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The fungus kingdom is large and diverse with around 1.5 million species. As well as some of the more characteristic woodland toadstools, it includes microorganisms such as yeasts and moulds.

Fungi are more closely-related to animals than plants and you can't often see them. Their main part is a complex mycelial network made up of thin branch-like hyphae that runs through the soil, leaf litter, wood and living plant tissue. The Earth’s largest living organism is a honey mushroom due to its mycelium which covers 965 hectares in the US!

They become more noticeable when fruiting as mushrooms or moulds. This is when you'll see the characteristic toadstool or mushroom.

How trees benefit from fungi 

  • Many fungi grow a mycorrhizal network around plant roots. It's like a second root system giving them greater access to water and minerals.
  • Most fungi are decomposers, making them essential recyclers. They break down dead tissues and return essential nutrients back into ecosystems.
  • Some fungi cause serious infections in plants and animals. Ash dieback is caused by the Hymenoscyphus fraxineus (previously known as Chalara fraxinea) fungus. The spores from this are spread by the wind and the movement of infected material. Find out more on our pests and diseases pages