In order to take care of a tree, one must first know its importance,
its significance, and its biology. Today, the tree is a vital
environmental factor and an essential design element that we must
care for and protect accordingly.
There is no life without water. Ideally, the water supply comes
from the natural environment of the tree. It is very dependent
on the soil structure and the habitat. There are always cases
where artificial watering is necessary, for example, with a too
small tree span, during the first five years after being planted,
when a tree needs sufficient soil moisture, or for trees whose
root area has been diminished by construction. The water quantity
that is artificially supplied to the tree should not exceed the
annual rainfall of 600 mm. For hardwoods the irrigation period
spans from April to the end of September, for softwoods until
the first frost. When possible, rain water should be used to water
trees.
Fertilizer should only be used if there is a need for it. Only
long-term fertilizers or special root fertilizers should be used.
The use of root fertilizers promotes root growth, and the tree
develops new soil areas due to the root growth. By using long-term
fertilizers, the tree is supplied with nutrients over a long period
of time, and the washing away of nutrients is also simultaneously
decreased because the tree does not have an excessive need for
nutrients.
In principle, the emphasis should be placed on maintaining healthy
trees as opposed to battling symptoms of illness. When planting
new trees, the greatest importance is therefore placed on the
correct selection of tree type and the creation of a tree-friendly
habitat and growth conditions. For older trees, the tree environment
should be optimized so that the best possible growth conditions
are created for the tree.
Pruning helps develop and maintain healthy and sturdy trees.
The natural appearance of the tree, its habitus, may not be destroyed
by the pruning - unless one is dealing with special crown shapes,
which can be kept constant through topiary pruning at short and
regular intervals.
Live branches are cut parallel to the branch collar. If no branch
collar is visible, the cutting angle is defined as the inverse
course of the branch bark ridge.
Dead branches are removed without harming live branches. The cut
is made close to the best developed branch collar.
The thickness ratio between a lateral branch that must be removed
and leader branch should be maximally 1.5:3.
When a leader branch is deflected, the diameter of the lateral
branch, as a new leader branch, should exhibit at least a third
of the leader branch thickness.
Formative pruning aims to develop a stable tree crown that is
well-matched to the habitat for young trees. Above all, one must
make sure to achieve a balanced and stable crown structure. The
trees should be grown so that the crown has a continuous leader
branch and a subordinate lateral branch. For trees in the street
area, the clearance must be established early on and in several
stages. For tree types that have problematic leader branch development,
especially intensive formative pruning can be necessary. Leader
branch development can also be supported by wooden slats, so that
the branches are pulled into the correct position.
In order to retain or create the required clearance, branches
are removed or cut back in the lower crown area. Creation of clearance
is begun with a young tree and continued over several years, step
by step, until the required height has been reached. Specifications
regarding the height of the clearance should be inquired about
at the appropriate location.
To ensure safety, all dead and broken branches with a diameter
of 2 cm and more are removed from the tree crown. No other corrections
of the crown are implemented during this maintenance process.
In most cases, this type of pruning is combined with maintenance
pruning.
Maintenance pruning increases the health of the treated trees.
Possible sources of infection and severely damaged branches are
removed. In most cases, this type of pruning is combined with
deadwood pruning.
Ihrough targeted removal of individual branches that have a diameter
of at least 5 cm, the crown is thinned out. This ensures the infusion
of light in the crown and prevents the crown from balding on the
inside due to a lack of light. Crown thinning should not be done
to an excessive degree, because as the old saying goes, less is
more.
In order to ensure road safety, the weight, levers, and wind
loads of crown parts that are in danger of breaking are reduced
by cutting back and removing lateral branches. If extreme intervention
is needed, then this should ensue over the course of several years.
The rule of thumb is as follows: The leaf mass of the individual
tree may only be reduced by one-third, so that the carbohydrate
supply by the leaf mass continues to be ensured.
Topiary pruning forces an unnatural crown shape. Topiary pruning
is solely based on esthetic criteria and has its origin in the
established architectural garden tradition.
Topiary pruning means cutting trees to form different shapes.
In order for these trees to retain the desired shape, regular
pruning is necessary. They are pruned annually, or at least every
two years. Due to the small cutting distances, the cutting surfaces
are kept small. When a shaped tree has not been pruned for several
years, it is not sensible to cut it into its old shape within
the time span of one year. The reshaping must take place over
several years .
