There were a great many trees planted in the 1920’s and 30’s to recognize persons who died in World War 1. There is a poignant quality about living memorials that surpasses that of statues or tablets. However, trees don’t live forever. In the future we may look at some of these memorials, groves or even small forests that have died away in the ensuing 90 years or so.
Here’s a link about a very ambitious project in the United Kingdom to re-start their living memorials.