Oxford County Soil & Water Conservation District seeks help tracking down the most impressive trees in the county.

The district keeps a register of big trees in the county, which catalogs the largest specimen of each native species found. There are 22 species yet to be nominated, many of which are smaller species of trees that may be found in wet areas, along streams and ponds.

Here are clues to help people find some of these trees:

• Jack Pine could be found in the area around Upton;

• Sweet Birch might be found from Rumford and Newry south along the banks of streams or moist, rich upland soils; on younger trees the bark has a very pronounced flavor of wintergreen;

• American Hornbeam might be found from Waterford northeast to Greenwood, Woodstock, Milton and Rumford;

• Black Tupelo might be found from Otisfield north and east to Norway, Sumner and Canton. It has also been reported on the South side of Pleasant Mountain in Denmark on flat, open, wet areas. Black Tupelo, though not large, can be as old as 500 years; and

• Sassafras might be found in the Waterford, Sweden, Stoneham area.

Nominators of winning trees will receive T-shirts and copies of Forest Trees of Maine, Centennial Edition 1908-2008. Nominations will be accepted until Sept. 30.

To learn more and nominate a tree, visit oxfordcountyswcd.org.