The Impact of Charcoal Iron Production on the Landscape of the South Lakes, Cumbria (UK) During the Eighteenth Century Using Archival Material Combined with Remote Mapping Techniques

ABSTRACT

The history of the charcoal iron trade in the Southern Lake District in Cumbria, England is well recognised, with activity controlled by a very small number of iron production companies intensifying during the eighteenth century. This activity, from the initial extraction of the ore, through the development of a transport infrastructure and the construction of furnaces, to the management of woodlands for charcoal production, has left its mark on the landscape. A wealth of untapped information is held in the region’s documentary archives, which provides data on the iron production companies themselves, primarily via account books and associated documents. These records include detail on the charcoal bought in—not only the dates and precise quantities, but the names of the source woodlands and even the names of the individual producers themselves. Using GIS, these sources have been examined in combination with remotely sensed data to provide new evidence of the impact of the iron trade on the woodlands of the Lake District. The results demonstrate that charcoal production was so vital to the iron industry that the woodlands were carefully and sustainably managed, the legacy of which we enjoy today.

KEYWORDS:

• Charcoal
• iron
• archives
• woodland
• GIS
• remote sensing

Introduction

Iron Production in Furness

The Furness area has long been an attractive location for iron production. The presence of extensive deposits of haematite, a low-phosphorus and rich iron ore, combined with abundant woodland for charcoal and a plentiful supply of waterpower, has meant that iron production has long been in existence, dating back possibly to the Iron Age, Roman or Anglo-Saxon periods (Bowden 2000). By the medieval period iron production was well-established, with Furness Abbey by 1273 holding sole rights to make iron (Bowden 2000), accompanied as a result by an equally well-established tradition of coppicing for charcoal manufacture.

The eighteenth century witnessed the introduction of advanced techniques of iron smelting and processing in the Furness area. The bloomery technique, whereby iron was smelted in a charcoal-fuelled hearth at a bloomsmithy (Newman 2007), was replaced by the more efficient blast furnace (Marshall and Davies-Shiel 1969; Bowden 2000). (For a description of the types of iron and production processes, see Historic England 2015). The main problem with a bloomery furnace was that the iron never reached a temperature high enough for it to be drawn off as a liquid and therefore the furnace had to be shut down to remove the bloom. Blast furnaces on the other hand enabled continuous iron production as both the iron and the slag melted into a liquid form that could be drawn off at the base of the furnace without the need to shut down the furnace (Marshall and Davies-Shiel 1969).

Eight blast furnaces were constructed in Furness between 1711 and 1748 (Figure 1) (Bowden 2000). The first two began production at Backbarrow and Cunsey in 1711 (Fell 1908), although the first furnace in Cumbria as a whole had apparently been operating at Cleator between 1694‒6 (Schubert 1957). The furnace at Backbarrow was established by two ironmasters from the Furness area, John Machell and William Rawlinson, who established the Backbarrow Charcoal Iron Company. According to the Ulverston historian Alfred Fell (1861–1942), who had spent his working life as a clerk and eventually manager of one of the larger iron-making companies, the Backbarrow Company quickly purchased mining leases and old bloomery forges and built a second furnace at Leighton near Carnforth in 1713 (Fell 1908, 209). The furnace at Cunsey was established by the Cunsey Company led by three ironmasters from Cheshire and Staffordshire, Edward Hall and Daniel and Thomas Cotton (Miller 2005, 2007). Further furnaces were established at Nibthwaite (1735–6), Duddon (1737), Newland (1746–7), Lowwood (1747) and Penny Bridge (1748). As the furnaces at Backbarrow, Leighton, Duddon and Penny Bridge were owned to a greater or lesser length of time by the Backbarrow Company, the surviving accounts shed considerable light on their charcoal consumption.

Figure 1. Eight blast furnaces were built in the Furness region between 1712 and 1747. Backbarrow Furnace was in production for the longest, from 1712 to 1967. For just 8 years between 1747 and 1755 all 8 were in production. (Based on Bowden (2000), and the Land Cover Map 2019 © UKCEH 2020. Contains Ordnance Survey data © Crown Copyright 2007, Licence number 100017572).

Charcoal Production

In addition to a useful description by Fell (1908), we are fortunate that a film by the prolific Burnley filmmaker Sam Hanna (1903–96) shows Jack and Bill Allonby undertaking a typical charcoal burn in the Furness area (Hanna 1973). A place in the wood was prepared by levelling the ground to create a charcoal burning platform (CBP), sometimes termed a pitring or pitstead, a circular platform of between 20 and 30 feet (6 and 9 m) in diameter. If the slope was steep, then the levelling required revetment on both the upslope and downslope sides of the platform. The ground had to be free of mole hills or rabbit holes to prevent air getting into the stack so that the burn would be slow and not ignite into flame. CBPs tended to be set in sheltered places to avoid exposure to even slight winds. Wind breaks or hurdles constructed of coppiced wood and bracken controlled the air flow. Charcoal production had to be close to a water supply as it was important to use water to cool the stack slowly towards the end of the burn. Fifty to sixty gallons of water for cooling was not unusual.

Fell says that the wood cutting would take place during the spring and summer with wood cut into lengths of two and three feet (60 and 90 cm) depending on its thickness. Charcoal burners, sometimes referred to as ‘colliers’ or ‘coalers’, preferred coppiced wood of ash, alder, hazel, or birch. Jack and Bill Allonby (Hanna 1973) used coppiced wood or underwood between 13 and 15 years old whereas Fell writes that between 15 and 25 years was the usual growth allowed but 14 years was sufficient (Fell 1908, 132). In late summer and autumn, the charcoal burners would begin building the stack by constructing a tripod of timber ‘shanklins’ three feet long (90 cm) and three to four inches (7.5 to 10 cm) in diameter in the centre of the platform. A centre pole or ‘motty peg’ provided a central pivot around which the cut wood was then stacked, the central pieces being almost vertical and gradually increasing in inclination as the concentric rings increased in circumference. A second layer of wood was added on top, again arranged vertically near the centre followed by another layer laid horizontally. Smaller pieces of wood followed by soil and grass turves filled the gaps to seal the whole stack. About one ton of finely sifted soil ensured a tight seal to prevent air entering the stack and thus speeding up the burn.

