Pick a Spot
We cannot suggest to you that you should go plant your young tree on land that does not belong to you. Most tree planting peeps in the know advise against that.
However, theoretically there are lots of places where one could plant trees, and it would potentially be undisruptive. But ultimately the choice is yours.
Where Not to Plant Trees
There are various places that would be not be a very sensible place to plant your young tree. Ultimately you are look for somewhere that will remain undisturbed, and not be an annoyance to others. So the following choices would be bad.
Verges are regularly mown, and in some cases trees can block views, of sign posts and side roads. This is problematic, and the trees will be mown down with a hedge trimmer.
If you live in a town, it might be tempting to plant your young tree in a street side planter. This is not a good idea, and survival rates will be low.
A park (such as Hyde Park in London) has lots of open grass areas. But these will be mown regularly and trees will not survive here.
You Could Plant Trees Here. . .
Close to Other Trees
Planting a young tree close to another tree is a good idea. This tree has space around it, and unlikely to be mown down as it to large. A tree of this size indicates this area has remained undisturbed for a few years at least. Plant you tree perhaps 2 meters away, and keep it close to the fence.
Side of Foot Path
Many footpaths in rural areas have areas around them that are devoid of trees, and make ideal places for young trees to establish.
The inside of a river bend is typically free from tall vegetation, and provided your young tree is plant securely it is will do well in moist newly formed soils.
Go To It
In short, you can't really go wrong, find somewhere that you tree can remain for some time and grow to its full potential. If it doesn't work, have another go somewhere else.