Effect of logging on the structure, diversity, and tree species composition of the forests of Papua New Guinea

The forests of Papua New Guinea (PNG) play a fundamental role in sustaining the livelihood of local communities and provide significant income to the country derived from the export of timber. After land conversion for agriculture, logging has been identified as the second most common disturbance factor. Conservation activities must be based on a better understanding of the impact of logging. This study analyzes the differences in terms of structure, diversity, and tree species composition between forest types and disturbance regimes in PNG forests. Data were collected from 117 circular plots surveyed according to the protocol of the National Forest Inventory. Sites were situated in unlogged and logged lowland (99 plots) and montane forests (18 plots). The survey recorded 4,558 tree specimens belonging to 258 families, 323 genera, and 789 species. Although data showed the need for a further sampling effort, some general patterns emerged. Montane forest is clearly distinct in terms of structure, diversity, and species composition. Unlogged and logged lowland forests differed only in terms of structure and species composition, but not according to diversity indexes. Thus, logging activities are having an impact mainly on lowland and most accessible areas. Our study established a baseline related to the tree species component of PNG forests. Together with other taxonomic groups, it will be used to monitor the implementation of initiatives aimed at promoting the reduction of emissions from deforestation and forest degradation (REDDþ), which can offer significant economic, environmental, and social benefits.