[tag=CC] | [tag=□] □ □
[tag=CC] | [tag=NN] □ □
[tag=CC] | [tag=IN] □ □
Together , elevation , slope , and aspect ( north vs. south facing ) exert enormous control on surface hydrology and ecosystems . This will allow you to either treat or dispose of any infected plants . The Yard & Garden Brief , “ Apple Scab ” contains detailed information about identifying and controlling this disease . For this method to succeed , it is beneficial if the SAR system is capable of determining a DEM with a single pass - - either by having a dual antenna system or tandem satellites . Although ERS-1 has been joined by ERS-2 , there are no plans yet in place to optimize either satellite for interferometry . For more information about fireblight , see the Yard & Garden Brief “ Fireblight , ” at http://www.extension.umn.edu/projects/ yardandgarden / ygbriefs / p223fireblight.html . If precise geodetic data can shed light on the spatial distribution of accumulating strain - - either through dense permanent GPS networks or SAR interferometry images - - then any hint that strain is accumulating faster in a given area ( e.g ., Donnellan et al ., 1993 ) would be important for devising better observing strategies , selecting target areas for intensive geological and geophysical study , and generally deploying our resources more effectively . Measurements on the ground are very time-consuming , labor-intensive and often constrained by lack of access . ( Note that the conservative performance estimates in Table 8.2 have not assumed this synergism nor any resulting reduction in systematic error due to platform orientation . Once the tree has rough and flaky mature bark , neither winter sun nor chewing animals can harm it , so tree guards will not be necessary .