The burn was started by lifting out the motty peg then dropping hot charcoal into the centre of the stack. A cap sod filled the gap left by the motty peg. The hurdles were set up and moved around to stop draughts. This was day and night work with the hurdles being moved constantly and more soil added if the burn was accelerating too fast at any point. Water was added, not to put out fire but to make steam to slow the burn and eventually stop it. Sod rakes were used to pull off the sods as the burn ended and water added very carefully to control the cooling. More soil would be added, and water carefully sprinkled over the stack using shallow dishes known as ‘says’.

The stack would take several days to cool. Jack and Bill Allonby estimated that 7 tons of wood would yield 1 ton of charcoal, the resulting charcoal being carefully loaded into sacks of 5 ft × 2 ft holding an estimated weight of between 25 and 30 kg before being carted away. It is worth noting here that the figure for the sack size is rather small in comparison to those stated elsewhere for the eighteenth century. In comparison, using figures provided by Fell (1908) and Armstrong (1978), the typical weight of charcoal can be estimated to be between 70 and 75 kg per sack or between 840 and 900 kg per dozen sacks.

Given the dependence of the Furness iron industry on charcoal and consequently the surrounding woodland, the impact of the industry on the landscape was likely to be profound.

Aims and Objectives

Whilst the broad industrial archaeology and history of the South Lakes is well recognised (Bowden 2000; Marshall and Davies-Shiel 1969, 1971), there is little understanding of the scale and impact of the iron industry on its landscape and, particularly, its woodland. Mapping the location and quantity of charcoal produced and consumed would provide new evidence of the impact that the industry would have had on the woodland. The longevity of the charcoal iron industry—into the beginning of the twentieth century—suggests that management of the woodlands was, to a degree, sustainable. How this was achieved is of great interest and could inform current and future methods of woodland management.

The primary objective of this study was to develop a methodology to support the evaluation of the impact of the charcoal iron trade on the landscape of the South Lakes. This included the transcription of a sample of archival records, in this case, those contained in the Backbarrow Company account books of 1731 to 1743, then entering them into a spatial database (GIS) and mapping the results. A key part of the work was to link these archives to the evidence provided by the mapping of charcoal platforms using LiDAR imagery. These results were interpreted to evaluate the impact of the iron industry on the woodland during this defined period.

Background

This paper builds on two research projects carried out by Historic England. The first is the Upland Pilot project of the National Archaeological Identification Survey (NAIS), using data derived from aerial photographs and LiDAR as part of an iterative process of field survey, geophysical survey, excavation, palaeoenvironmental work and scientific dating to understand the archaeology of upland areas (Oakey et al. 2015). The second is research carried out in the 1990s by the Archaeological Survey and Investigation (AS&I) team, mapping the physical remains of ironworks and related industries in and around the South Lakes, Cumbria (Bowden 2000; Jecock et al. 2009).

The NAIS Upland Pilot included archaeological investigations of post-medieval CBPs in Barbondale, Cumbria (Hazell et al. 2017; Hazell and Crosby 2023). The wood charcoal was analysed in detail, to identify the wood types used, and to look for evidence of past woodland management regimes. Subsequent work on documentary archives at both the Cumbria Archives at Barrow-in-Furness, and the Lancashire Archives in Preston established a clear link between the CBPs and the charcoal iron industry of Furness and, in particular, the potential of Backbarrow Charcoal Iron Company’s (hereafter the Backbarrow Company) documentary records to inform further research on the exploitation and management of woodland in the South Lakes (Pearson 2020, 2022).

Data Sources and Methods

The Archives

At the Lancashire Archives (Lancs. Arch.), the company accounts form part of the business records (Muniments) of the Machell family of Hollow Oak in Haverthwaite and Penny Bridge (Lancs. Arch. DDMC 30). Company journals survive in an almost continuous run from 1728 to 1744 together with Backbarrow Furnace bar iron ledgers dating from 1735 to 1745 and cast-iron ware ledgers for 1737 to 1742.

This study focuses on the input and analysis of the Backbarrow Company journals from 1731 to 1742 (Lancs. Arch. DDMC 30-2 to DDMC 30-9). Unfortunately, this is not a complete run as accounts for 1732–3; 1733–4; 1737–8; 1739–40 are missing. Nevertheless, account books survive for eight of the twelve years and in a wealth of detail as described below. Photographs of pages of the account books were taken where any reference was made to charcoal.

LiDAR Data

Data for the CBP mapping took the form of the Light Detection and Ranging (LiDAR) composite digital terrain model (DTM); a raster elevation model at 1 m spatial resolution with a vertical accuracy of ±15 cm RMSE. GeoTiff files in 5 km grids were downloaded then imported and mosaicked using Relief Visualization Toolbox (RVT 2.2.1) (Kokalj and Somrak 2019). RVT offers a variety of visualisation techniques for high resolution digital elevation models (DEMs). The mosaicked slope gradient images were then imported, and the platforms digitised using ESRI’s ArcGIS Pro®.

The interpretation and identification of platforms from the LiDAR imagery were checked against detailed maps of those located using ground surveys by (the then) English Heritage at Parrock Wood, Rigg Wood and Knott End Wood (Dunn and Lax 1998). Field verification was also undertaken in Longsleddale, Dalton Park Wood and Arnside Wood, which demonstrated a satisfactory level of consistency and positional accuracy.

