Gnawing prevention on individual trees

Removing gnawed trees or vegetation

To prevent beavers from foraging along a river bank or if gnawed trees pose a risk of falling, it may be considered to remove them through controlled felling. Removing existing woody vegetation may also reduce the risk of beavers digging in a vulnerable bank (Figure 1).

Permit requirements

Whether a permit is needed depends on local legislation and regulations and the ecological impact of the removal. Especially if beaver territory or foraging area is impacted and/or other plant and animal species are affected. Always check with local authorities before proceeding.

Mitigating factors that may support permit approval or make a permit unnecessary:

Only a few trees are removed.
Felled trees are left accessible to beavers (e.g., near the shoreline).
Leaving trees in place can help reduce further gnawing. Beavers are more likely to use the felled tree and less likely to target others.
Vegetation is replaced or compensated elsewhere in the same territory.

Removal woody vegetation Waalwijk - V. Dijkstra — Figure 1: Removal of woody vegetation from the riverbank. © V. Dijkstra

Considerations

Removing vegetation cannot completely prevent beavers from digging, as many burrows and several lodges have been found in areas without woody vegetation, although it can reduce the likelihood of burrowing at that location.

These measures are most effective when combined with offering an alternative site that is highly suitable for constructing a burrow or lodge. This further decreases the burrowing pressure on the bank where it is undesirable.

Anti-gnawing paste

Individual trees that have not yet been significantly gnawed can be treated with an anti-gnawing paste, such as Wöbra. This is a non-venomous paste that consists mainly of quartz sand. The growth and sap flow of trees is not affected by this paste and it looks transparent after it has dried.

When choosing and using an anti-gnawing paste, ensure it is non-toxic and does not impede the growth of the trees. Consider the application instructions, the effectiveness of the paste, and the duration before reapplication is needed.

Constructing mesh around trees

Individual trees that have not yet been significantly gnawed, can be conserved by using anti-gnawing mesh around the trees. Standard chicken wire could provide some protection, but is not always fully effective. If the mesh is too light or not secured enough, beavers could remove it and start gnawing anyway. This is most likely to happen if there are no or insufficient alternative food sources in the area.

More effective alternatives to chicken wire include woven wire (e.g. sheep fencing) or chain-link fencing. To prevent beavers from removing or pushing up the mesh, it is recommended to firmly secure it with ground pins.

Mesh around trees - D. Gow — Figure 2: Construction of mesh around individual trees to prevent beaver gnawing. In this picture, the used mesh material is actually too thin to properly protect against beavers. © D. Gow

Mesh around trees- radial growth - D. Gow — Figure 3: Mesh with metal tension spring to provide room for radial growth of the tree. © D. Gow

Specifications:

Minimum mesh size: 2.5 x 5 cm
Minimum wire thickness: 2 mm (to resist gnawing)
Recommended height: up to 1 metre

When constructing mesh around trees it is possible to provide room for potential radial growth of the trees by using a metal tension spring. The mesh should then be checked every few years to make sure it still functions properly.

Providing other tree species

To prevent beavers from gnawing on particular trees and shrubs in a certain area, placing attractive tree species - such as willow and poplar - in other adjacent areas can help to reduce the foraging pressure on particular trees.

Local experience

Below you can find experiences of this measure in different countries. If you want to contribute your own experience or additional information, please share your knowledge with us.

Czech Republic. Anti-gnawing paste

The effectiveness of anti-gnawing pastes depends on several factors, including the age of
the treated tree, tree species, local food availability, and individual beaver behavior. Czech
field experience shows that these pastes cannot be considered universally reliable.

In one monitored case in the Czech Republic, 73 newly planted young crack willows (Salix
fragilis) were treated with the anti-gnawing paste Wöbra. Over the course of three winter
seasons, 48% of the treated trees were damaged by beavers. The affected trees belonged to
a highly preferred food species and were young, vigorously growing individuals, which likely
increased their attractiveness despite the treatment.

Additional observations indicate that even where food availability within a beaver territory
was high, beavers were sometimes able to overcome the deterrent effect of the paste. In one
such case, treated ash trees were stripped of their coated bark, after which the underlying
cambium was gnawed (Figure 1).

Conclusion

These findings indicate that anti-gnawing pastes likely have a certain deterrent effect;
however, the degree of effectiveness cannot be reliably predicted in advance. In combination
with the financial costs and the need for regular reapplication, typically after one year, the
overall cost-effectiveness of this measure remains uncertain.

Ash Wobra - J. Uhlikova — Figure 1: Wöbra treated ash tree stripped of its bark. © J. Uhlíková

Czech Republic. Capsaicin-based repellent

In the Czech Republic, a capsaicin-based repellent derived from chili peppers
was tested in the form of a surface coating as a potential measure to reduce
tree gnawing by the European beaver. The effectiveness of this approach was
evaluated in a field experiment conducted during two winter seasons
(2023/2024 and 2024/2025).

The coating was tested using willow sticks placed directly within active beaver
territories. In total, 500 willow sticks were installed across multiple sites, with
250 sticks treated with the capsaicin-based coating and 250 left untreated as
controls. Despite testing different concentrations of the active substance, the
results showed no statistically significant deterrent effect of capsaicin on
beaver gnawing. Beavers consumed or gnawed both treated and untreated
sticks at comparable rates.

These results indicate that capsaicin-based coatings do not reliably deter
European beavers from gnawing woody material under field conditions. Based
on this evidence, capsaicin-containing coatings cannot be recommended as an
effective stand-alone mitigation measure for reducing beaver-related damage
to trees.