Sustainable harvesting of Frankincense trees in Oman
Sustainable harvesting of Frankincense trees in Oman
Final Report
December 2014
Principal Researcher: Mohsin Musalim Al-Aamri (Ph.D) Technical Assistant: Badar Musthal Al-Shanfari
Sustainable harvesting of Frankincense trees in Oman
Acknowledgements
By Dr. Mohsin Al Aamri
The execution of this project was made possible due to the generous financial support by “HSBC” bank. I express sincere gratitude on the behalf of ESO board and members to HSBC for extending help and support throughout the duration of this project.
However, this project was almost impossible without the overwhelming interest and support from ESO. His Highness Sayyid Tarik Shabib Al Said, Patron Environment Society of Oman. Her Highness Sayyida Tania Shabib Al Said President ESO, Executive Director of ESO, Lamees Abdullah Daar. Many thanks to my friend Dr Mehdi Ahmed Jaaffar Vice President ESO who was supporting all along since the project was contemplated, visiting the project in field, and helping out in writing the report. I am also thankful to Badar Al-Shanfari who worked hard with me during the hectic, hot and as well as cold days. I am also thankful to Shamis Al-Masahali and Mumen Al-Masahali for their warm hospitality at the beginning of the project, sharing their knowledge, helping in tree harvesting and selecting the locations. I also thank Ms. Nida El Helou former manager of ESO for her relentless efforts to make this project possible, and Mrs. Maïa Sarrouf Willson, Project Manager of ESO then. Many thanks to Ms. Alexsandra Celini for her help in weather data collecting.
Last but not least, I would like to thank my children, Sultan, Tafool, Ahmad and Junaid for their patience, during the project. I remember how sad they were in the week end, when they wanted me to take them somewhere and I say I am busy in the project, and I hope they will understand the importance of volunteering work.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ...... VI 1. INTRODUCTION ...... 1 2. PROJECT DESCRIPTION ...... 2
2.1. PROJECT RATIONALE AND STUDY NEED ...... 2 2.2. PROJECT OBJECTIVES ...... 3 2.3. PROJECT SITE ...... 3 2.4. PROJECT ACTIVITIES ...... 4 2.5. USED TERMINOLOGY ...... 5 2.6. PROJECT TEAM ...... 5 3. FRANKINCENSE OVERVIEW: CHARACTERISTICS, USES AND THREATS ...... 7
3.1. TAXONOMY ...... 7 3.2. ECOLOGY AND HABITAT ...... 7 3.3. DISTRIBUTION & AVAILABILITY ...... 8 3.4. PROPAGATION AND DOMESTICATION ...... 9 3.5. FRANKINCENSE: FROM TREE TO MARKET ...... 10 3.6. MEDICINAL USE ...... 12 3.7. THREATS TO THE BOSWELLIA SACRA POPULATION ...... 12 a) Over Grazing ...... 12 b) Gravel mining ...... 13 c) Incorrect Tree Tapping Practices ...... 13 d) Termite and Insects ...... 14 4. FIELD WORK METHODOLOGY ...... 16
4.1. OVERVIEW ...... 16 4.2. DESCRIPTION OF THE PROJECT FIELDWORK ...... 16 a) Tree Tapping: Definition and Concept ...... 16 b) Weather Stations ...... 17 c) Fieldwork Overview ...... 18 d) Sustainable Harvesting Experiments ...... 20 e) Flowering and Seed Experiments ...... 24 5. RESULTS ...... 26
5.1. SUSTAINABLE HARVESTING: OLIBANUM YIELD AND TREE SIZE ...... 26 5.2. SURVIVAL OF BOSWELLIA SACRA ...... 31 5.3. HEALTH STATUS AFTER FOUR YEARS OF TAPPING ...... 31 5.4. YIELD VARIATION DURING CUTTING CYCLE ...... 32 5.5. FLOWERING & SEEDS ...... 33 5.6. CLIMATE & AGRO-ECOLOGICAL ZONES ...... 36 a) Climate ...... 36 b) Temperature ...... 36 c) Relative Humidity ...... 37 d) Wind Speed ...... 37 e) Rainfall ...... 37 5.7. SUMMARY OF PRINCIPAL FINDINGS ...... 37 6. RECOMMENDATIONS ...... 40
6.1. TREE HARVESTING NORMS ...... 40 6.2. PILOT OLIBANUM FARM ...... 41 6.3. MANAGEMENT PLAN ...... 41 6.4. SCIENTIFIC RESEARCH ...... 42 6.5. AWARENESS ...... 42 7. CONCLUSION ...... 43 REFERENCES ...... 44
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APPENDIX 1: DESCRIPTION OF VARIOUS MEDICINAL USES OF FRANKINCENSE ...... 1 a) Inflammatory Diseases ...... 1 b) Heart Disease ...... 1 c) Asthma ...... 1 d) Skin Diseases ...... 1 e) Inflammatory Bowel Disease ...... 1 f) Cancer ...... 2 g) Diabetes ...... 3 h) Antimicrobial Effects ...... 3 i) Memory Problems ...... 3 j) Fertility ...... 4 APPENDIX 2: WEATHER STATION RESULTS OF LOCATION 1 (ARDIT) ...... 5 APPENDIX 3: WEATHER STATION RESULTS OF LOCATION 2 (AFULL) ...... 7 APPENDIX 4: WEATHER STATION RESULTS OF LOCATION 4 (KDAT) ...... 9
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LIST OF BOXES
BOX 1: DETAILS OF THE DIFFERENT SUSTAINABLE HARVESTING EXPERIMENTS ...... 23
LIST OF FIGURES
FIGURE 1: MAPS SHOWING THE SELECTED PROJECT SITES ...... 4 FIGURE 2: THE MOST DANGEROUS INSECTS TO BOSWELLIA SACRA ...... 15 FIGURE 3: DIFFERENT STAGES OF TAPPING BOSWELLIA SACRA AND HARVESTING THE RESIN ...... 19 FIGURE 4: YIELD IN GRAMS FROM THREE DIFFERENT TREE SIZES ...... 28 FIGURE 5: MEAN YIELD IN GRAMS IN FOUR AGRO-ECOLOGICAL ZONES ...... 29 FIGURE 6: MEAN YIELD IN FOUR YEARS IN THE FOUR PROJECT LOCATIONS ...... 29 FIGURE 7: YIELD VARIABLE DURING CUTTING CYCLES ...... 33 FIGURE 8: EFFECT OF THE CUTTING NORM ON THE FLOWERING PERCENTAGE ...... 35
LIST OF PHOTOS
PHOTO 1: OVERVIEW OF SITE 3 SHOWING FRANKINCENSE TREES ...... 4 PHOTO 2: OVERVIEW OF SITE 1, FRANKINCENSE TREES ASSOCIATED WITH JATROPHA DHOFARICA ...... 4 PHOTO 3: BOSWELLIA SACRA GROWS IN ROCK CRACKS ...... 9 PHOTO 4: BOSWELLIA SACRA’S NATURAL FLOWERS AND FRUIT ...... 10 PHOTO 5: OLIBANUM OOZING FROM PLANT DUCT ...... 10 PHOTO 6: BOSWELLIA SACRA TREE GRAZED BY CAMELS ...... 13 PHOTO 7 AND PHOTO 8: ROCK EXPLOSION AND GRAVEL STORAGE AROUND A PIT ...... 13 PHOTO 9: PROPER WAY OF CUTTING SIZE AND DEPTH WITHOUT HARMING THE TREE ...... 14 PHOTO 10: IMPROPER WAY OF TREE CUTTING ...... 14 PHOTO 11: THREE DIFFERENT CUTS IN THE TRUNK OF THE FRANKINCENSE TREE WITH THE RESIN MOST OBVIOUS IN THE OLDER ONE TO THE LEFT ...... 17 PHOTO 12: ESO’S FORMER VICE PRESIDENT, DR. MEDHI AHMED JAFFAR, CHECKING THE WEATHER STATIONS ...... 18 PHOTO 13: LEAD RESEARCHER CHECKING THE TREE TAGS ON THE FIELD...... 20
LIST OF TABLES
TABLE 1: SUMMARY OF THE FOUR LOCATIONS OF THE PROJECT FIELDWORK ...... 3 TABLE 2: SYSTEMATIC CLASSIFICATION OF BOSWELLIA SACRA ...... 7 TABLE 3: NUMBER OF TAPS DEPENDING ON TREE SIZE, IN A NORMAL AND DOUBLE CUTTING NORM ...... 20 TABLE 4: TRIALS IN THE SUSTAINABLE HARVESTING EXPERIMENT ...... 21 TABLE 5: HARVESTING SEQUENCE DURING THE STUDY ...... 22 TABLE 6: SUMMARY OF MEAN TEMPERATURES IN THE STUDY SITES ...... 24 TABLE 7: YIELD AND HEALTH STATUS OF TREES AFTER FOUR YEARS IN LOCATIONS 1 & 2 ...... 27 TABLE 8: YIELD AND HEALTH STATUS OF TREES AFTER FOUR YEARS IN LOCATIONS 3 & 4 ...... 27 TABLE 9: COMPARING YIELD (GRAMS), NORMAL CUT AND DOUBLE CUT ...... 31 TABLE 10: TEMPERATURE EFFECT ON TREE FLOWERING OF BOSWELLIA SACRA ...... 34 TABLE 11: EFFECT OF THE CUTTING NORM ON FLOWERING ...... 34 TABLE 12: TREE SIZE AND RECOMMENDED TAPS ...... 41
TABLE A1 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 1 ARDIT, IN 2011 5 TABLE A2 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 1 ARDIT, IN 2012 5 TABLE A3 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 1 ARDIT, IN 2013 6
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TABLE A4 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 2 AFULL, IN 2011 7 TABLE A5 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 2 AFULL, IN 2012 7 TABLE A6 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 2 AFULL, IN 2013 8 TABLE A7 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 4 KDAT, IN 2011 9 TABLE A8 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 4 KDAT, IN 2012 9 TABLE A9 : MEAN MONTHLY TEMPERATURE (C°), RAINFALL (MM), RELATIVE HUMIDITY %, WIND GUST KM/H AT LOCATION 4 KDAT, IN 2013 10
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Executive Summary
Frankincense, also called olibanum (from the Arabic word ‘luban’ which means milk) is an aromatic resin obtained from trees of the genus Boswellia. It is produced by tapping the tree and making a thin vertical slicing into the tree trunk. The English word is derived from old French “Franc encens” and is used in incense and perfumes as well as various medicinal uses. The resin is available in various grades, which depend on the time of harvesting, the area of production, the size on the trunk, the age and wellbeing of the tree, and weather conditions. The resin is hand-sorted to obtain the best quality.
Many environmental and anthropogenic factors threaten the population of Boswellia sacra such as over grazing, gravel mining, termite and insects and incorrect tree tapping practices. The latter is a major cause to the severe decline of the species as intensive tapping regimes cause poor natural regeneration and impact the fertility, flower density and seed germination of the tree.
This purpose of this study, funded by HSBC Oman, is to study the sustainable harvesting techniques of frankincense and to ascertain the effect of tapping methodology on yield production and tree wellbeing. There has been no previous significant field research addressing this pressing issue in Oman.
The fieldwork took place in four experimental research locations where 180 naturally grown trees of different heights, age groups as well as weather and terrain were monitored. Each location had 45 trees and the observations were carried out over four years. Three meteorological stations recorded weather parameters to determine their overall effects on the yield production.
The results showed that the initial cut size develops into a wider and deeper wound as tapping cycles proceed. The optimal size of tapping should not exceed a surface of 12 cm2 (3 cm high x 4 cm wide), barely shaving the external layer of the trunk. The number of taps depends on the tree height, the trunk size and the foliage cover and should be around 30 cm distance from each other. This harvesting best practice reduces the side effect of tapping on trees and guarantees their overall wellbeing and seed germination. Tree tapping should be stopped 2-3 weeks before the rainy season (Al Aamri, 2012).