The Backbarrow Company Account Books (1731 to 1742)

The account books contain the financial records of the Backbarrow Company, including transactions relating to two blast furnaces: Backbarrow and Leighton. Though not within the Furness area, the furnace at Leighton near Carnforth was the second of the Backbarrow Company’s furnaces and therefore appears in these account books.

Construction of the Backbarrow Iron Works began on the site of a bloomery forge in 1711 and entered on its first blast in 1712 (Fell 1908). Charcoal was used as fuel until c. 1920, when coke was substituted. The original charcoal furnace, with a waterwheel driving the iron bellows, remained in operation until at least 1870, and a replacement modern furnace finally ceased production in 1967 (Marshall and Davies-Shiel 1969).

Fell records that the building of Leighton Furnace began in 1713 within a well-wooded area, and he claims that the Leighton Furnace was ‘the most profitable of these early undertakings’ (Fell 1908, 210). The furnace was built on a stream with a suitable head of water and within an area where supplies of fuel in the form of both charcoal and peat (see later) were apparently plentiful (Newman 1999). Although its profitability reduced as the Halton Company of Lancaster began purchasing wood and charcoal in nearby areas, Leighton continued production of iron, except for a break in 1764, until 1806 when the furnace is rumoured to have blown up. It was never rebuilt.

The Backbarrow Company accounts for this period (1731–1742) were kept by Benjamin Ayrey who remained at Backbarrow for many years (Fell 1908). He was principal agent and bookkeeper and was credited with being the first person to introduce the ‘true Italian method of book-keeping into business in that part of the country’ (Fell 1908, 303–4). His obituary appeared in the Newcastle Journal of 15th September 1750 and praises his integrity and moral worth as well as his skill as an accountant. Ayrey’s account books are remarkably clear and meticulously kept for their time, with very few corrections.

Organisation of the Account Books

The account books contain two elements: (i) a journal of individual purchase transactions in chronological order, and (ii) a ledger that contains expense accounts that summarise the journal transactions. The latter’s summary accounts were specific to the type of goods, such as charcoal, iron ore or wood and others specific to individuals such as the agents and company partners. In addition, several accounts were kept for major woodlands or parklands such as Dalton Park Wood and Sizergh Park Wood for example. The journal of individual purchase transactions contains the most detailed level of information with descriptions of each purchase, its quantity, cost, the person to whom the payment was made, and when the transaction took place.

Cross-referencing between the various accounts was made possible through page numbers, enhanced in some books by the survival of a contents page or index on the inside of the front cover that lists all the separate named accounts in the ledger together with page numbers contained within the book for that financial year (Figure 2).

Figure 2. The index, here inside the front cover of a ledger from the Backbarrow Company account book, provides a list of all the accounts within the book together with page numbers. Lancs. Arch. DDMC 30-6 (Photo by author, 2019).

An example will illustrate how the system worked. In the Backbarrow Company’s account book for 1738–9, the index lists the charcoal account with a page number of 586 (Figure 3). Turning to page 586, there is a summary of all the charcoal transactions for that year, together with (i) the accounting period within which each transaction took place, (ii) the name of the person to whom money was paid, and (iii) the quantities and costs for each transaction. A page number for each of the transactions listed in the journal section of the book is provided in the second column. For example, page 586 in the Backbarrow ledger section of the account book of 1738–9 lists a debit to Anthony Wilson on the 24th of June 1739 for ‘Country Coales’ to the value of £413 19s 5d. That entry refers the reader to the detailed purchase entry in the journal section on page 630, which in turn lists all the suppliers of charcoal together with their location as well as the quantity and cost of the charcoal.

Figure 3. An example of how the journal of purchase transactions and the accounts in the ledger are cross-referenced using page numbers. Lancs. Arch. DDMC 30-6 (Photos by author 2019).

The purchases recorded chronologically in the journal section of the book for a whole financial year provide the most detailed information about the purchase of charcoal, often through an agent. They would have continued through the year but most purchases of charcoal for the Backbarrow furnace were grouped together at the end of an accounting period (Candlemas to Mid-Summer etc.). Going back to our example above, the journal entry for the purchase of charcoal on page 630 reads:

Charcoal at Backbarrow D^r [debited to] Anthony Wilson’s account the sum of £413 19s 5d for coales delivered by the country between Candlemas [February 2nd] and Midsummer [June 24th] 1739.

A list of ‘sundry persons’ follows together with a place name in most instances (Figure 4). The charcoal summary account also includes the value of any charcoal stock left over from the previous financial year (Figure 5). As we shall see later, this fact is important when calculating charcoal consumption by a furnace from year to year.

Figure 4. Backbarrow accounts Lancs. Arch. DDMC 30-6 with list of charcoal suppliers with place names. Note also that the date the charcoal was delivered was between February 2nd (Candlemas) and 24th June (Midsummer’s Day) (Photo by author, 2019).

Figure 5. The summary account for purchases at Backbarrow 1736–7 Lancs. Arch. DDMC 30-6. Note the amount ‘To stock’ on the first line indicating the amount left over from the previous year (Photo by author, 2019).

Data Entry of the Account Books

Not all the account books between 1731 and 1743 are available at the Lancashire Archives at Preston. As stated above, the financial years of 1732–3, 1737–8 and 1739–40 are missing. Nevertheless, the location of 563 individual purchases of charcoal were identified and mapped. A key part of the process was the identification of the location of the supplier. In some cases, this was straightforward, particularly when charcoal was purchased from estates such as Sizergh Park Wood, Dalton Park Wood, Arnside Park Wood and West Hall Park Wood. Purchases from large estates merited a separate account and provide a useful breakdown of the total cost of purchasing charcoal. Other smaller purchases are also reasonably easy to locate where a major topographic feature is mentioned (Figure 6). For less obvious locations however, a considerable amount of time was needed to identify them, especially those transactions termed ‘country coales’ from ‘sundry’ suppliers.

