New leaves

 At the end of sycamore twigs the new leaves and the pendulous flowers emerge together.

As with poplars and walnuts, maples like sycamore produce coppery leaves at first until the chlorophyll gets into production.  

 Others, like beech, produce bright green leaves straight away

While hazel leaves start green but often with a dark reddish patch in the middle of their new leaves for a week or so.