A comprehensive poster has been designed to inform practitioners on the sustainable harvesting of Frankincense, which is vital to the survival of this endemic tree. The completion of project activities resulted in important scientific findings, some of which are listed below.
Findings related to harvesting cycles
Tree harvesting can be continual for three years, but must be followed by a one to two year rest, in order to allow the scar to heal. Trees are to be harvested seven months per year (from November to May), and the harvesting period extends over 21-28 days rotational period. In the hotter months (April-March) the tree needs to be harvested in 14-days rotational period. The tree reaches its maximum olibanum yield productivity in its third or fourth harvesting sequence and in the third harvesting year.
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Findings related to harvesting methods
The trees that were heavily tapped throughout the study produced less flowers than the non-tapped trees. The yield estimation can be determined from a single tree according to location, height, form and the overall tree vigour. It was found that the lower part of the tree trunk produces more resin while the yield is reduced in the upper parts of the trunk. Frankincense trees flower, produce seeds and mature differently. The tree have a slow growing nature and is associated with poor seed germination which poses an implicit threat to Boswellia sacra reproduction.
Findings related to climatic conditions
Climatic factors have an effect on the Frankincense yield (amount of Frankincense produced). The trees studied in Monsoon affected areas have produced more resin than other trees. The main climatic factors responsible for desertification in Dhofar Mountains where frankincense naturally grows are mainly low precipitation and strong wind.
It is recommended to build on the following actions to conserve the frankincense tree population in Dhofar and promote its sustainable harvesting by: Establishing a tree harvesting norm that sets some basic harvesting guidance such as the number of taps per tree, starting time in each zone, harvesting frequency (how many cycles per year) etc. Establishing a pilot olibanum farm that could serve as a gene bank, a centre for research and a tourist attraction. Developing a management plan that sets certification of Omani frankincense and a permitting system for its harvesting. Investing in scientific research to further improve the understanding of frankincense varieties and harvesting and sorting. Spreading awareness among a diversified audience for the conservation of the tree.
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1. Introduction
In 2006, the Environment Society of Oman (ESO) submitted a research proposal related to the sustainable harvesting of Frankincense trees to HSBC Oman. The project was approved in 2010, and work started in February 2010 to determine the suitable way of harvesting frankincense trees in Dhofar without causing adverse impacts to the frankincense yield and the tree survival.
Four study locations were selected based on the slope of the land and the variation of weather patterns in the northern and southern slopes of the Dhofar mountain range. In addition to determining sustainable exploitation methods, the project committed to study the potential impact of climatic changes on the tree growth pattern. Three weather stations were installed to fit that purpose in three out of four locations of the study area.
This study is of crucial importance in setting best practices for frankincense yield production as no significant field research has been done in the past on the sustainable harvesting of olibanum trees in Oman.
This report aims to present the findings of the study in seven different sections. A project description is given in Section 2 presenting the study rationale, the project objectives, a description of the project site and activities and an introduction to the project team. An overview of the frankincense tree characteristics, uses and threats is given in Section 3. The fieldwork methodology is presented in Section 4, followed by the field work results in Section 5. A list of recommendations is given in Section 6 and finally, Section 7 concludes the report.
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2. Project Description
2.1. Project Rationale and Study Need
The Frankincense tree Boswellia sacra is without a doubt the most famous plant of Dhofar and has given the region a vital economic importance through its trade between eastern and western civilizations (Miller & Morris, 1988). Frankincense has long been the main source of income in Dhofar and the only known exported product of the region (Al-Gasani, n.d.). The frankincense tree produces the valuable resin through tapping and has many other uses deriving from its foliage and bark (Al-Amri, 2002).
The Dhofar mountains have been described by Ptolemy and 16th Century Portugese poet, Luisde Camoes, as the main source of frnakincense (Miller, Morris, 1988). The Greek historian Herodotus was familiar with frankincense and knew it was harvested from trees in southern Arabia. The resin is also mentioned by Theophrastus and by Pliny the Elder in Naturalis Historia. The tree has been of great importance as the only source of the valuable oleo-gum resin in Dhofar, and it is noteworthy to mention that frankincense is mentioned in the Bible as one of the three gifts the wise men gave to the young child Jesus.
Boswellia sacra population in Dhofar and in coastal plains around Reysut are in rapid decline due to over-grazing, gravel mining, invasion by termites and insects and incorrect tree tapping practices. In some areas, the populations of Boswellia sacra have appeared to have completely vanished. Incorrect tapping practices by unskilled labourers have been identified as one of the major threats to the survival of the tree in Oman. The aim of the study is to address the process of extracting the resin (tapping), which could be harmful to the tree if not properly handled and careful planned.
This study will enable the government to improve and further scrutinise its policy on the conservation of Boswellia sacra. Local harvesters of Boswellia sacra that previously gained significant proportion of their income due for harvesting olibanum trees should be informed of more sustainable means of harvesting. Influencing local knowledge to ensure long term impact of future harvest of wild and domesticated trees could be more sustainable and contribute to alleviate poverty in the surrounding communities. The study will attempt to draw attention to modern uses of olibanum, which adds value to its traditional uses. Future harvest of wild and domesticated trees could be more sustainable and hence contribute to alleviate poverty in the concerned communities.
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2.2. Project Objectives
The main aim of the study is to identify sustainable exploitation techniques of Boswellia sacra throughout its distribution range in Dhofar. The following objectives have been identified to achieve this aim: 1. Study sustainable tree harvesting techniques (better understand olibanum production from trees of different sizes, ages and locations and study the effect of tree tapping techniques on yield and tree survival) 2. Study the effect of environmental factors on the flowering, reproduction and seed germination of the tree; 3. Advocate for sustainable management options by providing contextualized information.
2.3. Project Site
Four locations were selected at the start of the project to conduct the field work. The selection was based on:
1. The slope of the land: this criterion is crucial because flat lands are accessible to camels and goats subjecting the frankincense trees to overgrazing which may jeopardize the research work.
2. The variation in weather characteristics: Frankincense trees have a strong link with the Khareef season, although they do not grow directly where Khareef hits most, but in the regions close to it. Therefore, the plots were chosen in the Northern and Southern slopes of the mountain range.
A summary of the locations is given in Table 1, a map is given in Figure 1 and photographs of the site are shown in Photo 1 and Photo 2.
Table 1: Summary of the four locations of the project fieldwork
Site Site Annual Elevation Location Coordinates Geology number name rainfall (m) N16°50'43.14" 1 Ardit Fzayh Limestone 109.8 128 E53°43'18.00" N16°52'15.12" 2 Afull Afull Limestone 357 180 E53°43'5.04" N17° 5'51.54" 3 Kdat 1 Sha’bont Limestone - 1146 E53°47'58.62" Shamal N17° 9'28.74" 4 Kdat 2 Limestone 156 941 Ikaat E53°48'50.40"
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Figure 1: Maps showing the selected project sites
Photo 1: Overview of site 3 showing Frankincense trees
Photo 2: Overview of site 1, Frankincense trees associated with Jatropha dhofarica
2.4. Project Activities
The project activities covered a period of four years (covering four seasons of fieldwork from February 2010 till June 2013) in four designated areas. In order to determinate and ascertain the above mentioned objectives, the project activities were designed to:
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• Systematically collect Frankincense yield, through tapping, in each location according to tree size and harvesting year. • Evaluate the wellbeing of each tree. • Collect and analyse the variation in weather data characteristics. • Monitor the flowering conditions of each tree under study. • Conduct seed germination in a laboratory to learn the impact of harvesting on yield and tree wellbeing.
2.5. Used terminology
Boswellia sacra is the tree that produces frankincense resin, it is variably referred to as frankincense tree or olibanum tree throughout the report.
Harvesting cycle refers to the process of harvesting trees throughout a season; it is also referred to as harvesting sequence or cutting cycle or tapping cycle.
Rep is referred to replication when a similar activity is replicated on a tree.
Sustainable harvesting refers to the extraction of yield, without harming or reducing the potential of the tree to produce the same (or an increasing) level of yield over time.
Tapping is the process of extracting the resin. It is variably referred to as taps, cuts or harvesting throughout the report.
Temperature regimes used throughout the report refer to mean minimum temperature, mean maximum temperature and mean of the mean temperature. This was recorded over three years in three meteorological stations.
Yield refers to the natural product obtained from the tree. It is variably referred to as resin, frankincense, frankincense resin, gum, oleo-gum, oleo-gum-resin or olibanum throughout the report.
2.6. Project Team
Members of the ESO administrative and research team are listed below:
Management team Mrs. Lamees Daar Executive Director Mrs. Suaad Al Harthi Program Director Mrs. Nida el Helou Projects Manager (2010) Mrs. Maïa Sarrouf Willson Projects Manager (2011-2012) Research and Conservation Manager (2014) Miss Asma Al Bulushi Projects Coordinator
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Mr. Bashar Zeitoun Administration Manager
Research team Dr. Mohsin Musalim Al Aamri Lead Researcher Mr. Badar Musthal Al Shanfari Technical Assistant
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3. Frankincense Overview: Characteristics, Uses and Threats
3.1. Taxonomy
Boswellia sacra, belongs to the family of Burseraceae, the correct scientific name for this plant has for long been confused. The first scientific collection of Arabian frankincense was introduced in 1846 by H.J Carter; he thought it was the same as the Indian species Boswellia serrata. In 1867 a Swiss botanist, Friedrich Flueckiger, re-examined Carter’s specimen and described the new species of Boswellia sacra. After three years, in 1870 another botanist revised the whole genus and considered Carter’s specimen again which he described as Boswellia carteri. The name was misapplied to the Arabian plants for many years, and recent research has shown that the African plant Boswellia carteri is driven from the Arabian plant Boswellia sacra (Howers, 1950; Miller & Morris, 1988).
Table 2: Systematic classification of Boswellia sacra
Kingdom Plantae Phylum Tracheophyta Class Magnoliopsida Order Sapindales Family Burseraceae Genus Boswellia Species Sacra Species Authority Flueckiger
There are four main species of Boswellia that produce frankincense, in particular Boswellia sacra, Boswellia frereana, Boswellia serrata and Boswellia papyrifera. Only Boswellia sacra is found in Oman and Arabia, and also occurs along the north eastern coast of Somalia (Miller & Morris, 1988).
3.2. Ecology and Habitat
Boswellia sacra is a medium-sized canopy tree reaching 5 - 13 m in height with a single trunk or, more commonly, several from the base. It is characterised by papery and peeling bark, densely tomentosed young branches, and all parts are highly resinous. The leaves alternate and are crowded at the ends of branches, imparipinnate and oblong-obovate in outline. The leaflets are sub-opposite, sessile, 6-8 pairs, increasing in size towards the tip. The terminal leaflet is the largest (15-40 mm long X 8-20 mm across), the tip is rounded, margin crenate- undulate, base truncate and thinly tomentose (Morris & Miller, 1988). Flowers are in axillary racemes crowded at the end of branches. The fruit is a capsule of 3-5-valved obovoid with an acute tip of 8-12 mm long x 6-7 mm in diameter, 3-
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5-angled or winged in section, reddish brown, glabrous, valves 1-seeded, seeds contained in bony endocarp (Miller & Morris, 1988).
The existing tree regeneration and the historical habitat of Boswellia sacra were found to be from sea level to the top of the hills at an altitude of 1’800 m. The Boswellia sacra tree morphology and physiology is designed by nature to tolerate drought (Al Amri, 2001). The tree stem is composed of pale brown bark with some outer flaking papery layers and a thick reddish brown inner resin- producing layer. The tree can survive for long periods without leaves, and photosynthesis happens through the bark as a backup system in the absence leaves.
In almost all cases, Boswellia sacra are found to grow in the cracks between rocks and shallow soil where no permanent ground water is available. That suggests the tree totally relies on rain water and mist supported by its ability to absorb and reserve water for the dry season (Al Amri, 2012; Miller & Morris, 2004). Most trees were found in hilly limestone areas; tree density increases from the foot slope to the hill summit. There are fewer trees sparsely found in valleys and plains.
