Complex Yew Decline Research

Project lead(s)  Dr Caroline Gorton | Forest Research; Prof Robert Jackson | University of Birmingham; Dr Andrew Hirons | Myerscough College
Lead Organisation(s)  Forest Research
Project status  Active
Project funding 25-26  £47,707
Research outcome(s)  Adaptation
Context
A gradual but significant decline of ancient yew trees has been observed in the south of England in recent decades. This decline is characterised by thinning canopies, the retention of 2-3 years’ worth of needles, and the death of lower branches. Often the level of yew midge galls (abnormal growths on yew trees caused by the larvae of the yew gall midge) is quite high. However, no pathogens have been definitively linked to the decline.

This project aims to collect data that will improve understanding of the relationship between the condition of the yew trees, their soil, and microbiome (the microorganisms present in a particular environment). Study sites will be chosen based on the severity of yew tree decline, and in some cases because apparently healthy trees are also present. The sites will also be distributed across England.

Research aims and objectives
Aim:

To assess the condition of yew trees, record their growth responses to moisture availability, analyse the nutrient levels of their soil, and characterise the microbiome.

Objectives:
  • Map the geographic distribution of yew tree decline in selected populations.
  • Characterise the soil conditions and microbiomes that support both healthy and declining yew tree populations.
  • Develop management practices that support yew tree populations.

 

Expected outcomes
  • Data will be produced to improve understanding of the factors causing yew trees to decline.
  • A report will be produced summarising the current status of yew tree decline.
  • Continue monitoring the trees and sites for an additional two years, gathering data to create a timeline of the decline (subject to additional funding).

Larval galls from yew gall midge developed from buds.

Title image: Crown Copyright. Forestry Commission – Isobel Cameron;
Body image: Crown Copyright. Forestry Commission – George Gate

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