Frankincense Production Research Articles

Frankincense tapping reduces the carbohydrate storage of Boswellia trees

Carbohydrates fixed by photosynthesis are stored in plant organs in the form of starch or sugars. Starch and sugars sum to the total non-structural carbohydrate pool (TNC) and may serve as intermediate pools between assimilation and utilization. We examined the impact of tapping on TNC concentrations in stem-wood, bark and root tissues of the frankincense tree (Boswellia papyrifera (Del.) Hochst) in two natural woodlands of Ethiopia. Two tapping treatments, one without tapping (control) and the other with tapping at 12 incisions, are applied on experimental trees. Trees are tapped in the leafless dry period, diminishing their carbon storage pools. If storage pools are not refilled by assimilation during the wet season, when crowns are in full leaf, tapping may deplete the carbon pool and weaken Boswellia trees. The highest soluble sugar concentrations were in the bark and the highest starch concentrations in the stem-wood. The stem-wood contains 12 times higher starch than soluble sugar concentrations. Hence, the highest TNC concentrations occurred in the stem-wood. Moreover, wood volume was larger than root or bark volumes and, as a result, more TNC was stored in the stem-wood. As predicted, tapping reduced the TNC concentrations and pool sizes in frankincense trees during the dry season. During the wet season, these carbon pools were gradually filled in tapped trees, but never to the size of non-tapped trees. We conclude that TNC is dynamic on a seasonal time scale and offers resilience against stress, highlighting its importance for tree carbon balance. But current resin tapping practices are intensive and may weaken Boswellia populations, jeopardizing future frankincense production.

Frankincense tree recruitment failed over the past half century

Boswellia papyrifera (Burseraceae) trees grow in dry woodlands south of the Sahara and produce frankincense, the economically important olio-gum resin used for cultural and religious ceremonies throughout the world and as raw material in several industries. Across its distribution area, this species is threatened by farmland expansion, fire, improper tapping and overgrazing. Most of its populations lack saplings and small-sized trees (e.g. <10cm). It is unknown whether the older, adult trees represent a single or several cohorts, representing single or plural regeneration and survival waves. To understand such long-term population dynamics, it is imperative to evaluate the age structure of the current populations. We used tree ring analysis to determine the age-diameter relationship. This study, (1) determines radial growth dynamics and age-diameter relationship of B. papyrifera, including verification of annual growth-ring formation, and (2) constructs the population age structure and discusses consequences thereof for population maintenance and long-term frankincense production. We could prove that B. papyrifera forms annual growth rings. The average radial annual growth rate of B. papyrifera is 1.15mm (s.d.=0.22) and varies significantly among the sampled trees. Age and diameter of B. papyrifera trees are significantly correlated. From the population-age structure, it becomes obvious that the current B. papyrifera populations lack successful recruitment since 1955, which we attribute to intensive grazing and fire associated with the escalating increase of human settlement in the area. Lack of recruitment leads to rapidly declining populations resulting in strongly reduced frankincense production. Management aimed at seedling survival and sustainable use of relic trees is urgent.

Resin secretory structures of Boswellia papyrifera and implications for frankincense yield

Frankincense, a gum-resin, has been tapped from Boswellia papyrifera trees for centuries. Despite the intensive tapping and economic interest of B. papyrifera, information on the resin secretory structures, which are responsible for synthesis, storage and transport of frankincense, is virtually absent. This study describes the type, architecture and distribution of resin secretory structures of B. papyrifera and its relevance for the ecophysiology and economic use of the tree. The type and architecture of resin secretory structures present in bark and wood was investigated from transversal, tangential and radial sections of bark and wood samples. The diameter and density (number of resin canals mm(-2)) of axial resin canals were determined from digital images of thin sections across the different zones of inner bark. Resin canals form a three-dimensional network within the inner bark. Yet, the intact resin-conducting and producing network is on average limited to the inner 6·6 mm of the inner bark. Within the inner bark, the density of non-lignified axial resin canals decreases and the density of lignified resin canals increases from the vascular cambium towards the outer bark. In the wood, only radial resin canals were encountered. Frankincense tapping techniques can be improved based on knowledge of bark anatomy and distribution and architecture of resin secretory structures. The suggested new techniques will contribute to a more sustainable frankincense production that enhances the contribution of frankincense to rural livelihoods and the national economy.

Manage or convert Boswellia woodlands? Can frankincense production payoff?

