NPS Spokesman Bill Line says the new tree is a Colorado blue spruce from a New Jersey nursery and stands taller than 26 feet.
That's quite a bit shorter than the old tree, which measured 42 feet high and stood in the same spot for more than three decades.
But Line says he expects the new tree to grow well above its current height.
The spruce was planted and installed over the weekend in the northeast quadrant of the Ellipse, the location of the National Christmas Tree since 1973.
The park service says the tradition dates to 1923 when President Calvin Coolidge held the first of what have become annual National Christmas tree lightings.