Abstract images are frequently used in logo design. Use of these simple pictograms makes sense whenever the depicted term is grasped faster than a description of the term.

However, such pictograms may resemble other, established logos. That is why you have to pay attention and try to prevent resemblance. Pictograms should always have a unique peculiarity that didn't existed before.

Keep in mind that not all terms are attributable distinctly. For example, in order to abstract a tree, you could draw a tree with round contours or pointed contours. Both of these pictograms wouldn't necessarily be clearly associated with a tree.

The pictogram with round contours would probably be interpreted as a deciduous tree, while the one with the pointed contours would rather certainly be seen as a conifer. Illustrating the general term "tree" itself in an unambiguous way is not possible.

Other terms, again, are representable clearly without ambiguity. For an example, think of traffic signs.