Shrinking resources and the issue of stewardship...

The following is a collection of information about herbs that are under threat of extinction and our suggestions for more ecologically sound substitutes: 

Aspidosperma quebracho (quebracho): Environmental Issues and Alternatives

Aspidosperma quebracho (quebracho, yellow quebracho) is an evergreen tree that predominates in the dry chaco forests of northern Argentina and Chile. It should not be confused with Schinopsis lorentzii (red quebracho of Santiago) or Schinopsis balansae (red quebracho of Chaco). These lowland forests have been the subject of severe loss of trees from 1969 to the present (Boletta, et al. 2006; Zak, et al. 2004). Seedlings do not naturally re-establish well due to ongoing disturbance of the cleared land (Barchuk and del Pilar Diaz 1999). Regrowth in cleared forests tends to be less biodiverse, includes many more invasive species, and to include fewer high-value trees such as quebracho (Bonino and Araujo 2005). Global climate change is actually bringing higher levels of rain to this area than usual which is further impairing quebracho and other native species in the normally dry forests (Bravo, et al. 2010).

Because the bark of quebracho is traditionally used for medicine, it is historically harvested in an unsustainable manner. Removing too much stem bark kills trees.

Even if these trees could be harvested sustainably (using only branch bark and engaging local people in efforts to better manage wild forests), the ecological costs of shipping this bark long distances to North America are substantial.

Given that many alternatives to quebracho exist with similar or superior properties, there is currently no reason to use this plant in North America.

Summary of Alternatives to Quebracho

 Bioregion /Alternative /Part Used

SW US / Asclepias asperula /root

NW US / Balsamorrhiza sagitatta or Ceanothus spp / root

East US / Asclepias tuberosa / root

References

 Barchuk AH, del Pilar Diaz M (1999) "Regeneration and structure of Aspidosperma quebracho-blanco Schl in the Arid Chaco (Cordoba, Argentina" Forest Ecol Manage 118:31-36.

 Boletta PE, Ravelo AC, Planchuelo AM, Grilli M (2006) "Assessing deforestation in the Argentine Chaco" Forest Ecol Manage 228:108-14.

 Bonino EE, Araujo P (2005) "Structural differences between a primary and a secondary forest in the Argentine Dry Chaco and management implications" Forest Ecol Manage 206:407-12.

 Bravo S, Kunst C, Grau R, Araoz E (2010) "Fire-rainfall relationships in Argentine Chaco savannas" J Arid Environ 74:1319-23.

 Zak MR, Cabido M, Hodgson JG (2004) "Do subtropical seasonal forests in the Gran Chaco, Argentina, have a future?" Biol Conservation 120:589-98.

Author: Eric Yarnell, ND

Last updated: 27 May 2011

Prunus africanum (Pygeum): Unsustainable Prostate Herb

Pygeum is a beautiful tree that grows across northern Africa, but the vast majority of it is harvested in Cameroon on the western side of the continent. It has long been known that most pygeum is wild harvested in an unsustainable manner (Nsawir and Ingram 2006; Cunningham and Mbenkum 1993). Mature trees are felled and all the bark stripped. Of course this kills the trees, which are not found in dense stands but generally spread out through the forest. Harvesting pygeum has significantly contribute to deforestation in Cameroon (Awung 1998).

It is understandable why people do this. They are generally impoverished and when it was discovered that people would pay for this bark, harvesting commenced. However, the people doing the harvesting are not paid well. Most of the profits go to European companies who process the bark into extracts and greatly amplify the price (Awung 1998).

There are local cooperatives cultivating and growing pygeum more sustainably (Awung 1998). Nevertheless, the fuel costs to ship the product across the ocean are still unsustainable. This is all particularly true in light of the fact that a super abundant, completely sustainable alternative with the exact same properties is readily available in North America: Serenoa repens (saw palmetto). Because its fruit is harvested, and it produces this in abundance, there is little problem with supply of saw palmetto.

 Summary of Alternatives to Pygeum

 Bioregion / Alternative / Part Used

SW US  / Urtica dioica / root

NW US / Urtica dioica / root

East US / Serenoa repens / fruit (this is the universal substitute for pygeum in North America)

References

Awung WJ (1998) "Underlying causes of deforestation and forest degradation in Cameroon" Underlying Causes of Deforestation and Forest Degradation, Africa, World Rainforest Movement. www.wrm.org.uy/deforestation/africa/cameroon.html

Cunningham AB, Mbenkum FT (1993) Sustainability of Harvesting Prunus africana bark in Cameroon. People and Plants, UNESCO, working paper 2.

Nsawir AT, Ingram V (2006) "Prunus africana: Money growing on trees? A plant that can boost rural economies in the Cameroon Highlands" FAO Nature and Fauna Journal 22:1-6.

Author: Eric Yarnell, ND

Last updated: 27 May 2011

Tabebuia spp. (pau d'arco): Environmental Issues and Alternatives

 Tabebuia (pau d'arco) has been a popular herb in the US for over 10 years. Unfortunately, this useful herb comes from the Amazon, and is harvested under conditions that are both threatening its existence and decimating the rain forest. Thus pau d'arco cannot be seen as ecologically-sustainable resource. Luckily, there are plenty of equally or more effective North American alternatives.

