I don't think it's S. corymbosa. Senna septemtrionalis is possible, it grows to 6.5 metres..
http://www.hear.org/pier/speci...
Look at the copied details on this leaf photo, it says "Weed tree in thickets in reed country, and 8 metres high!
http://www.hear.org/pier/image...
The leaf description.. I don't think we can see the petiolar nectaries but the rest fits.
"Leaflets 3-4 (5) pairs, the distal ones larger, broadly ovate to lanceolate, (3.5-) 4.5-10.5 cm long, (1.1-) 1.4-3.5 cm wide, glabrous, lower surface pale, apex acuminate or caudate, base obliquely rounded or cuneate, petiolar nectaries between all pairs or all but the distal pair of leaflets, none contiguous to pulvinus, the lowest one 1-2 mm long, stipules submembranous, narrowly lanceolate, 3-7 mm long, caducous"
I'm trying to understand the flower description, I noticed yours only has one long filament that I can see anyway, the photos I've looked at have two. The petals seem to be variable.
"filaments of 4 median stamens 1.3-2.2 mm long, those of 2 abaxial stamens dilated, ribbon-like, 7-10.5 mm long, that of abaxial central stamen 2-4 mm long."
