For Pierneef art and architecture were inseparable because for him both depended on the structuring of space and proportion. One can say that he interpreted the landscape through with a structural bias. He often treated mountains and rock formations as structures and even his trees were sometimes used like collonades through which the landscape in the background is seen in perspective. The Architectural structural elements in his paintings are emphasised by his simplification of subjects that reveal their basic structure. His reduced and simplified the landscapes consisted of geometric structures, with flat planes, lines and colour that represent the harmony and order in nature.His particular style was also called monumental-decorative style as the decorative elements were dominant and presented in broad, clear and simplified lines and planes, with the strong linearity depicted in a subdued palette of pale colours, usually tone values of the same colour. Clouds and trees were especially of interest to him and reflected the theme and the underlying symbolism of the painting. Not only did the specific trees have specific symbolic meanings to Pierneef but as they were also characteristic of particular geographic areas, he used them to describe the character and atmosphere of the particular area. He also used the trees as elements to structure the composition. (https://nladesignvisual.wordpress.com/author/sophiasuzette/page/12/)