Application. Study of DNA polymorphisms in forest trees has provided new insights into basic biology. Chloroplast, mitochondrial, and nuclear DNA polymorphisms are expected to play increasingly important roles for forest population geneticists, and further investigation of these polymorphisms may lead to applications in germplasm improvement and conservation programs.Abstract. DNA analyses have been used only occasionally to investigate genetic polymorphisms in forest tree populations. Nonetheless, these analyses have already contributed to significant discoveries, such as paternal chloroplast and maternal mitochondrial DNA inheritance in Pinaceae. DNA polymorphisms will be increasingly exploited in the future by forest population geneticists, because available technology permits large sample sizes and yields excellent resolution. The utility of chloroplast, mitochondrial, and nuclear DNA polymorphisms is expected to be greatest when less expensive genetic markers are unavailable, insufficiently numerous, or ineffectively polymorphic. For example, DNA fingerprinting may permit the unambiguous elucidation of genetic relationships within and among populations of woody species.