Go­ing for the burn – re­search shows im­pact of burn­ing moor­land heather

Heather burn­ing has been used for gen­er­a­tions to prompt re-growth on moor­land en­vi­ron­ments. Now new re­search has been con­ducted into its value

Western Morning News - - Morning News Country -

Burn­ing patches of heather is com­monly used for moor­land man­age­ment, both here in the West­coun­try and, more con­tro­ver­sially in the north of Eng­land and Scot­land where moors are man­aged for the ben­e­fit of red grouse, a quarry species for shoot­ing in­ter­ests.

A study com­mis­sioned by the Game and Wildlife Con­ser­va­tion Trust used aerial pho­to­graphs and field­work to look at the long-term ef­fect of ro­ta­tional burn­ing on moor­land veg­e­ta­tion.

It found heather cover dropped after a burn, and grad­u­ally rose to al­most com­plete ground cover on ar­eas burnt more than 17 years before. The high­est lev­els of sphag­num moss and cot­ton grass were found on ar­eas burnt be­tween three and ten years pre­vi­ously, and were very low more than 17 years after a burn. The GWCT – a pro­coun­try sports or­gan­i­sa­tion that car­ries out ex­ten­sive re­search into ru­ral man­age­ment – said it be­lieved the re­sults in the pa­per sup­ports other stud­ies which find the high­est cover of sphag­num mosses within ten years of ro­ta­tional burn­ing.

The GWCT re­ports: “Burn­ing is a com­monly used tool to man­age the veg­e­ta­tion on heather moor­land, es­pe­cially but not ex­clu­sively where it is man­aged for red grouse. It is used to stop heather grow­ing too tall and woody, and, after the burn, heather re­gen­er­ates to give new growth, which is con­sid­ered to be more nu­tri­tious and palat­able for grouse to eat. Heather burn­ing for this pur­pose is per­formed in a cy­cle, with dif­fer­ent patches burnt each year in win­ter, with the aim be­ing a quick, cool burn that does not af­fect the peat un­derneath. It gives a patch­work of dif­fer­ent height ar­eas for grouse and other wildlife.

“Ro­ta­tional burn­ing has been a tra­di­tional man­age­ment tool for cen­turies, but re­cently it has been the sub­ject of much de­bate, with con­cern that it can be en­v­i­ron- men­tally harm­ful, es­pe­cially when it is done on blan­ket bog.

“Some stud­ies have found ev­i­dence that heather burn­ing pro­motes heather growth, at the ex­pense of other plant species. But a long-term study car­ried out at the Moor House Na­tional Na­ture Re­serve in the North Pen­nines, run­ning from 1954, showed that car­ry­ing out pre­scribed burn­ing on a ten-year ro­ta­tion in­creased the cover of peat-build­ing species like sphag­num moss and cot­ton grass.

“Sites with longer burn­ing cy­cles had more heather and fewer species that are thought of as peat­build­ing (all plants can build peat, but some do so more quickly than oth­ers).

“Be­cause this study at Moor House has given so much in­for­ma­tion about the im­pact of heather burn­ing, much of what we know in the field is based on its find­ings. It is im­por­tant to look at other sites to see whether the find­ings ap­ply more widely.

“This study looks at the ef­fect of heather burn­ing on veg­e­ta­tion at dif­fer­ent times after burn­ing on an­other moor­land site in the Pen­nines, to test the find­ing from the Moor House ex­per­i­ment on a site that is ac­tively man­aged as a grouse moor.”

The study looked at moor­land which is man­aged for red grouse and has sig­nif­i­cant ar­eas of blan­ket bog. It ex­am­ined how the veg­e­ta­tion re­sponded after dif­fer­ent time in­ter­vals since burn­ing. It found heather cover was low­est in the plots that had been burned most re­cently, grad­u­ally in­creas­ing in cover over time while the cover of sphag­num mosses was low after a burn, in­creased to be high­est in the cat­e­gories burnt three-six and seven-ten years ago, before lev­el­ling and de­clin­ing in the older burns. Cover for cot­ton grasses was low straight after the burn, then rose in the three-six and seven-ten year cat­e­gories and dropped off again in 11-17 to be low in the 17+ year cat­e­gories.

The GWCT con­cludes: “Other pa­pers have rec­om­mended that to main­tain plant bio­di­ver­sity on moor­land, ro­ta­tional burn­ing or cut­ting should be car­ried out when the heather reaches 25cm in height, and that if it is al­lowed to reach 40cm, most other species will be lost and would then have to re­gen­er­ate from the seed bank or re­colonise from other ar­eas after burn­ing or cut­ting.

“This study rep­re­sents the find­ings at only one site, and it was not pos­si­ble to con­sider un­burnt ar­eas for ref­er­ence. It adds to our knowl­edge in the field, and sup­ports the find­ings at nearby Moor House, but more re­search is needed to un­der­stand the sub­ject more fully and at a wider range of sites. This study does sug­gest that in the shorter term after ro­ta­tional burn­ing, it is the peat-form­ing species that ben­e­fit.”

‘Ro­ta­tional burn­ing has been a tra­di­tional man­age­ment tool for cen­turies’

GWCT

Swal­ing on Ex­moor – con­trolled burn­ing of the heather is com­mon in moor­land en­vi­ron­ments across the UKRICHARD EALES

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