-- You say you're up a tree?

Well, you could be in an uncomfortable situation, but more likely you're in a treehouse, taking a bird's-eye view of all that lies below. If you're a child, you may throw down a ball, plan an escapade with your best pal or make a sudden departure for ground level by hurtling down the slide. If you're an adult, you may sit quietly enjoying the breeze, clink the ice cubes in your refreshing beverage and be glad, once again, that the kids have a treehouse.

Either way, more people are spending time among the leaves. The professionals, the people who build elaborate treehouses that can cost as much as a car or boat, say business is on the rise. The amateurs, people who build more modest treehouses with help from family and friends, say it's not uncommon for strangers to drop by and ask for advice on their own projects.

These three families built treehouses and consider them comfortable extensions of their homes. Here are their stories.

The Wallis Family

Hew Wallis, 6, and his brother, Aden, 3, scoot up the ladder, scurry into their cedar treehouse and poke their heads out the windows, laughing for the joy of it all. Then Hew pops down the tubular slide and practices a few Olympic moves on the monkey bars next to the swings. Aden, still in the treehouse, giggles with glee and plays peek-a-boo in the window.

Along with their 9-week-old brother, Kalen, Hew and Aden live with their parents, Lynne and Darren Wallis. He works at Fleishman-Hillard, a public relations firm, and she is a full-time mom. They moved to the house three years ago and built the treehouse last year.

The treehouse sits on a 16-by-20-foot freestanding platform that wraps around a sweet gum tree but is not anchored or attached to it. The slide and the swing set are attached to the platform. Underneath, at the base of the tree, is a sandbox. The entire setup sits on rubber mulch.

Neither of the Wallises had a treehouse while growing up -- but they liked the idea of building a treehouse for their boys. A year ago, they bought some books, looked at plans and sketched what they wanted. She lobbied for everything to be bigger, and they expanded on the original plan. Then he called on an engineer friend for help. "He designed it so it would be structurally right, and then he helped build it," Darren Wallis said.

They worked on the treehouse for "at least five intense weekends," spending 12-hour days on the project, Darren Wallis said. "I remember we wanted it ready for a Fourth of July party, and we didn't quite make it," he said. "Still, I like doing this kind of work. I like to create things." He said he did not keep track of how much the treehouse cost.

"Sometimes I look out the kitchen window and see squirrels on the banister or the deck of the treehouse," he said. "Then I look out the window again and see my squirrels -- my kids -- out there. I feel fortunate and proud that they have it."

The Guenther Family

J.J. Guenther, 9, has inherited something from his three older brothers that beats any set of Legos or faded sports jersey. J.J. has a two-story lookout tower, complete with drawbridge, that stands among dogwood and oak trees in the woods behind his family's home. The boys' parents, Jane and John Guenther, built the tower in 1992, when J.J.'s brothers were 5, 6 and 8.

Known as the Raccoon Club, the tower is not so much a treehouse as a house in the trees. John C. Guenther, an architect and partner at Mackey Mitchell Associates, did that on purpose.

"As a child, I built a treehouse in a tree. That treehouse was attached to the tree, and eventually, the tree died," Guenther said. "For my kids, I wanted them to have the view that you get when you're up in a tree but without damaging a tree."

The ground level of the cedar-shingled tower measures 8-by-8-feet with large, screened openings. A built-in ladder in one corner leads to a trap door that opens to an 8-by-14-foot deck that features reclining seat-backs. A sheet of clear plastic rests over a barrel vault roof on the second floor.

The tower sits on a slope about 100 feet from the family's home, and a state forest and park borders the Guenthers' property on three sides. The Raccoon Club has won numerous architectural awards. The entire project took "10 months of weekends" and the materials cost about $3,000.

"The best part about it was planning the tower and building it as a family activity," Guenther said. Karl, 20, Dan, 18, and Andrew, 16, don't spend much time at the lookout tower any longer, though occasionally they show it to friends and hang out for a while for old time's sake. J.J., a fourth-grader, makes the most of the treasure in his yard, inviting friends in his "Saturday of the Month Club" to come play in the tower.

Guenther and his wife, Jane, occasionally head down to the Raccoon Club. "In the fall, it is especially pretty," he said. "You can sit late in the afternoon and listen to the day unwind. You see the sun going down and the filtered light through the forest and hear the different birds and insects. It's a wonderful experience that makes you appreciate all of nature."

The Casolari Family

When Alex Casolari was 5, his older brother, Tony, would climb up into the new treehouse in their back yard, pull up the rope ladder and slam the trap door shut, leaving Alex frustrated and disappointed -- and on the ground. Alex, now 15 and a high school sophomore, has had his revenge. He just spent the summer fixing up the treehouse, making it over and making it better, and the effort helped him to earn a Boy Scout merit badge.

"The floor was starting to rot, and we had to decide whether to fix the treehouse or take it down. Everyone agreed we should fix it," said Carol Casolari, Alex's mother. The treehouse, high in a weeping maple in the family's back yard, is something of a landmark in the neighborhood. Easily visible from a nearby road, the 8-by-4-foot treehouse stands two stories high with a peaked roof. It rises to 24 feet off the ground and is attached to the tree with just four bolts. An 8-by-16-foot freestanding deck sits just under the treehouse.

"We built the treehouse for Tony and Alex over an eight-month period, and then about five years ago, we put the deck on to make it more adult-conducive," said Art Casolari, manager of Whittemore House, Washington University's private faculty club. The frame of the treehouse originally included parts from an old waterbed and a counter top. Now, it's made of more conventional building materials. The total cost over 10 years has been about $800.

The whole family uses the treehouse and the deck. The boys have slept in it, and the family watched Mark McGwire hit his 62nd home run on a small portable television. Also, they decorate the treehouse with lights at Christmas each year. Growing up in the area, both Art and Carol Casolari had treehouses. "I think having a treehouse speaks to a combination of nostalgia for your childhood and also gets you up high, to a soothing place away from the noise of traffic," Art Casolari said. The children love it, and, as Carol Casolari said, when you've got the neighborhood children in your yard, you always know where your own children are.

Over the years, the family's treehouse has withstood some severe weather, including a hailstorm this spring and a forceful wind shear several years ago that took shingles off neighbors' roofs, but left the tree house intact. The treehouse has some special protection. "When we first built it, we asked our parish priest to bless it," Carol Casolari said. "Father Kevin Callahan -- he's a monsignor now -- climbed up the rope ladder and blessed the treehouse for us." The family has no plans to arrange a blessing for the refurbished structure.

"But," Art Casolari said, "we may have to have an event to celebrate."

Aden Wallis, 3, top, and his brother Hew enjoy playing on the swing set attached to their backyard treehouse.