The trend for tree houses

[00:00.39] The noble tree house – all natural materials, sturdy construction, aloof from the troubles of the world.

[00:09.16] In a more dangerous time in human history, their position above the ground would protect the dweller against environmental difficulties and possible predators.

[00:19.78] As modern construction has improved, these arboreal residences have become less of a practical dwelling and more of a children's novelty - a secret den erected in many a back garden.

[00:34.39] But now, these fun shelters are appealing to adults too and many are booking themselves in for a few nights among the treetops.

[00:45.81] These tree house hotels can be found From Europe to Australia. Best of all, they come in a variety of interesting designs!

[00:55.37] From the traditional 'four walls and a roof' habitation, such as at TreeHouse Point, in Washington, North America, to the more artistic Nothofagus Hotel in Chilean Patagonia, whose twelve-sided walls make it look like a beehive.

[01:12.37] If that doesn't appeal, how about a tree pod?

[01:17.42] The Free Spirit Spheres resort on Vancouver Island in Canada allows guests to stay in one of three yellow spheres, which are suspended from trees.

[01:29.11] The company was founded in 1998 by Tom Chudleigh, who hand built the pods from cedar wood and fibre glass, and then added fixtures and fittings.

[01:40.79] Not only are they as safe as houses, they're popular! Visitor numbers have probably doubled in the past five years, Mr Chudleigh tells the BBC.

[01:52.75] Digs which are original seem to be a big draw.

[01:56.73] In Sweden, at the Treehotel, numbers have also risen.

[02:01.24] "In 2010, we had four rooms and around 1,500 guests a year.

[02:07.36] Today we have seven rooms and nearly 5,000 guests," Kent Lindvall explains.

[02:13.46] Mr Lindvall co-owns the Treehotel with his wife Britta Lindvall.

[02:18.78] Each of the domiciles there was designed by an architect, who was asked to make use of the light and surroundings.

[02:25.42] Their abodes include a mirrored cube, a bird's nest and a UFO.

[02:32.33] And how about an office? Microsoft, hoping to give its employees thinking space, has commissioned a three-building structure from Pete Nelson, tree house book author and designer and builder of tree houses.

[02:46.93] "Studies show people can work better in nature.

[02:50.12] They are more productive," says Mr Nelson.

[02:54.37] If you've no head for heights, then maybe a tree house getaway isn't going to be your home away from home.

[03:01.28] But the sense of adventure, the novelty of the setting and the opportunity to return to nature has given an increasing number of tree house-staying adults something to write home about.