The ratio of durian trees to mangosteen trees is 1 : 4.

• Durian → 1 unit, Mangosteen → 4 units
• Mangosteen − Durian = 4 units − 1 unit = 3 units
• 3 units → 165
• 1 unit → 165 ÷ 3 = 55
• Mangosteen = 4 units = 4 × 55 = 220

Final Answer: 220