Figure 6. Supplies of charcoal listed in the journal (Lancs. Arch. DDMC 30-6) can be georeferenced using the first edition of the Ordnance Survey 10,560 County Series map of 1890 (© Crown Copyright and Landmark Information Group Limited (2023). All rights reserved).

Several sources were used to track down place names contained within the account books. These included the Gazetteer of British Placenames (https://gazetteer.org.uk), and the Old Cumbria Gazetteer (https://www.lakesguides.co.uk/html/lgaz/lgazfram.htm), a compilation of names found on a variety of manuscript maps. County Series maps published by the Ordnance Survey and made available through the National Library of Scotland (https://maps.nls.uk/os/) were also an essential geographical source. The main problems encountered were changes in place names, sometimes subtle such as Blaikholme becoming Blake Holm. Overall, the locations of approximately 76 per cent of the charcoal entries were identified.

Purchase and Consumption of Charcoal 1731 to 1743

1. Backbarrow Furnace

 Table 1 and Figure 7 show the figures for charcoal purchased and consumed based on the annual accounts for charcoal at Backbarrow. The first line of each annual charcoal account states the amount of charcoal remaining in stock from the previous year. If this figure is added to the amount purchased during the remainder of the year and the amount remaining subtracted at the end of the year, then the amount of charcoal consumed can be calculated. Several observations can be made based on these figures. Backbarrow increased its charcoal consumption significantly year on year, from 211 dozen sacks in 1731–2 to a peak of 1755 by 1738–9, more than an eight-fold increase at a cost of just over £2300. Following a dip in consumption in 1739–40 to 1417 dozen sacks, consumption went up to 1723 in 1742–3. All the figures (charcoal to stock, purchased, and consumed) are broadly parallel to one another. It is interesting that the amount purchased annually appears to ensure that there was a healthy amount left over at the end of each year, perhaps providing a contingency to support continuous production the following year.

(b)	Leighton Furnace

Figure 7. Trends in charcoal consumption and purchasing at Backbarrow Furnace 1731–43. (Lancs. Arch. DDMC 30-2 to DDMC 30-9).

Table 1. Charcoal purchases and consumption at Backbarrow 1731–43.

Year	In stock (doz sacks)	Purchased (doz sacks)	Total (doz sacks)	In stock £	Purchased £	Total £	Price per doz /-	Consumption (doz sacks)
31–32	240	520	760	331	770	1101	29.62	211
34–35	549	813	1362	818	1217	2035	29.94	794
35–36	568	1396	1964	857	2023	2880	28.98	1264
36–37	700	1524	2224	1047	2206	3253	28.95	1372
38–39	852	1646	2498	1248	2386	3634	28.99	1755
39–40	743	1411	2154	1088	2045	3133	28.99	1417
41–42	737	1644	2381	1041	2286	3327	27.81	1723
42–43	658	1350	2008	921	1884	2805	27.91	No data

Notes: Quantities of charcoal are by numbers of dozen sacks. Consumption for 1742–43 cannot be calculated as there is no figure for the amount in stock at the start of the following year.

Leighton appears to have been a much smaller-scale operation with consumption of charcoal fluctuating from almost zero to 652 dozen sacks (per year) (Table 2 and Figure 8). Indeed, for the years 1734–5 and 1735–6 there appears to have been no iron production at Leighton judging by the charcoal consumption figures. The total amount of charcoal purchased and remaining from the previous years is almost the same as the amount remaining at the end of the year. The figures suggest that production at Leighton was not continuous, which might perhaps have been due to the need to build up charcoal stocks to a sufficient level to commence cost-effective iron production. Backbarrow purchased on average 1288 dozen sacks of charcoal (per year) for much of the period whereas Leighton purchased on average 247 dozen sacks per year, a five-fold difference between the two furnaces.

Figure 8. Trends in purchasing and consumption at Leighton Furnace 1731–43 (Lancs. Arch. DDMC 30-2 to DDMC 30-9).

Table 2. Charcoal purchases and consumption at Leighton 1731–43.

Year	In stock (doz sacks)	Purchased (doz sacks)	Total (doz sacks)	Stock £	Purchase £	Total £	Price per dozen /-	Consumption (doz sacks)
31–32	395	126	521	907	272	1179	43.17	453
34–35	68	88	156	110	131	241	29.77	1
35–36	155	331	486	241	497	738	30.03	3
36–37	483	269	752	735	387	1122	28.77	652
38–39	100	342	442	145	476	621	27.84	0
39–40	442	328	770	621	451	1072	27.50	No data

Notes: Quantities of charcoal are by numbers of dozen sacks. As with the Backbarrow figures, consumption for 1742–43 cannot be calculated as there is no figure for the amount in stock at the start of the following year.

The Cost of Procuring Charcoal

The account books provide an invaluable insight into the process of procuring charcoal and the lengths to which the company would go to achieve suitable levels of supply. William Jackson, an employee by the Backbarrow Company, played a central role in the procurement of charcoal for the Leighton Furnace throughout the period. A key challenge was to value woodland and negotiate the price of charcoal with landowners. In 1732 he was paid 15s 5d for expenses incurred ‘Valuing wood at Long Sleddall, Middleton Hall, Beethom, Arnside, & severall other places and parcells’ (Lancs. Arch. DDMC 30-2). The effort required to visit these locations was quite considerable given the likely state of the roads at the time.

