OVER THE NEXT FEW DECADES NASA AND ESA ARE PLANNING A SERIES OF SPACE-BASED OBSERVATORIES (HABEX) TO MEASURE THE SPECTRAL CHARACTERISTICS OF EARTH-SIZED EXTRA-SOLAR PLANETS IN REGIONS WHERE LIQUID WATER MAY BE PRESENT. IF THEY SUCCEED IN FINDING A PLANET WITH BOTH BIOGENIC GASSES IN THE ATMOSPHERE AND A RED-EDGE CHARACTERISTIC OF LIFE WE WOULD WANT TO KNOW WHETHER THE LAND-BASED LIFE ON THIS PLANET IS SIMILAR TO THE GREEN PHOTOSYNTHETIC SLIME COMMON FOR MOST OF EARTH S HISTORY OR WHETHER THIS LIFE HAS EVOLVED TO BE DIVERSE AND MULTI-CELLULAR. MULTI-CELLULAR PHOTOSYNTHETIC ORGANISMS ON EARTH (TREES) HAVE A DISTINCT BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION (BRDF) CAUSING DIFFERING REFLECTANCE AT DIFFERENT SUN/VIEW GEOMETRIES. IN PREVIOUS WORK WE EXAMINED WHETHER THE BRDF COULD DETECT THE EXISTENCE OF TREE-LIKE STRUCTURES ON AN EXTRA-SOLAR PLANET BY USING CHANGES IN PLANETARY ALBEDO AS A PLANET ORBITS ITS STAR. WE USED A SEMI-EMPIRICAL BRDF MODEL TO SIMULATE VEGETATION REFLECTANCE AT DIFFERENT PLANETARY PHASE ANGLES AND FOUND THAT EVEN IF THE ENTIRE PLANETARY ALBEDO WERE RENDERED TO A SINGLE PIXEL THE RATE OF INCREASE OF ALBEDO AS A PLANET APPROACHES FULL ILLUMINATION WOULD BE MEASURABLY GREATER ON A VEGETATED PLANET THAN ON A NON-VEGETATED PLANET (DOUGHTY AND WOLF 2010 ASTROBIOLOGY). WE HYPOTHESIZED THAT DEPENDING ON HOW ACCURATELY PLANETARY CLOUD COVER CAN BE RESOLVED AND CORONAGRAPH DESIGN THIS TECHNIQUE COULD THEORETICALLY DETECT TREE-LIKE MULTI-CELLULAR LIFE ON EXOPLANETS IN 50 STELLAR SYSTEMS. HOWEVER SUCH THEORETICAL WORK NEEDS EMPIRICAL VALIDATION. WE NEXT CARRIED OUT A PROOF OF CONCEPT OF THIS TECHNIQUE IN A MANNER SIMILAR TO SAGAN ET AL. (1993) BY USING GALILEO DATA TO DETERMINE IF MULTICELLULAR LIFE ON EARTH COULD BE DETECTED. HOWEVER WE WERE UNSUCCESSFUL LIKELY BECAUSE THERE WAS NO CHANGE IN PHASE ANGLE WITH THESE GALILEO DATA AND THE TECHNIQUE REQUIRES A LARGE CHANGE IN PHASE ANGLE (DOUGHTY AND WOLF 2016 PLOS ONE).