Mycorrhizal Inoculation

We at Eco Tree Care & Conservation Ltd have planned and planted large scale tree planting projects where we have worked side by side with soil scientists and horticultural experts. This has given us a broad network of expertise and access to the highest quality mycorrhizal products currently available on the market.

This expertise is essential as there are many products out there that are so general in there mycorrhizal content that they are not necessarily the correct choice for tree and woodland planting. Our planting experience & knowledge of mycorrhizal innoculation gives the best possible start to newly planted trees.

Native hedge planting in North London -
Mycorrhizal inoculation is standard on all
our tree & woodland planting schemes

Trees in a heeling-in bed prior to woodland planting
These trees have been inoculated prior to heeling in.
They will then also be re-inoculated at the time of planting

Mycorrhizal Inoculation & Woodland Planting - The History

In the early days of forestry research into woodland planting & tree survival, inoculation of young trees with mycorrhizal fungi of the Ectomycorrhizal type (EM) (see Mycorrhizal Inoculation - The Biology) involved macerating and liquidizing the roots of ‘donor’ trees. The seedling root was dipped into the slurry prior to planting.
The planting survival results were inconsistent and the preparation also did not have long shelf life.

It was only in the 1980s that EM mycorrhizal fungi were finally cultured on a commercial scale and induced to form spores. One of the first to offer a viable mycorrhizal inoculant for woodland planting was a company called ‘Plant Health Care’ in the USA. The inoculant was based on the species Pisolithus tinctorius, found on more than 100 species of woodland trees and shrubs worldwide. Trials by the company produced increased tree growth rates of up to 200 percent in the seedlings of several pine tree species.

Mycorrhizal fungi are not found in subsoil and dislike disturbed ground, so it is common to find that they are absent from gardens of new-build houses or where there has been recent landscaping. Inoculation of the roots of newly planted tree seedlings can dramatically increase the success of new plantings in such situations. Simply digging over beds or hoeing in a garden can disrupt existing mycorrhizal relationships, so there is certainly no harm is introducing mycorrhiza with the planting of trees and shrubs either singly or as part of a larger hedge or woodland planting project.

A cycle of negative feedbacks is common in gardens: disturbance damages the fungal partners of plants, making them less able to absorb nutrients, so the gardener adds a chemical ‘fix’ of inorganic fertiliser, which is toxic to the fungi, making them even less able to supply the plant. The cycle is self propelling.

This is the situation that modern farming now finds itself in, the living soil system has been killed with chemical fertilisers, pesticides, insecticides, fungicides and so on. The cycle is only being slowly broken by adoption of organic farming practice.

New Woodland and Tree Planting

Mycorrhizal fungi form associations with fine, actively growing fibrous roots, so the fungus need to be physically introduced to this part of the tree. For new plantings the simplest method, now well-established in forestry and landscaping, is to apply a solution containing the inoculant by dipping the roots in a liquid or gel formulation (see below).

This technique is only really suitable for dormant, bare-root trees which are only available between November and early April.

Established Trees

Well-established plants including mature trees can also be inoculated.

On a small back-garden scale this can be carried out simply by ‘pricking’ the soil with a fork all around the rooting zone of a tree and introducing the mycorrhiza by spraying the area with a liquid solution of mycorrhizae using a knapsack sprayer.

A more industrial technique employed is ‘Terravention’ which physically blasts fungal inoculants into the root system using pressurised nitrogen gas, and is particularly valuable in areas that are suffering from soil compaction, as the gas opens up air channels to some depth, such as in sites where there is a lot of pedestrian or vehicular traffic and on building sites.

The Royal Botanic Gardens, Kew reversed the seemingly-terminal decline of several specimens, including some of its oldest trees, with Terravention. A Platanus orientalis planted in the original garden in 1761 and a Sophora japonica from 1762 were both re-invigorated by Terravention in 1997, and a Cedrus deodara, marked for removal since two-thirds of its crown was completely defoliated, greened-up within months of treatment. All three continue to recover well.