The Leighton accounts sometimes provide a detailed breakdown of the costs especially when purchases are made from estates. Dalton Park Wood provides a useful example of the various tasks and expenses incurred by William Jackson when procuring wood and charcoal (Lancs. Arch. DDMC 30-2). In 1732 he was paid the sum of 11s 9d for sundry charges (Table 3). It was clearly his responsibility to ensure that the wood cutters and charcoal burners had all the materials they required to undertake their work, no matter how small or mundane. The bulk of the cost was for the charcoal at £227 1s 7d for 99 dozen and 2 sacks of charcoal at a rate of £2 5s 9¹/₂d per dozen. A breakdown of the cost is provided in exceptional detail (Table 4). From these figures we can see that the production of charcoal involved a chain of interlinking operations, each with its own specialists and costs. In this example, William Jackson negotiated the price, Thomas Relph and Partners and James Tatham and Partners cut the wood for Mick Cooper to cord (cutting the wood to standard lengths), before passing on to Anthony Rooth to wheel the cords of wood to Mick Cooper again for coaling. Anthony Rooth would then transport the charcoal to the Leighton Furnace.

Table 3. The sums of money (shillings and pence) paid to William Jackson in 1732 for expenses incurred at Dalton Park Wood (Lanc. Arch. DDMC 30-2).

Item	s	d
For 2^1/2 Quires of Paper and Pocket Book	3	5
A Grindstone for Wood Cutters	1	3
For mending Mellbands & laying a Hack	2	1
Thread for making and mending Coal Sacks	3	0
For hooping a Water Pail for Coliers		6
For a new Water Pail	1	6
Total	11	9

Table 4. A breakdown of the cost (pounds, shillings, and pence) of procuring charcoal from Dalton Park Wood in 1732.

Item	£	s	d
To William Jackson for expenses this year	1	6	4
To William Jackson paid Thomas Relph & Partners for cutting 181^5/8 cords	20	8	7^1/2
paid them for cutting by day 28^3/4	5	7	11
To William Jackson paid James Tatham & Partners for cutting 63 cords	4	3	3
To William Jackson paid Mick Cooper for cording 273^3/8	7	19	5^1/2
To William Jackson paid Anthony Rooth for wheeling in the same	3	14	9
To William Jackson paid for leading cover to the pitts	1	11	0
To William Jackson paid Mick Cooper for coaling 99 doz 2 sacks	22	10	3
To William Jackson paid Anthony Rooth for carriage of the same	22	14	6
To William Jackson paid for sundry small charges		11	9
To Thomas Ayers & Comp. for cord wood 273^3/8 cords	136	13	9
Total	227	1	7

Several interesting points emerge from these figures. The charcoal burn itself is not by any means the most expensive part of the labour costs. Rounding these figures up, cutting the wood contributed 35 per cent of the cost of labour, cording 9 per cent, and wheeling the wood to the platforms and transporting the charcoal to Leighton 30 per cent; coaling contributed a mere 26 per cent. If we include the cost of purchasing the wood from Thomas Ayers & Son who represented the owner then these percentages drop to 13, 4, 12 and 10 per cent respectively, because the cost of the wood contributed 61 per cent of the total cost. The total cost of procuring charcoal was thus considerable and the fact that it could command such a high price suggests that woodland was a very precious resource indeed.

Calculating the Acreage of Woodland Required to Make Charcoal

Several attempts have been made to estimate the acreage of woodland required to produce sufficient charcoal to maintain an iron furnace in blast (Lindsay 1975; Tabraham 2008; Armstrong 1978; Straka 2017). Lindsay (1975), using several sources (Fell 1908; Walker 1812; Mushet 1840; Baker 1943), estimated that 1.62 acres of coppiced woodland would make 1 ton of charcoal. Given the detail we have in the account books for the purchase of charcoal, new estimates can be attempted.

Dalton Park Wood, supplying charcoal to Leighton, offers valuable evidence of the relationship between the acreage of woodland, wood consumption and charcoal production. Unlike many other woodlands, particularly in the Furness area, Dalton Park Wood is very well-defined woodland within a predominantly agricultural landscape. The locations of 79 platforms, indicative of former CBPs, have been mapped from LiDAR imagery (Figure 9). A sample of platforms was field checked in April 2022 by the author (A. Pearson) to validate their existence. At one, charcoal fragments were extracted from the roots of a windthrown tree (a Fagus; beech) that had been growing on the platform itself. Microscopic analysis of the fragments identified one fragment to be Alnus (alder) (Figure 10(a)) and another to be Fraxinus (ash) (Figure 10(b)).

Figure 9. Potential charcoal burning platforms at Dalton Park Wood, as mapped from LiDAR imagery (© Environment Agency copyright and/or database right (2023). All rights reserved).

Figure 10 . (a) Charcoal fragment of Alnus (alder) recovered from Dalton Park Wood. (b) Charcoal fragment of Fraxinus (ash) recovered from Dalton Park Wood.

According to Tabraham (2008) the typical output from a single charcoal clamp kiln was a dozen sacks of charcoal weighing around 915 kg. If the 79 potential platforms that have been mapped at Dalton Park Wood were used to produce just over 99 dozen sacks of charcoal, then the number of sacks produced by each platform would be 15 sacks rather than 12, a not unreasonable difference given that we are only able to map platforms that have survived. If we take the location of the platforms as indicative of the former extent of the woodland, then we can estimate the acreage of woodland in 1732 to be around 114 acres (46 ha). Given these figures we can estimate that a dozen sacks of charcoal required roughly 1.15 acres of Dalton Park Wood to be cut/harvested.