The tree adopts two shapes: umbrella and cylindrical (Al Amri, 2012; Arthur, 1983). Shelter from the wind, sun exposure and partial monsoon are the main influence on Frankincense habitats, as well as environmental stress (high temperatures and little rainfalls) and rocky carbonic soils low in N, P, K (Al Amri, 2001). The project field survey results have indicated that the Boswellia sacra seeds seem to have a long dormancy period and high viability period, which enable the seed to stay underground for longer periods and only grow when there are favourable climatic conditions. In general Boswellia sacra grow on high and hard slopes. This could indicate that seed distribution is performed by resident wild birds and, of course, through water and wind.
3.3. Distribution & Availability
Frankincense trees grow in geographically limited regions located in Southern Oman (Dhofar), Yemen, Somalia and Western India. Between the latitudes of 5° to 25°north, and 40° to 80°east longitude this area is generally known to be frost free, dry and subject to annual monsoon rainfall from June to August (D. Arthur, 1983). In Oman there is only one species of Boswellia, Boswellia sacra and that is found only in Dhofar in locations stretching between the western border of Oman and 55° east latitude and 16° to 17° north longitude (Miller & Morris, 1988). Local residents believe that there are male and female frankincense trees. But in fact, the plant is bisexual (James, 1980). Trees reach sexual maturity at 4-
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5 years of age. Flowering and fruiting times vary with location. The main flowering usually occurs from April to May, and fruition takes place from June to July in the beginning of the rain season.
Photo 3: Boswellia sacra grows in rock cracks
3.4. Propagation and Domestication
Boswellia sacra are known to propagate via several means. The need to domesticate Boswellia sacra has become important with the increased demand for its products, as well as the urgent need to protect its population from extinction. Techniques for multiplication of this species include generation from natural seed germination (wildings by seeds), nursery seedling production and vegetative multiplication (by budding and by cuttings), as well as transplanting rooted cuttings and root sprouts/suckers.
Systematic classification of Boswellia sacra is described in (Table 2). For some twenty-six species of Boswellia are known to grow in countries bordering the Arabian Sea. Only dozen of them produce incense, while four species are the most important olibanum producers: Boswellia sacra, Boswellia frereana, Boswellia serrata and Boswellia papyrifera (Arthur, 1983).
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Photo 4: Boswellia sacra’s natural flowers and fruit
3.5. Frankincense: From Tree to Market
Olibanum first appears as pale yellow or pale amber-coloured and is tear- shaped, drop-shaped, egg-shaped or almost round lumps, varying from pea-size to walnut-size. Other grades may be orange-yellow, orange-red or brownish in colour, and the tears may be agglutinated into large lumps (Miller & Morris, 2004; Tuker, 1986).
The resin portion is composed of pentacyclic triterpenes, in which boswellic acid is the active functional group (Goyal, 2011). The gum portion consists of pentose and hexose sugars with some oxidizing and digestive enzymes. Boswellic acids with the molecular formula C32H52O4 form the main active component of olibanum, the four major boswellic acids (pentacyclic triterpenic acids) found in frankincense are: β-boswellic acid (BA), acetyl-β-boswellic acid (ABA), 11-keto-β- boswellic acid (KBA), and 3-O-acetyl-11-keto-β-boswellic acid (AKBA), which have been shown to be responsible for the inhibition of pro-inflammatory enzymes (Siddiqul MZ, 2011).
Photo 5: Olibanum oozing from plant duct
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Olibanum Absolute Olibanum Absolute (resin) is prepared directly from olibanum by alcohol extraction. Olibanum resinoied is then extracted again with ethyl alcohol, and requires further chilling, filtering and evaporating of the extract. The olibanum Absolute can be therefore considered to be concentrated tinctures of olibanum (Arthur, 1983). The absolute is used as a fixative. In combination with spice oils, particularly with high-grade cinnamon bark oil, olibanum absolute creates quite a surprising and complex odour. A typical effect in fragrance is obtained with combinations of olibanum, cinnamon bark, cinnamic alcohol, nitromusks and coumarin or coumarin derivatives. Excellent modifications are produced with ionones, methylionnones, labdanum extract or cistus oil, mimosa absolute, orange flower absolute and muguet bases (Coppen, 1995).
Olibanum Oil Olibanum essential oil is obtained in a good yield by steam distillation of olibanum raw. There is no strict correlation between colour and perfumery value (Mauptit, 1985). The essential oil is a mixture of (monoterpenes, sesquiterpenes and diterpenes) which is about 70-90% monoterpenes from the total olibanum oil and from this about 75-80% of it are alpha-pinene. Olibanum oil is in mobile liquid, pale yellow or pale amber-greenish in colour (Maupetit, 1983). Its odour is strongly diffusive, fresh, terpeney, almost green-lemon-like or reminiscent of green, unripe apples, but not terebinthinate. A certain pepperiness is mellowed with a rich sweet-woody, balsamic undertone, depending on upon the method of distillation of the oil (time vapour pressure).
The olibanum oil is used in fine perfumery as mentioned in olibanum Absolute (Arthur, 1983; Mauptit, 1983). It is known to give a delightful effect in citrus colognes where it modifies the sweetness of bergamot and orange oils. Olibanum oil in itself is a base for all the incense or olibanum type perfumes, it is an important ingredient in many oriental base, ambers, powder, perfume, floral perfumes, citrus colognes, spices, violet perfumes and other fragrances (Arthur, 1983; Mauptit, 1983).
Olibanum Resinoid Olibanum resinoid is obtained by the extraction of crude olibanum with a hydrocarbon solvent, usually benzene, rarely petroleum ether and acetone. When prepared by benzene extraction, the colour of the olibanum resinoid is dark amber to dark orange or reddish brown. Olibanum resinoid is a valuable fixative, but it also lends its own peculiar odour to the perfume. Since the essential oil content is only about 8%, the resinoid has a much more versatile application in perfumery than the essential oil (Al Amri, 2002; Arthur, 1983).
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3.6. Medicinal Use
Olibanum has been used since ancient times to treat many illnesses. In the last decade, the use of olibanum has become more popular in Europe and the USA for the treatment of various chronic inflammatory problems. Many studies have shown the effect of olibanum on the treatment of ailments (Birkner, 2006; Safayhi, 1997). There are many forms of using olibanum as drugs, tablets or diluent capsules generally taken orally, or as powder extract (Rao, 2012). Its bark decoction has a famous preparation which is called phytopharmacon H15 (Siddiqul, 2011; Simmet, 2001). The side effects of olibanum are relatively low and not severe when compared to the modern drugs and their side effects (Bone, 2011; Siddiqul, 2011).
Olibanum has been shown to be effective in treating various inflammatory diseases (Ammon, 2005), heart disease (Cuaz-Perolin, 2008), asthma (Gupta, 1998; Nusier, 2007), skin diseases (Michie, 1991), bowel disease (Rahimi, 2010; Alam, 2012; Gupta, 1997). It has also been used in the treatment of cancer (Alam, 2012; Estrada, 2010; Howers, 1950; Xia, L, 2005; Bone, 2011). A detailed description of the various medicinal uses of frankincense is given in Appendix 1.
3.7. Threats to the Boswellia Sacra Population
Several factors are causing the decline of Boswellia Sacra population in Dhofar, particularly over grazing, gravel mining, termites and insects and incorrect tapping procedures.
a) Over Grazing
Intense grazing pressure prevails in most of Dhofar, mainly by camels and goats feeding on foliage, terminal buds and bark removal (Mohamud Haji Farah, 2008). Leaves and seeds are highly valued as fodder for goats and camels, and the succulent stem is also used as fodder during the dry season. The project team observed a high level of over-grazing within the Boswellia sacra habitats, particularly on low slopes and mid slopes; which poses a challenge to animals feeding in the olibanum tree distribution area. The grazing of seedlings is also a threat to the Boswellia sacra species as it affects its regeneration potential.
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Photo 6: Boswellia sacra tree grazed by camels
b) Gravel mining
Gravel mining effects are far more devastating than any other land-use activity, and land degradation in the distressed area leads to soil removal, and decreased soil moisture and nutrient availability. Mining leads to plant mortality because it directly affects the soil through erosion and earth removal, deprives the plant of nutrients and water, and increases plant stress that reduces or curtails seed production. Reducing or eliminating the available seed bank disrupts the biological cycle and contributes to a diminished plant regeneration potential from seed to mature plant and back to seed.
Photo 7 and Photo 8: Rock explosion and gravel storage around a pit
c) Incorrect Tree Tapping Practices
Traditionally, skilled Omani labour was used throughout the production chain of frankincense (owner, renter, manager, worker, guards, and storage manager), using sustainable harvesting methods for extracting yield from the trees. The local knowledge on olibanum production was lost in the 1970s when the oil development sector expanded in the country. The movement of many Omanis
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Sustainable harvesting of Frankincense trees in Oman to a more comfortable urban life led to the collapse of the traditional system of knowledge of olibanum production, which was slowly replaced by unskilled labour from both migrants and Omani origins.
It is not uncommon to see over-tapping and the use of inappropriate tapping methods by unskilled labourers, and there is generally little supervision during tapping. More accessible trees are often tapped continuously with no rest periods in rain time or over the years.
Photo 9: Proper way of cutting size and depth without harming the tree
Photo 10: Improper way of tree cutting
d) Termite and Insects
Evidence from previous scientific work, shows the presence of harmful insects in the frankincense tree and on the tree bark (F. Strumia, 2007). Most of the insects detected inside the tree were observed just before their deterioration (F. Strumia, 2007). The most harmful two species are long-horned beetles (Coleoptera cerambycidae) and one of Buprestidae beetle (Coleoptera buprestidae), whose larvae develop under the bark and in the trunk of living frankincense trees.
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The most dangerous insects of these appear to be the Buprestidae species (Sphenoptera chalcichroa Obenberger) and Cerambycidae (Neoplocaederus atlanticus rungs) and Derolus martini ssp. hayekae Villiers (F. Strumia, L. daPPorto, m. deLLacaSa, P.L. ScaramoZZino, 2007).
Additionally, frankincense trees are an important source of food and nesting sites for other insects such as termites (infraorder: Isoptera). They are mostly present on weak trees as their main food item, cellulose, can be found in the dry wood of old harvesting cuts.
1. Sphenoptera chalcichroa 2. Specimen of 3. Male of Derolus martini ssp. Obenberger Neoplocaederus atlanticus hayekae Villiers, 1968 (Rungs, 1952), Male. Figure 2: The most dangerous insects to Boswellia sacra
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4. Field Work Methodology
4.1. Overview
A variety of methods were used in the study; interviews were conducted with stakeholders, the elderly who worked in olibanum who had enough knowledge to understand olibanum extraction and identify local ecological zones.
The knowledge available about frankincense trees is limited to the older generation who believed that the plants were subjected to successive tapping over extended periods, which tends to cause stress that interfere with the plant reproduction cycles and olibanum yield. The available information written by scientists on the yield per tree, amount cutting taps per tree, length of collecting, and intervals were based on local information, which varies from one to another.
Statistical analysis was performed using the SPSS package for its overall popularity and acceptance and ANVOA analyses was used to perform comparison between trees in different locations, t value was sought to find accurate results amongst 2 compared items. Means and percentages were also used where necessary.
4.2. Description of the Project Fieldwork
a) Tree Tapping: Definition and Concept
Ordinary Type of Tree Cut “Ordinary type of tree cut” is a term used for harvesting frankincense trees using permanent size and amount of taps according to bole of the tree size, and tree conduction. This technique is more acceptable for the sustainable harvesting of olibanum trees in Oman based on information obtained from local harvesters. The tapping spots are located in opposite positions. Photo 11 shows the stages of the resin after ordinary tapping.
Incorrect Way of Harvesting Incorrect way of harvesting indicates that the tree is harvested exceeding the ordinary tree tapping spots; the injuries are deeper, larger in size and no rest period was given. The tapping spots that are out of order are located on the tree bole.
