This picture shows a group of people, presumably a family, working in the garden of a rather impressive country house. This is one of those pictures which needs to be seen by someone who would recognise the house because it is quite distinctive and, assuming it is still standing, would probably be easy to identify.
The people seem to be planting trees or shrubs in lines along the edge of a lawn, and since this picture was taken in September 1971, those trees or shrubs would now be quite big.
The picture was taken on Kodachrome film.