Appendix


Appendix 1: References and further reading
Appendix 2: Quality criteria, specifications and test methods
Appendix 3: Genetic factors influencing resin composition and yields
Appendix 4: Packaging of turpentine and rosin
Appendix 5: List of importers and traders of naval stores
Appendix 6: Statistical tables


Appendix 1: References and further reading

Pinus species

CRITCHFIELD, W.B. and LITTLE, E.L. (1966) Geographic Distribution of the Pines of the World. USDA Forest Service Miscellaneous Publication 991. Washington, USA: USDA.

Production technologies

CLEMENTS, R.W. (1974) Manual, Modern Gum Naval Stores Methods. USDA Forest Service Southeastern Forest Experiment Station General Technical Report SE-7. Asheville, USA: USDA.

DIRECÇÃO GERAL DOS SERVIÇOS FLORESTAIS E AQUÍCOLAS (1962) [Resin Tapping - Basic Instruction for Resin Tappers.] Portugal: Junta Nacional dos Resinosos. (In Portuguese)

GAMA, A. (1982) [Processing of pine resin in Portugal.] Boletim do Instituto dos Produtos Florestais - Resinosos, no. 38: 26-30. (In Portuguese)

GREENHALGH, P. (1982) The Production, Marketing and Utilization of Naval Stores. Report of the Tropical Products Institute [now Natural Resources Institute], G170.

KRISHNAMURTHY, T., JUYAL, S.P. and UPADHAYA, L.P. (1971) A review of some investigations on pines for their oleoresin (review of tapping methods used worldwide). pp. Q1-Q35. In: Seminar on the Role of Pine Resin in the Economic and Industrial Development of India, New Delhi, April, 1971.

LAWRENCE, R.V. (1989) Processing pine gum into turpentine and rosin. pp. 123-142. In: Naval Stores. Production, Chemistry, Utilization. Zinkel, D.F. and Russell, J. (eds). New York: Pulp Chemicals Association.

McCONNEL, N.C. (1963) Operating Instructions for Olustee Process for Cleaning and Steam Distillation of Pine Gum. USDA publication ARS-687. (Available from the Southeastern Forest Experiment Station, Olustee, Florida, USA).

McREYNOLDS, R.D., KOSSUTH, S. V. and CLEMENTS, R.W. (1989) Gum naval stores methodology. pp. 83-122. In: Naval Stores. Production, Chemistry, Utilization. Zinkel, D.F. and Russell, J. (eds). New York: Pulp Chemicals Association.

VERMA, V.P.S. (1978) Field Guide to Modern Methods of Resin Tapping [in India]. Dehra Dun, India: Forest Research Institute.

Quality assessment of Pinus species

COPPEN, J.J.W., GAY, C., JAMES, D.J., ROBINSON, J.M. and MULLIN, L.J. (1993) Xylem resin composition and chemotaxonomy of three varieties of Pinus caribaea. Phytochemistry, 33: 1103-1111.

COPPEN, J.J.W., GAY, C., JAMES, D.J., ROBINSON, J.M. and SUPRIANA, N. (1993) Variability in xylem resin composition amongst natural populations of Indonesian Pinus merkusii. Phytochemistry, 33: 129-136.

COPPEN, J.J.W., GREEN, C.L., GREENHALGH, P., KEEBLE, B. and MILCHARD, M.J. (1985) The potential of some tropical pines as sources of marketable turpentine. pp. 138-147. In: Proceedings, Ninth International Congress on Essential Oils, Singapore, 1983, (Book 5).

COPPEN, J.J.W. and ROBINSON, J.M. (1988) Terpenoid constituents and properties of xylem oleoresin from exotic Pinus radiata. Naval Stores Review, (Mar./Apr.): 12-14.

COPPEN, J.J.W., ROBINSON, J.M. and KAUSHAL, A.N. (1988) Composition of xylem resin from Pinus wallichiana and P. roxburghii. Phytochemistry, 27: 2873-2875.

COPPEN, J.J.W., ROBINSON, J.M. and MULLIN, L.J. (1988) Composition of xylem resin from five Mexican and Central American Pinus species growing in Zimbabwe. Phytochemistry, 27: 1731-1734.

GREEN, C.L., KEEBLE, B. and BURLEY, J. (1975) Further gum turpentine analyses of some P. oocarpa, P. caribaea and P. kesiya provenances. Tropical Science, 17: 165-174.

SHEN ZHAOBANG (1994) Chemical utilization of non-wood forest products in China. Nanjing: Research Institute of Chemical Processing and Utilization of Forest Products. [Unpublished report.]