Under-exploitation Under-exploitation refers to the harvesting of Boswellia sacra which is usually located in non-accessible areas, where the harvester cannot reach.
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Photo 11: Three different cuts in the trunk of the frankincense tree with the resin most obvious in the older one to the left
b) Weather Stations
Following thorough research and with the assistance of the experts at the Department of Meteorology at Muscat International and Salalah Airports, the lead researcher installed three weather stations across the different sites in Afull, Ardit and Kdat2. In the third week of December 2010, the weather stations started recording the following indicators: air temperature, relative humidity, wind gust and speed and rainfall. The stations recorded these indicators every hour but the climatological summary shows the mean average of every indicator for the day. These stations were used to monitor the weather changes for the duration of the project. Climate change impacts on the growth of the frankincense trees cannot be determined in just three years particularly because climatic changes are recorded over a range of thirty years. However, the meteorological data compiled during the first year of the project will be considered as the baseline.
Data against which the changes in the weather patterns over the subsequent three years (project four years, weather data only three years) of research has not been assessed to project potential climatic changes. But the climate data compiled over the three years of research has allowed the lead researcher to discern potential impacts of the weather changes on both the growth and yield of the frankincense trees.
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Photo 12: ESO’s former vice president, Dr. Medhi Ahmed Jaffar, checking the weather stations
c) Fieldwork Overview
Before the start of the fieldwork, a part time technical assistant was hired and intensively trained in April 2010. Hiring a local assistant was part of the capacity- building component of the project. Highlighting the importance of safeguarding frankincense farming in each of the selected sites, the lead researcher and his assistant carried out the tapping of the trunks of the trees periodically throughout the year, except for the Khareef (monsoon) season.
The tapping of the trunk (Figure 3) was performed twice in each of the location; the first time is referred to as “tawqee”. The second tapping is referred to as “sa’f” and is done three weeks after tawqee by removing the resin and the layer. The last harvest of the season is done before the Khareef begins, “kashm”. During the Khareef season, the tapping exercise was put on hold due to the rainfall that might jeopardize the collection of the resin for the duration of the Khareef.
On 26th of February 2010, the first tawqee was performed on 45 trees with the assistance of the local frankincense harvesters in order to show the research team the proper technique of tapping without harming the trees. On the 18th of March 2010, sa’f was performed on the same trees. The frankincense produced by each tree was weighed and the data collected and stored in the project’s database. At the end of the project, a maximum yield could be calculated for each of the four sites.
A continuous and close tree-by-tree observation is essential to monitor the flowering process and collect the seeds. The seeds collected during the Khareef season in 2010 were stored to be used during the germination phase later during the project life cycle.
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Tree tapping and olibanum collection needs to be revised for long-term tree protection. All the parameters examined over the three years of research represent the baseline data of the project. The data collected in the subsequent years were benchmarked against this data to inform the lead researcher of the frankincense trees’ trends in terms of abundance, health and yield. At the end of the research, the lead researcher (Photo 13) has attempted to establish a correlation between the different characteristics of the frankincense trees and their yield.
1. First cut called tawqee 2. Tawqee after one hour 3. Second cut
4. One day after the second 5. Olibanum ready for 6. Harvesting recut harvesting Figure 3: Different stages of tapping Boswellia sacra and harvesting the resin
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Photo 13: Lead researcher checking the tree tags on the field
d) Sustainable Harvesting Experiments
The monitoring experiments of sustainable olibanum production covered three different tree sizes (30-50 cm, 50-70 cm and 70-90 cm), and involved two different types of cutting norms: normal and double, each sized 3 x 4 cm. A “normal cutting norm”, adopted from the traditional Dhofari system, involves a limited number of cuts on the tree (or taps). The number of cuts on tree is doubled in a “double cutting norm”. The number of taps in each of these norms depends on the tree size and is summarized in Table 3 below.
Table 3: Number of taps depending on tree size, in a normal and double cutting norm
Number of taps in a Number of taps in a Tree Size “Normal Cutting Norm” “Double Cutting Norm” 30-50 cm 3 6 50-70 cm 6 12 70-90 cm 9 18
The monitoring of trees consisted of the following factors: the percentage of flowering, the yield production, the tree health and the percentage of seed germination. A summary of all sustainable harvesting experiments is given in Table 4 below.
The trees were harvested during four years. The yield was collected in plastic bags in each harvesting cycle and weighted for each tree separately. For
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Sustainable harvesting of Frankincense trees in Oman replication purposes, five trees were selected for each tree size and for each cutting norm. Data was statistically analysed by SPSS program using one-way ANOVA test. Also a paired t-test was used to assess the overall differences between normal tapping method and double tapping method.
Table 4: Trials in the sustainable harvesting experiment
% flowering Yield Factors studied Tree health % seed germination Normal Cut Cut norm Double Cut 30-50 cm Tree size 50-70 cm 70-90 cm
It was essential to choose the locations with a slope to safeguard the sampled trees from animal grazing. Frankincense trees also grow in harsh soil conditions, which meant that the chosen plots, in addition to having steep slopes, are rocky. The prevailing factors for the selection of the trees for monitoring were i) the availability of trees of the same size in each site, and ii) their isolation from grazing. Factors such as bigger sizes or productivity were not taken into consideration.
During the four years study, two main lines of field research were pursued in four agro ecological zones: 1) Harvesting related to tree size, amount and frequency of tapping spots and olibanum production and tree health. 2) Relationship between tree size and olibanum production and flowering and seed germination.
Tappers in Dhofar believe through casual observation that several factors affect resin characteristics. For example, it is often suggested that male trees are non olibanum producers. However, scientifically there are no male and female trees as the frankincense tree is bisexual (P.James, 1980; Mohamud Haji Farah, 2008). Harvesters also believe that bark colour can determine whether the tree produces olibanum or not. However, bark characteristics generally change with age and growth. It is natural for young trees to have smooth and light-coloured bark that becomes rough and darker with age. It is also claimed that tapping bigger trees with more cuttings produces more olibanum. These first-hand observations may well be true, but there are no substantiating published
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Sustainable harvesting of Frankincense trees in Oman scientific research results. Field research was conducted to attempt to answer the following questions:
Is there a relationship between the size of the tree (based on stem diameter) and olibanum production? Is there a correlation between amounts of tapping spots and olibanum yield? Is there a relationship between olibanum yields and harvesting sequence? How can harvesting effect plant health and wellbeing? How does the yield vary from year to year in the same place?
Tree Size & Olibanum Production In each study location, 45 trees of three different sizes were studied. For each trunk size, 15 trees were tapped using a double cutting norm, 15 trees were tapped using a normal cutting norm and 15 trees were left untapped for control purposes. The trials aimed to obtain valuable information on frankincense harvesting and the effect of cutting norms on the health status of individual trees. The trials were completed after harvesting in June 2013. Over four years the trees were tapped periodically. For certain trees harvesting was stopped earlier due to deterioration of tree health as a result of harvesting. The harvesting sequence during the study is given in Table 5.
Table 5: Harvesting sequence during the study
Total harvesting Year Location 1 Location 2 Location 3 Location 4 sequence 1 3 4 3 3 13 2 9 9 9 9 36 3 10 0 10 10 30 4 9 9 10 9 37 Total 31 22 32 31 116
A detailed description of the different sustainable harvesting experiments is given in Box 1.
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Box 1: Details of the different sustainable harvesting experiments
Experiments on Trunk Size from 30-50 cm • Treatment (1): control treatment. No tapping. Replicated on fives trees. • Treatment (2): trees tapped using a normal cutting norm. Each tree is cut in 3 different places per cycle. Each cut size is 3 x 4 cm. Replicated on five trees. • Treatment (3): trees tapped using a double cutting method. 6 spots per cycle. Replicated on five trees. The total treatments 3x5 =15 tree
Experiments on Trunk Size from 50-70 cm • Treatment (1): control treatment. No tapping. Replicated on fives trees in each location. • Treatment (2): trees tapped using a normal cutting norm. Each tree is cut in 6 different places per cycle. Each cut size is 3 x 4 cm. Replicated on five trees in each location. • Treatment (3): trees tapped using a double cutting norm. Each tree is cut in 12 different places per cycle. Each cut size is 3 x 4cm Replicated on five trees in each location. The total treatments 3x5 =15 tree
Experiments on Trunk Size from 70-90 cm • Treatment (1): control treatment. No tapping. Replicated on fives trees in each location. • Treatment (2): trees tapped using a normal cutting norm. Each tree is cut in 9 different places per cycle. Each cut size is 3 x 4 cm. Replicated on five trees in each location. • Treatment (3): trees tapped using a double cutting norm. Each tree is cut in 18 different places per cycle. Cut size is 3 x 4 cm. Replicated on five trees in each location. Total treatments 3x5 cm =15 tree
Experiments on the Effect of Amount of Tapping Spots on olibanum Yield • Treatment (1): five trees were harvested using a normal cutting norm. • Treatment (2): five trees were harvested using a double cutting norm.
Experiments on the Yield Variation in Different Years Four locations were considered for the study: Location (1) Ardit : 15 trees harvested over 4 seasons, yield sequence 31 Location (2) Afull: 15 trees harvested over 4 seasons, yield sequence 22 Location (3) Kdat 1: 15 trees harvested over 4 seasons, yield sequence 32 Location (4) Kdat 2: 15 trees harvested over 4 seasons, yield sequence 31
The total treatments for this experiment were 15* x 4** x 2*** x 116**** = 13’920 * 15 tree by location, ** 4 locations, *** 2 cutting norms, **** total harvesting sequence in four years
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e) Flowering and Seed Experiments
The flowering percentage and the seed health indicate plants regeneration in tapped and untapped trees. It is suggested that heavy tapping affects the tree health and leads to low flowering percentage and less seed germination.
The flowering percentages were calculated directly by the Lead Researcher in the field in May 2012. It was done by visual monitoring based on amount of flowers covering the tree. When the seeds matured they were collected and placed in open-topped Petri dishes (100 seeds per dish) with moist filter paper and stored in room temperature with relative humidity. The moisture level of the dishes was kept constant by watering throughout the experimental period. Every day, germinated seeds were counted and removed. A single seed was considered to have germinated when the length of the radical was equal to length of the seed.
Experiments on the Effect of Cut Norm on Flowering Percentage • Treatment (1) five trees for each tree size as mentioned above in four locations were kept as control and not tapped • Treatment (2) five trees for each tree size in four locations were tapped regularly during the study, normal cutting norm • Treatment (3) five trees for each tree size in four locations were tapped regularly during the study, double cutting norm.
Experiments on the Effect of Temperature Regime on Tree Flowering Three temperature regimes were used: mean minimum temperature, mean maximum temperature and mean of the mean temperature. This was recorded over three years in three meteorological stations and is summarised in Table 6 below.
Table 6: Summary of mean temperatures in the study sites
Mean minimum Mean maximum Mean of the mean Site Name temperature (°C) temperature (°C) temperature (°C) Afull 22 35 27.7 Kdat 16 34 24 Ardit 22 31 26
Experiments on the Effect of Tree Tapping on Seed Germination Two treatments were designed to monitor the effect of tree trapping on seed germination: Treatment (1): fives trees were selected in each location and in each of the three tree sizes. Harvesting was done by applying the double cutting method.
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Treatment (2): control treatment. No tapping. Replicated on fives trees in each location, and in each of the three tree sizes Treatment (3): fives trees were selected in each location and in each of the three tree sizes, normal cutting norm.
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5. Results
5.1. Sustainable Harvesting: Olibanum Yield and Tree Size
At the outset and comparing yields from big trees and small trees, shows without doubt, that the big trees produce more resin than the smaller ones. Over four harvesting seasons the amount of olibanum yield obtained from location 1 out of the biggest trunk tree (size 70-90 cm) was 6.196 kg. The tree was tapped using a double cutting norm (18 taps per cycle) and for a total of 31 cutting cycles. The tree is still healthy and survives. The lowest yield from the same trunk size (70- 90 cm) was in location (3) with only 637 grams, this tree received 32 cutting cycles with 8 cuts per cutting cycle and still survives.
