Northern white cedar (Thuja occidentalis L.) stands throughout the upper Midwestern United States have failed to recruit individuals to the canopy consistendy for several decades. To examine local and landscape factors that influence cedar regeneration we recorded the abundance of cedar seedlings and saplings in 24 lowland cedar stands in the Chequamegon-Nicolet National Forest, Wisconsin, during summer 2001. Cedar seedlings (height <22 cm) were common (median = 1800 ha-1), but the largest size class (height ≥100 cm) was extremely rare (∼1 ha-1) and heavily browsed. We used information-theoretic model averaging of linear mixed-effects models to identify local and landscape variables important for predicting the density of seedlings and saplings. The density of newly germinated seedlings was higher along transects farther from roads and with more mature cedar. Large seedling and small sapling densities were higher along transects with open canopies located in landscapes with a higher ratio of deciduous to coniferous forest. Increased edge-to-area ratios of cedar stands and edge density of the surrounding forest were associated with lower densities of large seedlings and small saplings, respectively. Results indicated a strong demographic effect with the density of large size classes being strongly dependent on the density of smaller size classes. Because the landscape factors considered are linked to browsing intensity, a reduction in deer (Odocoileus virginianus Zimmermann) density coupled with landscape-sensitive forest management may help to foster cedar regeneration in northern Wisconsin.
|Original language||English (US)|
|Number of pages||16|
|Journal||American Midland Naturalist|
|State||Published - Oct 1 2008|