They attribute the decline to a change in forest composition. This type of forest relied on frequent, small fires to clear out the understory and allow new trees to grow. A recent history of fire suppression, however, has allowed other trees to slowly take over. Sugar maple, a fast-growing shade tree, is one such species. Census data at the reserve and other locations show a significant increase in the proportion of sugar maples during the past 20 years.
Dogwoods are an understory tree.
They don't do well in full sunlight, and they also don't do well under maples, which form a complete canopy, allowing little sunlight to penetrate. Dogwoods are more suited to forests where the canopy is not as dense. The dogwoods' decline has wide-reaching implications for forest dynamics, Pierce says. Losing these trees could seriously impact songbird populations. Dogwoods produce nutritious fruits in the fall, which serve as a food source for forest songbirds.