African dry forests provide non-timber forest products (NTFPs) of high commercial value, such as frankincense and gum arabic. Nonetheless, their deforestation and conversion to croplands is intensifying. Expected higher financial return from crop production is a main driver of conversion, but research supporting this underlying claim is scarce. We compared the financial returns for two crop production options (sesame and cotton) and forest use, in a dry forest area known for its frankincense production in northern Ethiopia. Net revenue was highest for sesame and lowest for cotton agricultural use. The forest based revenue was intermediate. The revenues from the crop production options were more sensitive to a range of uncertainties than the forest land use. Our results show that forest land use that includes commercial NTFPs is financially competitive to some commercial crop options and offers returns of better reliability. The hypothesis that forest based revenues are lower than crop based ones is not supported by our results. Therefore, the continued deforestation of dry forests cannot be explained by lower returns alone, but other factors such as awareness, market access, property right and institutional issues may also play a role to drive deforestation and conversion of dry forests to croplands.

Frankincense production is determined by tree size and tapping frequency and intensity

Resin production in trees probably depends on trade-offs within the tree, its environment and on tapping activities. Frankincense, the highly esteemed resin from dry woodland frankincense trees of Boswellia papyrifera is exploited in traditional ways for millennia. New exploitation practices lead to weak trees and non-sustainable resin production. For 500 trees from four populations of B. papyrifera we evaluated how frankincense yield is affected by different tapping intensities (number of incision spots) and frequencies (number of resin collection rounds during the dry season), since both of them have been intensified recently. These effects are considered for trees of different size, since larger trees probably provide more resources for resin production. We predicted that frankincense production would initially increase with tapping intensity and tapping frequency, but later level-off because of resin depletion. Frankincense production varied highly: yield per tree per year of all 500 monitored trees averaged 261g (±231, but largely varied and ranged from 41 to 1829g. We indeed found that resin yield increased with tapping intensity, but not anymore beyond an intensity of 6–9 incision spots. Yield peaked around the seventh collection round, and declined thereafter. Yield increased with trunk diameter, but leveled-off beyond trees with a stem diameter of >20cm. These patterns were similar across populations, and between contrasting areas. Our results suggest that high tapping intensity risks short-term resource depletion, warranting tuning down the intensity of the current collection practices. Less intense tapping rounds per season will reduce damage, increase the health of tree populations, and contribute to long term frankincense production. This study thus allows for developing less damaging and more sustainable management for frankincense trees.

Benefits, Challenges, and Enabling Conditions of Collective Action to Promote Sustainable Production and Marketing of Products from Africa's Dry Forests

AbstractCollective action has been identified, by governments and nongovernmental organizations, as a mechanism to improve smallholder farmers' bargaining power and access to input and output markets. In many developing countries, supporting collective action has and continues to be an important policy instrument. However, in the collection and marketing of forest products, recognition of and support for producer organizations, is limited. Data, from focus group discussions, key informant interviews, and an analysis of formal producer organizations' functioning and organizational aspects, were used to examine the motives, benefits, challenges, and enabling conditions of collective action in promoting the sustainable production and marketing of shea, frankincense, and honey from dry forests in Burkina Faso, Ethiopia, and Zambia, respectively. Lessons and key recommendations, including those related to policy, are presented on how collective action through formal producer organizations could be assisted to promote responsible forest products collection and marketing practices that benefit small‐scale producers in Africa's dry forests.

Commodity Chain of Frankincense from the Dry Woodlands of Nuba Mountains, South Kordofan State, Sudan

Frankincense is one of the major commercial NTFPs in the Sudan produced by tapping the bark of Boswellia papyrifera (Del.) Hochst trees. It is one of the major NTFPs of the Sudan traded locally and internationally. The aims of the present study include: (1) to identify the chain actors and their functions (2) to estimate benefit distribution and value added along the chain; and (3) to determine the mechanisms by which actors control and maintain access to benefits. The study was conducted in the Rashad locality, South Kordofan state, Sudan in 2008/2009. A combination of Rapid Rural Appraisal tools including key informant interview, in-depth semi-structured interviews, group discussion and direct observations were used for primary data collection. Eight major actors involved in the value chain were identified and their activities and characteristics examined. The average annual net income of tapper, producer, village trader, and urban merchant was estimated to be 74, 740, 1,300, and 11,230 USD, respectively. The results clearly demonstrate the upward skewed benefit distribution among the value chain actors. The total relative commercialization margin was 62.5% indicating that the actors involved in marketing of the product accrued higher proportion of the end market price. While those involved in the production activities, tappers and producers, receive less income counting about 37.5% of the end market price. The results also illustrate that there is limited value added processing in the commodity chain. Commercial benefits in the commodity chain are gained, maintained and controlled through different mechanisms. The study concludes that frankincense production and marketing is financially profitable for producers, village traders and urban merchants. However, frankincense tappers and producers receive less income. Technical, financial, and institutional support could result in an increase in local actors’ income and contribute to sustainability of the supply of the product.

