Soldier meets elite soldiers to gather tops of trees, including small parts of logs (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

The “tops” of “of Trees Tncluding Small in MAN (soldier) +SAS (elite military unit). Ijn Ye Olden Days when we did calculatuins with logarithms, they were divided into the characteristic and mantissa, before and after the decimal point