A study examined whether using a tree diagram (a graphic, multidimensional classification device) as a prewriting organizer would provide students with a systematic method of searching for and organizing the content of their descriptive writing to meet some communication goal. One-hundred twenty-three seventh grade students were classified as above average, average, or below average language arts students on the basis of IQ and standardized test scores. The students were placed into two groups: three classes taught by the researcher and one class taught by another study staff member. From the two instructional groups, five students from each ability classification were randomly chosen, with the 15 students from the researcher's classes serving as the experimental group and those from the other staff member's class as the control. All 123 students were administered a writing attitude scale. The students in the control group were taught to write descriptive paragraphs by emulating good writers, while those in the experimental group were taught to use a tree diagram as a way of identifying the main attributes of an object to be described. The results showed that using the prewriting organizer significantly improved the quality of the experimental group students' descriptive writing. In addition, these students were found to have a more positive attitude toward writing. (Copies of tests used in the study are appended.) (FL)