The decision was taken after a survey was conducted jointly by the Forests and MCC officials, an official release here said.
The saplings would not be planted in areas where development works had been planned in future.
About 13,000 saplings would be planted on a 40-acre land on the ONGC-MRPL premises, 12,000 saplings on rural roads and highways falling within the Mangaluru forest limits, which includes the National Highway stretch between Nanthoor and Talapady, Surathkal to Mukka and between Mudipu and Melkar.