The exploitation of the natural forests by the English Planters of the 17th century saw the start of an industrial revolution in Ireland. Additionally, it cleared land which could be used more profitably for farming.
Woods near the sea or on navigable rivers provided timber for shipbuilding, although this never became a major industry. However, some woods were preserved by the Crown for naval vessels. Ships for the East India Company were built with timber from near Kinsale. The manufacture of barrel staves became a significant industry. It is said that in 1625, all the wines of France and Spain were casked in barrels of Irish Oak, taken from the river valleys of the southwest. For timber to be exploited profitably, a wood had to be near a port so that the timber could be easily transported to it. When trees in Glenflesk, 10km. East of Killarney, were felled, the timber had to be carried on horseback to Castlemaine Bay, 40km. away! Generally, transporting timber more than a mile (1.6 km.) from where it was cut exceeded the cost of felling. The more inaccessible Kerry forests were, therefore, preserved for some years.
The greatest cause of forest destruction, particularly in the more remote valleys of Cork and Kerry was in the making of charcoal for the local iron works. Large areas of forest were clear- felled; coppicing does not seem to have been used to any great extent. Most trees when cut down will coppice, that is, will produce a number of stems from the cut stump. These can be grown on and harvested on a rotational basis, thus providing a regular supply of timber. This system was widespread in English forest management and it is inconceivable that it was unknown in Ireland since most of the foundry masters and charcoal makers were of English descent. Presumably, the apparent abundance of forest and the need to clear the land for farming ran counter to the use of coppicing.
By 1756 , iron smelting had ceased. But the woodlands in the Killarney Valley, as no doubt elsewhere, continued to be used as a source of timber for a number of crafts. Most of the products made were for purely local use. For example, barrels were needed for the storing and transport of produce; butter was exported via Cork to England and there were also two breweries in Killarney! Boats were a major form of local transport, and although these were of relatively small size, vessels of up to 40 tons were built at the end of the 18th century on the lake shore at the mouth of the River Laune. These were then taken down the river to the sea. There was also a tradition of furniture making, using local timber such as Arbutus and Yew as decorative inlay. This was almost a ''tourist related'' industry and in the 19th century many visitors to Killarney remarked on the variety of toys and ornaments made of wood and particularly Arbutus. A further aspect of forest destruction was the use of Oak bark in the tanning of animal hides. In the southwest, tanneries existed in the 17th century at Kanturk and in the 18th and 19th centuries in Killarney. Tanners preferred to strip the bark from living trees, thereby killing them. Because of the havoc that they could wreak in a wood, tanners met with the hostility of other wood workers. So much so, that laws were enacted to control the setting up of tanneries and to prevent the debarking of live trees. Bark had, therefore, to be taken from felled Oaks, and it was preferable from the tanner's point of view that the Oaks were felled in Spring, since when the sap was rising the bark was most easily removed. The removal of the bark for tanning was, incidentally, of advantage to the charcoal maker because bark is rich in sulphur as an impurity in the charcoal.
The tanner's craft is one which requires considerable knowledge of chemical processes and yet is one of the oldest crafts known to mankind. In the tanning process, raw skins are converted into leather, preserving the skin and giving it necessary strength and durability. Tannin, a naturally occurring substance in many plant species, reacts with substances such as albumen and gelatine which are present in the skin. The process, which is both chemical and physical in nature, causes a union of these substances with the tannin to form a firm but supple compound. This is insoluble in water, resists decay and penetrates all the other components of the skin without damaging its natural structure. Oak heads the list of preferred plants because of the richness of its tannin and the quantity produced. The bark from young Oak trees was most preferred but the bark from older trees could also be used. The method of stripping the bark was to score around the tree at intervals of about 2 feet with a hatchet or bark knife. Slits were then made along the trunk and large semi-cylindrical plates of bark were levered off. Since tannin is soluble in water the plates of bark had to be stacked so that the rain could not penetrate them.
At the tan-yard, the bark was ground to a fine powder and mixed with water to form the liquor. The hides, which had already gone through a number of processes to remove unwanted hair and fat and the salt with which they had originally been preserved, were soaked in a series of more and more concentrated liquors. After some months, the hides were lightly oiled with cod liver oil and hung up to dry. The process of turning a skin into workable leather was a long and protracted one, and a skin could remain in the tan-yard for 18 months or more.
An early reference to tanning in Killarney dates back to 1735. In 1853, five tan-yard were identified in Griffith's Valuation for the town but on the 1894 Ordnance Survey map only one tannery was shown. The availability of locally produced leather probably influenced the establishment of Hilliard's shoe factory which started production in Killarney in 1868.