thanks for sharing. But it's not really true only a third of the National Bonsai and Penjing Museum is open in the winter. What you're seeing is a consolidation of trees for winter storage in more central locations. That may mean some trees are off exhibit, some are relocated into the same buildings, regardless of their spring and summer positions in "North American" "Japanese" and "Chinese" pavilions.
Interesting to note the pots of the large, older pines are surrounded with bamboo barriers that are backfilled with mulch to protect them from cold weather....