Pine Resin

Conifer resin is a non-wood forest product of natural and biological origin, obtained from needle-leaved trees of the genus Pinus through natural or controlled methods. This substance, primarily composed of terpenoids, is secreted by trees either naturally as part of their defense system or as a result of artificial interventions. Conifer resin is mainly divided into two fundamental components: terpentine and colophony (rosin). The volatile terpentine is used as a solvent in paints, varnishes, and pharmaceutical products, while colophony serves as a raw material for soaps, adhesives, cosmetics, and various chemical industry products.

Application of Acid Paste on the Cut to Initiate Resin Flow Under the Tapping Resin Method - (AA)

Classification and Extraction Methods

Natural conifer resin production is categorized under three main techniques:

1. Tapping Resin: Resin collected directly by exudation from wounds made on the living tree trunk. In Türkiye, this method is widely used, with the Acid Paste Method being the most prominent. In this technique, the bark and cambium layer are removed to expose the living wood surface, onto which a mixture containing sulfuric acid is applied to stimulate resin secretion. Materials used in this process include stripping rasps, window-cutting rasps, polyethylene bags, staple wire, and a 35% sulfuric acid paste.
2. Sulfate Resin: Obtained as a by-product during cellulose production via the kraft process. During the cooking of resinous pine chips, distillation of the released gases yields sulfate terpentine, while alkaline black liquors yield compounds such as crude tall oil and fatty acids.
3. Extraction Resin: A type of resin obtained by treating resinous pine roots with solvents. In a study conducted in Türkiye using an alcohol-benzene solvent system, a yield of 22% was achieved. Yield varies depending on the solvent used, with chemical analyses recording the highest acid number at 174.87 mgKOH/g and saponification number at 180.33 mgKOH/g.

Conifer Resin Production Using the Tapping Resin Method in Maritime Pine (Pinus pinaster) Forests - (AA)

Biological and Chemical Structure

Conifer resin is a complex chemical mixture containing terpenoid compounds with diverse molecular structures, including monoterpenes (C10), sesquiterpenes (C15), and diterpenes (C20). These terpenes play an active role in tree defense. For instance, compounds such as limonene and 3-carene exhibit repellent effects against insects and microorganisms. Terpentine transports resin acids to the wounded area of the tree; once deposited, these resin acids gradually solidify through oxidative polymerization, forming a protective barrier.

Resin Production and Economy in Türkiye

Planned conifer resin production in Türkiye began in 1959. According to the General Directorate of Forestry’s action plans, production increased from 3 tons in 2015 to approximately 600 tons by 2022. The most commonly used species are Pinus brutia (Turkish pine), Pinus nigra (Austrian pine), and Pinus pinea (stone pine). Average resin yields per tree are 1,040 g, 1,285 g, and 1,168 g respectively for these species.

Based on 2021 price levels, revenue per tree is 29.58 ₺ from Austrian pine, 26.86 ₺ from stone pine, and 23.92 ₺ from Turkish pine, while the production cost for all species averages 32.22 ₺. This indicates that resin production is currently not economically viable under existing conditions. However, changes in production volume, resin prices, and cost structures could alter this outlook.

Technological Applications of Conifer Resin

Chemistry and Industry

• Terpentine: Used in paints, varnishes, solvents, pharmaceuticals, and cosmetics
• Colophony: Used in soaps, paper adhesives, glues, candles, rubber, inks, chewing gum, and plastics

Biotechnology and Green Chemistry

• Natural-origin bioherbicides and bioinsecticides in agriculture
• Antifungal compounds

Sustainable Material Development

• Biodegradable plastics and eco-friendly packaging materials

Traditional Technological Uses

• Waterproofing wooden boats
• Preservation of artworks and historical objects
• Production of candles and torches due to resin’s high flammability

Resin Industry in Cuba: The Case of Pinus caribaea

In Cuba, the species Pinus caribaea is utilized for both timber and resin production. Resin production began in 1985, reaching an annual volume of 1,200 tons by 1989, but declined to below 200 tons following the economic crisis of 1990. Production resumed growth after the 2000s and has stabilized at approximately 1,200 tons per year. The future target is 5,000 tons per year.

The resin collection method involves creating a 65 cm wide debarking zone on the tree trunk, making small “V”-shaped incisions (picas) along a central groove, and directing the resin into collection containers using metal funnels. Each tree yields approximately 4 kg of resin annually, with a yield of about 2 tons per hectare. Each worker collects 15–30 tons of resin over an area of 6–10 hectares.

Applications

Conifer resin offers a broad range of applications primarily through its two main components: terpentine and colophony:

• Terpentine is frequently used in paints, varnishes, solvents, pharmaceuticals, and cosmetics.
• Colophony serves as a key ingredient in soaps, adhesives, paper glues, printing inks, rubber, chewing gum, and plastics.
• It is also used as a raw material in certain antiseptic and disinfectant products.
• Traditionally, it has been used for waterproofing, illumination, and wood preservation.

Sustainability and Forestry Policies

Conifer resin production is important for the sustainable use of natural resources. Systems that allow simultaneous harvesting of both resin and timber are implemented. As in Cuba, trees are harvested 2–4 years after resin collection, enabling dual utilization of the resource. In both Türkiye and Cuba, resin producers typically operate under state-controlled forestry institutions, and production processes are conducted with consideration of environmental impact.