[□] □
[□=□] □
[□ | □] □
Sometimes the spots may be mistaken for fungal rust , but these are not signs of a contagious disease . Then dig a trench out from the base of each plant . Such a capability would represent a revolutionary advance in the understanding of ocean dynamics , and would provide the missing dimension to large-scale currents derived from radar altimeter measurements . While species composition per se usually cannot be detected with single-channel SAR , plant communities often can be , due to differences in vegetation height , density , or architecture . Dig a hole for each tree that is no deeper than the root ball , and about twice as wide . It is important to note that differential interferometry requires a high-quality DEM before centimeter-level changes can be detected . Less well known is the fact that sea level could rise very quickly due to accleration of ice discharge into the oceans .