Great Chinese Trees
Chinese chestnuts were planted widely when people realized that American chestnut was doomed, sometimes in forest settings because people hoped that blight resistance could spread directly to remaining American trees. These forest Chinese trees are eventually over-topped and die out. They also leaf out and bloom much earlier than pure Americans, and natural hybrids are essentially unknown from these experiments. In fact, making a controlled cross between Chinese and American species (the F1 cross) has a number of difficulties and some crosses work better than others.
Chinese trees do seem to be more tolerant of heavier soils and have resistance to ink root rot. There are magnificent older trees in many public sites and farm sites. These can be admired in their own right, and are useful as sources of resistance. Now that the Chinese genome has been sequenced, we will eventually be able to determine the variation in resistance among different Chinese sources (through alleles or through different mechanisms for blight resistance.)