The figures from one woodland cannot be applied universally. A consignment of 160¹/₂ dozen sacks of charcoal were delivered to the Leighton furnace from West Hall Park in 1743. LiDAR imagery reveals 116 possible CBPs evenly distributed over a well-defined piece of woodland (Figure 11). The number of sacks produced on average by each platform would be 16.5, a figure not too dissimilar from that at Dalton Park Wood (15 sacks). However, West Hall Park is significantly smaller in acreage, approximately 87.2 acres, therefore producing a dozen sacks of charcoal for every 0.54 acres; double the yield per acre of Dalton Park Wood and perhaps indicative of higher density tree planting and/or a different species of tree.

Figure 11. Potential charcoal burning platforms at West Hall Park, mapped from LiDAR (© Crown copyright and database rights 2023 Ordnance Survey (100025252)).

The actual calculations for the Dalton Park Wood and West Hall Park are of course based on the implicit assumptions that all the CBPs identified are contemporary and that they were only used once. Furthermore, there is no proof that the woodland was indeed being coppiced. Landowners could agree to fell standard trees for charcoal and timber rather than limit the harvest to the underwood and deadwood.

Turning back to the figures derived from the Backbarrow Company account books, the average amount of charcoal purchased in each year to supply Backbarrow Furnace was 1288 dozen sacks. The woodland required would therefore be 695 acres at 0.54 acres per dozen sacks or 1468 acres at 1.14 acres per dozen sacks. Other furnaces were in production at the same time, including Leighton where on average 247 dozen sacks were consumed each year meaning that 133 acres would be required at 0.54 acres per dozen or 281 acres at 1.14 per dozen. The furnaces at Cunsey, Penny Bridge, Nibthwaite and Duddon were also in blast at times during this period so their requirements would have to be considered if we are to weigh up the capacity of the local woodland to support the entire iron production in the area. We would also need to know the extent of the contemporaneous woodland, a subject that is considered below.

Distribution of Surviving Charcoal Burning Platforms

The evidence from Dalton Park Wood and West Hall Park has provided very detailed and useful evidence of charcoal production in the South Lakes during the mid-eighteenth century. We know that the charcoal fuelled the production of iron from the blast furnace at Leighton. We have also been able to estimate how much woodland would have been required to produce charcoal. Now we can look at the wider picture and consider the distribution of charcoal suppliers as documented in the account books and mapped from the LiDAR imagery at the regional level.

 Figure 12 shows the locations of charcoal supplied to the Leighton and Backbarrow furnaces between 1731 and 1742 as recorded in the account books. Both furnaces were owned by the Backbarrow Company. The supply zone for each furnace is clearly defined. The density of the sources of charcoal are much higher for Backbarrow than Leighton with much of the charcoal being supplied from the Rusland area of the Lake District, between the lakes of Coniston and Windermere. In contrast, the supplies of charcoal for Leighton are much more dispersed and fewer in number. This contrast is even more marked when we consider the number of sacks of charcoal supplied to each furnace. The total number of sacks for Backbarrow Furnace represented by the dots on the map is 113,227, whilst for the Leighton Furnace the figure is 17,937. Judging by this evidence, the potential for Leighton Furnace to procure charcoal supplies was significantly limited and probably reflects the distribution of woodland in the eighteenth century. It is perhaps understandable therefore that Leighton relied heavily on locally available peat that was used with charcoal in a ratio of 2 to 3 with 8000 cart loads being brought in every year (Newman 1999). Iron smelted with a combination of charcoal and peat produced inferior pig iron which sometimes had to be re-smelted and sold at a lower price. We must assume, therefore, that the production costs were sufficiently low for the furnace to remain profitable and later experimentation with peat smelting by John Wilkinson at Lindale in 1778 (Cranstone 2007) indicates continuing interest in peat as an alternative or supplement to charcoal.

Figure 12. Distribution of charcoal supplied to the Leighton and Backbarrow furnaces between 1731 and 1742 together with the distribution of current ancient woodland mapped by Natural England (Open Government Licence Version 3). Contains OS data © Crown copyright and database right (2023).

 Figure 13 shows the distribution of possible CBPs mapped using LiDAR imagery. The total number mapped is 8402. As these sites have been identified using remote techniques without field verification there is no guarantee that they are all CBPs. For example, sites of former charcoal burners huts could have similar characteristics. Furthermore, it is also an assumption, without corroborating documentary evidence, that they are all linked to the iron industry. Nevertheless, we know from the account books that between 1731 and 1742 charcoal was supplied from as far afield as Ullswater, Ambleside and Longsleddale and that platforms are concentrated around known charcoal iron furnaces, such as Nibthwaite and Duddon.

Figure 13. Distribution of charcoal burning platforms as identified using LiDAR imagery. Ancient Woodland mapped by Natural England (Open Government Licence Version 3). Also contains OS data © Crown copyright and database right (2023).

A striking feature of the map is that the majority (80 per cent) of CBPs that have survived remain in broadleaved woodland (Table 5). In terms of the others, 9 and 7 per cent are in areas of acid grassland and improved grassland respectively. This suggests that the impact of the iron industry on the woodlands of the South Lakes did not leave a landscape denuded of woodland, indeed, woodlands once used for charcoal production appear to have largely remained intact since the early part of the eighteenth century. The correlation between platform distribution and current woodland extent also suggests that the woodland area was already defined by the beginning of the blast furnace era meaning that the broadleaved woodland extent has remained reasonably constant over the past 300 years. If we consider those platforms that remain in woodland today, approximately 50 per cent are within 7.5 km of a furnace (Figure 14). In fact, as proximity to a furnace increases, so too does the number of CBPs within the woodland.

Figure 14. Distance to nearest furnace for platforms within existing woodland.

Table 5. Platforms located within UK Biodiversity Action Plan broad habitat classes as depicted on the Land Cover Map 2019 published by the Centre for Ecology & Hydrology (Morton et al. 2020).

