Asian in origin, Sawtooth Oaks (Quercus acutissima) are found in two distinct environments in North Carolina and most of the southern United States. In cities and suburbs they line residential streets and parking lots in huge numbers. In undeveloped areas they are used in hunting lands to attract and feed game animals with their prodigious crops of acorns.
Small groves of Sawtooth Oaks can be found in patches all around the Falls Lake area, most of them planted on what was once private land prior to the construction of the Falls Lake Dam in 1980-1983. There is a particularly interesting grove located between the Dam itself and the Visitor’s Center in an upper meadow. This grove has several large, mature Sawtooth Oaks about 40 to 50 feet in height surrounded by younger trees (probably offspring) 10 to 25 feet in height, and many young saplings and seedlings. Sawtooth Oaks have invasive potential, and this process, although slow given the age of the grove, can be seen in this location.
The leaves of the Sawtooth Oak are shiny and lustrous, somewhat resembling a glossy Chestnut, Chinkapin, or Beech leaf. The serrated margins with long, prominent bristles are characteristic of Quercus acutissima, and led to the “Sawtooth” name.
The bark is brown and gray with deep furrows. The trees in this grove have deep vertical furrows with red pigment within the grooves. The bark can become very corky in appearance with age.
Adjacent Water Oaks have similar vertical furrows with red pigment inside, but the bark is much smoother.
The ground under the oaks is heavily littered with the remnants of last fall’s acorn crop. The acorn’s cap is very distinctive with the scales reflexed with long finger-like, wavy projections. I could not find a single acorn that had the nut remaining in the cap during an early June search.
Sawtooth Oaks remain highly popular for wildlife plantings and,surprisingly, are recommended by the Wildlife Services of a number of southern states even though they are not native trees. They are inexpensive, rapid growing, produce acorns in just 5 to 6 years (native oaks require up to 25 to 30 years), and drop huge numbers of acorns in the early fall. The big liabilities are the displacement of native oaks and the invasive potential.
Sawtooth Oaks are incredibly popular now among urban and suburban landscapers. They are hardy in urban soils, fast growing, disease resistant, and have a naturally pleasing shape. The young trees shown below are typical, showing a full pyramidal shape, broad and rounded.
The drawbacks seem to be largely ignored. The huge acorn crops produce heavy litter and must be a street-cleaner’s nightmare. Walking under the trees in fall is treacherous, like walking on soft ball-bearings. The leaves turn an unattractive brown in the fall and hang on the tree through most of the winter. The prodigious acorn crops result from huge numbers of flowers in the spring, so heavy that the trees’ large, pendulous catkins can provide shade before the leaves even come out. One wonders what the spring pollen count must be like in a parking lot totally surrounded by wind-pollinated Sawtooth Oaks. In spite of the obvious drawbacks, these Asian oaks only seem to be increasing in popularity and use.