Using digital cover photography to track the canopy recovery process following a typhoon disturbance in a cool-temperate deciduous forest

Climate extremes impact the function, structure, and composition of terrestrial ecosystems, while ecosystem responses to climate extremes differ with variations in frequency, intensity, and timing of the extreme event. We examined the canopy recovery processes following a typhoon disturbance in a cool-temperate deciduous forest in northern Japan based on 6-year data of canopy coverage imagery using a digital cover photography (DCP) approach that estimates canopy metrics relevant to leaf and woody masses, spatial dynamics, or arrangement of foliage elements. The DCP-derived imagery detected increases in leaf area index and foliage cover within 2 similar to 3 years after the typhoon (i.e., recovery to the pre-typhoon state). Meanwhile, the recovery in leaf area and foliage cover observed after 6 years resulted from a spatial re-arrangement of the foliage elements (i.e., small within-crown gap fraction, foliage clumping) with increasing canopy space availability. Thus, the recovery of the spatial arrangement of foliage elements after the typhoon to the pre-typhoon state takes longer than the recovery of the leaf and woody masses. This study provides an important ecological implication in terms of possible resilience adaptation for ecosystem function and structure following extreme climate events.