	Platforms	Platforms (%)
Acid grassland	754	9.0
Broadleaved mixed and yew woodland	6831	81.4
Coniferous woodland	214	2.6
Improved grassland	588	7.0
Total	8387

Any suggestion that the supply of charcoal to the blast furnaces devastated the surrounding woodland in the South Lakes should therefore be dismissed. Nevertheless, platforms outside current woodland do exist and if we estimate that between 0.75 and 1.5 acres of woodland were required for each platform, then approximately 2334 acres (3.6 sq. miles or 9.3 sq. km) of deciduous woodland have since been lost. The distribution of these platforms outside modern woods is worthy of note. For example, Figure 15(a) shows an almost continuous chain of platforms along the eastern and western valley sides of Longsleddale, north of Kendal. This continuity is not mirrored by the current woodland extent as there are clear gaps between the patches of woodland (Figure 15(b)). If we assume that platforms are very likely to have been created within woodland to keep the transport of wood to a minimum, platforms located outside woodland areas can be taken as representing areas of former woodland. Figure 16 attempts to reconstruct the former extent of woodland using this evidence. If the restoration of broadleaved woodland were to be considered in future either to areas of surviving poor-quality woodland or areas where woodland once existed, then we have the evidence to guide where the restoration could be targeted. This restorative work would create larger continuous broadleaved woodland patches with clear benefits to nature and biodiversity with the reassurance of being based on a strong evidence base and help to achieve the target of 17 per cent woodland cover within the Lake District National Park (LDNP) by 2050 (LDNPA 2023).

Figure 15. (a) Platform distribution (red dots) in Longsleddale. Inset map shows all CBPs (red dots) and furnaces (black squares). © Crown copyright and database rights (2023) Ordnance Survey (100025252). (b) Charcoal burning platform in Longsleddale in an area of pasture but formerly of woodland. (Source author)

Figure 16. Former woodland extent (orange) as indicated by the charcoal burning platforms outside current ancient woodland extent (green). Ancient woodland mapped by Natural England (Open Government Licence Version 3). Also contains OS data © Crown copyright and database right (2023).

Managing the Woodland Resource

If the broadleaved woodland extent has remained reasonably stable over the past 300 years, how has this been achieved? The story of their survival is complex but as Voysey (1985) suggests, it was the commercial value of the broadleaved woodlands which saved them from extinction.

Sustainable management of the woodland was essential if the needs of the iron industry and other woodland-dependent industries were to be satisfied. At the beginning of the eighteenth century, however, according to Fell (1908), the protected coppice woods that existed were very small in extent. Charcoal was chiefly drawn from the loppings of timber trees and from coppiced wood. During the early years of Backbarrow Furnace, one hundred and thirty individuals supplied charcoal to Backbarrow even though the company had seventy woods in its own possession. Fell writes that ‘many of these woods were very small and hardly worthy of the name, but charcoal was so precious a commodity that every parcel, however small, was welcomed and sought after’ (1908, 130). Fell also describes how charcoal was brought in from some distance, listing Borrowdale, Ambleside, Skelwith, Rosthwaite, Ulpha, Duddon Bridge, Troutbeck, Borrans, Long Sleddale, Winster, and Arnside.

Taking the total area of woodland likely to have existed in the eighteenth century in the southern half of the Lake District and using the figures that we have estimated for acreage of woodland required for charcoal production (0.54 to 1.14 acres per dozen sacks), the woodland resource would last between 9.5 and 20 years. Given that trees of between 15 and 20 years were preferred for charcoal production (Fell 1908), the availability of woodland at the right stage of growth for charcoal would therefore have been a continuous cause for concern. However, according to Flinn (1958), as demand grew for wood, estate managers would ensure that close planting with careful thinning of the coppice wood was standard practice and as the eighteenth century progressed, coppices were cultivated and replanted specifically for the iron industry, much like those covering the valleys and hills of Furness as described in Thomas West’s Guide to the Lakes in Cumberland, Westmorland and Lancashire (1778):

Much of the vallies, and the bases of most of the hills, are covered with young wood, which at certain periods is cut down and charred for the use of the neighbouring furnaces. On this account, the copses, which consist of various kinds of trees, constantly, in the summer, exhibit every pleasing colour of youthful vegetation. (West 1778, 282)

Even though the iron industry was the main consumer of wood as witnessed by West, other woodland industries such as bark production for tanning, potash-making for soap, wood turning, bobbin making, cooperage and basket making would also have encouraged landowners to plant and maintain woodland in south Cumbria.

Charcoal was clearly vital to the iron masters. They required guaranteed supplies of charcoal at a price that was fixed at a level that would ensure a profit. The cost of charcoal was a major determining factor in the profitability of an iron works. For example, an account of nine years’ work at Backbarrow between 1772 and 1780 (Lancs. Archives DP 373) shows that the total sales of iron amounted to £37,000 from which £22,964 (62 per cent) would have been deducted as charcoal expenditure and just £7205 (20 per cent) as iron ore. The total profit was a mere £3683 (10 per cent).

Signed agreements between the iron masters and landowners were important to both parties. Several indentures or articles of agreement for the supply of charcoal are contained in the Machell family papers. An article of agreement between Hall and Partners of Cunsey Furnace, the Backbarrow Company, and William Kirkby of Ashlock, Henry Taylor of Kendal and Richard Postlethwaite of Ridding was signed on 5th February in 1733/4 for the supply of timber for charcoal (Lancs. Arch. DDMC 30-23). An agreement was signed on 18th February 1733 by Thomas Strickland of Sizergh Hall, Westmorland, to Backbarrow Company for trees at Sizergh Park to be felled for charcoal (Lancs. Arch. DDMC 30-24). Transport agreements are also included on the Machell family records. For example, the Backbarrow Company appointed Thomas and Henry Williamson of Windermere to row charcoal produced in Yowbarrow Woods across Lake Windermere, from Windermere Waterhead to Backbarrow in 1742 (Lancs. Arch. DDMC 30-41). Apportionment of charcoal between furnaces was also the subject of agreement as witnessed by the agreement between Backbarrow, Nibthwaite, Cunsey, Duddon, Coniston and Spark Bridge furnaces (Lancs. Arch. DDMC 30-46). Delivery of iron ore and charcoal to Leighton Furnace was agreed between Backbarrow Company and William Jackson of Rusland on 23rd April 1745 (Lancs. Arch. DDMC 20-48). The establishment of a new furnace at Penny Bridge demanded agreements be established between the company and charcoal suppliers. Draft articles of agreement for the proposed furnace included charcoal supply (Lancs. Arch. DDMC 30-71 and DDMC 30-72).

