

Current zoning laws still allow residents to rent basement apartments if the owners are occupants and residents like Christensen want to make sure the owner-occupancy requirement stays.

The addition of the requirement two years ago has revitalized the tree streets, he said.

Since its passage, the number of elementary school age children in the tree streets has increased by 26 percent, contrary to citywide trends of declining enrollments.

Absentee landlords were buying half of the homes for sale in the neighborhood but since the ordinance change, owner occupants have bought 85 percent, Christensen said.

The community can be more balanced with students and families if there are owner occupants as well, he said.

"Once you settle down and put down roots you can start giving to the community, he said. "That sense of community is wonderful and that's what we're trying to conserve."

But to Sue Cox, joint owner of M & S Investments, says the living situation in their home does not hinder the neighborhood's goals.

She and her husband purchased their house under the original zoning laws before the requirement was made and their house was never intended to make money.

"We bought it as a labor of love," Cox said. "We have 12 children and 20 grandchildren. We bought the home to help put our kids, grandkids and relatives through school."

The new requirement allowed for amateurization, which lets people keep their current housing situation until they make the money back that they invested before the change, she said. The requirement also was made to be 20 years retroactive.

M & S investments requested their property to be excluded from the mandate and when the city didn't do this, they pursued the lawsuit in 2000.

Cox explained one of the reasons they are an exception is that since their home is on the busy road, 9th East, their property stands apart from the other homes in the tree streets.

They also invested about half a million dollars on renovation to their home before the requirement was made.

The owner-occupancy laws were made to make it a friendly family neighborhood, she said. They want a neighborhood with little kids playing, but kids playing near the busy street could be dangerous.