Dutch elm disease

Dutch elm disease

Observation - Dutch elm disease. Description: This tree looks to me like it is either recovering from disease or the infection has been retarded by very cold weather. It is producing seed from a surviving branch and new growth from the trunk below the part that is flowering. Is this known from previ

This tree looks to me like it is either recovering from disease or the infection has been retarded by very cold weather. It is producing seed from a surviving branch and new growth from the trunk below the part that is flowering.
Is this known from previous years or is it an exception?
Would the seed be worth harvesting to attempt cultivation of a resistant variety?
The first photo is of another smaller healthy tree with better access for a close up.