Individual-tree- and stand-based development following natural disturbance in a heterogeneously structured forest: A LiDAR-based approach Steven Hill a, ⁎, Hooman Latifi a , Marco Heurich b , Jörg Müller b a University of Wuerzburg, Department of Remote Sensing, Oswald-Kuelpe-Weg 86, 97074 Wuerzburg, Germany b Department of Nature Protection and Research, Bavarian Forest National Park, Freyunger Str. 2, 94481 Grafenau, Germany abstract article info Article history: Received 5 September 2016 Received in revised form 23 December 2016 Accepted 27 December 2016 Available online 29 December 2016 Large-scale severe natural disturbance events drive spatial and temporal patterns of forests by altering forest structure, composition, and functions. In the Bavarian Forest National Park in Germany, windthrow events led to large disturbances caused by the European bark beetle (Ips typographus L.). Until recently, it was assumed that at the initial stage of regeneration, trees tend to form a homogeneous stand structure, whereas structural heterogeneity is an attribute of later developmental stages. Yet recent studies provide evidence that under cer- tain conditions structural heterogeneity can arise much earlier in stand development. Here we combined LiDAR data and forest growth modeling based on individual trees to develop a workflow for studying forest de- velopment in post-disturbed areas in the upper montane regions of the national park. The current forest structure was derived from LiDAR data of individually detected trees and a set of forest structural attributes were derived. The results served as input to simulate tree development spatio-temporally for a period of 80 years. Several spa- tial statistics, including landscape and spatial point pattern metrics, were calculated to assess the structural het- erogeneity. The results showed that naturally regenerating forests on post-disturbed sites reveal structural heterogeneity already at the early-seral stage. Moreover, a significant portion of the eventual old-growth struc- tural heterogeneity might already be determined in the early successional stages. Our workflow highlights the use of multi-sensor aerial remote sensing to provide detailed structural information useful for the investigation of early-phase forest dynamics. © 2017 Elsevier B.V. All rights reserved. Keywords: Forest disturbance Forest development LiDAR Aerial imagery Growth modeling Spatial point pattern analysis 1. Introduction Forests are complex dynamic systems that contribute several crucial ecosystem services. Future forest management and conservation re- quire the development of appropriate target objectives and the evalua- tion of different management strategies. The scientific knowledge needed for this includes a holistic description of forest status and devel- opment (Koch et al., 2009). The structural composition of forests in particular has become an im- portant factor in the analysis and management of forest ecosystems (Franklin et al., 2002; McElhinny et al., 2005; Pommerening and Stoyan, 2006). Forest structure is basically defined as “the physical and temporal distribution of trees in a forest stand” (Oliver and Larson, 1996) and is the result of natural processes as well as human intervention (Gadow et al., 2012). Forest structure is both a product and driver of ecosystem processes (Spies, 1998). Spatial structure is an important factor affecting forest stand dynamics, growth, and yield, and it also controls a range of forest functions, including soil protection and recreation (Pretzsch, 2009). In addition, other important ecosystem values, such as habitat and species diversity, are also related to spatial stand structure (Bergen et al., 2009; MacArthur and MacArthur, 1961; Pommerening, 2002; Vierling et al., 2008). Several studies have revealed that changes in the forest structure also affect species diversity (Lehnert et al., 2013; Müller et al., 2008) and composition (Bässler et al., 2010b; Müller et al., 2010). Natural disturbance events, e.g., fires, windthrow, and insect out- breaks, are among the most crucial drivers that alter the structure of for- est stands (Franklin et al., 2002; Turner, 2010; Swanson et al., 2011). Throughout the 20th century, the number of such disturbance events in Europe increased (Schelhaas et al., 2003; Seidl et al., 2014). These events are particularly important for forest evolution as they alter forest landscape and enable regeneration. However, natural forest develop- ment in post-disturbed areas in Central Europe is only insufficiently documented; almost all forest areas are influenced by human Ecological Informatics 38 (2017) 12–25 ⁎ Corresponding author. E-mail addresses: steven.hill@uni-wuerzburg.de (S. Hill), hooman.latifi@uni-wuerzburg.de (H. Latifi), Marco.Heurich@npv-bw.bayern.de (M. Heurich), Joerg.Mueller@npv-bw.bayern.de (J. Müller). http://dx.doi.org/10.1016/j.ecoinf.2016.12.004 1574-9541/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Ecological Informatics journal homepage: www.elsevier.com/locate/ecolinf