Why do copper nails kill trees

Let the tree die - this is how you let it die in a targeted manner

The protection of trees in Germany is expressed in country-specific tree protection statutes, which are among the strictest in the world. However, not all tree species and sizes meet the criteria and fall through the tightly knit mesh of legal regulations. Furthermore, one of the few exceptions can apply to a tree that is actually protected, which makes it unavoidable. If immediate felling is out of the question, affected gardeners decide to let the tree die. This guide explains how you can target it.


Disregard of the tree protection statutes can be expensive

The suffering caused by an undesirable tree should not lead to the regional tree protection statute being ignored. Please first consult the legal requirements under which the removal of trees is permitted in your community. Since the tree protection statutes in Germany are a matter for the federal states, the regulations can differ significantly from one another locally. Violations are punished with heavy fines of up to 50,000 euros.

Usually fruit trees are not protected, with the exception of chestnuts and walnut trees. In some federal states, birches, poplars and willows are also not covered by the protection provisions. In principle, protected tree species are only subject to the tree protection statute above a specified size. In North Rhine-Westphalia, for example, the regulations only apply from a trunk circumference of 80 cm, measured at a trunk height of 100 cm. In the case of multi-stemmed trees, removal is prohibited if a single stem diameter is 50 cm or more. If a tree that is worthy of protection poses a threat, a special permit can be obtained upon application.

Ringeln - method from forestry

In forestry, ringing is traditionally used to remove unwanted trees from the stand. With this method, an approximately 10 cm wide strip of bark and the cambium wood underneath is removed from the lower trunk area. In the period that follows, the tree gradually dies because the flow of sap is interrupted. Specifically, the substances obtained from photosynthesis are no longer transported from the crown to the roots. However, because water and nutrients continue to flow from the roots into the canopy with this approach, the process takes between 12 and 36 months for the tree to die. This is how the procedure works:

The best time is in summer

The months of July and August are particularly suitable for letting a tree die by ringing. At this time, the affected tree has invested much of its reserves in the growth of new shoots. The roots only gradually begin to restore their supplies, so that the tree is weakened at this stage. Since this method does not cause any noise, concentrates on the lower trunk area and a curled tree remains for a few more months, breeding birds in the crown are not disturbed in any way.

Appropriate tools

The ringing is neither associated with risky climbing maneuvers nor with the use of machines. Only the following tools are required:

  • Draw knife (double-handle knife)
  • Wire brush
  • Tear hook or finishing knife
  • working gloves

Since this technology can dispense with the use of a helper, the ringing is widespread in small forest operations due to the low staffing requirements. As soon as chainsaws are used, a second man is always required for safety reasons.


Proceed as follows to make a tree die in a targeted manner by ringing it:

  • Peel off a 5 to 10 cm wide strip of bark with the draw knife
  • Remove inwardly curved pieces of bark with the tear hook or finishing knife
  • Scrape off the cambium underneath with the wire brush

Please ensure that you only remove the bark and cambium. Cambium is the cell division layer between the bark and wood that overlaps the wound in the event of cuts. If the wood is damaged, a rotting process starts, which makes the decaying tree a potential source of danger.

The ever smaller leaves are a visible sign of the gradual death of a tree. While the tree is still standing, the smaller branches fall off first, followed by the larger branches. The entire wood will collapse within 1 to 3 years.

Overview of advantages and disadvantages

As archaeological finds have shown, the ringing was already used in the Neolithic to let trees die in a targeted manner. Given the following advantages, it is understandable that the method has survived to this day:

  • There is no sudden change in the plant society
  • There is no stick rash, like after clearing
  • The entire process is comparable to natural tree mortality
  • Neighboring trees can gradually adapt to the changed wind conditions
  • No use of heavy, noisy machines and therefore no disturbance to breeding birds

Despite the many advantages, there are a few disadvantages to consider when ringing a tree:

  • A long duration of action of 1 to 3 years, sometimes longer
  • Falling branches are a hazard
  • Too deep ringing turns a tree into an uncontrolled source of danger
  • If the cambium is not completely brushed, the tree is preserved
  • Conifers weakened as a result of curling attract bark beetles
Tip: It belongs in the land of urban legends that a tree can die on copper nails. The self-healing powers of trees triumph over an attack with nails made of copper, lead or other toxic substances, in that the injured regions are quickly sealed off.


In addition, the high level of effort entices you to use the chainsaw anyway. This harbors several dangers that call the success of the ringing into question. Either cambium bridges remain so that the tree recovers, or the wood is damaged so that the tree can suddenly fall over. Furthermore, in the middle of the breeding season, the Federal Nature Conservation Act is disregarded, which prohibits any disturbance of birds and small animals between March 1st and September 30th.

Tip: Are you aiming to just kill a stubborn tree stump? Then the specialist trade will have granules with calcium cyanamide (calcium cyanamide) ready for you. The well-known fertilizer disintegrates tree stumps and their roots within 3 to 12 months.

If unwanted trees are not subject to the Tree Protection Ordinance or may be removed according to a special permit, clearing is not always the ideal solution. As an alternative, affected gardeners decide to specifically let the tree go down. They have copied a traditional method from forestry. In order to gently and gradually let a tree die off, an approximately 10 cm wide strip of bark together with the cambium is removed. The flow of sap then comes to a standstill and the wood collapses. This process can take up to 3 years.