• bhagavatā — by the Lord (Balarāma)
  Instrumental of bhagavān. Vyāsa names Him as bhagavān precisely while He's repeatedly breaking trees over His own head — to insist the title belongs to the one who endures and acts, not only to the one who is worshiped from a distance.
• bhagne bhagne — again and again being broken
  Doubled locative absolute of √bhañj (to break) — śāstric idiom for repeated action. The repetition is itself the verse's content; the asura cannot stop, and Bhagavān does not need to stop him until the moment is ripe.
• ākṛṣya — pulling out, uprooting
  Ā- + √kṛṣ (to draw). Same root as Saṅkarṣaṇa, but used now of the demon — the asura is a counterfeit-saṅkarṣaṇa, drawing things out of the earth to destroy them. The Lord draws beings to Himself; the asura draws beings to ruin.
• nirvṛkṣam — treeless
  Compound: nir- (without) + vṛkṣa (tree). The forest is no longer a forest. Asuric activity drains its world of the very category that defines it — a quiet doctrinal note about how evil empties existence of its own contents.
• punaḥ punaḥ — again and again
  The chapter's keynote of futility. The same idiom Gītā 8.16 uses for saṁsāra: punar āvartino 'rjuna. The demon is in a private saṁsāra of his own violence, repeating the same gesture without escape.

By the end of the duel the forest is gone — every tree the demon could lift has been lifted and broken. Asura-bala empties the world of its standing things; Bhagavān stands while the trees fall around Him.