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Urban Food Garden

FRUIT TREE FUNCTIONS

Fruit trees perform three key functions. As no single fruit tree performs all three functions it is important to understand these functions and where it is best to apply them in your garden.

FUNCTION 1 : Food Production

The main function of any fruit tree is to produce food for you to eat. To maximise the amount of produce you harvest from any given tree and to make it as easy as possible to harvest that produce a tree should be small enough to comfortably throw a bird net over without having to get up on a ladder.  There are three ways to keep a fruit tree to a size that is small enough to be managed effectively:-

  1. PLANT TREES THAT HAVE BEEN GRAFTED ONTO DWARF ROOTSTOCK
    Dwarf trees are smaller and slower growing, though they still will need some pruning.

  2. REGULARLY PRUNE THE TREE TO KEEP ITS SIZE SMALL
    Standard sized trees can be kept small by pruning them two or three times a year.

  3. ESPALIER TREES
    This involves supporting the tree on a trellis, which is done by a combination of heavy pruning and training of the branches
    not pruned to a shape that you want, usually elongated.

Trees that are too big to get bird netting over will produce more fruit than small ones, but most of the fruit is likely to be eaten by birds before they can be harvested  However the down side of only having espaliered or dwarf fruit trees is that they offer little in the way of shade.  In places that have hot dry Summers it is important that at least some of your trees offer decent shade.

Espaliered Corella pear tree.  For ease of handling fruit trees whose primary function is to produce fruit should be no higher than you can comfortably put a bird net over without having to get up on a ladder.

FUNCTION 2 : Shade

As well as providing food to eat fruit trees can offer shade for both people and livestock. But letting a fruit tree grow large enough to provide shade has some negative side effects.  They are:-

  • DIFFICULT TO NET
    Fruit trees that cannot be netted often result in most, if not all, of the crop being lost to birds.

  • NEED MORE WATER THAN ESPALIERED OR DWARF FRUIT TREES
    A mature fruit tree, with a full crop in the height of summer, will need about thirty litres of water per day. Whereas smaller trees need much less water.

  • HARDER TO HARVEST THE CROP
    If there is a harvestable crop it will be difficult to pick as you must get up on ladders to gather much of the fruit.

  • THE RISK OF TOO BIG A HARVEST
    A standard sized fruit tree can produce a huge crop. If the tree does produce a crop that isn’t eaten by birds you can end up with way too many fruit for the average family to eat or bottle.

If you want larger food producing trees that will also offer you shade then there are two things you can do to minimise this problem.

  • PLANT ORNAMENTAL SHADE TREES
    Ornamental trees usually do not require the maintenance associated with pome and stone fruit trees, such as regular pruning, thinning and harvesting.
  • PLANT BIRD RESISTANT FRUIT TREE VARIETIES
    Plant fruit tree varieties whose fruit either does not or is less likely to be eaten by birds. Examples being citrus trees and feijoas. Though what trees will not be attacked by birds will vary in different regions.

Hyline hens in my chicken run.  In the background is a Morello cherry tree which the chickens can shelter under in hot weather.  The tree produces cherries but it is too high to cover with a net, so most years (but not all) wild birds get all the cherries.  The primary purpose of the tree is to provide shade, any fruit that can be harvested from it is a bonus.

FUNCTION 3 : Protection For More Sensitive Trees

Trees that are frost sensitive or do not do well in windy conditions often do better when planted alongside hardier evergreen fruit trees.  These hardier trees grow more quickly, acting as a buffer to both frost and strong winds.  Some examples of hardier food producing trees are:- 

  • FEIJOA
    Hardy evergreen medium sized tree that produces an edible fruit not unlike the taste of fruit salad. For more information on Feijoa trees see the FEIJOA webpage.

  • OLIVE
    Hardy and drought tolerant. Thought its fruit can be targeted by birds.

  • TREE LUCERNE (TAGASASTE)
    Fast growing mid-sized evergreen tree with fine leaves.  Although it does not produce fruit its leaves provide excellent animal fodder. Rabbits, guinea pigs and chickens love to eat it.  Tree Lucerne also fixes nitrogen into the ground, which the trees next to it will also benefit from.

Example of two frost sensitive trees protected by a tougher tree.  LEFT: Tangelo tree.   RIGHT: Beyond the Tangelo you can see a Feijoa tree (with windfall fruit underneath) and beyond that a Wheeny grapefruit tree.  These mature citrus trees do not need protection from hardier trees, but they did when the trees were small.

CONCLUSION

By selecting a combination of tree sizes and types it is possible to grow plenty of fruit and nuts to eat, provide shade for people and animals, as well as offer protection for more sensitive trees.

Note that this information is based on observations of trees in a backyard in Ballarat, Australia.  The threat posed by birds and weather conditions very greatly from region to region and what is stated here may not directly apply to your situation.  To gauge whether the climate in your area is similar to Ballarat’s climate see: BALLARAT & DISTRICT’S CLIMATE.

Also not that these functions listed above can also be applied to nut trees.

FRUIT AND NUT TREE FUNCTIONS SUMMARY

(flip me)
  • FOOD PRODUCTION
  • PROVIDE SHADE FOR ANIMALS AND PEOPLE
  • GIVE PROTECTION TO FROST AND WIND SENSITIVE TREES

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