Height growth of regeneration in boreal forest canopy gaps – does the type of gap matter? An assessment with lidar time series.
Udayalaksmi Vepakoma, Benoît St-Onge, Daniel Kneeshaw.
Large canopy gaps in old-growth forests, formed as a result of tree fall events over time, could be composed of regeneration in various stages of growth different from that of single mortality events. Though important to understand forest dynamics such complex processes are rarely monitored due to limited techniques. Applying object-based techniques on a series of three lidar datasets acquired over nine years in boreal forests, we characterised gap events into old gaps, gap expansions and new random gaps. Combining broad species class from high resolution images, and individually locating gap saplings on the lidar surface, specieswise height growth across gradients of height was estimated. The results indicate distinct height growth patterns of both hardwood and softwood gap saplings in different gap events. The methods can potentially be extended to develop accurate juvenile growth patterns.