In January of 1986 Hermann Block played with the idea of growing closed
rooms from woven trees. At this time some people were putting
short-living willow rods to Tippi-similar buildings.
Hermann didn't know of anyone who taking advantage of the annual growth
rings of trees to form buildings.
He was inspirated by a 1926 author, Arthur Wiechula who wrote a book
titled "Wachsende Häuser aus lebenden Pflanzen entstehend" ("Grown
Houses of living Plants"). He has a firm belief that growing building
with trees is achievable. Some of his reasoning comes from reading the
books that had earlier inspirated Arthur Wiechula. These authors are
Emanuel Swedenborg and Jakob Lorber. Hermann draws on these to motivate
himself and others.
Hermann started a planting in Spring of 1986, of Alnus glutinosa which
he had available, at a property of a friend. A Tree-Circle with 4 meter
diameter. 150 small trees where need with the height of 100-150cms.
Within a few years a wonderful summerhouse grew and now his friend uses c6
this as part of his showrooms.
Hermann continued to do plantings to test different types of trees. At
his brother's place he planted Beech/Fagus sivatica, at another friend
who lives near a lake
he planted Alnus glutinosa again. In 1993 Hermann
accepted an offer of Konstantin Kirsch to plant a large project on
Konstantin's leased land at Forsthaus Triesch, close to Nentershausen at
Bebra in Nordhessen.
It was here that Hermann was fortunate to receive 700 pieces of
150-175cm tall Tilia cordata. With these he created three overlapping
circles. Each room is 5 meters in diameter. These relative long trees he
wove into forms to shape the rooms.
Unfortunately due to other commitments he was unable to attend to the
different projects. He thought maybe Konstantin can make the work.
Unbeknown to Hermann, Konstantin also was too busy to tend to the
project. Only after many years had past was Hermann able to return to
the project. A frightful site greeted his eyes on arrival. From the
small plants, an impressive tree-circle, but without structure. These
large trees would be impossible to weave. He was determined not to lose
this project, so he decided to cut down the larger trees (10-15cm) and
start with the new regrowth. During this time he had assistance from
some Seminar participants for the hard work.
Once Hermann settled in to his new home in South Bavaria, the opportunity
arise to do a planting of Ash trees for a summer-house. The principle
became to weave the trees first into the form of the dome and then weave
the branches 
together fill in the spaces between the trees.
Having worked out system to his grown domes. He decided that he wanted
to share this knowledge with a wider audience. Taking his courage in
both hands he started in the public sector of the district garden close
to where he lives. Teaching his knowledge and using his experience to
help stimulate others. In a free area of the garden he planted two
projects, one is hornbeam (Carinus betulus) and the other is maple (Acer
platanoides).
This has inspired the students of Memminger Lindenschule to plant a
'Green Classroom'. This classroom was created by planting
of 500 pieces Tilia tomentosa. As a result of this building he could plant a summer-house on a playground of
hornbeam and two summer-houses of Tilia tomentosa in private gardens.
Hermann now has started growing a bench and some chairs outdoors and
also in containers. The framing of the projects uses steel grid and some
bars. Some of the chairs in containers are ready for sale.
He does have a book available for sale. The title is "Wir pflanzen eine
Laube" ("We plant a summer-house", ISBN 3-938175-22-2 at www.amazon.de). It is also in German. Hermann says that he has written in this book his
knowledge and experience. Though out the book are numerous pictures and
that it should be possible to follow the steps on how to grow their own
summer-house even without the text.
He has an excerpt from his book on his website.
If you can speak fluent German it would be well worth a look at his
Live Houses.