Global review on forest road optimization planning: Support for sustainable forest management in Amazonia

Forest Management in the Brazilian Amazon has social, economic and environmental relevance, as it allows for the sustainable use of natural resources, while at the same time conserving a majority of the ecological processes of the forest. Among forest operations, the construction of new roads is essential for effective sustainable forest management (SFM). However, it is the most expensive part of forest infrastructure and has the greatest environmental impact. Several methods to optimize forest road planning (FRP) have been studied worldwide, although the literature is scarce on the subject of FRP in areas of SFM in Amazonia. Thus, the objective of this study was to carry out a systematic review of the global literature, on FRP optimization in the last decade (2009–2019), as a way to support future planning activities for road infrastructure in SFM in the Amazon. To guide this objective, three questions were raised to determine what the dominant factors affecting FRP in the study period, specifically what were the: (i) spatial variables; (ii) spatial decision analysis and; (iii) optimization methods for road layout. The bibliographic search was conducted according to the Prisma methodology where a set of keywords was entered into the Scopus, Science Direct and Web of Science indexing databases. In this study, all articles published in English-language journals between 2009 and 2019 were considered, resulting in 62 articles for analysis. There was a growing trend in publications, with most studies developed at the level of strategic planning (46.8%). Also, it was observed that the majority of studies occurred in the forests of Iran (33.9%). The results to the questions of this study found that: (i) there were 45 spatial variables, with slope the most studied (54.7%); (ii) Eleven methods of analysis for spatial decisions, with methods based on Analytical Hierarchy Process – AHP the most studied (36.6%) and; (iii) Thirty different methodologies for optimizing the design of forest roads, mainly methods based on Dijkstra’s algorithm (40.5%). Some of the encountered methods have already been implemented in Amazonia to optimize the planning of infrastructure in areas of SFM. In this context, the combination of approaches, variables and analysis for FRP optimization that have been successfully tested in other forests of the world, could feasibly be applied in future planning of logging operations in the Amazon in order to verify the potential of these different procedures and methods, provided that they meet the objectives of the SFM.