This project aims to investigate what the potential effects of a changing climate, particularly increased temperatures, might have on the population dynamics of the insect pests associated with the UK’s most widely planted conifer tree species, Sitka spruce. By establishing experimental plots over a range of elevational gradients (and hence temperature/climatic gradients) in Sitka spruce forests in Wales, and by using a variety of insect trapping techniques, the current project will investigate how indigenous pests of Sitka spruce are likely to respond to projected changes in temperature and precipitation.

Research objectives

The key objectives are to identify the influence of temperature and precipitation on:

• Bark beetle population dynamics, particularly abundance and population densities, timing of emergence and flight periodicity.
• Other insect pests of Sitka spruce, particularly defoliating insects including the primary pest of Sitka spruce, the green spruce aphid ( E. abietinum), along with sawflies and Lepidoptera pests (e.g. Epinotia spp.).
• Response of natural enemies, particularly those associated with the green spruce.

Results so far

Insect sampling was conducted over a three-year period (2013-15) and has revealed that most insect pests associated with Sitka spruce are generally higher at lower elevations, where temperatures are on average are a couple of degrees warmer than experimental plots at higher elevations. In addition the natural enemies associated with some of these insect pests (particularly the green spruce aphid) were also higher at the lower elevations, which is interesting since they may be influential in the population dynamics of some insect pests in some years. However, the insect material collected from this study is still being processed, with specific groups of insects being identified down to family or species level.

Status

Insect sampling for this project was undertaken over a three-year period (2013-15). A vast amount of material was collected over the three-year sampling period and the insects from these samples are still being processed and identified. The bark beetle data set collected from the study is currently being analysed, with initial outputs from the project expected in 2018-19.

Related Resources

Impact of pests and pathogens under changing management

Impact of insects on tree growth

Combating climate change – a role for UK forests

Biosecurity Programme Board

Contact

Dr David Williams

Funders and partners

This research is currently funded by the Forestry Commission under the programme, Advice and Scientific Support for Tree Health

Forestry Commission policy
This research underpins the evidence base for the delivery of healthy and resilient forests and wider ecosystems which is part of the Tree Health and Plant Biosecurity Action Plan