the term is LOLLYPOPPING lol but we know what you mean. its the technique of pruning the lower branches and little shoots on the inside of the plant, leaving the outter canopy to florish with buds come flowering!
i just got done lolli popping some under growth on my beast. it basically is because the bottom buds are little and fluffy and shitty and dont pull there own weight cuz they dont get light so the plant is supposed to be more efficient if u cut off the little buds and let the energy go towards the bigger upper buds