Sternberg has cultivated and studied trees since 1952 and has assembled one of the largest PCN oak genus (Quercus) living reference collections for North America at Starhill Forest, his research arboretum.
It was one of 30 worldwide arboreta featured in the New Trees book compiled in 2009 by John Grimshaw for the International Dendrology Society, and has been dedicated in trust to Illinois College.
Sternberg has served as an honorary director for Wild Ones: Natural Landscapes, lectures frequently for various colleges, trade and professional organizations, and other institutions, and is very active in the preservation of historic trees.
He served as English version editor for Chinese Seed Plants of the Big Bend Gorge of Yalu Tsangpo in Southeast Tibet by Hang and Zhou.
He performed many technical reviews for the National Arbor Day Foundation's Library of Trees series, and supplied photographs for the US Forest Service Field Guide to Native Oak Species of Eastern North America, the Belgian Guide Illustré des Chenes, and educational posters and web pages produced by the Illinois Department of Natural Resources and the Live Oak Society.