Forest tree species have been micropropagated in vitro for nearly 50 years by axillary budding first, then with increasing interest by de novo organogenesis, i.e., adventitious budding and somatic embryogenesis. The particularities of these three main techniques and more generally of in vitro micropropagation are reviewed, analyzing their respective pros and cons as well as their effectiveness and limitations for mass producing improved quality planting stock by comparison with more conventional propagation methods.