Peatland ACTION - Technical Compendium - Restoration - 9 Scrub removal

General Guide 

•    Scrub/woodland removal is only carried out on sites under Peatland ACTION where it can be demonstrated that wider restoration activities are being carried out to improve the ecology and hydrology of a peatland. Without these improvements it is likely scrub removal will be an ongoing, costly requirement.  

•    In other scenarios, consider whether the management options and capital items under the Agri-Environment Climate Scheme (AECS) are sufficient.

•    Consult local Scottish Forestry conservancy because in some situations you may need a felling permission.  

•    Check first that the scrub is not of conservation value, e.g. Supporting guidance for Managing Scrub of Conservation Value. In peatlands, scrub is generally regarded as having a negative effect on the underlying peatland vegetation and hydrological functions, there can be cases where the scrub is a valuable habitat. 

•    Consider bird breeding season in decisions around timing of scrub control.  

•    In addition to removal of the scrub, the seed source should be eliminated and the hydrology of the site addressed by other restoration techniques in order to reduce the incidence of scrub regeneration. 

Aim of the technique 

To remove scrub where this is of no conservation value, and where the continued presence of scrub contributes to the dry or drying condition of the peatland (See Section 9 for further background). 

Terminology 

Definitions are as follows (from: Supporting guidance for control of scrub and woody vegetation - Scottish Government Rural Payments Services website)

Light scrub: 50 % or more of the scrub or woody vegetation is less than 1.2 metres in height and a grazing understory is clearly visible. Scrub stems are typically no more than eight centimetres thick. 

Intermediate scrub: 50 % or more of the scrub or woody vegetation is more than 1.2 metres in height and there is limited grazing understory. 

Heavy scrub: 50 % or more of the scrub or woody vegetation is more than 1.2 metres in height and there is no, or very little, grazing understory. Mature gorse fits within this category. 

 Best practice 

• Light Scrub: cut the scrub as low as possible to ground level, or remove manually by pulling the roots out if small enough. Hand pulling can cause ground disturbance that encourages further germination of scrub, so it is only appropriate where seedlings are small, and thinly spread. The surrounding vegetation should be pressed down after removal. 
• Intermediate & Heavy Scrub: cut the scrub as low as possible to ground level, or mechanically uproot (see also section 8.4 - on ground smoothing).   
• It may be possible to flail or mulch dense scrub (gorse and rhododendron) at the edge of a site. If a mulcher is used, the cuttings can sometimes be collected and burnt on corrugated sheets or composted. 
• Conifers: stumps should be cut below the bottom whorl of branches. This ensures that herbicide treatments are not required. 
• Broadleaves: treat cut stumps >1.5 cm diameter with glyphosate, by wiping or other targeted method (and, if re-sprouting, 2 years after cutting).   
• Leaving cut vegetation on site following control of intermediate or heavy scrub is not always appropriate for nutrient sensitive sites, or where regeneration of underlying vegetation is required.  Where large amounts of scrub are to be cut it may be preferable to remove the cut material from the site.  
• However, in some cases, it may be less damaging to fell to waste some or all of the scrub and to leave the cut material to be gradually incorporated into the peatland surface, rather than extracting it. Where this is the case, felled material should be cut into one metre sections, snedded and left lying flat on the surface. This promotes rapid inclusion in the bog. Cut material may be used to infill drains, using the trunks to weigh down brash. 

Appropriate Machinery  

• Usually carried out by hand with chainsaws or loppers. 
• Hand cutting and lopping may be appropriate for clearing small areas. For larger scrub control projects brush cutters and chainsaws are effective. 
• Brush cutters can be used on scrub with a basal diameter up to five centimetres, for larger scrub a chain saw is more efficient.  
• Chainsaw work is a high-risk activity, which could have additional risks on peatlands, such as the escape route being soft or not as available. 

When most likely to succeed 

• When carried out in conjunction with efforts to raise the water table and removing any other modifications.  
• When appropriate removal techniques are followed. 

When most prone to failure 

• When carried out in isolation and not as part of a wider restoration plan to raise height of water table.
• When appropriate removal techniques are not followed.  

Points to Remember 

• Areas that have been cleared can regrow into dense, impenetrable scrub within a few years. It is essential that you undertake follow-up treatment to tackle any regrowth.  
• Spraying of herbicide to kill trees is not regarded as a desirable method, since cutting conifers below the bottom whirl of branches always kills them.  For killing native trees or rhododendron, consider the justification carefully.
• If spraying herbicides within one metre of the top of the bank of a watercourse or near water, the spray operator must have SEPA authorisation. 

See our technical compendium for other techniques in the series.

Peatland ACTION Project Officers are available to help you with your project. Please contact us as at [email protected] to be put in touch with your local Officer.