For medium trunk size (50-70 cm) the maximum yield obtained was 8 kg and 570 gram in location (2). The tree was tapped during 22 cycles with 12 cuts per cutting cycle. The tree is in good health, the lowest yield from this trunk size (50- 70 cm) was 318 gram, and the tree is still alive.
In tree size 30-50 cm, the maximum total yield obtained was in location (1) with 1 kg and 756 gram on a tree that had 6 cuts and 31 cutting cycle. The lowest was 92.5 gram in location (3) as a result of 32 cutting cycles at 3 cuts per cycle.
The mean yield for small trees (30-50 cm) in all locations was 21.6 grams and for the medium trunk size (50-70 cm) was 54 grams, while it was 74 grams for the large trees (70-90 cm).
The total amount of yield obtained per tree and the health status of the trees in the four locations of the project is shown in Table 7 and Table 8. This information is presented along with the frequency of cutting cycles.
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Table 7: Yield and health status of trees after four years in locations 1 & 2
Location 1 Location 2 Trunk size/No Cuts Rep 1* Rep 2 Rep 3 Rep 4 Rep5 Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 30-50 cm 3 cuts Total yield (g) 1200 601 609 649 649 365.3 359.8 254.4 232.8 175.9 Cutting cycle (No.) 31 31 31 31 31 22 22 22 22 22 Health status No death No death 30-50 cm 6 cuts Total yield (g) 735 240 1104 1756 1385 929.7 106.9 233.5 379.9 118.7 Cutting cycle (No.) 31 22 22 31 31 13 13 13 13 13 Died 4th Died Died Health status No death Healthy Healthy year 3rd year 2nd year Control no cut No death No death 51-70 cm 6 cuts Total yield (g) 1335 1070 782 898 1838 1877 424 665 860 703 Cutting cycle (No.) 31 31 31 31 31 22 22 22 22 22 Died Died Health status No death Healthy 4th year 4th year 51-70 cm 12 cuts Total yield (g) 2815 1832.1 2167.9 708.3 3726.6 669.4 1223 1305.1 8570.2 1119.9 Cutting cycle (No.) 31 31 22 22 31 22 22 22 22 13 Died Health status 4th year Control no cut No death No death 71-90 cm 9 cuts Total yield (g) 2878.7 2230 1606.3 3199.9 1000.2 2878.7 695 1713 980.3 921 Cutting cycle (No.) 31 31 31 31 31 31 22 22 22 13 Health status No death 71-90 cm 18 cuts Total yield (g) 2236.5 2083.3 684.7 1154.1 6195.8 1032.8 1773 2121.6 4285.8 2745.4 Cutting cycle (No.) 31 22 22 27 31 22 22 22 22 22 Died 4th Died Health status year 4th year Control no cut No death No death *Replication
Table 8: Yield and health status of trees after four years in locations 3 & 4
Location 4 Location 3 Trunk size/no Cuts Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 30-50 cm 3 cuts Total yield (g) 180.2 544.7 486.1 906.8 198.5 223.1 92.5 280 167.2 548.5 Cutting cycle (No.) 31 31 31 31 31 32 32 32 32 32 Health status No death No death 30-50 cm 6 cuts Total yield (g) 214.2 249.7 204.8 260.1 96.8 456.7 268.3 219.6 317.6 218.5 Cutting cycle (No.) 22 22 22 22 22 22 22 22 22 22 Health status No death No death Control no cut No death No death 51-70 cm 6 cuts Total yield (g) 1860 1581 749 806 969 969 413 467 722 318 Cutting cycle (No.) 31 31 31 31 31 32 32 32 32 32 Health status No death Healthy 51-70 cm 12 cuts Total yield (g) 1318. 190.6 520.6 1907.7 748.3 969.4 326.4 257.8 485.4 1617 Cutting cycle (No.) 22 22 22 22 22 22 22 23 22 22 Health status No Heath No death Control no cut No death No death 71-90 cm 8 cuts Total yield (g) 2136.1 2395.2 1426.1 927.6 1012.1 266.2 1931.9 636.8 1672.8 484.1 Cutting cycle (No.) 31 31 31 31 31 32 32 32 32 22 Health status No death No death 71-90 cm 16 cuts Total yield (g) 4763.5 1241.9 2161.4 2475.8 2369.5 1539.6 1524.7 893.3 971.9 689.6 Cutting cycle (No.) 31 31 31 31 31 32 22 22 32 22 Health status No death No death Control no cut No death No death
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Statistical analysis amongst different tree sizes is shown in Figure 4 and the results indicate a statistically significant relationship between tree size and the yield in all locations in aggregate and per individual location. Differences were observed between yield trees trunk size 30-50 cm 50-70 cm and 70-90 cm.
74 80
70 54 60
50 a 40 21.6
30 b Yield Yield ingrams 20 c
10
0 30-50 cm 50-70 cm 70- 90 cm Tree size Figure 4: Yield in grams from three different tree sizes Columns with similar letter are not significantly different according at p ≤ 0.01 a, b and c show statistical variations
Yield variation, as presented in Figure 5, reveals significant differences between locations. The highest mean yield in location (2) was 69 g, which was significantly higher than locations three and four, but not significantly different compared to first location where the mean yield was (62 g). The mean yield in the third location was the lowest (29 g) which indicates significant differences comparing with the other three locations.
Location (4) has shown a mean yield of 50 g with a statistically significant difference of 0.5 with location (1) and (2) and on 0.01 with location (3). The higher yield level of resin in locations (1) and (2) as compared to those in locations (3) and (4) could be attributed to levels of rainfall. Locations (1) and (2) face the sea with higher recorded precipitation levels than the other locations.
The result of yield variation during the four years study showed in Figure 6 indicated that, in general, levels of resin productivity of Boswellia sacra trees in two middle years 2011-2012 (57 to 57.8 grams per tree) were higher than those in the first year 2010 and the last year 2013 (39.5 to 36 grams per tree). This could be attributed to the fact that resin production needed stress which reaches maximum value in the second and third years then fourth year slowly reduces.
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80 69 70 62 60 50 50 40 a 29 30 Yield Yield ingrams a 20 10 b ac 0 1 2 3 4 Location
Figure 5: Mean yield in grams in four agro-ecological zones Columns with similar letter are not significantly different according at p ≤ 0.01
70
60 57 58
50
40 40 36
Yield Yield (g) 30
20 ab 10 ac ab C
0 1 2 3 4 Years Figure 6: Mean yield in four years in the four project locations Columns with similar letter are not significantly different according to LSD at p ≤ 0.0
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Comparing yield from the normal cutting norm to the double cutting norm The olibanum yield extracted from the same tree size has been compared using the two adopted cutting norms. The normal cutting norm is referred to as (a) and the double cutting norm as (b).The results are presented in Table 9.
Trunk size 30-50 cm. Results for location (1) and location (2) show that a double cutting norm (6 taps per tree) produces more resin than the normal cutting norm (3 taps per tree) in all harvesting seasons (2010, 2011, 2012 and 2013). The mean yield in four years was 6 g in a normal cutting norm (a) versus 16 g in a double cutting norm (b) in location (1), and 17 g (a) versus 26 g (b) in location (2).
In location (3) and location (4) the olibanum yield were low compared to the trees in location (1) and (2). High variation could be noted between trees and tapping cycles, with no permanent trend from one year to another. The mean olibanum yield is 8 g (a) and 15 g (b) in location (3), which is not significantly different to results in location (4): 15 g (a) and 10 g (b). This result does not show a significant statistical difference between cutting norm (a) and cutting norm (b).
Trunk size 50-70 cm. In locations (1), (2) and (3), the analysis of variants of the olibanum revealed a significant difference between the two cutting norms. There was a noticeable increase in yield in the double cutting norm in all four years except for the second year in location (2) and the third year in location (3), where the yield was higher in a normal cutting norm. In location (4), there was no significant difference in yield in harvesting seasons 2010 and 2013, as opposed to 2012, where the mean yield was significantly higher using a double cutting norm.
Trunk size 70-90 cm. The result of olibanum yield obtained from big trees varied significantly between the two cutting norms (p≤ 0.01) with respect to all years in all locations. The mean for all locations except for location (1) was different but not consequently significant. The mean value was: 34 g (a) - 31g (b) Location 1 10 g (a) - 58 g (b) Location 2 29 g (a) - 34 g (b) Location 3 28 g (a) - 72 g (b) Location 4
In conclusion, the double cutting norm produces more olibanum then the normal cutting norm. Unexpected results can be interpreted as a result of a harvester refraining from harvesting some trees, soil fertility or other genetic reasons.
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Table 9: Comparing yield (grams), normal cut and double cut
Trunk size Cut norm 2010 2011 2012 2013 Mean Location 1 30-50 cm 3 cut a /6 cut b *25-36** b 21-25* b 29-38** b 28-43** b 6-16** b 50-70 cm 6 cuts/12 cut b 39-76 ** b 27-36 * b 41-90 ** b 48-104 ** b 27-28 ns 70-90 cm 9 cut a/18 cut b 75-84* b 70-50 **a 78-103**b 76-100** b 34-31 ns Location 2 30-50 cm 3 cut a /6cut b 27-11** b only a No cut 13-28** b 17-26b ** 50-70 cm 6 cuts/12 cut b 46-52 b* 37-32 a** No cut 54-69 b** 50-65 ns 70-90 cm 9 cut a/18 cut b 51-108b** 41-95 b** No cut 59-125 b ** 10-58b** Location 3 30-50 cm 3 cut a /6cut b 9-14 a** only a cut 10-14 b** 7-13 b** 8-15 b ns 50-70 cm 6 cuts/12 cut b 19-32 b** only a cut 17-50 b** 15-10 a** 14-23 ns 70-90 cm 9 cut a/18 cut b 32-36 b** 28-17** a 34-54 b** 32-35 ns 29-34 b** Location 4 30-50 cm 3 cut a /6cut b 5-10 a** only a 18-9 a** 14-10 a** 15-10 ns 50-70 cm 6 cuts/12 cut b 40-43 ns only a 45-51 b* 39 - 40 ns 36 -25 ns 70-90 cm 9 cut a/18 cut b 49-88 b** 40-55 b** 56 -101 b** 45 - 96 b** 28-72 b** **significantly different according at p ≤ 0.01 * sig at 0.05. ns not sig *First number yield normal cut second yield for double cut.
5.2. Survival of Boswellia sacra
Of the total 180 trees studied over 4 years, and 116 total harvesting cycles in all locations (22- 32 in one tree) recorded and assessed, 172 trees have survived against only 8 dead trees. That represents about a 95.56% survival rate.
5.3. Health Status after four years of tapping
Based on the methodology used and the results, Boswellia trees were classified into groups according to their wellbeing and size. Three classes/grades were also given based on the tree vigour and on tree health and trunk size: small tree size (30-50 cm), moderate (50-70 cm) and large (70-90 cm).
Location 1: Fzayh (Ardit) At location (1) small trunk sizes (30-50 cm) with 6 double cuts per tree, showed one dead tree in the third year after a total of 30 cutting cycles (22 yielding and 8 non yielding cycles).
Moderate tree sizes (50-70 cm) showed three dead trees. Two of these trees had a normal tapping norm (6 cuts per tree) and one tree double cutting norm (12 cuts per tree).
In the category of large tree size (70-90 cm) there were two dead trees in the third year after a total of 39 cutting cycles (31 yielding and 8 non-yielding cycles). All trees were subject to double tapping norms (18 cuts per tree). The biggest
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Sustainable harvesting of Frankincense trees in Oman loss was in location (1) as 6 trees were lost from a total of 45. The ‘control’ trees (not tapped nor harvested) survived.
