User blog comment:Gen. Grievous1138/Story of how I entered Middle-Earth/@comment-4750818-20141006161306/@comment-4750818-20141007115705

Grievous, how would you attack Ents with four lightsabers? Ents aren't hurt much by swords. Also your Mordor spiders, Orcs, and other foul beasts won't be very effective against a large army of Huorns.

50 Ents and a few hundred Hurons were capable of destroying 10'000 Orcs and 500 Uruk-Hai in Isengard with no losses. The Hurons later came back to destroy the remaining Uruk-Hai at the Battle of the Hornburg.

Had Treebeard ordered an attack on Mordor it would have done great damage to Sauron's forces. In fact, Trolls are Morgoth's imitation of Ents (but Trolls are much weaker and less intelligent than Ents) in the same way that Orcs are Morgoth's imitation of Elves (but the Orcs are much weaker than Elves).