- -   AGRICULTURE CORE CURRICULUM  - -


(CLF7000)  Advanced Core Area:  PLANT AND SOIL SCIENCE

  (CLF7600)   Unit Title:  PRUNING

____________________________________________________________________________
  (CLF7609)   Topic:  PRUNING EVERGREEN         Time      Taught in Year(s) 
                      (FRUIT) TREES             1 hour       3 and 4       
____________________________________________________________________________

         Topic Objectives:  Upon completion of this lesson the student will 
         be able to:

         Learning Outcome #:

           (K-15)  - Discuss methods of pruning evergreen fruit trees.

         Special Materials and Equipment: Materials for a pruning 
                     demonstation

         References: None

         Evaluation: Quiz by instructor

TOPIC PRESENTATION:  PRUNING EVERGREEN (FRUIT) TREES

A.  The evergreen fruit trees that we are concerned with include citrus, 
    avocado and the olive.  These are sub tropical trees which require 
    somewhat different pruning techniques than the deciduous fruit species.

B.  Most citrus trees require no pruning for two or three years after 
    transplanting to the field (or yard).

    1.  Any shoots arising from the trunk below the head of the tree 
        however, are removed.

    2.  Wraps placed around the tree trunks to prevent sunburn also reduce 
        or prevent most trunk sprouts.

    3.  Any suckers arising from below the bud union must be removed.

    4.  Most citrus will naturally form into a spherical shape without 
        pruning.

    5.  When the tree is 3 or 4 years old, selective thinning may be done to 
        remove branches which are too closely spaced or crossed and 
        entangled.

    6.  Pruning for the next five years should be limited to the removal of 
        branches which interfere with the formation of sturdy framework 
        branches.

    7.  Pruning cuts should be made as near a vertical plame as possible.
        Greater sprouting of new buds results near horizontal cuts.

    8.  Bearing orange and grapefruit trees require little pruning.  Most 
        experiments indicate that yield from healthy trees is reduced in 
        proportion to the severity of pruning.

    9.  In backyards where orchard equipment is not used, skirts of the 
        citrus will produce fruit down to ground level.

C.  The avocado has become an important commercial crop in areas where the 
    temperature stays above 26 degrees Fahrenheit.

    1.  Elsewhere the avocado makes a beautiful specimen tree and is grown 
        for its lush tropical appearance.

    2.  The trees are usually headed low and then allowed to develop 
        naturally.

    3.  Trim out weak and poorly placed branches and keep the center from 
        becoming congested.

    4.  Avoid leaving large openings in the canopy as the avocados thin bark 
        sunburns easily.

D.  Although the olive is an evergreen, pruning is generally done in the 
    winter.

    1.  The fruit is all borne on the new shoots of the previous year.

    2.  An unpruned tree generally produces only in alternate years.

    3.  Annual pruning will encourage new growth each year, thus leading to 
        annual production.

    4.  The central leader or modified leader is the preferred system for
        olives.

    5.  On a bearing tree only about one-third to one-half of the fruiting 
        branches need to be thinned out annually.

    6.  All suckers should be removed as they begin to grow.

          __________________________________________________________
          ACTIVITY:  
                      
          1.  Demonstrate the pruning of a citrus, avocado and olive
              tree to the class.
          __________________________________________________________


7/25/90 sg

#%&C