Pau d'arco (also known as ipe) is a valuable hardwood, in part because it is very rot-resistant. However, it grows in a highly dispersed pattern throughout Amazonia. This means that in order to obtain pau d'arco, highly destructive logging practices are generally employed (Schulze, et al. 2008). Basically a road has to be cut for long distances into the forest to get to the scattered trees, and significant damage to many other parts of the forest occur in the process. Ultimately much of logged land then ends up being converted to farm or pasture, meaning the forest cannot recover. The tree also grows very slowly, so recovery after harvest is poor. Additionally, massive amounts of the tree are harvested for use as commerical lumber, adding to the impeorilous deforestation that is occuring.

The amount of pau d'arco harvested for consumption is tiny compared to the amount used as commercial lumber and the rapid depletion of this tree for commercial lumber imperils the resource.

This same pattern has already been played out before with a non-medicinal tree with similar growth characteristics, Swietenia macrophylla (big-leaf mahogany). Harvesting this widely-dispersed tree set off the boom in destructive Amazonian logging. Big-leaf mahogany is now officially listed as an endangered species in the Convention on Trade in Interional Species. Pau d'arco is beginning to suffer a similar fate.

Luckily, several sustainable alternatives to pau d'arco exist in the United States. Two species long used from the southwestern US found in the same family as pau d'arco (Bignoniaceae) are Chilopsis linearis (desert willow) and Tecoma stans (yellow bells). Desert willow, like pau d'arco, supports the epithelial cells and their ability to resist fungi, and can be reasonable substitute when such support is required. It is not known if desert willow has the capacity to support healthy cellular function like pau d'arco, though many other herbs exist with this action and are sustainable alternatives (such as Artemisia annua). Yellow bells also faciliiates a hostile environment for microbes, and is additionally useful as supplemental support for healthy pancreatic function. Yellow bells may be sufficiently rare that it is not a preferred alternative.

A Pacific Northwest native tree with similar properties is Thuja plicata (red cedar). From other parts of the northern hemisphere, Thuja occidentalis (arbor vitae) bark can be substituted. Both these trees are common, not threatened by overharvesting for any purposes, and are not popular herbs of commerce as to suggest a potential for becoming overharvested.

In summary, there is no ecologically-defensible reason to use pau d'arco for use in North America. Sustainable, local alternatives with similar activity are readily available. The lesson of the near extinction of big-leaf mahogany is now being repeated with pau d'arco, and individuals who use it should think twice before they blithely contribute to a reapeat occurence. Overharvesting of pau d'arco is contributing to rapid degradation of the Amazon for many other reasons.

 Summary of Alternatives to Pau D'Arco

 Bioregion / Alternative / Part Used

SW US / Chilopsis linearis / leaf

NW US / Thuja plicata / bark or leaf

East US / Thuja occidentalis / bark

References

Dauber E, Fredericksen TS, Peña M (2005) "Sustainability of timber harvesting in Bolivian tropical forests" Forest Ecol Manag 214:294-304.

Keefe K, Schulze MD, Pinheiro C, et al. (2009) "Enrichment planting as a silvicultural option in the eastern Amazon: Case study of Fazenda Cauaxi" Forest Ecol Manag 258:1950-9.

Schulze M, Grogan J, Landis RM, Vidal E (2008) "How rare is too rare to harvest? Management challenges posted by timber species occurring at low densities in the Brazilian Amazon" Forest Ecol Manag 256:1443-57.

Schulze M, Grogan J, Uhl C, et al. (2008) "Evaluating ipe (Tabebuia, Bignoniaceae) logging in Amazonia: Sustainable manage or catalyst for forest degradation?" Biological Conservation 141:2071-85.

Author: Eric Yarnell, ND

Last updated: 27 May 2011

Ulmus rubra (slippery elm): Environmental Issues and Alternatives

Also known as Ulmus fulva, slippery elm is a well known herb, the inner bark being a tasty and mucilaginous. Sadly, this lovely and helpful tree is susceptible to Dutch elm disease, a fungal infection that can directly kill the tree or make it highly susceptible to bark beetles. The result has been the death of most large, old trees in the Southeast (though smaller ones still survive) and an ongoing extinction threat to the species. Most mature elms in Britain and Europe have been eradicated by the disease.

While small suckering hedgerows and bushes of slippery elm can survive and be kept in cultivation, harvesting from any mature tree is not recommended due to the potential increased risk of introducing infection.

There are so many other effective and plentiful demulcents, it just does not make sense to use slippery elm in our opinion.

Alternatives to Slippery Elm

All the following are easily cultivated or abundant demulcent herbs:

 Althaea officinalis leaf or root

Symphytum officinale leaf or root

(short-term use only)

Verbascum thapsus leaf or flower

Zea mays stigmata

References

Cooley JH, Van Sambeek JW (1990) "Ulmus rubra Muhl. Slippery elm" In: Silvics of North America. Burns RM, Honkala BH (ed). US Forest Service Agriculture Handbook 654. http://www.na.fs.fed.us/pubs/silvics_manual/table_of_contents.shtm