Wood - a fascinating material

 INTRODUCTION

Wood is a wonderful material. It embodies the beauty and the odor of forests, the ecology of a natural building material and the microscopic aesthetics of a complex 3-dimensional anatomical structure.

The secondary cell wall of plants, constructed of parallel cellulose fibers embedded in an amorphous matrix is impregnated with lignin and minerals as a stabilizing factor for altitude records, e.g. the “Tall Tree”, 112 Meter height, a Sequoia tree from the California National Park. Shrubs and herbs use this principle to a lesser extent.

About tree dimensions. Look for the human. (Source)

For the increasing lack of sand and therefore of concrete as a construction material architects today tend to wood as an alternative. Asian engineers are famous for their buildings made with the help of a bamboo scaffold.

Hong Kong building with bamboo scaffold. (Source)

In Europe, architects are increasingly working with natural materials to follow the ecological demands of their customers. They reinvent proven technology with wood as a basis. From a wooden house to a wooden skyscraper: a big step.

The concept for Germany’s first high-rise building in Germany made of wood. (Source)

WOOD MICROSCOPIC VIEWS

All attributes of wood can be derived from a microscopic analysis. The odor of a Christmas tree (resin channels!), the characteristics of furniture wood, the mechanical stability of timber. A tree trunk with its 3-dimensional structure needs 3 cutting planes to be fully understood: a cross section, a tangential cut, a radial cut.

• THE CROSS SECTION

The cross section is most easy to understand: 

Due to the lack of water, the wood vessels in autumn time (left part upper image) are smaller in diameter, the plant invests in stability by thick cell walls.

Thanks to plenty of water in springtime, and due to the need to supply the developing leaves with water, the wood vessels for water are large in diameter.

• THE TANGENTIAL CUT

The tangential section plane gives information about the assimilate/water transport from the inner part of the stem to the outer areas.

The elliptical cell groups taken in radial section are responsible for the material transport from inner to outer stem areas. These groups seem to be compressed between the axial structures; it looks as if they are not “allowed” to claim too much space. Axial transport seems to be more important.

The tangential sectioning is the most interesting cutting direction for a commercial use of wood. A very familiar view from your parquet flooring or your wardrobe shelf.

• THE RADIAL CUT

The radial sectioning needs some luck. Otherwise you do not find the radial orientated cells which you already have seen in cross section when doing the tangential cut. These elongated cells are responsible for transport of water and assimilates from the core to the periphery of the tree trunk.

In any case, wood is a nice material to teach a 3-dimensional understanding of water/assimilate transport within trees.