Although there are potential uses for G. keule, the tree has never been cultivated for exploitation. This may be attributed to its scarcity, isolation and difficult propagation. There is no information about the exploitation of G. keule by pre-Columbian populations, i.e. before the 16th Century, but since the earliest mention of the tree, documents have indicated some of its uses, especially its fruit. Traditional uses and knowledge of G. keule may disappear because of the need to conserve the tree and cultural changes in local rural communities (Muñoz and Garrido 2004a). One of the persons most informed about the uses of the plant was the Spanish author Hipólito Ruiz, who led an expedition to Peru and Chile. However, the many setbacks the expedition suffered, including a fire in Peru and a shipwreck in Portugal, both in 1785, resulted in loss of material and records from Chile, especially from Concepción (Jaramillo-Arango 1952; Ruiz 1998). In general, the use of the tree includes its exploitation for food and timber with potential for ornamental and medicinal purposes (Muñoz-Concha and Garrido 2006).
1.10.1 Fruits
The first mention of the uses of G. keule was in the Spanish chronicle of Jeronimo de Vivar in 1558 (Torrejón and Cisternas 2003), who described a syrup and beverage being made from the fruit. In his writings of 1674, De Rosales described the fruit as tasty and edible, either
fresh or cooked, while noting the presence of the endocarp (De Rosales, 1877). Another Jesuit, the Catalan Father Andres Febrès, a missionary in the Concepción area, wrote one of the first Spanish-Mapuche dictionaries (Febrès 1765) which included the word queul, stating
‘a yellow fruit with a small stone within’. The abbot Molina (1782) described the tree as producing delicious fruit. Ruiz and Pavon (1798) described the fruit as non-juicy but sweet, pleasant and strong flavoured. Later, the same authors compared the shape and size of the fruit with a small hen’s egg, with an attractive lustrous yellow colour (Ruiz 1998).
In work that reviewed many species as fruit plants for potential cultivation in England, Lindley (1824) described G. keule as the most promising of Chilean species. Reiche (1901) recommended the cultivation of the tree as the second in importance among Chilean native species after Araucaria araucana and indicated that if a crop was developed, it would provide fruits as valuable products (Reiche 1937). Albert (1924), a German scientist who contributed to rural and environmental affairs in the early 20th Century in Chile, listed plant foods of the country and mentioned jam of G. keule fruits as suitable for exporting to Europe in small quantities.
The fruits, produced in abundance in the autumn (San Martín and Donoso 1996; San Martín 2005), are well known by local people (Hechenleitner et al. 2005) who have used by them for years (Le Quesne and Stark 2006). Consequently, collecting fruits is considered a traditional activity (Muñoz 1986). Muñoz and Garrido (2004a) mentioned the fruits were collected by local people in April and May in some rural localities in the VIIth and VIIIth regions. Fruits were used in Concepción (Reiche 1937) and sold in abundance in the local market (Espinosa 1948), although several years later Donoso (1984) reported the fruits to be scarce but still in demand in the same markets. Serra et al. (1986) also mentioned that, until recently, farmers harvested and sold the fruits at markets. More recently, Maldonado (1990) purchased fruits at markets in Concepción as a source of material for germination experiments, while Saavedra and Matamala (2000) reported that local people from Tomé (VIIIth region) harvested fruits to sell.
The edible sarcocarp of the fruit has an appealing smell and yellow colour (San Martín 2005), with a soft flesh (Reiche 1937), good flavour (Moesbach 1992), juicy with a sweet pulp (Reiche 1901; Albert 1924), aromatic (Albert 1924) and savoury (Kubitzki 1993). The fruits are used to prepare jam (Espinoza 1897; Albert 1924; Reiche 1937; Muñoz 1973; Rodríguez
compote (Espinosa 1948) and alcoholic beverages (Hechenleitner et al. 2005). The fruit is consumed fresh, cooked, grilled (Albert 1924) and canned.
Using sensory evaluation, fresh fruit showed high acceptability and hardness, sweetness and aroma (Muñoz and Garrido 2004b), with low acidity, bitterness and astringency (greater in the peel than in the pulp). Soluble solids measured in the pulp of ripe fruits were, on average, 18.9 ºBx, a measurement common in the food industry to estimate sugar content. The value recorded, with other agronomic characteristics, makes the fruit an interesting potential crop for development (Muñoz et al. 2003). Fruits can also be consumed by cattle (San Martín and Donoso 1996). Le Quesne and Stark (2006) indicated that the seeds are edible, a fact not reported elsewhere in the literature, although Muñoz (1986) stated the seeds are soft, oily and have a taste reminiscent of the seeds of the Chilean palm, Jubaea chilensis.
When consumed to excess, fruits induce headaches (Ruiz 1998) or cause intoxication (Gil 1932; Santa Cruz 1932), especially when ripe and even when processed in syrup (Mariani 1965). They may be hallucinogenic (Schultes 1983) and irritant (Emboden 1979). Rodríguez (2004) mentioned that in order to prevent intoxication, local people soaked fruits in water before preparing jam. The fruits were formerly an important narcotic in Chile (Mabberley 1997), but this statement should be regarded with caution as the author was probably reviewing the literature of Schultes (1983). However, Mariani (1965) mentioned the intoxicating property of fruits is used by the machi, the Mapuche shaman, although he did not consider the species as being amongst the most important plants with narcotic properties for the Mapuche people. Emboden (1979) also stated that the Mapuche people utilize fresh fruit for narcotic properties, while Schultes (1983) added that they valued the tree as a psychoactive drug. Acevedo and Córdova (2004) mentioned that the fruits may act as stimulants (aphrodisiacs), although evidence and additional information were not provided.
