Here's why:

* Neem trees are perennial: They live for many years, and their stems harden over time.

* Neem trees grow tall: They can reach heights of 30-50 feet, requiring a strong, supportive structure.

* Neem wood is durable: It's known for its strength and resistance to pests and decay.

While the stem of a young neem plant might be slightly softer, it quickly becomes woody as the plant matures.