Chestnut trees were planted by landlords on their estates during colonial times in Ireland (part of Ireland is still colonized) as symbols of statues. The horse chestnut are not edible (they are poisonious) but the sweet chest nut are edible. In the picture you will see the differences in the shells and the nuts themselves. The horse chestnut is native to the Balkans. The sweet chestnut is native to western asia, north africa and southern europe.
Blackberries can be found just about anywhere they grow just about in any environment. The berries are edible and the young shoots can be boiled like asparagus. Young shoots can be identified by their light green colour. Older shots are more woodie.