दक्षिणी बिहार के निम्नलिखित में से किस जिले में शुष्क पर्णपाती वन आवरण का अधिक सघन संकेंद्रण पाया जाता है?

In the context of Dry Deciduous Forests in Bihar, which of the following tree species is specifically noted as being primarily found in the southern part of the state?

Which structural characteristic primarily defines the Dry Deciduous Forests located in Northern Bihar?