What do dendrochronology and other timber-dating methods tell us about the history of English post mills?

Figures & data

Figure 1. Standard post mill design with principal timbers annotated. Based on a drawing of Gransden Windmill by Graham Black. Key: 1 Central main post; 2 Tailpole; 3 Cross trees; 4 Quarter bars; 5 Crown tree; 6 Side girts; 7 Corner posts; 8 Wallplates, or upper side rails; 9 Lower side rails; 10 Weather beam; 11 Windshaft; 12 Sheers

Figure 2. Bourn Windmill (Cambridgeshire). Note the open trestle supported on brick plinths, pitched roof shape and two plain sails (photo: Martin Davies)

Figure 3. Gransden Windmill in its working days in the early 1870s—a rare early photograph of a typical early post mill. Note the open trestle supported on brick plinths, the two plain sails with cloths unfurled and the curved roof shape (photo: Revd Frederick Le Grice. From Gransden Society Archives)

Figure 4. Distribution of surviving post mills in UK (total: 47 mills): With dendro’ data

Without dendro’ data

Table 1. Surviving post mills in the UK and their current designation status

County (and number of surviving post mills)	Name of Mill/Location	Dated	Ordnance Survey grid reference	Status (historic/ rebuilt/new)	Listed Building designation	Date of designation
Bedfordshire (1)
	Stevington Mill		SP 99194 52760	Historic	II*	1952
Buckinghamshire (2)
	Brill Windmill (Nixey’s Mill)	Y	SP 65198 14146	Historic	II*	1951
	Pitstone Windmill, Ivinghoe	Y	SP 94510 15677	Historic	II*	1951
Cambridgeshire (5)
	Bourn Windmill	Y	TL 31189 58005	Historic	I SAM	1962
	Great Chishill Windmill	Y	TL 41321 38843	Historic	II*	1967
	Gransden Windmill	Y	TL 27715 55522	Historic	II* SAM	1983
	Madingley Mill	Y	TL 40795 59513	Historic	II*	1962
	Six Mile Bottom Mill, Burrough Green		TL 58822 58183	Historic	II*	1980
Derbyshire (1)
	Dale Abbey (Cat and Fiddle Mill)		SK 43793 39778	Historic	I	1952
East Sussex (5)
	Argos Hill Mill, Mayfield		TQ 57020 28298	Historic	II*	1953
	Cross in Hand (New Mill)		TQ 55793 21755	Historic	II	1952
	Windmill Hill Mill, Herstmonceux	Y	SK 82086 27946	Rebuilt 2004	II*	1952
	Icklesham (Hogg Hill Mill)		TQ 88713 16025	Historic	II	1961
	Nutley Windmill	Y	TQ 45099 29082	Historic	II*	1973
Essex (7)
	Ashdon (Stevington End Mill)		TL 59522 42537	Historic	II	1967
	Aythorpe Roding Mill		TL 59034 15159	Historic	II*	1967
	Bocking Mill		TL 76307 25967	Historic	I	1951
	Finchingfield (Duck End Mill)		TL 68547 32974	Historic	II	1953
	Ingatestone (Mill Green Mill)		TL 63967 00741	Rebuilt 1959	II*	1952
	Mountnessing Mill		TQ 63099 97967	Historic	II*	1952
	Ramsey Mill		TM 20921 30407	Historic	II*	1952
Greater London (1)
	Keston Mill		TQ 41545 64028	Historic	I	1955
Hertfordshire (1)
	Cromer Windmill, Ardeley	Y	TL 30452 28642	Historic	II*	1967
Kent (3)
	Chillenden Mill, Goodnestone		TR 26899 54238	Rebuilt 2005	II*	1963
	Rolvenden Mill		TQ 83815 31537	Historic	II*	1962
	Stocks Mill, Wittersham		TQ 91304 27305	Historic	II*	1952
Leicestershire (1)
	Kibworth Harcourt Mill	Y	SP 68875 94404	Historic	II* SAM	1986
Lincolnshire
	Wrawby Mill		TA 02607 08753	Rebuilt 1961-65	II*	1951
Norfolk (3)
	Garboldisham Mill		TM 00275 80472	Historic	II*	1958
	South Walsham Mill		TG 379 129	New 1990s onwards	Unlisted
	Thrigby Post Mill	Y	TG 467 122	Rebuilt 1980s	Unlisted
Oxfordshire (1)
	Chinnor Mill		SP 749 010	Rebuilt Q4 20^th century	Unlisted
Suffolk (7)
	Aldringham cum Thorpe (Thorpeness Mill)		TM 46815 59837	Historic	II	1951
	Drinkstone Post Mill	Y	TL 96418 62202	Historic	I	1954
	Framsden (Webster’s Mill)		TM 19181 59753	Historic	II*	1955
	Friston Mill		TM 41131 60114	Historic	II*	1983
	Holton Mill		TM 40226 77444	Historic	II	1953
	Saxtead Green Mill		TM 25336 64426	Rebuilt 1958	II* SAM	1984
	Stanton (Upthorpe Mill)		TL 97133 73299	Historic	II* SAM	1970
Surrey (4)
	Lowfield Heath Mill, Charlwood		TQ 23491 40723	Rebuilt 1980s	II	1991
	Outwood Mill		TQ 32770 45551	Historic	I	1958
	Reigate Heath Mill		TQ 23435 50036	Historic	II*	1951
	Tadworth Mill		TQ 23630 55396	Historic	II	1983
West Midlands (1)
	Mill at Avoncroft Museum (Danzey Green Windmill)	Y	SO 95181 68207	Rebuilt 1970s	II	1986
West Sussex (3)
	Clayton (Jill Mill)		TQ 30366 13368	Historic	II*	1957
	High Salvington Windmill (Durrington Mill)	Y	TQ 12270 06666	Historic	II	1949
	Keymer (Oldland Mill)		TQ 32118 16210	Rebuilt 1990s	II	1957
Total Count (47)

