Answer: The ants are finding a source of food on your tree - some sugary sap of some kind. Check to make sure there are no aphids because ants 'herd' aphid colonies and milk them of honeydew, which is a sugary residue. Spray your tree with a strong stream of water to dislodge any aphids you find. To keep ants from climbing up your tree, place 'Tanglefoot' at the base of the trunk. Tanglefoot is an extremely sticky substance that traps insects if they fly or walk onto it. To protect the trunk of your tree, first wrap it with paper and apply the Tanglefoot to the paper. You may have to remove the paper coated Tanglefoot trap and replace it as it becomes filled with ants - if there are enough dead ants trapped, live ants will use them as a bridge and cross the Tanglefoot barrier!
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