In the sculpture with the evocative title Große Baumsäule I (Large Tree Column I), Karl Hartung takes a form of a tree trunk, at first glance derived from nature, and transforms it into a new, abstract sculptural column. However, the proximity to the aesthetics of nature is artistically broken by the choice of material – a shiny, polished gold bronze. This piece was cast during the artist's lifetime - he could have chosen a brown patina for the bronze cast of his tree column, but he deliberately chose a polished bronze with material aesthetics that provide an attractive contrast to the natural form of a tree trunk. This results in a very special effect that emphasizes the form.

Karl Hartung began his apprenticeship as a wood sculptor exactly 100 years ago, in 1923. In the 1930s, he continued to work artistically with trees, types of wood and trunk shapes, partly out of a lack of materials and partly out of sheer obsession. His daughter Hanne reports that her father always brought home home sticks, branches and twigs that were of a particularly interesting shape, which culminated in an incidence in 1950: he even dragged the trunk of a large beech tree into his studio, which inspired him to create one of his most famous and important major works, the “Torso Schreiten” (Torso Striding). A hybrid being between tree and human, it can be found in museum collections all over the world today. This phenomenon also corresponds to Hartung's intention to never imitate nature mimetically, but to become its equal in terms of design.

The "Baumsäulen" even represent a separate group of works within the complex of multifaceted columns in his late work.

It seems both tragic and significant that Hartung found a form of design and a theme so shortly before his death, which specifically refers to the column as a connection between heaven and earth, as he was already seriously ill at this point (asthma) and the columns still involved a considerable amount of work, for which his dwindling strength was still sufficient. Shortly before, he had completed a major commission for a column: The approximately 4-metre-high column made of Roman travertine stone, Columna, which is a landmark of the Germanic National Museum in Nuremberg where it still adorns the inner courtyard today. However, the tree has always been a symbol of life, if not the symbol of life itself. It stands for change, resilience and steadfastness. His love of wood as a material and his fascination with trees remained strong until the end of his life. Perhaps his series of tree pillars is a memorial to nature and life itself. In any case, the tree column can be seen as a symbol for a "monument to vegetation" (quote K. H.) and as a hybrid of tree and column, combining two of his symbolic themes. [AH]