Location 2: Afull In location (2) there were two dead trees, both of small trunk size (30-50 cm). Both had been tapped with a double tapping norm (6 cuts per tree). One tree died in the second year after 17 tapping cycles. Another tree died in the third year after a total of 30 tapping cycles (22 yielding and 8 non yielding cycles). The ‘control’ trees (not tapped nor harvested) were healthy.
Locations 3 & 4: Kdat 1 and Kdat 2 There were no dead trees recorded in locations (3) and (4), even among the ‘control’ trees.
Possible Reasons for Tree Mortality The reason for tree mortality was generally due to tree harvesting except for one tree in location 2 which was over grazed by goats. Eight trees died throughout the experiment, six of them in location (1) and two in location (2). Seven of eight trees were over tapped.
5.4. Yield variation during cutting cycle
The research team noticed a direct relation between the cutting cycle and the yield obtained during the cutting cycle, as presented in Figure 7. For the same tree, the yield increases but not continually with the cutting cycles and reaches a maximum in the third or fourth cutting cycle. The yield then starts to slowly decrease to reach a minimum in the sixth or seventh cycle. It then increases again but does not reach the previous maximum peak. This cycle trend was known by local harvester.
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60
50
40
30 Yield (g) Yield
20
10
0 cycle 1 cycle 2 cycle 3 cycle 4 cycle 5 cycle 6 cycle 7 cycle 8 cycle 9 Cutting Cycles
Figure 7: Yield variable during cutting cycles
5.5. Flowering & Seeds
Flowering is central in the life cycle of all angiosperms as it assures the preservation of species through seed formation. Given that the fruit /seed yield is a direct function of floral induction, plants have evolved a mechanism to ensure that flowering occurs at appropriate times guaranteeing productive success. While environmental stimuli such as temperature, photoperiod and water availability are the main factors responsible for flower induction, indigenous physiological signals such as growth status, plant size/ age hormones and nutrient flow, are secondary factors that ensure floral initiation at the right time.
Three temperature regimes were used: mean minimum temperature, mean maximum temperature and mean of the mean temperature. This was recorded over three years in three meteorological stations.
The effect of different temperature regimes on flowering is illustrated in (Table 10). The highest instance of flowering was found at location (2) where the recorded temperatures for three years was 22˚C for the mean minimum, 35˚C for the mean maximum, and 27.7˚C as the mean of mean. These numbers do not differ from those in location (1), where the recorded temperature is 22˚C for the mean minimum, 31˚C for the mean maximum and 26˚C for the mean of mean. The recorded temperatures in location (4) are lower than the other two locations, with 16˚C as the mean minimum, 34˚C as the mean maximum and 24˚C
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Sustainable harvesting of Frankincense trees in Oman as the mean of mean. There was no data for location (3) as there was no weather station in this location.
Seed germination differed between the years and between the different trees monitored. Some trees flowering cover were high with zero seed viability, we notice non-viable seeds or dormant seeds varied in some years. There was a high incidence of insect attack and a high proportion of seeds without embryos that was observed in seeds, maybe because of heavily tapping olibanum trees.
The results of four years of field study show without doubt, a direct relationship between tree tapping to obtain olibanum resin and tree regeneration (Table 11). At locations (1) and (2), trees were subject to experimental tapping and they produced fewer flowers and fruits than trees that were saved as control with no tapping (Table 11). Furthermore, tapped trees produced smaller fruits with seeds of lower weight and reduced seed vitality. The question is why harvesting was more productive in location (1) and location (2) as compared to location (3) and (4). Two reasons are suggested. The first reason suggests that there might be competition inside the plants on using carbohydrates, to ensure healthy sexual flowering productivity and the creation of olibanum.
The second reason is that olibanum have a protection function to recover from tree trunk injuries caused by the harvester and that is also used to combat the risk of infections from insects and fungus infections. The same olibanum resin has been found to have antimicrobial activities against various micro-organisms such as fungi, and gram-positive and gram-negative bacterial strains so the priority for the plant is to protect itself by olibanum production then by the creation of new flowers.
Table 10: Temperature effect on tree flowering of Boswellia sacra
Location 1 Location 2 Location4 Mean Mean Mean Mean Mean Mean Temperature Mean Mean Mean max minim max mini max mini (°C) 31 22.6 26 35 22 27,7 34 16 34 Flowering ns 38.8 ns 44 ns 34.5 trees (%) ns = no significant difference
Table 11: Effect of the cutting norm on flowering
Cutting norm Flowering (%) Control no cut (%) Normal cut (%) Double cut (%) Location 1 44 12 29 Double cut 29 ns ns - Normal cut 12 ** - ns Control no cut 44 - ** ns
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Location 2 68 25 32 Double cut 32 ** * - Normal cut 25 ** - * Control no cut 68 - ** ** Location 3 44 38 35 Double cut 35 ns ns ns Normal cut 38 ns ns ns Control no cut 44 ns ns ns Location 4 44 39 35 Double cut 35 ns ns ns Normal cut 39 ns ns ns Control no cut 44 ns ns ns LSD **sig at 0.01, * sig at 0.05. ns not sig
In location (2) a one-way ANOVA test (Figure 8) revealed a significant difference in flowering percentage at P ≤.0.01 for control non tapped trees. Double cuts and normal cuts showed a significant difference at P ≤.0.05.
At location No (1), significant differences were recorded in flowering percentage between control tapped trees and normal tapping way. There was no significant effect on flowering in location (3) and (4). There was an inverse relationship (Figure 8) between flowering percentage and cutting norms, that has shown statistically no significant difference.
There are proportionate relationships between tapping spots and flowering density. When trees have appeared to be suffering they became weak, nonetheless, trees that were dying produced more flowers before death compared to less suffering trees, maybe an instinctive behaviour to help protect the tree offspring.
80 70 60 50
40 control
Flowering % Flowering 30 normal cut doubl cut 20 10 0 1 2 3 4 Location
Figure 8: Effect of the cutting norm on the flowering percentage
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5.6. Climate & Agro-Ecological Zones
a) Climate
The meteorological observations were carried out at the three meteorological stations placed in the field. One was placed in Ardit location (1) while the second was placed in Afull No (2) and the third was put in Kdat location (4). The climate data was monitored from the beginning of 2011. Observation at each station were recorded and analysed. Location (1) and less so location (2), received seasonal rainfall as a result of the monsoon winds from the Indian Ocean saturated with cool moisture and heavy fog. Locations (3) and (4) were less affected by the monsoon and are naturally higher in temperature.
The monsoon season starts at late June and extends to late September. It remains dry during the rest of the year. However, occasional rains fall out of season causing floods and influencing watersheds and the coastal plain. It is generally hot and humid during summer months, but cool in coastal areas during winter and relatively cold in the mountains. The coldest period falls in the months of December, January and February.
By local knowledge and land cover indicators, the order of precipitation from highest to lowest are in location (1), (2), (3) and (4) respectively. Unusual heavy rain patterns have been recorded throughout the study period, especially in location (2) Afull, which does not reflect the average pattern in the region. In 2013 the total rainfall reached 542 mm which was extremely unusual. As mentioned earlier in the report, climate change cannot be determined in just three years particularly since climatic changes are recorded over a range of at least thirty years. Due to this, the average temperature, wind speed and total rainfall for each year were calculated separately for each location.
Generally speaking macro –climate of the agro-ecological zone depends on: • The wind speed, latitude, altitude and distance from the sea; • Wind and amount of exposure to the sun.
b) Temperature
Temperature was compared between the three stations over three years, as shown in the Appendix. The tables in Appendix 2 to 4 show the mean of the coldest month December, which was recorded at 16.3C in location (4) in 2011. The mean hottest temperature was recorded in May in the same location and year and was 39.8C. The highest temperature was recorded in August 2011 in
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Sustainable harvesting of Frankincense trees in Oman location (4) and was 40.6C. The coldest and hottest temperature in other locations and in three years’ varies between the above mentioned value.
c) Relative Humidity
The mean maximum humidity was recorded in August 2012 and reached 94% in location (1), while the mean for the drier month in location (4) was 25% recorded in March 2013. A comparison of relative humidity in the three locations reveals that the humidity reduces when moving towards a northern destination. The records at Kdat location (4) show a drier mean than Ardit location (1) and Afull location (2).
d) Wind Speed
Wind speed was recorded in three locations. Afull location (2) and Ardit location (1) face the coast with mountains projecting from behind. Afull is located in a wadi slope. These factors influence the wind characteristics. Based on monthly average wind speed the calmest month was recorded in Afull location (2) in October and November at 6 and 7 km/h, respectively. In July 2012 wind speed at location (4) reached 20 km/h at the beginning of monsoon.
e) Rainfall
It goes without saying that three years of study is hardly sufficient to indicate the actual situation of climate in the area. In general the rainy season coincides with the monsoon period which is from July to September. In addition to the direct rains there is also the moisture that comes with mist. There are also occasional rains the fall out of season causing floods and influencing watersheds and the coastal plain. This can be seen by high vegetation growth in Ardit location (1). It is evident that this location receives more rain then location (2) Afull while it is less in location (4) Kdat. During the study, heavy rainfalls were recorded in the study area reaching a maximum of 542.9 mm in location (2) in 2013. Throughout the study areas the average rainfall was between from 10.2 mm in location (4) in 2012 and 542.9mm in Afull location (2) in 2013.
5.7. Summary of Principal Findings
The principal findings described below are based on the results of four years of field study:
1. The main threats to frankincense trees in Oman are overgrazing, soil removal for the purpose of mining, urbanization, exploitation and
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haphazard over-tapping methods causing deep incisions on the stem leading to the death of the tree.
2. The agro meteorological factors do have an effect on the yield of frankincense trees. Trees in agro-ecological zones one and two are affected by the monsoon as they produce more resin compared to the trees less affected by monsoon in agro-ecological zones three and four.
3. Tree harvesting can be continual for three years, followed by a one-two year rest, in order to allow the scar to heal.
4. Incisions should be limited to the outer red phloem, should not reach the inner xylem and should avoid branch nodes.
5. The trees are generally harvested seven months per year. From November through May, while harvesting period extends over 21-28 day rotational periods. In the hotter months (April-March) the tree needs to be harvested in 14-day intervals.
6. In each harvesting season the cutting spots should cover no more than ¼ of the tapping bole, and should be done on opposite sides of the exploitated area to avoid causing detrimental harm to the tree.
7. The trees in agro-ecological zones one and two are mostly affected by monsoon and are less impervious to diseases and insects compared to trees in agro-ecological zone three and four.
8. The best way of harvesting frankincense (as described above) reduces the side effect on the trees hence their overall wellbeing and seed germination.
9. The yield estimation can be determined from a single tree according to location, height, form and the overall tree vigour.
10. The tree reaches its maximum olibanum yield productivity in its third or fourth harvesting sequence and in the third harvesting year.
11. The tree’s general appearance indicates if it should be excluded from tapping. Small changes in the tree appearance could include the production of liquid olibanum substitute instead of ordinary white milky olibanum.
12. It was found that the lower part of the tree trunk produces more olibanum while the yield is reduced in the upper parts of the trunk.
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13. The bark recovers itself within one year in normal exploitation. However, to return to the previous bark thickness in order to be ready for tapping again in the same place, more time is required and is dependent on agro- meteorological factors.
14. The main climatic factors responsible for desertification in Dhofar Mountains where frankincense naturally grows are mainly low precipitation and strong wind.
15. It is now evident that frankincense trees flower, produce seeds and mature differently. The tree have a slow growing nature and is associated with poor seed germination which poses an implicit threat to Boswellia sacra reproduction.
16. In locations one and two, trees included in the study that were heavily tapped produced less flowers than controlled non-tapped trees and some died.
17. The size of harvesting spot should be around 12 cm2 (3 cm high x 4 cm wide), barely shaving the external layer and about 30 cm from each other.
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6. Recommendations
It can be stated with reasonable confidence that the way the harvesting of Boswellia sacra is performed has a direct effect on the trees’ wellbeing as well as its fertility, flower density and seed germination. Therefore, sustainable exploitation of the wild populations of the tree should be applied.
