Seed collection to preserve ash genetic diversity, especially regarding adaptation to local environments, may have some role to play in ash conservation. Collection of seeds from lingering ash would be especially useful, because these seeds may pass on some heritable EAB resistance, although not nearly as reliably as scion (twigs used in grafting) from these trees.
If you want to collect ash seeds for long-term storage by the USDA Forest Service National Seed Laboratory for preservation of ash diversity, we suggest that before collecting, you contact Becky Loth, National Coordinator of ash seed collection (bloth@fs.fed.us), to find out about any ongoing seed collection efforts in your area. This way, you can to make sure that 1) your efforts are not duplicating the efforts of others in your area; 2) you get the appropriate information to ensure that you properly identify, collect, store, and send the seeds; and 3) you can arrange to send the seeds to an appropriate storage facility.
“Methods for Collecting Ash (Fraxinus spp.) Seeds” is a helpful publication, downloadable from the USDA U.S. Forest Service.
You can also see additional guidance on seed collection from the USDA Agricultural Research Service