Various methods for predicting annual tree height increment (∆ht) and height-to-crown base increment (∆hcb) were developed and evaluated using remeasured data from permanent sample plots compiled across the Acadian Forest of northeastern North America. Across these plots, 25 species were represented upon which total height (ht) measurements were collected from mixed-species stands displaying both single- and multi-cohort structures. For modeling ∆ht, development of a unified equation form was found to result in higher accuracy and less bias compared to a maximum-modifier approach. Incorporating species as a random effect resulted in predictions that were not significantly different compared to predictions from species-specific equations for nine of the ten most abundant species examined. For ∆hcb, equations that modeled changes in hcb over two time periods (i.e., an incremental approach) were either not significantly different from or significantly closer to zero compared to predictions that estimated hcb at two time periods (i.e., a static approach). Results highlight the advantages of incorporating species as a random effect in individual-tree models and demonstrate the effectiveness of modeling tree crown recession directly for application in mixed-species forest growth and yield models.
|Original language||English (US)|
|Number of pages||15|
|Journal||European Journal of Forest Research|
|State||Published - Oct 31 2014|
Bibliographical noteFunding Information:
Acknowledgments This work was supported by the National Science Foundation-Center for Advanced Forestry Systems (Award # IIP-0855370), University of Maine-Cooperative Forestry Research Unit (CFRU), US Forest Service (USFS) Agenda 2020 program, and Canadian National Science and Engineering Research Council. Collection and management of data by the following agencies were greatly appreciated: CFRU, USFS-Northern Research Station, and Nova Scotia Department of Natural Resources. We thank the Associate Editor and two anonymous reviewers for their comments that improved the content of this work.
- Crown recession
- Growth and yield
- Height increment
- Mixed-species stands
- Multi-cohort stands