crossing3dforest: an R package for evaluating empty space structure in forest ecosystems

Traditionally, forest structure is mostly described by vegetative elements; however, the complementary empty space also contributes to the forest spatial structure. We developed an R package ( crossing3dforest ) to support the entire processing of Terrestrial Laser Scanning point clouds to quantify the size, shape, and connectivity of empty spaces within the mid and low strata of forest stands, using an approach based on the percolation theory. The package functions, which are designed for step-by-step single stand analysis, can be executed sequentially in a pipeline. A case study is presented to demonstrate the crossing3dforest potentials for characterising the forest empty space architecture. TLS point clouds collected in ten different pure beech (Fagus sylvatica L.) stands, representative of five distinct forest management regimes, were analysed and characterised. The adopted empty space approach can be integrated into forest structural analysis to identify animal-habitat associations and establish appropriate habitat structure for wildlife management. Graphical abstract