What tree is most difficult to deal with?

The tree often considered most difficult to deal with is the Black Locust (Robinia pseudoacacia). Its rapid growth, aggressive spreading through root suckers, and thorny branches make it challenging to manage in landscapes and natural areas. Additionally, the tree can produce allelopathic chemicals that inhibit the growth of other plants, further complicating removal efforts. Its resilience and adaptability often lead to it becoming invasive in many regions.