Douglas fir growth rates boosted by fungi

Douglas fir growth rates boosted by fungi

The importance of the relationship between fungi and plants has been further validated by a study, details of which were published in the Journal of Ecology. 

The results demonstrate for the first time the connection between the growth rate of adult trees and surrounding fungal networks.

The phenomenon of the carbon, water and nutrient trading between fungi and plants - known as mycorrhiza – has garnered increasing interest during recent years, but so far investigations have focused predominantly on seedlings. This is likely due to the difficulties associated with designing studies that demonstrate causative or correlative links in a dynamic forest ecosystem characterised by many variables.

The new study represents an important first step towards filling significant knowledge gaps in our understanding of mycorrhiza, because it focused on adult plants, rather than seedlings.

Researchers from the University of Alberta were able to demonstrate a positive correlation between certain fungi and higher radial growth rates in Douglas firs, by measuring ectomycorrhizal networks (EMNs) and growth rings over 16 years.

The research also showed that amongst the 350 trees studied, individuals with more connections to many types of fungi, rather than just one or two, exhibited far more vigorous growth.

"We found that the more connected an adult tree is, the more it has significant growth advantages, which means the network could really influence large-scale important interactions in the forest,” said Joseph Birch, who led the study for his PhD thesis at the University of Alberta Faculty of Agriculture, Life & Environmental Sciences.

“These networks may help them grow more steadily even as conditions become more stressful, and could even help buffer trees against death,’ Birch said.

For example: networking with multiple fungi that are stratified throughout the soil profile may enable trees to access scarce water during periods of drought.

Studies of saplings have shown that mycorrhiza networks even enable plants to support one another during times of stress. Resources are sent from ‘source’ to ‘sink’ individuals, which are more resource limited.

Understanding the role of mycorrhizal networks in soil ecology is of increasing interest because it could help in understand tree responses to stress in changing climates.

Birch said he hopes his findings spur further research, to investigate different kinds of forests in different locations, because it’s likely the connections and relationships between trees change over time.

"It's a very dynamic system that is probably being broken apart and re-formed quite a bit, like family relationships, so we don't know how they will change under future climates either. Maybe a dry year or a beetle outbreak impacts the network,” Birch said.

"Knowing whether fungal networks are operating the same way in other tree species could factor into how we reforest areas after harvesting them, and it could inform how we want to plant trees to preserve these networks."

Source: Science Daily


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