The tsunami in March 2011 heavily damaged the Pinus thunbergii Parlatore erosion-control coastal forests of northeastern Japan. The restoration is in process but has been challenged by waterlogging resulting from soil compaction of artificial growth bases. In this study, a pot experiment was conducted to elucidate the waterlogging responses of two-year-old P. thunbergii seedlings in terms of waterlogging duration. Three waterlogging durations were set (7 days, 17 days, and 32 days, water table at soil surface) during August, followed by a waterlogging-free recovery period (28 days) in September. In this experiment, the responses of both above- and belowground organs during waterlogging and after the release from waterlogging were elucidated, focusing on parameters, such as transpiration and photosynthesis rates, as well as fine root growth and morphology. As a result, we found that under the conditions of our experiment, if the waterlogging duration is within 17 days, P. thunbergii seedlings can recover physiological activity in about a week; however, if the waterlogging duration is over 32 days, recovery after the release from waterlogging largely varied among seedlings. For the seedlings that could recover, recovery took at least 2 weeks, which required new fine root growth. In cases where the damage was irreversible, seedlings showed an overall decline. These results suggest that it is important to manage the waterlogging conditions so that P. thunbergii seedlings can recover without prolonged negative effects.

The rupture of Fund & atilde;o Dam spilled contaminated tailings across the Doce river basin, severely damaging municipalities such as the urban Barra Longa and the rural Gesteira. The wave of tailings led to the sediment deposition in rivers margins, causing the loss of riparian forests and cropping areas. Sediment analyses confirmed the presence of toxic compounds (sodium and ether amine) and a very low fertility. In consequence, there was a sharp decline in agro-pastoral production in Gesteira, leading to land abandonment and rural exodus. In the urban area of Barra Longa, the wave of tailings damaged the urban floodplain and the square, which were rehabilitated using grey infrastructure. Alternatively, we proposed a new landscape recovery plan for both Barra Longa and Gesteira based on Nature and Community-based solutions that contemplate the inclusion of green infrastructure, the remediation of toxic compounds, the restoration of soil fertility, permeability and stabilization, riparian forest rehabilitation and the recovery of agro-pastoral productivity, ultimately aiming at reducing the flood risk and land abandonment.