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Special care should be given to the plants during the first year of establishment during which they are especially vulnerable.

  1. Weeding: The plants should be kept from weed competition during establishment. Complete weeding should be done at least around each plant. Weeds between the plants may be cut or completely removed. If chemical weeding is applied, care should be taken in terms of time, weather condition, and doses of application (reference is made to the instruction of the individual herbicide).

  2. Rouging: Once the result of the progeny test is available, the undesired families or ramets are cut and removed.

  3. Thinning and pruning: In addition to rouging, the trees may be thinned and the branches systematically pruned in order to make an open crown with large flower production, and facilitate seed harvest.

  4. Fertilization and watering: Water and fertilizer should be applied whenever necessary to give the trees optimal growth conditions. Conditions are especially important during flowering and fruit development. The amount and type of fertilizer differs from species to species.

  5. Flower induction: If flowering fails or is unsatisfactory, it may be induced or promoted by (1) imposing stress or (2) applying flower inducing hormones during flower differentiation.

Note: Small plants are generally more vulnerable to herbicides than bigger plants.

Imposing stress: Various methods of stress-imposing promote flowering:

Full or partial girdling. A piece of bark on the trunk is removedRoot pruning by subsoiling. Roots are cut by the help of a tractor pulled chisselplough.Strangulation. A wire is tightened around the trunk to limit the passage of nutrient and water in the cambium.

Water stress can be imposed if water availability can be manipulated by artificial watering or irrigation. A brief drought during floral differentiation will usually induce flowering. The watering should be re-continued after flowering.


  1. The time of imposing the stress factor is crucial for the effect. In some species flower differentiation occurs long time before the flower buds are visible.

  2. Some of the stress factors may seriously damage the tree that may affect the fruit development and seed maturing. Secondarily, it may affect the amount of future crops.

Hormone application: The active hormone in flower differentiation is gibberellin. Artificially manufactured versions of the hormone are sold under various trade names. Hormones can be applied by spraying flowering branchlets with the remedy or by applying to the cambium:

Spraying branchlets with flower inducing hormones.Hormone application by syringe into the cambium.

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