Natural gas leaking from pipes caused several minor fires at the Pepper Tree Farm apartment development in Wheaton during the last two weeks, Montgomery County fire officials said yesterday.

The leaks were apparently caused by the shrinkage of wood wall studs through which the pipes leading to the stoves in the apartments were placed, according to county building and fire officials. As a result of the shrinkage, the officials said, the pipes were "pinched," causing some to crack or break.

The leaks prompted an intensive investigation ofthe 636-unit complex, at 14104 Whistering Pines Dr., and fire officials said all faulty pipes are being replaced.

Two weeks ago a gas leak at the complex left about 100 residents without heat and hot water for several days, residents said.

Subsequently, workmen, replacing a faulty pipe, touched off a small explosion and fire at 14104 Weeping Willow Dr. The fire was quickly extinguished and there were no injuries, fire officials said. Other fires occurred in several garbage and utility rooms 10 to 14 days ago, fire officials said.

The gas system in the three-year-old development is a private one and is being repaired by workmen hired by Grady Management, Inc. which manages the luxury development.

Workmen and county fire officials have been checking each apartment in the complex for leaks and a Grady spokesman said half of the apartments have been inspected so far! He said three plumbing crews are working to replace faulty pipes, which involves tearing down kitchen walls.