By PAUL FATTIG

TAKILMA -- When Michael Garnier heads for the top floor of his resort, he takes care to strap on rope climbing gear.

After all, his destination is a tree platform 51 feet above the ground, high in an old oak tree.

"We've had people from four years old to 67 up here," he yelled while dangling from the rope. "It's safe."

While that may be questioned by those with a touch of acrophobia, safety is a primary concern among treehouse builders, stressed Garnier, owner of a bed-and-breakfast resort known as Out 'n' About that includes treehouses.

"People need to know what trees they can use, how to build treehouses so they are safe," he said in an on-the-ground interview. "There are no permits set up for building treehouses but you still have to build it so that it meets standards."

Those standards will be addressed in the second annual World Treehouse Association conference, which gets off the ground Saturday morning and continues through Sunday at Garnier's resort.

Speakers scheduled for the event include Seattle-area resident Peter Nelson, author of two treehouse books, including "Tree Houses: The Art and Craft of Living Out on a Limb." Nelson is the association co-founder along with Garnier.

Interest in treehouses is growing, Nelson said in a telephone interview.

"A treehouse automatically brings people back to their childhood," he explained. "It's a special, private place all their own.''

Yet he doesn't disagree with those who say a treehouse is merely a place for children.

"A lot of kids in their 20s and 30s, and some in their 70s, are interested," Nelson said. "It's a subject everybody loves, something that makes everybody smile."

This year's conference will include tips on building the structures as well as ways to reduce damage to the host trees.

Last year, the first-ever such conference drew nearly 60 treehouse buffs from 15 states and five countries.

Cost to attend the full conference is $100. The fee is dropped for one-day attendees. For more information, try the Internet at www.treehouses.com. Or call (800) 200-5484.

The conference site is located in rural Takilma, an unincorporated hamlet about 30 miles south of Grants Pass.

Although remote, Garnier's treehouses were featured in Wednesday's Wall Street Journal. They had also been shown on TV's "Good Morning America" and in the August 1997 issue of Smithsonian magazine.

Garnier, 49, who hails from Gary, Indiana, never had a treehouse as a youngster.

But he had always been in intrigued by life out on a limb. He has worked as a medic in the Army, labored in the woods, helped start a local medical clinic and tried his hand at various businesses.

Garnier built his first major treehouse in an oak on his property in 1990. However, Josephine County Building Safety Department officials, citing public safety, said he couldn't rent out his treehouses because they violate the fundamental concept of building codes.

He was ordered to shut down his operation.

Garnier skirted that edict by selling T-shirts -- or "tree-shirts" -- for up to $75. The shirts came with a free night in a treehouse.

While Garnier and the county continued to resolve their differences, the treehouse aficionado has continued to study treehouse design.

Four treehouses can be found on his property as well as five others he refers to as platforms.

Consider the "Piratree," which has a platform resembling a ship that Black Beard may have sailed through the tree tops, and the "Treepee," a platform with a teepee on it.

Not the least is the "Cavaltree." It consists of a cavalry tent atop a log platform fenced by a log stockade.

The one reached by rope -- the others have stairs -- high in an old oak is a platform known as "History." The tree was used as an historic corner marker on the property, he explained.

The largest structure is the "Treeroom Schoolhouse Suite." Supported by 16 different trees and three supports, It has modern plumbing, complete with a claw-foot bathtub in the full bath, electricity and a queen-size bed.

It was in that treehouse that 109 people stood in 1996 to conduct a stress test, providing some 16,000 pounds of stress, he said.

This past summer, he built a treehouse in red oaks along the Suwannee River in Florida.