How do you get rid of aphids on a large oak tree?

To remove aphids from a large oak tree, you can start by spraying a strong jet of water to dislodge them from the leaves. Introduce natural predators like ladybugs or lacewings, which feed on aphids. If the infestation is severe, consider using insecticidal soap or neem oil as a targeted treatment, applying them according to the manufacturer's instructions. Regular monitoring and maintaining tree health can also help prevent future infestations.