Part 3 Conclusions and recommendations

摘要

1.Coastal forests and trees can, under certain conditions, act as bioshields to protect lives and valuable assets against coastal hazards, including: tsunamis, cyclones, wind and salt spray and coastal erosion. 2. The degree of protection offered by coastal bioshields depends on a number of variables, including: (ⅰ) the characteristics of the hazard itself (e.g. type, force, frequency); (ⅱ) the features of the site (e.g. bathymetry, coastal geomorphology); and (ⅲ) the characteristics of the bioshield (e.g. type of forest/tree, width, height and density of the forest). 3. Care must be taken to avoid making generalizations about the protective role of forests and trees based on evidence from one or a few areas; the many factors that influence the protective role of the forests/trees must be understood and taken into consideration before lessons can be learned and applied elsewhere. 4. Coastal forests and trees are not able to provide effective protection against all hazards (e.g. extremely large tsunami waves, flooding from cyclones and certain types of coastal erosion); provisions for other forms of protection and (in extreme events) for evacuation must be relied upon. Care must be taken not to create a false sense of protection against coastal hazards. 5. The importance of incorporating coastal protection as an integral part of coastal area planning and management is recognized. 6. The options for protection include: soft and hard solutions and a hybrid of the two. If none of these is appropriate and viable, it may be necessary to zone coastal land use to prevent (further) settlement and construction of valuable assets in the vulnerable zone. 7. It is important to match the species with the site in order to avoid high mortality and low performance of the planted trees. Some forest types and tree species cannot survive or thrive in areas exposed to specific coastal hazards; therefore, they are not candidates for protective measures. 8. Development of bioshields is not possible in all situations owing to, inter alia, biological limitations, space constraints, incompatibility with priority land uses and prohibitive costs. 9. The level of knowledge and understanding of the functions of forests and trees in coastal protection is still insufficient and there is a lack of multidisciplinary research and cooperation in this field. Specific areas needing further attention include research in non-mangrove coastal forests and collection of data and development of models on interaction between the physical and ecological parameters. 10. There is a need to recognize that many years are required to establish and grow bioshields to a size and density that could offer protection against coastal hazards. 11. Considerable research and field initiatives related to forests and coastal protection have been carried out over the past several years; they provide a useful foundation for further work to improve understanding of the protective role that forests can offer.