Forests　usually　present　medium　radar　backscatter　in　SAR　images;　however,　they　can　have　extremely　high　backscatter　if　ground-trunk　dihedral　reflection　cannot　be　neglected.　In　this　paper,　we　demonstrated　the　extremely　enhanced　backscatter　in　L-band　ALOS　PALSAR　image　of　a　coastal　forest　plantation　in　Zhangpu,　China.　With　the　revised　water　cloud　model　and　field　measurements,　we　explained　the　mechanisms　for　the　enhance　backscatter.　It　is　due　to　the　ground-trunk　corner　reflector　because　of　the　internal　structure　of　the　forest　and　strong　penetration　of　the　L-band　microwaves,　and　the　high　wetness　of　the　forest　understory.　The　understanding　presented　in　this　paper　is　useful　for　choosing　the　models　and　information　retrieval　methods　to　monitor　this　kind　of　forest.　©　2012　IEEE.