Implementing new guidelines to manage and maintain the Boswellia sacra sustainably is a challenge for all stakeholders involved: local communities, research institutions, traditional communities, harvesters, nurseries, and government entities. The following recommendations are based on the information and data collected from 4 years of field study.
6.1. Tree Harvesting Norms
This study shows the need to set clear guidelines for all stakeholders, particularly harvesters and managers of the Boswellia sacra tree. These guidelines should:
Specify what techniques to consider given our current knowledge and the known impacts on harvesting olibanum tree.
Prohibit tapping the tree before it reaches 6 years of age and a tree height of at least 1m. The bole and main branches should also be at least 30 cm from ground level.
Specify the size of the tapping spots, which would ideally be around 12 cm2 (3 cm high x 4 cm wide), barely shaving the external layer, with taps being approximately 30 cm apart.
Adapt the recommended number of taps and tapping period on frankincense trees as suggested in Table 12.
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Table 12: Tree size and recommended taps
Tree Foliage Tapping Start of Branching form Intervals End of tapping height cover (Spots) Tapping Grazed 1 Bole and major Natural 2 branches less than Poorly 3 30 cm in diameter foliated Well 5 1-3 m foliated Grazed 2 Bole and major Natural 3 October End of May branches greater Poorly after Khareef Before 4 than 30-50 cm in foliated From October (Monsoon) Khareef diameter Well to May every (Monsoon) 6 foliated 23 days Any time In Grazed 5 non-affected Any time In Bole and major Natural 6 May to June area non-affected branches from 50-80 Poorly every 14 days (Monsoon) area 10 cm in diameter foliated (Monsoon) Higher Well 12 than foliated 3 m Grazed 10 Bole and major Natural 14 branches greater Poorly 16 than 80 cm in foliated diameter Well 18 foliated
6.2. Pilot Olibanum Farm
Establish a pilot olibanum farm, the location of which can be western Raysut, or near Thumrait or in the Sadah - Hasik area. As Oman generally suffers from water scarcity, treated water can be used. The farm will serve as: • A genebank for olibanum trees to be used as a collection spot for all regions of Dhofar. • A centre for olibanum research and investigation on its domestication, irrigation, fertilization and controlling tree shape. • A tourist attraction centre to show sustainable ways of harvesting frankincense trees.
6.3. Management Plan
The main aim of a management plan is to ensure the sustainable harvesting of frankincense trees within Dhofar. The management plan is recommended to be put in place amongst frankincense harvesters and different government bodies such as (but not limited to) Ministry of Agriculture and Fisheries Wealth, Ministry of Environment and Climate Affairs, Office for the Conservation of the Environment, Museum of Frankincense Land, Dhofar Governorate and Ministry of Cultural Affairs. Olibanum harvesters should be trained in sustainable
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Sustainable harvesting of Frankincense trees in Oman harvesting techniques, and their work should be checked or monitored to ensure the norms put in place are thoroughly followed.
This would allow frankincense harvesting to be done only by trained and registered harvesters under a permit system. Certificates of Origin could be issued for Omani frankincense, which would protect and optimise the value and the reputation of Omani olibanum.
6.4. Scientific Research
More research is needed as there are still gaps in this study that need to be addressed to enable on-going and improved understanding of the nature of Boswellia sacra and implications of its olibanum oozing and harvesting. Additional factors need to be studied to deepen our understanding of the quantitative and qualitative variations of olibanum production.
The potential variation in growth and the resin yield and the opportunity for the selection and improvement of Boswellia sacra could be attributed to the trees’ genetic variation within species hence it is recommended that further studies are done to establish the link scientifically.
6.5. Awareness
Conservation of any organism in human dominated area depends on the active involvement of locals. At every stage of protection for achieving this target, it is recommended that awareness is raised showing the importance and conservation of native plants for a diversified audience. The popularization of good practice is needed among different segments of the society and could implemented through lectures in schools, mediatised information, field visits, booklets, interviews, workshops and conferences.
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7. Conclusion
Wild frankincense is harvested in Dhofar, particularly as a source of livelihood and sustainability of the Boswellia sacra is critical. If the tree is not harvested with care its population may gradually reduce, resulting up in irreversible extinction.
Frankincense is an internationally highly valued resource and its conservation is important to ensure the long-term sustainability of frankincense production. The research advocates the need to seriously consider the commercial viability of cultivating Boswellia sacra tree if the tree’s harvest is to be sustainably and optimally used.
Much progress has to be made as this is the first study of its kind in Oman. However, there is a role to play in avoiding the catastrophic loss of genes, species and ecosystems. Conservation actions will be at various scales and vary from weeks to decades. Progress towards reaching outcomes will require specific actions in biodiversity conservation and close work with local communities and industry representatives.
There are numerous challenges that hinder the delivery of environmentally effective and economically efficient plans for frankincense production. Building capacity and monitoring progress are critical to reach the sustainable management of Omani frankincense. Permanent and ongoing dialogue among all relevant stakeholders should be encouraged, and data and information obtained in this study provide a strong basic framework for further studies.
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40. Rao BA, Shivalingam MR, Chowdary KP, Sunitha N, Rao VS. Preparation and evaluation for controlled release of olibanum resin coated microcapsules of carbamazepine. Int J Pharm Biomed Res. 2012
41. Mohamud Haji Farah, Non-timber forest production (ntfp )extraction in arid environments: Land use, frankincense production and the sustainability of B. sacra in Dhofar Oman, Ph.D. Thesis, University of Arizona, 2008
42. F. Strumia, L. Dapporto, M. Dellacasa, P.L. Scaramo, Z .Zino, Notes on some insects associated to frankincense tree (Boswellia sacra fluckiger 1867 Burseraceae) in Dhofar (Sultanate of Oman), Atti Soc. Tosc. Sci. Nat ,. Mem., Serie B 114, 2007
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Appendix 1: Description of various medicinal uses of Frankincense
a) Inflammatory Diseases
Inflammation is the reaction of our body to something that has happened to the immune system, when we feel pain, redness, or swollen. Olibanum has shown to be effective in treating various inflammatory diseases (Ammon, 2005).
b) Heart Disease
Studies has shown direct link between inflammations and building up of plaque inside the blood vessels, causing hardening of the arteries. This is the major cause of coronary heart disease and has been found to be linked with inflammation (Cuaz-Perolin, 2008). Boswellic acid (AKBA) reduces chronic inflammation through the inhibition of nuclear transcription factor-kappa B (NF- KB), which is an important factor in the development and progress of chronic inflammatory diseases. The treatment using olibanum targeting this transcription factor to treat chronic inflammation in atherosclerosis could be developed (Cuaz-Perolin, 2008).
c) Asthma
The effects of olibanum on anti-asthma treatment is based on Boswellic acids inhibit of leukotriene biosynthesis that reduces and prevents the inflammation in many chronic inflammatory diseases like asthma (Gupta, 1998; Nusier, 2007). The study shows a definite role of olibanum in the treatment of bronchial asthma.
d) Skin Diseases
Olibanum extracts are used to reduce redness and irritation in the skin and produces an even skin tone. It also used as a skin remedy for bruises and infected sores (Eyre, 2003). The olibanum extracts found to have a soothing effect on irritated skin; the olibanum effect is due to the Pentacyclic Triterpene (steroid- like) structure shared in different Boswellic acid compounds (Michie, 1991).
e) Inflammatory Bowel Disease
Boswellic acids, which are the active ingredients of the olibanum of Boswellia sacra, have shown to be specific, non-competitive inhibitors of 5-Lipoxygenase. 5-Lipoxygenase is the key enzyme of leukotrienes. The leukotrienes were proven to play an important role in keeping the inflammation active in chronic
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Sustainable harvesting of Frankincense trees in Oman inflammatory diseases of the colon (Rahimi, 2010). The olibanum has shown to have wound healing, anti-ulcer, and anti-diarrheal properties (Alam, 2012) and to be effective in the treatment of chronic colitis. In comparing study using olibanum in treatment inflammatory bowel diseases is not better, at least it is similar to the effect of sulfasalazine, a chemical drug used in the treatment Inflammatory bowel diseases (Gupta, 1997).
f) Cancer
Many Plants were known to have antitumor compounds (Estrada, 2010). Olibanum from various Boswellia species were more promising as they contain triterpenoids with antitumor properties. The four antitumor activities triterpenic acids (BA, ABA, KBA, and AKBA) isolated from the olibanum of Boswellia tree (Alam, 2012) were studied and it was found that these acids inhibited the synthesis of DNA, RNA, and protein in human leukemia HL-60 cells in a dose- dependent manner. Among them, AKBA induced the most pronounced inhibitory effect on DNA, RNA, and protein synthesis, in which the effect on DNA synthesis was found to be irreversible. This compound significantly inhibited the cellular growth of HL-60 cells, but did not affect cell viability (Xia, L, 2005). The anticancer activity of AKBA is attributed to the inhibitory effect on the lipoxygenases, leading to the inhibition of cell proliferation and induction of apoptosis in tumour cells.
Prostate Cancer Triterpenoid compounds are derived form a C30 pentacyclic that contains (Howers, 1950) five carbon rings found in Boswellia tree and have an inhibitory effect on the growth of prostate cancer cells. Also, tirucallic acid, isolated from the olibanum, works as an effective Akt inhibitor, which apply cytotoxic effects in human prostate cancer cell lines in vitro and in vivo (Estrada, 2010). Akt is a serine/threonine protein kinase which has an important role in multiple cellular processes such as cell proliferation, apoptosis, transcription, and cell migration. (Estrada, 2010; Howers, 1950). Akt1 has been associated as a major factor in many types of cancer since it can block apoptosis and promote the survival of the cell.
Brain Tumour Surgical removal of brain tumours is difficult and in procedures for patients with malignant brain tumours, highly active forms of leukotrienes and other inflammatory mediators are produced in the brain and around tumours, causing localized fluid build-ups and damages to the health nerve cells (Simmet, 2001). A study showed positive impacts on patients with brain tumours treated with ethanolic extract of the olibanum containing Boswellic acids. The application of
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Sustainable harvesting of Frankincense trees in Oman this preparation (which is called phytopharmacon H15) for a period of 7 days, has shown a reduction of peritumoral brain oedema by 22 to 48 %. In contrast to the cells of untreated patients, the cells of the treated tumour tissue showed no tendency to proliferate within 2 weeks (Bone, 2011). The study also showed the ratio of tumour over volume decreased in these patients, suggesting the antitumor effect in addition to the anti-oedema activity.
g) Diabetes
A new study showed that the effect of aqueous extract of the leaves and roots of Boswellia trees decreased the blood glucose level in diabetic patients. Continuing the use of leaf and root extract for 28 days showed a decrease in serum glucose, cholesterol, triglyceride, urea, and creatinine levels and enzyme activities, in addition to significant hypoglycaemic effects (Kavitha, 2007). Type I diabetes is an autoimmune disease in which a chronic inflammatory process finally causes beta-cell death and insulin deficiency (Ahmadpour, 2012). Extracts from the olibanum have been shown to possess anti-inflammatory properties, especially by targeting factors or mediators related to autoimmune diseases (Shehata, 2012). The study shows that Boswellia extract has anti-diabetic effects and could prevent complications of diabetes in the kidneys and liver.
h) Antimicrobial Effects
The volatile oil isolated from the olibanum has been found to have antimicrobial activities against various microorganisms such as fungi, and gram-positive and gram-negative bacterial strains (Rahimi, 2010). Among the Boswellic acids, AKBA was the most active inhibitor of bacterial pathogens. However, the activity of AKBA was limited to gram-positive bacteria. AKBA was found to be the most active compound against the entire gram-positive bacterial pathogens tested (Raja, 2011). AKBA can be used in the development of an antibacterial agent against oral pathogens and can be used in mouthwash for preventing and treating oral infections.
i) Memory Problems
It is believed in traditional medicine in Oman that olibanum extracts improve learning and memory, and has been used in the elderly for the enhancement of memory and in pregnant women to increase the memory and intelligence of their off springs (Sharifabad, 2007). New studies showed that there is a significant increase in the power of learning at post-learning stage, short-term memory, and long-term memory in rats whose mothers received aqueous extract of olibanum orally during the gestation period. Better learning and
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Sustainable harvesting of Frankincense trees in Oman memory performance in the offspring of the mothers who consumed frankincense during their pregnancy is related to an increase in the somal volume of hippocampal neurons in cornu ammonis (Sharifabad, 2004). The new study supports the traditional belief that olibanum has beneficial effect in enhancing memory and learning functions.
j) Fertility
The olibanum contains Boswellic acids and other pentacyclic triterpenes, which have a chemical structure similar to that of steroids. In a study that was conducted to examine the effect of olibanum on the reproductive system and fertility of adult male rats, oral administration of olibanum increased the fertility in rats (Nusier, 2007). In addition, the number of implantations and the number of viable foetuses also increased, which may possibly be due to the increase in sperm motility and sperm density. Fertility regulation with plant preparation has been reported in traditional medicine (Nusier, 2007). Olibanum is reported to be used by some as an aphrodisiac and a fertility promoting agent. No doubt on effect olibanum compound in fertility, mainly by its effects on pituitary gland cells as suggested.
