You prune an apple tree to motivate strong and sturdy structure (on a young tree); and maintain good condition in addition to encourage fruit production (on a fully grown tree). The most perfect time of the year to prune an apple tree is in late winter or early spring, just before new development starts to sprout. The only thing you have to cut or eliminate in summertime when your tree is actively establishing, is the sucker.

1. A lot of tree roots grow in the leading 60cm of soil. The roots of a tree are important to the health and stability of
the tree.
Roots likewise have requirements of their own. Being below ground they do not have the capacity for
photosynthesis and for that reason can not produce their own carbohydrates that have to be transferred down
from the leaves by means of the phloem vessels simply under the bark. They also respire, which means they
require oxygen. The oxygen comes from the air and makes its way to the roots through pores in the soil which
permit gaseous exchange through pores in the roots called lenticels and along channels in the wood called
medullary rays (the prominent lines you can see in Oak timber). This is why you will seldom discover tree roots
listed below 60cm. The oxygen just does n`t diffuse that far.
Mycorrhizae (significance fungus roots) are a wide range of fungis that have actually developed along with trees.
Basically they grow either into the trees roots (endomycorrhizae) or type sheaths outside (ectomycorrhizae) and
they benefit from the tree's carbohydrates whilst the tree advantages from their higher capability to take up
minerals from the soil. The area where tree, soil and microbes communicate is understood as the rhizosphere.
In the natural woodland environment trees will shed branches and leaves which are broken down by numerous
saprophytic (dead eating) fungis, germs and animals. This increases the amount of natural product in the soil.
Organic matter assists to support soil Ph, increases the nutrient holding capability of soil it also increases the water
holding capacity of free draining soils (sand, chalk etc) and increases the draining capability of soil prone to water
logging (clay). In short it improves soil texture and in the longer term, with the assistance of
http://treemania7.blogspot.com/2018/07/tree-ruffians-when-beautiful-point.html small animals, enhances the
structure. The other outcome of having lots of little animals moving around in the soil is they create channels for
gaseous exchange.
In the garden environment soil can typically be doing not have organic matter. Foot traffic and car traffic (lawn
mowers etc) cause soil compaction which crushes the channels in the soil that tree roots rely on for water and air
to reach them. Fertilizers and pesticides interfere with nutrient levels and poison the tree. All this can make for a
quite hard environment for the tree to grow. Next to roadways or driveways can be far even worse. Soil
compaction can be a considerable issue and salt from winter gritting can trigger serious issues for tree and soil
organisms alike.
Using mulched wood chip can substantially improve the soil conditions over longer periods of time. It's not the
quick fix that fertilizer and mycorrhizal injection offer nor does it deal with compaction as quickly as utilizing an air
spade but in the long run it can supply substantial advantages to trees, shrubs and general soil health. A layer of
mulched wood chip spread over as much of the root crown as is possible and preserved at about 75mm deep will
likely improve the health of your trees in the long term

2. A healthy tree should be able to withstand parasitic fungis. This is based on good soil science, attempting to
recreate the conditions that trees experience in the woods.