How to best manage selective logging for carbon and biodiversity retention in the Brazilian Amazon

Tropical forests are currently under incredible pressure by land-use change, putting in
risk global sources of carbon stocks and biodiversity. Selective logging is one of the
most extensive land uses and is currently expanding under a sustainable activity label.
However, the damage caused by logging depends greatly on how forests are managed. In this manuscript I ask how logging intensity affects above-ground carbon stocks (Chapter 2), soil organic carbon stocks (Chapter 3) and tree diversity (Chapter 4) after logging in the Brazilian Amazon. Additionally, I explore whether implementing extensive logging with low intensity (land-sharing logging) or sparing a continuous piece of land coupled with intensified logging (land-sparing logging), retain more carbon stocks and tree diversity. To explore the disturbance effects of logging I set 0.5 ha plots in unlogged and logged forests in Brazil. I measured local intensity by m3 of wood removed inside each plot. I simulate equivalent land-sharing and land-sparing harvests on spatially explicit emulated forests. Then, I predicted for above-ground carbon stocks (Chapter 2), soil organic carbon stocks (Chapter 3) and tree abundance (Chapter 4) in function of logging intensity. I found that above-ground carbon stocks and abundance decreased with logging intensity (Chapters 2 and 4). Logging intensity did not affect soil carbon stocks and diversity values (Chapters 3 and 4). However, in Chapter 3, unlogged forest was higher in soil carbon stocks than logged forest. Land-sparing logging retained in general more above-ground carbon, soil carbon stocks and tree abundance. In chapter 4, spared lands contributed significantly to species number in land-sparing scenarios. These findings illustrate the capacity of land sparing to retain more carbon and tree diversity than land sharing with equivalent yield and the benefits of primary forest in allocated lands.