Many tree species are used in traditional and modern medicine. Tree remedies are considered to be stronger, more powerful and more sustaining and protective than their healing counterparts from other plants. Remedies derived from trees, however, form a consistently small proportion of the whole plant remedy repertoire.
Since earliest times, people have gathered substances from trees to create herbal medicines to treat certain diseases.
Forest-dwelling indigenous people possess a valuable and intimate knowledge of the forest. This includes the use of forest vegetation as their primary source of medicine. This accumulation of information regarding the medicinal properties of trees has been passed down from generation to generation.
Unfortunately, the loss of forests through deforestation has resulted in the displacement of many indigenous peoples and much of this knowledge has been lost.
As forests (in particular tropical forests) are cleared or degraded, many potential cures for life-threatening diseases are also being lost. In addition, erratic and badly managed harvesting of tree elements kills trees.
Medicines can be extracted from the wood, bark, roots, leaves, flowers, fruits or seeds of trees.
Sustainable extraction of medicine from wild trees can provide an economic justification to conserve forests and the trees found there.
Although synthetic drugs have replaced many medicines that originate from trees, trees remain the main source for some specialist drugs.
Even though the proportion of medicines derived from trees is relatively small in comparison to those from other plants, some of today’s most important natural drugs come from trees.
Bark, the special outer protective covering of a tree that shields the living tree from the environment and defends it against diseases and insect attack. Consequently, the bark of many trees has medicinal properties useful to mankind.
The pain-relieving potential of the bark of the Willow Salix, has been recognized throughout history. Willow bark was commonly used during the time of Hippocrates when people were advised to chew on the bark to relieve pain and fever. Willow bark, also known as “nature’s aspirin”, contains Salicylic acid, a precursor to aspirin.
The anti-malarial drug quinine was developed from the bark of the Cinchona tree, which grows in the tropical forests of Peru and Bolivia.
An extract from the bark of the Pacific yew Taxus brevifolia, produces taxol, which is a potent drug in the treatment of certain types of cancer.
The leaves from many trees are also used for medicinal purposes. Leaves from the Maidenhair tree Ginkgo biloba, have traditionally been used in Chinese herbal medicine. The leaves from many trees are also used for medicinal purposes. Leaves from the Maidenhair tree Ginkgo biloba, have traditionally been used in Chinese herbal medicine.
There is growing evidence to suggest an association between access to urban green spaces and human mental health and well-being. Patients with views of trees from their windows recover faster and with less complications. Also, mental fatigue is reduced by exposure to trees and nature and the ability to concentrate is improved.
A joint study carried out by the University of Exeter, UK and the University of Trnava, Slovakia found that people who live in more densely forested areas are less likely to be taking anti-depressant medication.
A study conducted in Kenya by the World Agroforestry Centre (ICRAF) found that trade in herbal medicinal products is increasing in urban areas.
The majority of traditional medicines are sold as wild plant parts and this is putting increasing pressure on wild plant populations.
The study concluded that formalization of the market in Kenya has the potential to increase managed cultivation.
“Cultivation would not only provide a sustainable supply of medicinal products but also increase the incomes of poor smallholder farmers while addressing current problems of over-harvesting and resource degradation, which have reduced the abundance of wild materials,” said Jonathan Muriuki, lead author of the study and research scientist at the World Agroforestry Centre.
There is a need to identify tree species that are capable of being used for various resources, such as food and wood production as well as medicines. This could then promote recognition of the value of particular species and result in their inclusion and consideration in forest- management planning.
References: Global Trees Campaign; Trees of the world, an Illustrated Encyclopedia and Identifier, Tony Russell, Catherine Cutler and Martin Walters; Donald Purves, Herbalist; World Agroforestry Centre; The Forestry Commission UK; Food and Agriculture Organization of the UN.