Using Fungal Inoculation and Mechanical Modification Techniques to Enhance Wildlife Tree Habitat – Post Treatment Effectiveness Monitoring and Evaluation

The following article summarizes the essay regarding post treatment and evaluation of the project’s effectiveness (Menning 2011), which was originally conducted five years in advance (Menning 2006).

Introduction to the Topic

In British Columbia, around 70 species of birds, amphibians and mammals depend on so called wildlife trees. They are dead or dying trees with particular characteristics, e.g. size, condition and species.
Wildlife trees are often associated with older trees, as they can offer a large size, heavy branching or internal decay. However, oftentimes, wildlife trees cannot be found in second-growth stands, which have formerly been managed without intention for wildlife tree retention, nor in areas where a deprivation of valley bottom habitat has manually removed large areas of lowland forest. That’s why using fungal inoculation and mechanical modification techniques have been used in order to enhance the progress of live tree decay concerning the enlargement of previously mentioned endangered species’ habitat. This article summarizes the post treatment (five years later) of the project.

Background of the Research Project

Wildlife trees are existential for nesting, denning, feeding, perching or roosting. As many endangered or threatened species such as the William’s Sapsucker, Western Screech-Owl, Spotted Owl and Flammulated Owl need mentioned decaying trees in order to survive, it is crucial to find a way to restore their habitat.
The natural amount of time that is necessary to establish a proper wildlife tree can take up to more than a hundred years, whereas the methods used in this and similar projects aim at a  5-15 year span.
In 2006, fungal inoculation and mechanical modification techniques were sampled on 120 trees in different locations in the surroundings of the Bridge-Seton watershed in British Columbia. The project in 2011 is the direct evaluation from 2006.

Methods, Materials and Study area

The procedure of fungal inoculation was inducted by drilling a hole into the chosen tree and applying a dowel, which served as an inoculum provider. Some of the trees were modified by chainsaw techniques.

The evaluation of 2011 focussed on how the sampled trees had altered over five years, whereas three main aspects were considered.

Firstly, the evidence of wildlife use was registered, which gave a direct insight on whether new habitat has been established. Further, any change in tree condition, such as stem damage or breakage, blowdown and internal decay was noted and photographed. In addition to this, the viability of the treatment fungus was inspected by sampling several inoculated trees of each location.

Trees of each location and species were partial-destructively sampled. This process consisted of removing the middle-upper fraction of the stem. This section was cut into either horizontal or longitudinal fragments to get an insight in whether and where the fungal inoculation had spread.
The remaining lower part of the tree (“stub tree”) were re-inoculated twice Fomitopsis pinicola. If the stems still had some live limbs on it, it was ring-girdled below the new inoculation point. This procedure kills the upper part of the stub tree.

Investigated species include Douglas-fir, Ponderosa pine and Cottonwood.

All investigated territories were located west and northwest of Lillooet, BC. Precisely: Cayoosh Creek, Carol Lake, Jones Creek, Carpenter Lake Rd., Marshall Lake rd., Seton Creek and Seton River Rd.
The altitudes of the considered locations ranged from 650-1100m above sea level, mostly directed towards south, southwest and southeast.

Results of the Study

Concerning the Douglas-fir, inoculation mostly evoked minor staining. The decay is in most cases still in early stages, however, a few trees’ decay was more advanced, resulting in stronger staining and noticeable wood softening. Moreover, an enhanced pitch flow could be registered, which showed that the tree tried to get rid of the inoculum. In one of the trees, a woodpecker had begun to build a cavity nest, yet it didn’t succeed due to insufficient wood softening.

The Ponderosa pine showed its reaction towards the fungal inoculum by exuding abundant pitch. The intention was to surround the inoculum dowel with pitch in order to limit the colonization and spread of the fungus. Furthermore, several ponderosa pines had been killed by the mountain pine beetle as the trees showed a significant saprot decay. In addition, they displayed heart rot decay, which is typical of the used inoculum.

The analysis of the cottonwood trees sampled (two exemplars) showed significant staining and wood softening, while one of the trees was killed by fire in 2009. The fungus was well established both trees.

The viability of the fungus throughout the five years could be verified in the laboratory, whereas a further heart rot fungus (Ganoderma applanatum) could be isolated.


The outcome of destructive sampling partially confirmed the effectiveness of the fungal inoculation treatments of 2006.

Regarding the high amount of pitch flow, especially ponderosa pines’, the live trees turned out to be fairly effective at limiting or delaying the progress of decay linked to the inoculation treatment.
Due to the fact that only two trees were inoculated and topped, the efficiency of topping treatment remained inconclusive.
Inoculating and stem girdling combined with destructive sampling killed the upper part of the tree, however, it did not limit the pitch flow towards the inoculum dowel.

  1. pinicola is known for the fact that it colonizes dead wood, therefore, this species is not ideal for future inoculation approaches on live standing trees.

The timeframe of only five years is too short to see more significant modifications. However, it the decay rate was representatively enhanced in comparison with natural decay.


Further effectiveness could be improved by choosing a host-specific species fungi.
In order to reduce sap flow, partial and full-stem girdling should be applied below the inoculum dowels, especially in the treatment of ponderosa pine. In addition to this, ponderosa can be topped in order to create a dead “stub tree”.
In regard of the treatment of cottonwood, effectiveness looks promising, taken that more suitable fungi are chosen. Denning and nesting habitat may be supplied for target species, e.g. fisher and western screech-owl.


Altogether, using fungal inoculation and mechanical modification techniques raises the decay rate on wildlife trees. Provided that a suitable fungus is chosen, the procedure is an efficient means of alteration, which can be used to raise the amount of wildlife trees in for example second-growth stands. This process is essential to restore habitat of species that depend on wildlife trees, since many of those species are endangered or threatened.

  • Source Todd Manning. November 2011. Using fungal inoculation and mechanical modification techniques to enhance wildlife tree habitat – post treatment effectiveness monitoring and evaluation Project #11.W.BRG.10 – 2011 Final Project Report. Prepared by Manning Habitat Enhancement Services, for BC Hydro Compensation Program. Available at : [Accessed 03/2021].