This paper adds to the limited knowledge of stand dynamics in pinyon-juniper woodlands byreporting on the changes in species composition, numbers of trees, arrangements of trees, andtotal height and volume in a stand from late 1938 to early 1991. This information should behelpful in managing pinyon-juniper woodlands to sustain their productivity and maintain theirmultiple-use values. The annual increase of 1.2 trees per acre does not reflect the massiveinvasion of trees suspected by many people.