Additional note

Naval Stores Review is published bi-monthly and contains trade news, information and technical papers on all aspects of the pine chemicals industry. It also includes papers from the annual International Naval Stores Conference organized by the Pulp Chemicals Association. The present annual cost of subscription (late 1994) is US$ 80 (six issues and the International Yearbook). The address for subscriptions is: Naval Stores Review, Kriedt Enterprises Ltd. 129 S. Cortez Street, New Orleans, LA 70119, USA.

The address of the Pulp Chemicals Association is: PO Box 105113, Atlanta, GA 30348, USA.

Appendix 2: Quality criteria, specifications and test methods

Rosin

Although several other criteria determine rosin quality and acceptability for different applications, colour and softening point are usually sufficient indicators of quality to satisfy purchasers of rosin from traditional and proven sources. Rosin is graded on the basis of colour, the palest being the most desirable and designated WW* ('water-white'). This grade and the slightly lower grade WG ('window-glass') are the most commonly traded rosins. A superior grade, X, is sometimes offered. Darker grades are N, M, K, I, H and lower. Rosin is a glass, rather than a crystalline solid, and the point at which is softens when heated is referred to as the softening point (rather than melting point). A softening point in the range 70-80C is usual, the higher end of the range representing the better quality.

* The notation follows the USDA colour scale for rosin which is used universally in international trade.

Since rosin is an acidic material and the manufacturer of downstream derivatives depends on its acid functionality, a high acid number (and saponification number) is also an indication of good quality. The better quality rosins usually have an acid number in the range 160-170. Provided that the acid number is high, the detailed resin acid composition of rosin is usually of little consequence or interest to the end user. An exception is rosin derived from P. merkusii which, because of the presence of a rather rare resin acid, has an acid number which is higher than normal; it may reach 190 or more. The percentage of unsaponifiable matter indicates the amount of non-acidic material in the rosin, so the lower this value, the better; anything above about 10% unsaponifiable matter would be considered a poorer quality rosin.

There are no international standards for rosin, and although the American Society for Testing and Materials (ASTM) describes standard test methods, it stipulates no specifications to which rosin should conform. The appropriate controlling bodies of some producing countries do provide specifications but, inevitably, companies and traders involved in the rosin industry have their own 'in-house' specifications which will vary from company to company, and this makes it difficult to generalize and quote 'typical' analytical data.

Table 6, which was compiled from trade sources, presents some specifications for gum rosin of different origins and may be used as a guide for assessing the acceptability of rosin by those thinking of entering rosin production.

Data such as the contents of volatile oil, insoluble matter, ash and iron (which should all be low) may be specified by producers of rosin. Other, less well defined properties, such as the tendency of the rosin to crystallize (which is undesirable), also affect its value; Chinese and, to some extent, Indonesian rosin have this particular shortcoming.

Table 6. Some trade specifications for gum rosin

Origin

Colour

Softening point (C)

Acid number

Saponification number

Unsaponifiable matter (%)

China, PR

WW

70-85

162-175


max 7.5

Portugal

WW

min 70

165-171

171-177

4.3-5.5

Brazil

X/WW

70-78

155-170

165-185

max 10

Indonesia

WW/WG

75-78

160-200

170-210


For determination of these physical data, reference should be made to the definitions and methods of analysis given by the ASTM. The following test methods concerning rosin are described (Annual Book of ASTM standards, Section 6):

D 269-92

Insoluble matter in rosin

D 464-92

Saponification number of rosin

D 465-92

Acid number of rosin

D 509-70

Sampling and grading rosin

D 889-58

Volatile oil in rosin

D 1063-51

Ash in rosin

D 1064-58

Iron in rosin

D 1065-92

Unsaponifiable matter in rosin

D 3008-90

Resin acids in rosin by gas-liquid chromatography

E 28-92

Softening point by ring-and-ball apparatus

Turpentine

Specifications for 'gum spirit of turpentine' have been published by several national bodies including the American Society for Testing and Materials (ASTM D 13-92) and the Bureau of Indian Standards (IS 533:1973). These standards were devised largely for the quality assessment of turpentine intended for use as a solvent, i.e., in whole form rather than as a chemical feedstock in which the composition is of prime importance. They generally specify parameters such as relative density or specific gravity, refractive index, distillation and evaporation residues.

The International Organization for Standardization (ISO), which is a world-wide federation of national standards institutes, has issued a standard, the main requirements of which are shown in Table 7.

A draft ISO standard for 'Oil of turpentine, Portugal type, Pinus pinaster (1994) includes physical data very similar to that in Table 7 but with the addition of a range for optical rotation (20C) of -28 to -35. Compositional ranges are also given for a number of constituents of the turpentine including alpha-pinene (72-85%) and beta-pinene (12-20%).

