One of these trees was turned into a Chapel, one was a gathering place for illegal education, one has roots that won't quit after 13,000 years, and folklore tells us that one was the meeting spot for Robin Hood and his band of merry men.
One of the 10 hemlock species, the one that grows up the Appalachians from Georgia to Canada, will probably be gone by the end of this century. It will still exist in arboretums and on some private properties, and maybe in the far north, but its great swaths of forest will most likely have rotted out because of a non-native pest. Another reason why you should never transport firewood! - you risk spreading pests living in the wood to new areas.
Flower diplomacy? Yes, we got 3000 cherry trees from Japan in 1912 thanks to the work of Elizabeth Scidmore, a diplomate's wife. In 2012, we made a gift of 3000 dogwood saplings to Japan to commemorate the event. Some of those flowers went to memorials honoring those who lost their lives in the Fukushima nuclear disaster.
Hemlock sounds dangerous because we have a vague of it being used as a poison to kill Socrates. This post explains how the common name of that plant came to be associated with a family of large conifer trees in North America.