edible trees & shrubs
fruit and nut tree functions
Fruit and nut 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 and nut tree is to produce food for you to eat.  In order 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 :-

  • PHOTO - espaliered apple tree
    Espaliered Ballerina apple tree.  The top of the tree can be reached comfortably without having to get on a ladder.  The down side is that if offers little shade.
    No higher than the height that you can comfortably reach to the topmost branch without having to stand on a ladder.
  • Small enough in size that it can be completely covered with bird netting, again without having to stand on a ladder to put the netting on

There are three ways to keep a fruit tree to a size that is small enough to be managed  effectively :-
  1. Buy a tree that has been grafted onto dwarf rootstock.
    Though even dwarf trees usually need some pruning.
  2. Regularly prune the tree to keep it's size small.

  3. Espalier the tree, which involves a combination of heavy pruning and training of the branches not pruned to a shape that you want, usually elongated.
A small espaliered fruit tree will often produce more fruit than a large unpruned fruit tree simply because you can better protect the fruit from pests and you don't miss fruit hanging in hidden and hard to get parts of the tree.  They also need much less water and space than a standard commercial sized fruit trees. 

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, such as here in Australia, it is important that at least some of your trees offer you decent shade.

FUNCTION 2 : shade
PHOTO - chicken under Morello cherry tree
Morello cherry tree in the chicken run.   Due to blackbirds I am rarely able to harvest more than 30 % of the crop but the tree provides plenty of shade for the chickens on hot days.
As well as providing food  to eat fruit trees can offer shade for both people and livestock.  But by letting a fruit tree grow to it's more natural size you can cause these problems:-

  • 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.
  • Harder to harvest the crop as you have to get up on ladders to pick much of the fruit.
  • If the tree does produce a full 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 trees that will also offer you shade then there are two things you can do to minimise this problem.
  1. Use ornamental trees that won't require the maintenance associated with apple trees such as pruning, thinning and harvesting.
  2. Plant fruit tree varieties who's fruit either does not, or is less likely attract birds.  Examples being citrus trees, feijoas, quince and some apple trees such as crab apples.

FUNCTION 3 : protection for more sensitive trees
PHOTO - Tangelo and Feijoa trees
Tangelo tree planted next to a Feijoa tree.  The Feijoa tree's bulk acts as a wind break and offers protection against frost.  All citrus trees are susceptible to frost and wind damage.
Trees that are frost sensitive or do not do well in windy conditions often do better when planted along side hardier fruit trees, especially if they are evergreen.

Some examples of hardier trees are  Feijoa and olive trees. 

The tree lucerne (Tagasaste) also does well in this role.  Although it does not produce fruit it is an excellent fodder crop.  Rabbits guineapigs and chickens love to eat tree lucerne leaves.  Tree lucerne also fixes nitrogen into the ground, which the fruit trees next to it will also benefit from.

As well you can also use a variety of ornamental trees for wind and frost protection.

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

This information is based on observations of trees in a backyard in Ballarat, Australia.  The threat posed by birds and weather conditions very greatly throughout the world and what is stated here may not directly apply to your situation.