A Detailed Guide to Renewal Methods for Aged Mandarin Orange Trees

For aged trees caused by advanced tree age, overly dense planting, damage from pests and diseases, or poor management, renewal and rejuvenation should be carried out promptly. There are three methods: main branch renewal, skeleton renewal, and rotational renewal.

1. Main branch renewal. This method is suitable for severely declining plants. The method is: saw off at 0.7 m to 1 m from the base of the main branch, heavily cut back the scaffold branches to promote the emergence of new shoots, and at the same time carry out deep plowing and fertilization over an appropriate area to renew the root system. After 2 to 3 years, the canopy can be restored and fruit can be produced again.

2. Skeleton renewal. For aged trees whose some branches can still bear fruit, cut back the branches at the outer part of the canopy at a thickness of 2 cm to 3 cm or less, or remove all 2- to 3-year-old lateral branches while retaining the bases of the scaffold branches. With proper management, fruit can be produced after two years.

3. Rotational renewal. For trees whose some branches can still bear fruit, carry out rotational heavy cutback pruning over 2 to 3 years, and thin out some of the overly dense and weak lateral branches, retaining most of the relatively vigorous branches and leaves. Within the several years of renewal, a certain yield can still be maintained each year.

After canopy renewal, the trunk and main branches should be wrapped with rice straw or whitewashed, the saw cuts should be trimmed flat and smooth and coated with preservative or grafting wax, the ground should be covered for sun protection, and fertilizer and water management and pest and disease control should be strengthened, with appropriate bud thinning to ensure vigorous growth of new shoots.