Historical gardens, parks, cemeteries, and cultural landscapes are significantly shaped by their often impressive old tree populations. These trees are essential both as a design element and as a habitat for diverse, often endangered species. However, sooner or later, the decline of valuable trees is unavoidable. In this context, the question arises to what extent special genetic traits of trees can be documented, and when and through which propagation methods the preservation of genes should be pursued from the perspectives of garden monument conservation and nature conservation. This volume addresses this topic through numerous interdisciplinary contributions from theory and practice.