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Appendix 2: Weather station results of location 1 (Ardit)
Table A1 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 1 Ardit, in 2011
Ardit - 2011 Months Temperature (C°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 20.9 29.9 24 0 8.5 80.6 57 0 27 9 February 21.3 30.6 25 10.3 5.9 81.5 55 0 43 10 March 22.9 32.6 27 5 5.9 84.8 49 0 41 10 April 24.3 32.9 28 19.3 27.6 91.8 70 0 46 14 May 25.6 33.6 29 1.3 52.2 90 72 0 49 12 Jun 24.4 32.1 28 8.9 54.9 100 83 0 38 13 July 23.1 29 25 25.2 71.6 100 94 0 30 6 August 23.3 29.6 25 16.5 65.2 100 94 0 35 6 September 23.3 30 26 4.3 55.7 100 85 0 38 9 October 24.1 35.7 28 5.8 16.4 87.4 61 0 30 8 November 23.4 33.5 27 60.2 10.3 97.7 59 0 48 12 December 19.1 31.7 25 8.3 6.8 71.6 33 0 51 17 Mean 22.9 31.7 26.4 165.1 31.7 90.4 67.66 0 39.66 10.5
Table A2 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 1 Ardit, in 2012
Ardit - 2012 Months Temperature (C°) Rainfall Humidity (%) Wind Gust(km/h) min max mean (mm) min max mean min max mean Jan 17.6 28.3 24 3.8 5.9 81 53 0 48 11 February 20.8 32.6 25 15.9 5.9 86.9 52 0 48 12 March 21.7 33.6 26 2.4 5.9 90 52 0 53 12 April 24.4 30.9 28 0 33.3 87.7 73 0 40 11 May 25.1 32.2 29 0 49.7 92.4 71 0 46 12 Jun 25.6 32.2 28 0.4 59.2 97 81 0 38 11 July 23.8 29.5 26 28.1 72.9 100 90 0 38 13 August 23.6 29.2 25 24 72.9 100 94 0 33 8 September 23.9 30.3 27 0.6 54.9 100 82 0 40 8 October 24.2 33.6 27 0 19 91.7 67 0 27 8 November 24.3 30.6 27 0 19 83.3 59 0 30 8 December 21.6 31.3 26 16.6 11.2 86.2 55 0 46 11 Mean 23 31 27 91.8 34 91 69 0 41 10
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Table A3 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 1 Ardit, in 2013
Ardit - 2013 Months Temperature (C°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 16.8 29.5 24 23.4 5.9 77.3 50 0 53 12 February 19.2 31.1 24 0 6.8 88.8 54 0 43 10 March 21.9 33.7 26 9.7 6.8 93.6 61 0 46 10 April 24.1 34.6 28 0 26.2 95.1 72 0 45 11 May 26.4 33.4 30 1.2 52.4 90 75 0 38 10 Jun 25.6 31.4 29 0.2 56.4 95.1 62 0 41 12 July 20.1 27.9 24 56.8 76 99.7 90 0 40 13 August 19.7 28.9 23 7.6 69.8 93.1 86 0 38 8 September 22.5 30.2 26 4 59.9 92.2 79 0 41 10 October 24.3 35.7 28 0 6.8 87.3 68 0 43 9 November 24.3 32.4 28 14.9 18.2 86.8 58 0 45 11 December 19.3 31.4 26 10 7.7 79.7 42 0 67 12 Mean 22 32 26 127.8 33 90 66 0 45 11
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Appendix 3: Weather station results of location 2 (Afull)
Table A4 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 2 Afull, in 2011
Afull - 2011 Months Temperature (C°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 19.3 31.1 24 0 7.7 83.4 55 0 32 9 February 20.1 34.3 25 11 6.8 84 50 0 57 11 March 21.5 36.3 28 0.4 5.9 89.1 41 0 51 11 April 23.6 37.8 28 12 7.7 96.2 65 0 41 12 May 25.6 39.7 31 0.9 12.9 89.4 64 0 38 11 Jun 25.3 36.2 30 0.2 45 95 73 0 40 12 July 23.3 32.7 26 10.1 54.4 100 87 0 33 9 August 23.7 33.7 26 4.4 51.9 100 86 0 28 9 September 23.7 34.2 27 0.6 43.8 98 76 0 28 10 October 23.6 38.3 29 1.4 6.8 86.5 50 0 35 8 November 22.5 33.8 27 113.5 8.5 96.9 55 0 51 12 December 18.3 33.6 25 87.2 5.9 65.1 28 0 50 20 Mean 22.5 35. 27.2 241.7 21.4 90.3 60.8 0 40.3 11.2
Table A5 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 2 Afull, in 2012
Afull - 2012 Months Temperature (C°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 15.8 30.9 24 4.1 5.9 85.1 48 0 53 10 February 19.9 34.7 25 53.2 5.9 86.1 46 0 66 13 March 20.4 36.4 27 71.1 5.9 90 44 0 59 13 April 23.3 36.7 29 0.2 9.4 88.2 63 0 38 9 May 24.4 36.2 30 0 13.8 89.9 62 0 41 11 Jun 26.8 37.9 30 0 33.9 91.3 70 0 38 12 July 24.3 33.8 27 7.3 51.3 98.9 79 0 32 12 August 24.2 32.8 27 8.4 56.2 100 84 0 33 9 September 24.3 35.1 29 0 28 93.6 72 0 41 10 October 22.8 36.9 29 0 7.7 91.3 54 0 25 7 November 22.7 34.3 27 0 9.4 83.5 50 0 27 6 December 20.9 34.4 26 32.2 9.4 90.1 47 0 56 10 Mean 22 35 28 176.5 20 91 60 0 42 10
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Table A6 : Mean monthly temperature (c°), rainfall (mm), relative humidity %, wind gust km/h at location 2 Afull, in 2013
Afull - 2013 Wind Gust (km/h) Months Temperature (C°) Rainfall Humidity (%) min max mean (mm) min max mean min max mean Jan 16.5 31.5 24 418.3 5.9 82.9 46 0 66 12 February 18.8 34.4 24 71.7 5.9 87.6 48 0 80 11 March 20.3 36.9 27 21.5 6.8 90.1 50 0 46 10 April 23.4 38.8 29 0.2 7.7 92.7 63 0 37 11 May 26.3 40.3 31 1.7 8.5 86.3 63 0 32 11 Jun 26.3 39.5 30 0.5 8.5 87.5 68 0 28 11 July 24.4 32.1 27 12.3 56.8 100 82 0 35 12 August 23.9 32.8 27 3.1 50.2 100 82 0 35 11 September 23.9 34.9 28 0 38.7 90.7 70 0 32 11 October 23.7 39.4 29 0 5.9 85.9 56 0 40 10 November 23.1 36.3 28 10.9 6.8 87 53 0 37 11 December 19.1 35.7 26 2.7 7.7 82.2 36 0 51 13 Mean 22 36 28 542.9 17 89 60 0 43 11
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Appendix 4: Weather station results of location 4 (Kdat)
Table A7 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 4 Kdat, in 2011
Kdat - 2011 Months Temperature (c°) Rainfall Humidity (%) Wind Gust(km/h) min max mean (mm) min max mean min max mean Jan 10.2 28.7 18 49.4 7.5 99.7 54.9 0 43 14 February 10.7 28.9 19.4 22.5 6.8 89.4 38.3 0 43 15 March 14.6 32.5 22.8 8.8 6.8 89.4 31 0 41 16 April 18 35.8 24.9 98 6.8 95.2 46.8 0 45 18 May 20.6 39.7 38.7 1.3 5.9 95.2 40.9 0 43 16 Jun 21.3 38.9 28.3 0 5.9 97.7 44.4 1 41 16 July 20.8 40.3 29.4 3.4 5.9 97.4 44.6 0 49 16 August 20.9 40.6 28.2 0.2 6.8 94.7 53 0 48 16 September 22.3 40.1 31.1 0.7 5.9 85.2 19.4 0 48 13 October 17.7 35.2 24.7 8.4 6.8 96.9 34.7 0 43 14 November 14.3 27.8 20.5 151.6 13.8 100 64.7 0 53 18 December 9.1 24.2 16.3 0 6.8 86.9 41.7 0 41 18 Mean 17 34 25 344.3 7 94 43 35 16
Table A8 : Mean monthly temperature (C°), rainfall (mm), relative humidity %, wind gust km/h at location 4 Kdat, in 2012
Kdat - 2012 Months Temperature ( c°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 6.6 27.4 17.4 0 6.8 96.8 42 0 45 14 February 9.3 30 18.6 0 6.8 93 41 0 41 17 March 11.9 33 22 0 6.4 80.5 19 0 54 19 April 18.9 36.3 27 10 6.8 82.6 22 0 41 18 May 19.3 38.5 27.9 0 6.8 82.4 31.7 0 48 16 Jun 21.3 40.9 30.5 0 6.8 89.6 31.5 0 48 15 July 20.8 38.4 25.9 0 6.8 97 65 0 43 20 August 20.8 40 28 0 7.7 94 52 0 38 16 September 18.7 40.8 22.8 0 6.8 86.4 28.5 0 45 13 October 17.2 34.6 25.3 0 6.8 88.8 25.6 0 41 13 November 14.4 30.2 21.6 0 6.8 92.5 43.2 0 35 13 December 11.3 29.4 19.8 0.2 11.3 95.4 50.5 0 45 14 Mean 16 35 24 10.2 7 90 38 0 34 16
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Table A9 : Mean monthly temperature (c°), rainfall (mm), relative humidity %, wind gust km/h at location 4 Kdat, in 2013
Kdat - 2013 Months Temperature (c°) Rainfall Humidity (%) Wind Gust (km/h) min max mean (mm) min max mean min max mean Jan 10.2 28.7 18 0.2 7.5 99.7 55 0 43 14 February 10.7 28.9 19 3.2 6.8 89.4 38 0 38 17 March 14.6 32.5 23 21 6.8 87.8 25 0 41 16 April 18 35.8 25 63.3 6.8 95.2 47 0 45 19 May 20.6 39.7 29 17.9 5.9 91.5 35 0 43 16 Jun 21.9 39.4 31 0 5.9 85.8 25 0 49 16 July 20.4 39.6 25 1.5 7.7 98.1 71 0 43 20 August 19.7 39.8 27 6.2 7.7 94.3 51 0 53 15 September 18.3 37.9 27 0 6.8 93.8 37 0 37 13 October 17.1 32.9 25 0 5.9 86.5 36 0 43 14 November 13.9 29.5 21 0 15.5 95.9 58 0 37 16 December 8.2 26.2 18 0.7 9 92.3 44 0 35 14 Mean 16 34 24 114 7 93 44 0 42 16
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