Ecology and ethnobotanical usage of Dracaena cinnabari on Socotra Island – Republic of Yemen

Abdulraqeb Shamsan Al-Okaishi, M.Sc.

Doctoral thesis

Ecology and ethnobotanical usage of Dracaena cinnabari on Socotra Island

Abstract:

This dissertation entitled “Ecology and ethnobotanical usage of Dracaena cinnabari on Socotra Island-Yemen Republic” consists of four papers. Two papers are focusing on ecological part and two on ethnobotanical part. The first paper is entitled “Sap Flow Measurements in a Socotra Dragon’s Blood Tree (Dracaena cinnabari) in its Area of Origin”. The Second paper is titled “Long-term in situ sap flow monitoring in a mature Dracaena cinnabari tree on Socotra. The third titled “Local Management System of Dragon’s Blood Tree (Dracaena cinnabari Balf. f.) Resin in Firmihin Forest, Socotra Island, Yemen”. The fourth and last paper entitled “Exploring historical distribution of Dracaena cinnabari tree using ethnobotanical knowledge-Socotra Island, Yemen”. The first and second papers are focused on sap flow measurements of Dracaena cinnabari tree using the heat field deformation method with single and multi-point sensors. Both studies were conducted in situ on adult tree in its area of origin-Socotra Island for the first time. The findings of first paper indicated that sap flow variability in different parts of D. cinnabari is higher than in dicots and this variability is stimulated by sunlight and the maximum was in stem influenced by sun exposure, similar to that observed in adult Dracaena draco tree. The results also show that water movement in both Dracaena species may occur in any direction. The second sap flow measurement was conducted on the same tree but in driest period of year. The study confirms the free lateral flow. The study emphasized the importance of fog for replenishment of internal storage and the dynamic water flow between roots and stem derived by transpiration and sun exposure. The findings highlighted the useful of plant architecture and anatomical structure and the connection from the root through the stem and branch to the leaves in D. cinnabari internal and external water management. Overall, the study shows the ability of D. cinnabari tree to benefit from atmospheric water for survive long periods of drought and poor soil on karst rock area. The third paper was conducted in Firmihin Forest, it described the traditional management system for dragon’s blood resin, which have been famous product in ancient time and is still collected until today. The study findings that the current tapping technique which include cutting part of the bark is damaging the tree. Results show that most of the trees in the study area have wounds. The study concludes that the current traditional management system is unsustainable and more environmentally friendly harvesting technique and forest certification scheme can be introduced for improving overall management of this species which is listed as vulnerable by the IUCN (International Union for Conservation of Nature) Red List. The fourth paper recorded place names (toponyms) in four selected areas on Socotra Island. The findings revealed that some existing phytotoponyms (place names referred to plants) referred to D. cinnabari. The distribution of these place names serves as a reminder of the wider expansion of this species in the past over the entire surface of the island, especially in the middle and high altitudes. The tracking of the historical names of dragon’s blood revealed the presence of several old names, especially for the dragon’s blood resin, as well as a weak similarity with the current names. The results show similarity between current Dracaena trees’ names in the Arabic language. As a result of appearing the name “Ahrieb” in its various forms on Dracaena trees in the Arabic language, the study suggests adopting the name as a common Arabic name for the trees and “Dum al-akhawin” for the resin which appeared continuously in the old literature due to its famous medicinal use. The overall study shows special adaptation of D. cinnabari tree for harsh arid environment and its survival strategy. More studies on ecology and ph

Abstract:

ysiology of D. cinnabari means better management decision. The study shows rich ethnobotanical knowledge of local communities on Socotra Island which can be innovative tool for better understanding of individual species ecology and general Island environment especially with unique, isolated and preserved language.

Abstract:

This dissertation entitled “Ecology and ethnobotanical usage of Dracaena cinnabari on Socotra Island-Yemen Republic” consists of four papers. Two papers are focusing on ecological part and two on ethnobotanical part. The first paper is entitled “Sap Flow Measurements in a Socotra Dragon’s Blood Tree (Dracaena cinnabari) in its Area of Origin”. The Second paper is titled “Long-term in situ sap flow monitoring in a mature Dracaena cinnabari tree on Socotra. The third titled “Local Management System of Dragon’s Blood Tree (Dracaena cinnabari Balf. f.) Resin in Firmihin Forest, Socotra Island, Yemen”. The fourth and last paper entitled “Exploring historical distribution of Dracaena cinnabari tree using ethnobotanical knowledge-Socotra Island, Yemen”. The first and second papers are focused on sap flow measurements of Dracaena cinnabari tree using the heat field deformation method with single and multi-point sensors. Both studies were conducted in situ on adult tree in its area of origin-Socotra Island for the first time. The findings of first paper indicated that sap flow variability in different parts of D. cinnabari is higher than in dicots and this variability is stimulated by sunlight and the maximum was in stem influenced by sun exposure, similar to that observed in adult Dracaena draco tree. The results also show that water movement in both Dracaena species may occur in any direction. The second sap flow measurement was conducted on the same tree but in driest period of year. The study confirms the free lateral flow. The study emphasized the importance of fog for replenishment of internal storage and the dynamic water flow between roots and stem derived by transpiration and sun exposure. The findings highlighted the useful of plant architecture and anatomical structure and the connection from the root through the stem and branch to the leaves in D. cinnabari internal and external water management. Overall, the study shows the ability of D. cinnabari tree to benefit from atmospheric water for survive long periods of drought and poor soil on karst rock area. The third paper was conducted in Firmihin Forest, it described the traditional management system for dragon’s blood resin, which have been famous product in ancient time and is still collected until today. The study findings that the current tapping technique which include cutting part of the bark is damaging the tree. Results show that most of the trees in the study area have wounds. The study concludes that the current traditional management system is unsustainable and more environmentally friendly harvesting technique and forest certification scheme can be introduced for improving overall management of this species which is listed as vulnerable by the IUCN (International Union for Conservation of Nature) Red List. The fourth paper recorded place names (toponyms) in four selected areas on Socotra Island. The findings revealed that some existing phytotoponyms (place names referred to plants) referred to D. cinnabari. The distribution of these place names serves as a reminder of the wider expansion of this species in the past over the entire surface of the island, especially in the middle and high altitudes. The tracking of the historical names of dragon’s blood revealed the presence of several old names, especially for the dragon’s blood resin, as well as a weak similarity with the current names. The results show similarity between current Dracaena trees’ names in the Arabic language. As a result of appearing the name “Ahrieb” in its various forms on Dracaena trees in the Arabic language, the study suggests adopting the name as a common Arabic name for the trees and “Dum al-akhawin” for the resin which appeared continuously in the old literature due to its famous medicinal use. The overall study shows special adaptation of D. cinnabari tree for harsh arid environment and its survival strategy. More studies on ecology and ph

Abstract:

ysiology of D. cinnabari means better management decision. The study shows rich ethnobotanical knowledge of local communities on Socotra Island which can be innovative tool for better understanding of individual species ecology and general Island environment especially with unique, isolated and preserved language.

Keywords

Ethnobotany, Sap flow, Dracaena cinnabari, Ecology, Toponym

Keywords

Sap flow, Ethnobotany, Dracaena cinnabari, Ecolgoy, Toponym

Language used: Czech

Date on which the thesis was submitted / produced: 12. 1. 2021

Thesis defence

• Supervisor: prof. Dr. Ing. Petr Maděra

Mendel University in Brno

Faculty of Forestry and Wood Technology

Doctoral programme / field:
Botany / Forest Phytology