With genetic engineering desirable characteristics can be introduced or enhanced in organisms. Furthermore, transgenic trees have shown promising results in greenhouse and field trials. Results on transgenic trees in field trials have been published but international and detailed compilations of what has been carried out are limited. To get an overview of the development of genetic engineering and genetically modified trees in the field, a meta-study has been carried out with information from public databases, books, and other publications. The study focused on transgenic trees in field experiments, excluding fruit trees. Traits that have been modified have been compiled. Furthermore, trends, patterns, and deviations were analyzed for the following parameters: tree species, characteristics and the years in which field trials were conducted or permitted. The countries included in this study were the EU (European Union), USA, and Brazil. Results indicate that different species of poplar and eucalyptus were the most studied tree species while resistance, growth and wood properties were the mainly investigated traits. When comparing the number of field trials that were started and got permission until 2000 and after 2001 respectively, there was an increasing trend in all study areas. However, significant results were demonstrated only for the USA. When comparing field trials until 2010 respectively after 2011, there was an increasing trend in the EU and Brazil, but not in the USA. The difference was only significant for the EU.