DRONES are being used to map the best areas to focus rhododendron removal efforts in Scotland’s rainforests.

Forestry and Land Scotland (FLS) has been working for more than 25 years to turn back the relentless tide of invasive rhododendron that is smothering much of the west coast and threatening unique rainforest habitat.

Rhododendron ponticum is an aggressively spreading invasive non-native species that can overpower any woodland and kill off the ground covering plants that serve as the base-layer for habitats.

Forestry Journal: An aerial view of rhododendron An aerial view of rhododendron (Image: FLS)

Colin Edwards, FLS’s national environment manager, said: “We’ve made steady progress in a lot of areas but the two most effective advances in recent years have undoubtedly been that advent of drones and a greater degree of cooperation and improved partnership working.

“The aerial view that drones give us are incredibly valuable in helping us to assess the extent of the rhododendron issue at any given site and helping us to prioritise, plan and execute our treatment operations to make them as effective as possible.

“That unparalleled mapping ability has given us a better picture of what we’re dealing with and has also helped to galvanise opinion amongst our neighbours and partners  that concerted action needs to be taken."

The Alliance for Scotland’s Rainforest is a voluntary partnership of more than 25 organisations – with support from Plantlife Scotland and Woodland Trust Scotland – that is committed to collaborative action for the benefit of Scotland’s rainforest.

Rhododendron removal work across Cowal, The Trossachs and in West Argyll has given FLS valuable, hard-won experience that is now informing its approach to tackling this INNS. 

Over the last decade, FLS has treated invasive rhododendron within approximately 11,000 hectares in the rainforest zone, requiring an investment of some £13.5 million.

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With around 8,000 hectares already treated and now only requiring follow-up treatment, work still needs to be done on around 2,500 hectares within these priority areas.

The old ‘cut and burn’ technique has been superseded by newer, more effective stem-injection techniques that halve the time required to treat an area and, with a 90-100 per cent success rate, significantly reduced the need for re-treatments.

Colin added: "Our approach to rhododendron control in the Rainforest zone is to work at scale and at pace in key priority areas and with as many willing partners and adjacent landowners to tackle this weed and prevent re-seeding into our cleared sites.

“Modern approaches to survey and control activity are vital to enable control efforts to be successful."