How often do you think about trees? On a hot day walking around Seoul under the scalding sun I wish there were some trees to shade me. And I love to go for a walk and smell pine trees or Cedar wood. And I hate to see trees (and mountains) being cut down to make way for yet more construction. But I don’t know all that much about trees. And I don’t  think there are that many trees I could actually name. As we were walking around the grounds of the tomb of King Sejong the Great, we saw a Korean alder tree. (I knew it was an alder because it said so on the sign.) The Korean name is 오리나무. O-ri-namu. 오 (o) means 5, 리 (ri) is a unit of Korean measurement, and 나무 (namu) means tree. And apparently, years ago these trees were planted 5 ri apart along the roads so that travellers could work out how far they had gone. Hence the name ‘5 ri tree’. Clever idea.

But how far was a ri?

The ri originally came from China (li 里). According to wiki, in China the li was not a fixed measurement at first and could vary depending on the amount of effort needed to cover the distance. I couldn’t find any information to suggest if this was the same in Joseon. Or what distance a ri was during this time. But the ri is still used as a measurement in Korea today where 10 ri = about 4.5 km.