Table 2. Summary totals of types of designations of post mills

		Unlisted	3
Listed Buildings	Listed Building Grade	II	11
		II*	27
		I	6
Total listed			47
Scheduled Ancient Monument (SAM)	of which	SAM	5

Table 3. Post mills where dendrochronological dating investigations have been conducted – in earliest mill date order

Name of Mill/ Location	Main post and other timbers with the oldest dates (if older than MP)	Dates of measured sequence	Sapwood	Felling date range of main post	Felling date range of oldest timber (if not main post)	Dendro method (RW = ring width; O = O^2 isotope)	Reference source
Bourn Windmill	Main post	1402–1503D	–	after 1515		RW	Bridge et al. 2022a
Nutley Windmill	Main post	1410–1529D	5	1533–1565		RW	Bridge 2002
Pitstone Windmill	Main post	1410–1536D	–	after 1545		RW	Miles et al. 2004
Madingley Mill	Main post	–	–	Undated		RW	Carter et al. 1996
	Crown tree	1351–1567D	26(+1NM?C)		1568–1570	RW	Carter et al. 1996
Drinkstone Post Mill	Main post	1464–1586D	21C	Winter 1586/87		RW	Bridge 2001
Kibworth Harcourt Mill	Main post		–	after cal AD 1574-1620		O	Bridge et al. 2022b
	All others	1582–1773	Several C		1773/74	RW	Bridge et al. 2022b
Gransden Windmill	Main post	1496–1619D	?h/s	1628-1660		RW	Bridge et al. 2022c
	Crown tree	1555–1644I			Winter 1644/45I	O	Bridge et al. 2022c
Cromer Windmill	Main post	1568–1678D	14 ?C	?1678		RW	Tyers 1998
	Rear upright	1555–1666D	4		1661–1700	RW	Tyers 1998
Brill Windmill	Main post	1615–1746D	7	1748–1780		RW	Miles et al. 2007
	Meal beam	1585–1685D	23C		Winter 1685/86	RW	Miles et al. 2007
Great Chishill Windmill	Main post	1755–1849D	12	1850–78		RW	Bridge 2015
	Stud	1628–81D	h/s		1693–1726	RW	Bridge 2015
Danzey Green Mill at Avoncroft Museum	Main post	1675–1754D	h/s	1769–1804		RW	Howard 1994
High Salvington Windmill	Main post	Not sampled		Unknown		RW	Moir 2013
	Hurst beam	1769 D	(+11NMC)		1780	RW	Moir 2013
Thrigby Post Mill	Main post	1692–1790D	14C	Late 1790		RW	Fletcher 1984
Windmill Hill Mill, Herstmonceux	Main post	1711–1813D	21C	Winter 1813/14		RW	Bridge 2005
	Cross tree	1754–1812D	14C		Winter 1812/13	RW	Bridge 2005
Stocks Mill, Wittersham	Main post	Undated			undated	RW	Arnold et al. 2003

Sapwood key: h/s = heartwood-sapwood boundary; NM = not measured; C = complete sapwood. Dates with subscript _D indicate ring width derived date; subscript _I indicates oxygen isotope derived date.

Figure 5. Bourn: Scientifically dated timbers at Bourn Windmill, Cambridgeshire. Based on an original drawing by John Reynolds

Figure 6. Nutley Windmill (East Sussex) in 2020 (photo: Martin Davies)

Figure 7. Scientifically dated timbers at Nutley Windmill, East Sussex

Figure 8. Inscribed date of 1627 on LH lower side girt at Pitstone Windmill (photo: Martin Davies)

Figure 9. Pitstone Windmill (Buckinghamshire). Note the full set of four plain (cloth) sails (photo: Martin Davies)

Figure 10. Scientifically dated timbers at Pitstone Windmill, Buckinghamshire. Based on a drawing by John Brandrick

Figure 11. Madingley Mill in Cambridgeshire. Formerly located at Ellington and before that at Easton, both then in Huntingdonshire (photo: Martin Davies)

Figure 12. Scientifically dated timbers at Madingley Mill, Cambridgeshire

Figure 13. Scientifically and typologically dated timbers at Drinkstone Post Mill, Suffolk. Typologically dated phases are marked (T). Based on a drawing by Vincent Pargeter and John Brandrick

Figure 14. Scientifically dated timbers at Gransden Mill, Cambridgeshire. Based on a drawing by Graham Black

Figure 15. Scientifically dated timbers at Cromer Windmill, Ardeley, Hertfordshire. Sampled timbers are numbered. Based on an original drawing by Robin Webb

Figure 16. Scientifically dated timbers at Brill Mill, Buckinghamshire

Figure 17. Two pre-used old timbers that were upcycled during a past rebuild into wall studs in the buck wall at Great Chishill Windmill. Martin Bridge is drilling a dendro sample from one of them, which when analysed showed it was from a tree felled in the period 1693–1726 (photo: Martin Davies)

Figure 18. Kibworth Harcourt Mill, 2016 (photo: Martin Davies)

Figure 19. Dendro samples from main posts of some English post mills: span of ring sequences and estimated felling date ranges. This figure shows the span of the ring-width sequences of main posts from various post mills in England. The coloured section of bar represents heartwood rings, hatched sections represent sapwood rings, and actual or estimated felling dates/date ranges are also shown. Windmill Hill Mill is shown as HRSTMNCX

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