Clearly, the ethnobotanical knowledge of G. keule must be improved through more precise responsible for the intoxicating effects, but are destroyed when the fruit is cooked. In contrast, Urzúa et al. (1982) were unable to detect alkaloids in G. keule; Palma (2008) reported that alkaloids were not detected in immature or mature fruits, but in leaves. Santa Cruz (1932) mentioned processed fruit would still be intoxicating and suggested, as also reported by
Emboden (1979) and Schultes (1983), that the chemical compounds responsible for this effect may be essential oils, the latter being more potent in fresh than in dried fruits. Clearly, more research is needed to clarify the nature of the secondary products synthesised by G. keule.
1.10.2 Wood
Several authors described the wood as very durable and hard, with a beautiful grain (Ruiz and Pavon 1798; De Rosales 1877; Muñoz 1962; Rodríguez et al. 1983; Donoso 1984), especially at the base of the trunk (Albert 1924). Jaramillo-Arango (1952) and Ruiz (1998) considered the wood as fine, with a good lustre after being polished. Albert (1924) reported the wood is white-yellowish in the sapwood and dark red in the heartwood, somewhat fragrant when fresh, with regular weight, hardness and elasticity. The wood has been used for general carpentry, furniture production (Ruiz and Pavon 1798; De Rosales 1877), construction of buildings, charcoal and firewood (Espinosa 1948; Rodríguez et al. 1983). Reiche (1901) mentioned G.
keule as one of the main Chilean woods with potential use for building, furniture and lathe work, especially in the central-south region of the country, while Albert (1924) also recommended it for the production of luxury furniture, veneer and inlay work. In the few places where usable trees remained, wood was used for furniture until 20 years ago (Muñoz 1986). Muñoz and Garrido (2004a) mentioned the wood was commercialised at Cauquenes, in the VIIth region of Chile. Anatomically, Stern (1955) reported the wood of G. keule to be diffuse-porous, with vessel diameters of 20 - 64 m, scalariform perforation plates, with tracheids, vascular rays generally being 2 cells in width and 5 - 12 cells in height without secretory cells. This investigation was extended to include additional samples by Stern and Greene (1958).
1.10.3 Other uses
Ruiz and Pavon (1798) observed that fragrant odours are released when leaves of G. keule are abraded, leaves having a bitter and “balsamic” taste. Ruiz (1998) added that because of their resin content, the leaves stick to the teeth when chewed; when crushed between the fingers, they emit a fragrance suggestive of rosemary and spirits of turpentine. In judging its aromatic
that the leaves are aromatic and yield a medicinal oil, although Gil (1932) stated that, in the 1930s, the tree was not used in medicine. The last author also observed essence-bearing cells in the leaf parenchyma and the mesocarp, in agreement with Doweld (2001). Rodríguez (2007) extracted essential oils of G. keule by steam distillation and obtained an average yield of 0.73 ml/100g of dry leaves. She also reported the public’s acceptance of soap and air deodorants made with these essential oils.
In the first work on the chemical constituents of the essential oil of G. keule, Oses et al.
(2002) detected α-terpinene, 3-carene, camphene and 1,8 cineol, and suggested antimicrobial properties of this essential oil. In a more recent chemical characterization of G. keule essential oils, Bittner et al. (2008) detailed the constituents and proportions as 1,8 cineol (35.57 %), α-pinene (7.30 %), limonene (5.40 %), β-α-pinene (5.30 %), α-terα-pinene (7.17 %), (+)-3-carene (5.17 %), β-phellandrene (0.70 %) and other compounds (33.39 %). The same authors found that G. keule oil was effective against granary weevils, suggesting its potential for insect control in grain storage. Clearly, an adequate source of plant material must be developed before any commercial initiative is launched, because of the difficulties associated with conservation of G. keule.
The chemical composition of bark and wood has been investigated. Vilegas et al. (1991) detected a novel cinnamoylglucose and two coumarins, namely scoparone and scopoletin in the bark, confirming earlier results of Urzúa et al. (1982). However, scopoletin and other 2 coumarins were not detected in later analyses and were possible artefacts (Vilegas and Lanças 1995). Additional compounds have been detected in bark and wood, these being linear unsaturated fatty acids, steroids such as sitosterol, and unidentified phytosteroids, as well as lauric, tridecanoic, myristic and pentadecanoic acids (Vilegas and Lanças 1995).
In relation to its ornamental potential, the tree was described as one of the tallest and most splendid in Chile, with a rich green colour (Ruiz 1998) and a beautiful, leafy profile (Valenzuela 1919; Donoso and Escobar 1985; Moesbach 1992) of potential ornamental value (Muñoz 1986). Rodríguez (1988) and Riedemann and Aldunate (2003) considered the foliage and fruits, with their contrasting colours, as excellent attributes for ornamental purposes. They recommended cultivation of the tree on good quality, humid soils avoiding full sun. Reiche (1896) recommended its planting as a fruit and ornamental tree in places not subjected to freezing temperatures, while Rodríguez et al. (1995) suggested its use for public parks, streets and flower gardens. G. keule has been planted as ornamental in Concepción (Bullock and Stern 1959). The tree has potential as a fruit crop, as an ornamental, as well as for the chemical industry because of its essential oils (Del Fierro 1998).