The arboretum has many special trees, including memorial trees and plaques; some may be damaged directly, but their setting moreso.
The uses as access to Coopers Field and to the Nursery study centre can be provided in alternative ways that avoid impact on this sensitive area of the historic park.
Access to Coopers Field is only occasional and hardly a problem. 'Do minimum' and access via the south side of the Music College (by the tennis courts) should be considered. The latter would be direct onto Coopers Field, with a new bridge, still intrusive but at a less sensitive and less frequented point.
Access to the Nursery study centre should have been considered under that planning application. We are told the Ambulance station route cannot be used, but access for occasional vehicles could be achieved with benefits for access to the playing fields (for events like Race-for-Life) round the north of the changing room building. School buses/minibuses would park outside (in public car park or take over the haphazard uncontrolled parking area to the north of the carpark entrance); construct a separate new footbridge for children to walk through.
Bridge - the Bridge design should be minimal, taking vehicles one-way with a waiting area in the woodland for the very infrequent occasions when vehicles meet.
Roadway - 4 metre roadway is over-wide. It will encourage two-way traffic, and vehicles will go over the edge onto the grassland in practice. This is especially true of wider vehicles (HGVs etc.). As rising bollards controlled from the Nursery are proposed at the North Rd entrance, similar bollards could be placed at the exit from Coopers Field and controlled to ensure vehicles do not meet.
The black tarmac used two years ago to surface the old park track is unnecessarily intrusive; the brown surface of the other roadways was and is preferable.
In summary, I argue for rejecting the whole scheme for its severe impacts on the Park. The present application says too little of impact on trees and nothing on alternatives or balancing impacts against 'benefits'. A scaled down project, with minimal bridge and roadway, excluding the whole loop to the Nursery, would have much less impact but should be compared with alternative options as above, and these put out for public consideration.