It's a something "too little." I say that because the photo is too little. It's very hard to say what it is from the quality photo you have provided. Seeing the leaf makes me want to guess New Zealand Tea but it is only a guess.

While you're at it, check out the Northern Nut Growers Assn. website - they have 'Marketplace' and 'Scion Trade/Swap' pages, in addition to links to state/regional nutgrowers associations that might have some of the stuff you're looking for. And lots of good information! I've accumulated over 30 varieties each of pecan and hickory, mostly from trades, inexpensive purchases, or shared material from other nut-growing enthusiasts around the country. We all like to share - and if we get stuff distributed out to alternate sites, if we lose a selection, it's not 'gone forever'. Oaks - grafting works great with members of the white oak group - no incompatibility issues that I'm aware of, though some(like Q.stellata) don't make great rootstocks, 'cause they're so slow-growing. Bur oak works best for me as a rootstock, 'cause it's readily available, adaptable to a wide range of soil types, and grows vigorously. (white)Oaks are just about as easy and successfully grafted as pears/apples, but timing of graft placement is a little more critical. Peroxidase enzyme incompatibilities make grafting members of the red/black oak group problematic, even when a selection is grafted onto its own seedlings. I originally got into oaks for wildlife mast production, then got hooked up with some folks who were making selections for low tannin levels, as a potential human food crop. Most of my cultivated stuff is bur oak, swamp white oak, and various hybrids of white oak species. There are some oak cultivars in the nursery trade, like 'Crimson Spire' that are propagated by grafting/budding, as they don't come 'true' from seed. I've never had issues getting material from NCGR - I do have university agriculture dept. affiliation, but I'm not involved in horticulture/agronomy research. Do think you have to provide a FedEx or UPS account number for them to bill shipping charges to - but it's been several years since I got anything from them; that may have changed.

Don't know...but I like it!

Regarding the elder it looks just like those in a Seattle park planting that is supposed to be all local natives. Friend and I guessed they were received as blue elderberry (Sambucus mexicana, syn. S. cerulea) but are obviously not that species, having a different structure and being in leaf and flower in December! A related species from Mexico?