Can cover data be used as a surrogate for seedling counts in regeneration stocking evaluations in northern hardwood forests? [electronic resource] / Todd E. Ristau, Susan L. Stout.
Imprint
Newtown Square, PA : U.S. Dept. of Agriculture, Forest Service, Northern Research Station, [2014]
Assessment of regeneration can be time-consuming and costly. Often, foresters look for ways to minimize the cost of doing inventories. One potential method to reduce time required on a plot is use of percent cover data rather than seedling count data to determine stocking. Robust linear regression analysis was used in this report to predict seedling count data from percent cover data based on 3,800 plots on which both count and cover data were collected. Results showed very poor relationships of cover data to seedling counts overall. The weakest relationships were found in plots that had received a shelterwood seed cut without any other regeneration preparation in the past. The better relationship came from plots where competition was reduced through herbicide application and shelterwood seed cutting. Immediately following herbicide application, when total seedling numbers were lowest, the relationship of cover to counts was best, with r-squared values as high as 0.8 for black birch, and between 0.4 and 0.6 for the smallest black cherry and red maple. These numbers quickly declined as seedlings developed. Cover data cannot reliably serve as a surrogate for seedling counts.
