However, Fischer noted that the study was exploratory and the range of selected tree species and works of art is small and ...

and 20th-century abstract art. They found that the values of α in these artworks range from 1.5 to 2.8, similar to the range of this value in natural trees. “We find α in the range 1.5 to 2.8 ...

therefore it’s not possible to draw strong conclusions. The authors studied a series of works by abstract painter Mondrian that depict the same tree but in increasingly less realistic ways.