There is a tradition in Estonia of preserving and naming the biggest trees of each major species, and also for large groves or unusual trees. My map of Estonia contains perhaps two hundred such marked trees, and all the ones I've visited so far (something like 30 or 40 of them) have signs or other markings, and usually some parking and a path to the tree or trees. I have no idea of the origins of this custom, and I have not yet ever found anyone else visiting the trees to ask. But I like it, and I've very much enjoyed finding and visiting various trees.
The tree at right above is called the Mäe-Lehtsoo Tamm, and it's located near the small lake (Punde) pictured at right, near the town of Urväste in south-central Estonia. If I understood the sign correctly, it is the second-largest oak in all of Estonia. The area around the tree had recently been cleared of brush, along with the hillside above it, giving a clear view of the entire tree. This was a nice presentation, but the tree itself looks like it's not in such good shape. There are many large broken branches, and much of the tree looks quite sickly.........
........... This oak tree is the largest one in Estonia — a very famous oak called the Tamme-Lauri Oak. If you enlarge the picture of the sign at right, you can read all about it. A drawing of this particular oak adorns the Estonian ten-kroon note.
Tom Dilatush (see his blog for the mentioned pictures)