It has been found that the nut collection method employed is important to the sustainability of the Brazil nut tree. However these methods can vary on a regional basis throughout the Amazon. The collection practices are generally termed as “wild harvesting” or “extractive” harvesting, where man power is used to collect the forest produce in situ from the natural environment.
For the most part, Freeworld source their Brazil nuts from northernBoliviawhere a study found that a collection rate of 93% of all fallen nuts appeared to have a minimal effect on regeneration, with populations retaining a healthy demographic structure (Zuidema & Boot, 2002). It has also been found that in the medium-term the long-lived nature of Brazil nut trees may provide a demographic insurance against nut overexploitation because seed production occurs over most of its multi-century lifespan (Zuidema, 2003).
Freeworld has built up a reliable supply base inNorthern Boliviasince the early 1990’s, now importing around 250 container loads of shield nuts per annum. From a food commodity trader’s point of view, communication is key to building these relationships; we visit the region at least annually to meet with our wide supply base and share views on the Brazil nut market, locally, nationally, and internationally.
Annually in February / March thousands of workers leave the main processing hub of Riberalta to enter the forest and begin collection. The majority of our nuts are collected in the north-east, some distance away from Riberalta and other large established communities. Here the river system is a key part of infrastructure with the Rio Madre de Dios linking Riberalta to the nut producing areas. The nut collectors, locally called “Castaneros”, use the main river system the Rio Madre De Dios for transport to the collection areas and to bring back their produce on large barge boats for processing in Riberalta. Depending on the flow of the river this journey to and from Riberalta can be a long and disrupted process.
The harvesting tends to follow a cycle year on year. Brought on by the rains, the nuts fall in December, January, February, and into the beginning of March. The collectors’ tactic is to try to hold off leaving for the forest until around 90% of the “cocos” have fallen to the ground. They do this not only for safety (a 2 kg coco falling from 35m height can be deadly), but also to maximise the number of nuts that can be collected at one time, thus reducing logistic costs. They also need to strike the right balance between collection volume and the length of time cocos have lain on the damp ground (this is to try to minimise the occurrence of rotting nuts).
Once in the forest the collectors follow well established trails leading through the dense undergrowth, that link up the dispersed trees. These trails require at least annual management to prevent the vegetation encroaching. This hacking back of vegetation may in turn help the regeneration of young Brazil nut saplings by allowing some sunlight into the undergrowth.
It is hypothesised by scientists in the field that regular collection visits by resident collecting communities during the coco falling season causes an increased level of pressure on the trees’ sustainability. There are two reasons for this, both of which are related to the impact that continual collection has on the rodent dispersal agent, the agouti. Firstly, as the cocos are collected continually over a 2 or 3 month period, the agouti has a limited window of time in which to forage for cocos on the forest floor. This can result in a reduced number of nuts that are cached by the agouti and subsequently develop into young seedling trees. The second negative effect that continual collection can have, is the over hunting of the agouti for meat by the resident collection communities. This can again reduce the level of Brazil nuts that are dispersed with a chance of regenerating by the agouti (Myers, et al., 2000).
The routine style of collection carried out in northern Bolivia may be better in terms of sustaining the Brazil nut tree population. When the cocos are on the forest floor for up to 2 months, the main seed dispersal agent, the agouti, may have ample opportunity to feed on fallen nuts and bury excess nuts before the human collectors enter the forest. Furthermore, as the collectors are not a “resident” community, the hunting pressure on agouti’s to supplement their diet, may also therefore be reduced due to a short the period of collection of 1 to 2 months.
Further research is required in this area. Although Peres et al, suggest that management of hunting pressure on seed dispersers, such as the agouti, within the Brazil nut producing regions is one way to maximise the probabilities of seed germination and seedling survival.
Freeworld believes it can help encourage good collecting practice through making information widely available via its supply chain. Distributing publications on “Best Practice” is one method Freeworld is perusing.