Which of the following is not a forest plant/ tree?

Forests are ecosystems dominated by trees and other woody vegetation, typically adapted to shaded, humid environments with well-drained soils. 

Neem, Sheesham, and Bamboo are all examples of trees or plants commonly found in forests.

However, Tomato is not a plant typically found in a forest ecosystem. Tomatoes are herbaceous plants that are grown as annual crops for their fruit. They require full sun, warmth, and well-drained soils to thrive, which are not the typical conditions found in forest ecosystems. Therefore, Tomato is the correct answer.