Utilizing Quantile Regression to Develop a Stand Density Index for Mixed Species Stands From FIA Data

Presenter Information

R. Knapp, University of New Hampshire
M. J. Ducey, University of New Hampshire

Event Website

http://www.nafew2009.org/

Start Date

6-23-2009 1:30 PM

End Date

6-23-2009 1:50 PM

Description

Identifying relative stand density values is important for accurate prediction of net biomass and carbon accumulation, for estimating growth rate and mortality risks of individual trees, and managing stands for multiple goods and services. Developing stand density indices for mixed species stands has been particularly challenging. Utilizing data from the USDA Forest Inventory and Analysis database, we developed a mixed species stand density index for the northeastern United States. This additive index utilizes quantile regression to identify maximum stand density values for mixed species stands. A quantile selection technique was used to ensure that single-species maximum density values calculated using the new index are in agreement with currently accepted or implied maximum values contained in other silvicultural guidelines. This technique has broad application and offers a robust way for dealing with the complex structures of mixed species stands.