Pulverised Fuel Ash (PFA)

I fell in love with PFA when working as an ecologist for the Central Electricity Generating Board (CEGB, RIP thanks to Margaret Thatcher), exploring orchid-covered sand dunes at the back of the old Rye House Power station (Lee Valley) and realising them to be 30 year old fly ash heaps. (They're still there).

PFA seems an uninspiring material - the ash left over after burning coal powder in a power station.  Left alone it develops an interesting sequence of plants, starting with halophytic (salt-loving) species which tolerate the high levels of salinity in fresh ash.  As it weathers down the salts wash out, and a diverse community dominated by annuals and legumes takes over.  Later on (5-10 years) come the orchids, which can form beautiful and dense clumps, persisting until scrub woodland develops at 30+ years.

My work on this material has included organisation of a conference on its conservation potential (Hatfield, June 1990), studies on its soil development, and introduction of orchids to Tilbury and Drax power stations (by indirect seeding) and a site near Nottingham (rescue relocation).  I have also studied the springtails colonising this material, and found clear evidence of successional changes as bare PFA is replaced by woodland. In June 2013 I showed Fred Pearce around PFA sites in the Thames gateway, and the day was written up in the New Scientist magazine in this article in July 2013 .

Southern marsh orchid Dactylorhiza praetermissa on old PFA



Shaw PJA (2011). Management of brownfield sites for biodiversity Aspects of Applied Biology 108: 179-192.

Shaw PJA (2009). Succession on the PFA/Gypsum Trial Mounds at Drax Power Station: The First Fifteen Years. Journal of Practical Ecology and Conservation Vol. 8 (2) 1 - 13

Shaw PJA (2009). Soil and fertiliser amendments and edge effects on the floral succession of Pulverised Fuel Ash (PFA). Restoration Ecology, 17, 68-77.

Shaw PJA (2003).  Collembola of pulverised fuel ash sites in East London.  European Journal of Soil Biology 39, 1-8.

Shaw, PJA (1998). Morphometric analyses of mixed Dactlyorhiza colonies (Orchidaceae) on
 industrial waste sites in England.  Botanical Journal of the Linnean Society, 128, 385-401

Shaw, PJA (1998).  Classic sites: Nob End, Bolton.  British Wildlife 10, 13-17.

Shaw, PJA (1998).  Conservation Management of Industrial Wastes. Practical Ecology and
 Conservation 2 13-18.

Shaw, P.J.A. (1996).  Role Of Seedbank Substrates in the Revegetation of Fly Ash and Gypsum in
 the U.K.  Restoration Ecology 4 (1), 61-69.

Shaw, P.J.A. (1995).  Establishment of sand dune flora on power station wastes.
 Land Contamination and Reclamation 3 148-149.

Shaw, P.J.A. (1994).  Orchid woods and floating islands - the  ecology of fly ash.  British Wildlife
 5, 149-157.

Moffat, A.J. & Shaw, P.J.A. (1993).  Establishment of trees on mixtures of pulverised fuel ash and
 gypsum.  I.  Tree performance.  Land Degradation and Rehabilitation 4 87-97.

Shaw, P.J.A. & Moffat, A.J. (1993).  Establishment of trees on mixtures of PFA and gypsum.  II.
 nutrition and trace elements.  Land degradation and rehabilitation 4 123-129.

Shaw, P.J.A. (1992).  Successional changes in vegetation and soil development on unamended fly
 ash (PFA) in southern England.  Journal of Applied Ecology 29 728-736

(Shaw, In press - possibly for ever!).  Nature reserves, orchids and fly ash: the dynamics of Dactylorhiza colonies during ecological succession.  In The Ecology of Urban Environments: Proceedings of a conference 6-12-2003, Sheffield.

last modified 15-07-2013
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