17775
These were built around a pair of wooden box-girders , the upper and lower members of which were built up from several thin strips of pine , with connecting webs of birch plywood .
 pine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 pine