Table 7. Physical property requirements of the International Organization for Standardization specification for gum spirit of turpentine (ISO 412-1976)

Relative density (20/20C)

Refractive index (20C, D line)

Distillation (% v/v)

Evaporation residue (% m/m)

Residue after polymerization (% v/v)

Acid value

Flash point (C)

0.862-0.872

1.465-1.478

max 1 below 150C
min 87 below 170C

max 2.5

max 12

max 1

min 32

Turpentine purchased by the chemical industry as a source of isolates for subsequent conversion to pine oil, fragrance and flavour compounds, and other derivatives, is assessed on the basis of its detailed composition. The major demand is for turpentines containing a high total pinene content. P. elliottii turpentine contains around 60% of alpha-pinene and 30% of beta-pinene. P. radiata turpentine, noted earlier as being of exceptionally good quality, generally contains more than 95% of total pinene, of which over half is beta-pinene; it has virtually no high-boiling constituents. However, the relative proportions of other components may also influence an individual buyer's quality evaluations; 3-carene, which is found in significant proportions in the turpentine of some Pinus species (such as P. roxburghii and P. sylvestris) is of little value, and even if it is present in relatively small amounts it may be undesirable for certain applications. Depending on the variety, P. caribaea turpentine may contain up to 50% or more of beta- While such a composition does not diminish its value as a solvent for paints, it would not be attractive as a source of pinenes for derivative manufacture.

Appendix 3: Genetic factors influencing resin composition and yields

Some of the factors which affect resin yields have been referred to earlier. Genetic factors play a major role in determining both yields and composition (quality) of the resin, and a provisional judgement on the suitability of a standing resource of pines for tapping can often be made simply by consideration of the species concerned. For example P. patula, which is widely planted in Africa, gives a very poor quality resin in low yields, and is not tapped commercially anywhere in the world. P. caribaea provides turpentine and rosin of acceptable, but not exceptional quality, but it is now being recognized as a particularly high-yielding species; in Africa and Brazil it has out-yielded P. elliottii, a species often used as the benchmark by which others are judged. P. radiata, on the other hand, produces probably the best quality turpentine in the world, but resin yields are poorer than P. elliottii, for example, and it is not widely tapped.

Table 8 gives an indication of the relative quality and quantities of resin which might be expected from some species of Pinus.

Table 8. Resin quality and yield characteristics of some Pinus species

Species

Quality

Quantity

P. elliottii

++

++

P. pinaster

++

+

P. massoniana

+

+

P. merkusii

+

+

P. caribaea

+

+++

P. radiata

+++

+

P. roxburghii

+

+

P. kesiya

+

+/-

P. oocarpa

+/-

+/-

P. sylvestris

+/-

+/-

P. patula

-

-

Note: Resin characteristics are rated on a scale from very good (+++) to poor (-)

The list is not intended to be exhaustive, and no attempt has been made to provide specific quantity values based on yield data reported in the scientific literature. Such data encompass a wide range of variables (age and size of trees, climate, tapping method, etc.) and it could be misleading to quote precise figures. Site-specific factors can affect the rating either favourably or adversely, so a relatively poor rating does not mean that the species cannot be used (P. oocarpa and P. sylvestris are tapped in Mexico/Central America and Russia, respectively). Conversely, a high rating does not ensure profitability if that particular species is tapped; if temperatures are low the resin will not flow, no matter how good a yielder the species may be intrinsically.

A relatively recent development is the interest shown by foresters in Pinus hybrids. By controlled crossing of appropriate species it is possible to combine the desirable features of one species with those of another at the expense of the less favourable attributes. Recent work in South Africa, following earlier research in Australia, has confirmed the potential for improved wood production of P. elliottii x P. caribaea hybrids over the parent species. Of equal importance to naval stores production, was the finding that the hybrid also gives enhanced resin yields. In the future, Pinus hybrids may become a valuable resource for combined wood and resin production, if they are found to be suitable.

In spite of the generalizations which can be made about the suitability of certain pine species for naval stores production, intrinsic variation in resin properties can also occur within a species according to the natural population from which the trees are derived, i.e., the provenance origin; P. caribaea shows some variability between and within each of the varieties (var. caribaea, var. hondurensis and var. bahamensis). As resin composition (measured in terms of the turpentine and rosin) is easily determined and is less influenced by environmental factors than yield, most of the available information on provenance variation relates to composition rather than yield. Compositional variation is most often seen in the turpentine and can sometimes be quite marked. The turpentine from one provenance might have a high (and therefore desirable) pinene content, whereas turpentine from a different provenance might be richer in 3-carene. Rosin composition is much more stable within a species than turpentine.

