My 5 year old monkey puzzle tree (approximately 4 feet tall) exhibits a strange growth pattern. The area on each branch, from the trunk to the tips of those branches, have total dieback. Following that, after a few weeks, the distal 1/3 of the branch begins new green and healthy growth. The proximal 2/3 of the branches never re-green. The tree continues to grow very slowly but in the above described manner. Is this the usual growth mode ?