Advanced laser systems reveal hidden carbon in Ireland’s hedgerows and woods

EPA funded research has found that hedgerow and woodlands in Ireland could make a significant contribution to reducing the amount of carbon in the atmosphere. Using Laser Radar, known as LiDAR, the project has provided amazing detail about the amount of carbon stored in Ireland’s hedgerows.   The LiDAR system scans a hedge picking out its detailed structure and providing a precise image of the plants that make up the hedge.   This detail is then processed to estimate the amount of carbon contained in the hedgerows. 


The work was carried out by Dr. Kevin Black of FERs Ltd, in partnership with researchers from Teagasc and Treemetrics Ltd, an emerging company in this new field.


The research shows that hedgerows and wooded areas of Ireland are a small but significant carbon store.  Better management of hedgerows may contribute further to the removal of carbon dioxide from the atmosphere.  LiDAR and other high tech remote sensing technologies can enable us to quantify this in a cost effective manner.


Dr Frank McGovern, Head of Climate Change research, Environmental Protection Agency, said:

“This research is relevant in two ways; firstly it shows how advanced technologies can be used to measure carbon stocks in the Irish landscape in a cost effective manner.  Secondly, it also quantifies one of the key ecosystem services of hedgerows in taking up carbon dioxide and storing it as biomass.

“Remote sensing technologies are emerging as a powerful tool for environmental monitoring. The EPA and Ireland needs to be at the forefront of using these in challenging areas such as land management and climate change.”

Hedgerows are estimated to cover approximately 4 per cent of the Irish landscape (~270 kilohectares). The Rural Environment Protection Scheme (REPS) facilitated the planting of 10,000km of new hedgerow and rejuvenation of some 3,000km more. However, other pressures may have led to loss or degradation of other hedgerows.


A full hedgerow assessment is needed if Ireland is to use hedgerows as part of actions to address the causes of climate change.  This would need to be linked to appropriate incentives towards better management of this important resource. A key recommendation of the report is that institutions and government departments in Ireland should develop a coherent strategy for effective use of various Earth Observations data.


The report notes that LiDAR data has multiple uses beyond the immediate focus of this study.  It urges more efficient and effective gathering and sharing of such data to maximize the return on investment.


How the technology works:

Light Detection And Ranging (LiDAR) and Terrestrial Laser Scanning (TLS) are similar to RADAR in operating principle, but use light signals in the near infra-red. LiDAR and TLS transmit pulses of light and determines the distance of objects from the time it takes for the reflection to bounce back from, the object to the receiver. 


Key outcomes: 

  • Preliminary estimates suggest that hedgerow and nonforest woodlands could potentially sequester 0.66–3.3 t CO2/ha/year.
  • A national, LiDAR-based, inventory of hedgerows is feasible and would be cost-effective based on market price for CO2 greater than €6 t-1 CO2.
  • It is recommended that additional research and inventory capacity are developed to order to  include hedgerows into the National GHG inventory 

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