The documentary archives also provide ample evidence of an increasingly strained relationship between woodland owners and the ironmasters. Evidence of disagreements between furnace owners and charcoal suppliers is common. For example, in 1753–4 there was a dispute between the masters of Low Wood Iron Works and wood owners about the felling of timber for charcoal (Lancs. Arch. DDMC 30-76). Wood owners were accused of fraudulent intent for allowing their woods to grow beyond the customary number of years prior to coppicing and then refusing to cut the wood for charcoal thus breaching an agreement. Further evidence lies in the Muniments of the Sandys family of Esthwaite and Graythwaite (Lancs. Arch. DDSA 42) which contain a draft circular that was sent prior to a meeting of disgruntled wood owners and colliers to take measures ‘against oppression’ by North Lancashire ironmasters on 2nd July 1748 (Lancs. Arch. DDSA 42/10). Attempts, albeit with limited success, were made to ease the pressure on charcoal supplies by establishing furnaces in Scotland at Invergarry (1722), Bonawe (1752) and Craleckan (1754) in areas where there was a plentiful supply of charcoal.

Apart from the furnace at Backbarrow, the charcoal iron industry in Cumbria could not compete with coke-fired furnaces and the industry went into decline from the latter part of the eighteenth century. The conifer economy grew as the commercial broadleaved coppiced woodland declined, a trend that gathered pace during the early part of the twentieth century. Commercial coppicing virtually ceased before the end of the nineteenth century but much of the broadleaved woodland survived as its scenic and wildlife value gained recognition (Voysey 1985). The establishment of the Lake District National Park in 1951 was a key factor in the survival of the remaining broadleaved woodland.

Conclusion

In the past, those reliant on woodlands to source its products and resources, be it directly for wood or indirectly for by-products such as charcoal or bark, had a vested interest in managing the woodlands sustainably as a continuous resource. This research has demonstrated that such sustainable management was the case in this part of the South Lakes during the post-medieval period to the extent that large areas of the woodland exploited for the eighteenth-century iron trade still exist today. This is not unique in Europe and has parallels for example with the French Pyrenees (Fouédjeu et al. 2022).

Today, trees and woodlands are widely recognised and valued for their Natural Capital and their vital role in providing essential Ecosystem Services, including carbon sequestration, biodiversity, preventing sediment erosion, water regulation, and recreation, health, and wellbeing (see UK Government 2021, 7–8). Furthermore, as ‘industrial woodlands’ they hold embedded cultural and heritage values, both tangible and intangible, that result from this history of exploitation. Without this use-history, these areas of woodland would not exist today.

Understanding the character and extent of woodland modification, together with how they were sustainably managed historically, is crucial not only for understanding their characteristics today, but also for how they should be managed in the future. Careful future management can maintain woodland character whilst producing renewable and sustainable resources that are identified useful and marketable e.g. coppiced wood products. Yet often ‘[t]he wooded landscape is considered a “natural” backcloth taken for granted that will care for itself’ (Rotherham 2007, 112), and this ‘cultural severance’ (Rotherham 2022) and the loss of active management poses challenges, including the loss of the knowledge and heritage skills necessary for traditional woodland management. Re-instating on-going active management will help re-invigorate and keep those skills alive.

Even though this research is in its early stages, the results illustrate the wealth of historical evidence contained within the account books of the Backbarrow Charcoal Iron Company. Combining this evidence with that derived from remote sensing has provided an invaluable method of understanding the interdependence between the iron industry and its surrounding physical and cultural landscape. This study has demonstrated that the survival of the industry relied on the sustainable management of the woodland as a resource. The legacy of this can be seen in the landscape of the South Lakes today as the extant areas of woodland associated with many of the mapped charcoal burning platforms that would have been active 300 years ago.

Future work will expand the evidence base to include account books from later periods of the eighteenth century and into the early part of the nineteenth century to examine how successful the woodland management was at maintaining a constant supply of charcoal to the industry.

Acknowledgements

The authors would like to thank the referees for their very helpful comments and suggestions.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

We are grateful for the funding provided by Historic England to carry out this work, and especially to Gill Campbell, Head of Fort Cumberland Laboratories for her continued support and insightful comments during the drafting of this paper. We also thank the staff of the Lancashire Archives in Preston and the Cumbria Archives at Barrow-in-Furness for their help and support. Thanks also the Arts and Humanities Research Council (AHRC) for funding the Keyence VHX7000 3-D digital microscope (AHRC Award AH/V011758/1) used to take the high resolution images of the charcoal.

Notes on contributors

Alastair Pearson

Alastair Pearson is Lecturer in Geography at the University of Portsmouth. His research focuses on landscape evolution concentrating on the analysis of historical landscape change using geographical information systems (GIS). Email: [email protected]

Zoë Hazell

Zoë Hazell is Senior Palaeoecologist at Historic England. She is an Environmental Archaeologist with a background in Quaternary Science, and an interest in past landscapes, environments and wood uses—especially around the crossovers of their natural and cultural heritage significance. Email: [email protected]