If natural stands of pines are being considered for tapping, it is essential to survey the different areas where it grows in order to determine the extent of any major variation in resin quality; tapping trials at different sites should also be carried out to assess productivity. If plantation pines are derived from different provenances, samples from each provenance should be tested to ensure that they are all suitable for exploitation. Although the variability of turpentine composition may appear to impose constraints on the utilization of a pine resource, in practice it does not, particularly for a small producer. The turpentine is likely to be used locally, in whole form, rather than as a source of chemical isolates for which composition is crucial. Variations in resin yields are far more important.

If individual trees are examined, pronounced differences in resin (turpentine) composition and yields become apparent even within the same provenance. Trees of comparable size growing close to each other (and therefore experiencing identical climatic and edaphic conditions) can yield vastly different amounts of resin. In order to evaluate the productivity of a particular site, tapping trials should be designed to take account of this variability by testing a sufficient number of trees. In spite of the disadvantages, these differences offer some long term scope for improvements in quality and productivity by elite germplasm selection. In a few cases, seed orchards have been established from which superior seed can be purchased (P. elliottii in the United States, for example).

Appendix 4: Packaging of turpentine and rosin

Turpentine

International shipments of turpentine are usually made in container size (20-tonne) bulk tanks. In response to the world-wide concern for adequate safety measures to ensure the safe handling and transportation of materials that are actually or potentially dangerous substances, increasing attention is being paid by importing countries to the packaging and labelling of 'dangerous goods'. As turpentine is a flammable material it is classified under this heading.

Within the European Community, a 1979 Council Directive (79/831/EEC), which has now become mandatory, details 'laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances'. The Directive requires every package to show the name and origin of the substance, the danger symbol (e.g. a flame in a red diamond indicating a flammable liquid) and standard phrases indicating special risks (e.g. 'flammable') and safety advice. The minimum size and placement of labels is also specified. When dangerous 'substances' are transported they become 'goods', and when conveyed from one country to another they are subject to international regulations according to the means of conveyance. When sending shipments by sea, the regulations of the International Maritime Dangerous Goods (IMDG) code have to be observed. As with dangerous substances, dangerous goods have to be marked with warning labels.

Turpentine is shipped under United Nations number 1299 which means that the container must meet certain requirements; this number falls within Class 3, Packing Group III, and has to be quoted in all shipping documents. A new producer contemplating the export and international shipment of turpentine should obtain more detailed information from national transportation authorities or prospective importers.

When it arrives in the country to which it is being shipped, the importer may divide the consignment into lacquer-lined steel drums for local sales. If the importer is willing to take the turpentine in drums, they should be new galvanized steel drums of about 200 litres (170-185 kg net) capacity. Internal lacquering of the drums is usually preferred, but care should be taken to avoid cracking the lacquer layer when handling because this has an adverse effect on the turpentine.

Rosin

Requirements for the labelling of rosin for transportation into, and within, the European Community are currently (late 1994) under discussion and may not be resolved for some time. Prospective exporters of rosin to the EC or elsewhere are therefore advised to seek up-to-date information from importers in the countries concerned.

Rosin may be packaged in a variety of forms. On discharge from the still, the molten rosin is often fed into new, galvanized steel drums of around 225-250 kg (net) capacity. The drums have domed tops so that after they have been set aside for the rosin to cool and solidify (with resulting contraction in volume), the tops can be hammered flat. Alternatively, flat-topped drums can be filled in two or three stages over several days to allow for the change in volume on cooling. International shipments of rosin are also usually made in container loads. In the larger producing countries in which there are large end- consumers of rosin, transportation of molten rosin in specially designed tank-cars is feasible; this is unlikely, however, to be something which a new, smaller producer would contemplate.

End users are showing a growing preference for less robust forms of packaging to enable easier opening and handling, and in this case, silicone or polypropylene-lined multi-wall paper bags can be used. The sacks can be filled either with molten rosin directly from the still (which is then allowed to cool to form a solid block) or with flakes of solidified rosin. The flakes are formed by discharging hot rosin onto a moving belt; by the time it has reached the end of the line, the rosin has solidified into a thin sheet which can easily be broken up and transferred to bags. For ease of handling, 25 kg bags are a convenient size.

For relatively small naval stores operations, the quantities of rosin produced or the intended markets may not warrant investment in new drums or other forms of more expensive packaging, so simpler ways of handling and transporting the rosin can be used. The molten rosin from the still can be drained either into cardboard boxes supported by suitable frames, or into split drums. Solidified rosin from split drums can be broken into lumps and bagged. The disadvantage of this method is the formation of an appreciable quantity of powdered rosin which is prone to oxidation and discolouration, and which results in a poorer quality product.