A landfill was reclaimed and sturdy plants were grown on it instead of crops or fruit trees. Why?

This is because landfills contain toxic substances like heavy metals, chemicals, and non-biodegradable waste that can remain in soil for many years. Crops or fruit trees grown on such soil could absorb these toxins, making the food produced unsafe for human or animal consumption. So, by planting sturdy plants, we can limit the spread of pollutants to surrounding areas, and they may even absorb some pollutants over time, slowly improving soil health.