“Bleeding” pines in Extremadura – Spain

bleeding pines

Resin obtained from living Pinus pinaster trees has been a traditional non-timber forests product in other regions of Spain for decades. However, it had never been produced in Cijara, an ecological area located in Extremadura, in the South West of Spain, before. In this area, 15,000 hectares of Pinus pinaster trees were planted in the late 50’ with the aim of protecting the soil and preventing sediment transport into a reservoir. Nowadays, their size and their density (around 300 trees/hectare) are ideal for resin production.

Crude resin containing forest debris (pine needles, insects, etc.) is obtained from Pinus pinaster by tapping living pine trees trunks periodically and by adding stimulating paste containing sulphuric acid. The wounds neither cause permanent damage to the tree, nor devaluate its timber. Distillation of resin produces rosin and turpentine (about 70 and 20%, respectively). Turpentine is mainly used as a solvent whereas rosin has many different applications (cosmetics, pharmacopoeia, paints, agronomy, food processing …). Rosin demand has considerably increased in the last few years, mainly because this raw material substitutes pollutant petroleum derivatives.

From 2013, the Department of Environment of Extremadura Regional Government (D.G.M.A.) has been promoting resin tapping in Cijara, as they distribute ‘matas’ (5,000 pines lots) among self-employed laborers from the region, educates and coordinates them, and supervises tapping. In 2013, 31 lots were tapped, and they were increased to 46 lots in 2014 and to 57 in 2015. Total resin production was 209 Tons in 2013 and 350 Tons in 2014, while 500 Tons are expected in 2015.

Traditional resin tapping methodology from other regions of Spain (Tierra de Pinares, Segovia) has been adopted in Cijara, which mainly consists in tapping living pine trees trunks periodically (every 7-14 days, depending on the temperature and rain), and by adding stimulating paste containing sulphuric acid. The traditional wound is a 3*12 cm rectangle, although it also can be a strip or a v-shaped wound. These wounds have to be caused in spring and summer, when high temperatures help resin flow, so resin tapping takes place in Spain from May to October.

Before tapping, the faces of the pines have to be prepared, which entails the removal of the bark and the installation of the collection system (gutter and resin receiver). We strongly believe that research is needed in order to adapt traditional resin tapping methods from other regions differing in soil, climate, silviculture, topography, etc. to ours.

The research project we present in the XIV World Forest Congress its being carried out from June 2014 by CIDEX, assisted by the D.G.M.A. Its main objectives are the optimization of resin tapping methodology of Pinus pinaster in Extremadura and the evaluation of the production potential. In the first season of the project, 110 trees were tapped applying three different methods, 3*12 cm (traditional), strip and v-shaped wounds, and resin yield was monitored in each tree, in order to correlate with dasometric variables and method.

In 2014 season, mean resin yield was 1.5 kg/tree. The maximum resin yield was 7.6 kg, in a tree whose diameter at breast height was 48.5 cm, its height 15.5 m and diameter at crown 8.6 m. The minimum resin yield was 0.25 kg in a tree having a diameter at breast height of 28 cm, 17.9 m height and 3.3 m of diameter at crown. Results indicate that yield is strongly dependent on genetic factors. Data collected in monitored trees also indicates that the most influential dasometric variable appears to be diameter at breast height, the traditional 3*12 cm wound method appears to be slightly more productive and yield also depends on the amount of sunshine in trunk and on density.

To sum up, trees having a diameter at breast height higher than 35 cm, are dominant or isolated and receive high amount of sunshine are usually good producers. However, some of them are not because of genetic factors. For the following seasons, our research project recommendations are increase plot size, include more variables (different sulphuric acid concentration, labor mechanization,…), and carry out processing tests (resin composition, rosin and turpentine quality).

We strongly recommend that resin tapping keeps on being carried out in Cijara, as every lot generates 9 months of labor for one person, and we think that resin tapping should be promoted in other areas in Extremadura, where it is also suitable. Other non-timber forest products (edible pine nuts, mushrooms…) should also be promoted in this area in order to provide labor all year round. Silviculture should be oriented to resin tapping, aimed at good resin producers trees selection and lower densities.

Blogpost and photo submitted by Ana de Hoces (Spain) – ana_hoces(at)hotmail.com

The content, structure and grammar is at the discretion of the author only.


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5 thoughts on ““Bleeding” pines in Extremadura – Spain

  1. Interesante, recién a los 65 años empezaron a extraer la resina?. Existe data de cantidad Vs calidad de resina por especies y por altitud?, precios y mercados potenciales

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    • Si, en 2012 se llevó a cabo esta iniciativa para promover la creación de empleo en esta zona donde nunca se había resinado. Los pinos actualmente tienen un tamaño óptimo para ser resinados, ya que hasta que se alcanza un diámetro a la altura del pecho de 30 cm la resinación no es recomendable. La única especie que se resina en España y Portugal es Pinus pinaster, y la producción por pie es muy variable, en este proyecto hemos registrado producciones menores que 300 gramos por pie y campaña y otras superiores a los 6 kg, dependiendo principalmente de factores genéticos. Toda la resina que se produce se vende a empresas de primera transformación españolas y portuguesas a un precio aproximado de 1 euro/kg.

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