Context

A gradual but significant decline of ancient yew (Taxus baccata) trees has been observed in the south of England in recent decades. No disease-causing organisms have been definitively linked to the decline syndrome, although the level of larval galls, caused by the the larvae of the yew gall midge (Taxomyia taxi), is often high.

This project aims to collect data that will improve understanding of the relationship between the condition of the yew trees, their soil, and microbiome. 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.
• Subject to additional funding, a timeline of the decline will be developed through a further two years of monitoring.