Why Don’t Trees Freeze?

Last night was the coldest night we have had here in Connecticut in about 20 years; it got down to 8 degrees below zero Farenheit.  That reminded me of a question often asked of me:  Why doesn’t the water in the trees freeze and cause them to burst open like frozen pipes?

Water is stored in trees in two ways; as free water and water stored molecularly.  Free water in the xylem vessels and tracheids that would freeze and burst those cells is purged from the tree.  The remaining water in the tree is stored as individual or small groups of molecules bound to other molecules in the trees’ cells.  Stored that way, the water molecules cannot arrange themselves into the expanding crystal lattice that causes pipes to burst.