Limitations to sustainable frankincense production: blocked regeneration, high adult mortality and declining populations

Summary1. Resins are highly valued non‐timber forest products (NTFP). One of the most widely traded resins is frankincense, tapped from several Boswellia tree species (Burseraceae). Exploited Boswellia populations often show poor regeneration, but the demographic consequences of these bottlenecks are unknown. Here we report on the first large‐scale demographic study of frankincense‐producing trees.2. We studied 12 populations of Boswellia papyrifera in northern Ethiopia, varying in altitude and productivity. Six of these populations had been tapped before and were tapped during the study. Survival, growth and fecundity were determined for 4370 trees and 2228 seedlings, in 22.8 ha over a 2‐year period. We also studied a remote population where no grazing and tapping took place. Matrix models were used to project population growth and frankincense production under four restoration scenarios.3. Population structures of both tapped and untapped populations showed clear gaps. Small seedlings were abundant in all populations, but none developed into persistent saplings. Such saplings were only present in the remote population. Fire and grazing are the likely causes of this regeneration bottleneck.4. Adult mortality was high (6–7% per year) in both tapped and untapped populations, probably caused by beetle attacks and fire. Unexpectedly, tapped populations presented higher diameter growth rates and fecundity compared to untapped populations. These differences are probably caused by non‐random selection of exploited populations by tappers.5. Under the ‘business as usual’ scenario, population models projected a 90% decline in the size of tapped and untapped populations within 50 years and a 50% decline in frankincense yield within 15 years. Model simulations for restoration scenarios revealed that populations and frankincense production could only be sustained with intensive management leading to full sapling recruitment and a 50–75% reduction in adult mortality.6. Synthesis and applications. Regeneration bottlenecks and high adult mortality are causing rapid decline in frankincense‐producing tree populations in Ethiopia. This decline is unlikely to be a consequence of harvesting and is probably driven by fire, grazing and beetle attacks. Fire prevention and the establishment of non‐grazing areas are needed. Our results show that other factors than exploitation may seriously threaten populations yielding NTFP.

Constraints to smallholders production of frankincense in Metema district, North-western Ethiopia

Frankincense, an aromatic exudate obtained from several Boswellia species, is an important commodity with the potential to invigorate economic development of the drylands of Ethiopia. Local people have been producing and trading frankincense for centuries to diversify their income sources. However, local people's involvement in the production of frankincense varies considerably among the producing dryland regions of the country. The objectives of this study were to investigate: (i) the potential of frankincense production, (ii) socio-cultural, economic and policy factors affecting the involvement of local people in the production of frankincense, and (iii) the current status of Boswellia woodlands in Metema district, which is one of the major frankincense producing areas in Ethiopia. The results showed that Boswellia papyrifera comprised 51% of the species composition of the vegetation of the district with 253.5 kg/ha/year production potential. The total annual frankincense production potential of the district was estimated to be 79,168 tons. However, almost all inhabitants do not benefit economically from the species due to: (i) cultural influence (67%), (ii) unattractiveness of income from frankincense compared to other economic activities in the area (38%), property tenure (27%), government policy on incense production (20%), poor knowledge on frankincense production (19%) and unawareness of the potential of frankincense as a source of income (5%). The absence of direct economic benefits for the local people from the woodlands is triggering their widespread degradation mostly from human induced fire, improper forest use and agricultural land expansion.

Economic analysis of closing degraded Boswellia papyrifera dry forest from human interventions — A study from Tigray, Northern Ethiopia

In Ethiopia, environmental degradation leads to a reduction of forest areas with economically important tree species like Boswellia papyrifera. In an attempt to reverse this development and assist natural rehabilitation, closing degraded forest from free grazing, fuel wood collection and other interference is practiced in Tigray. Sustainability of this management will, among other things, depend on the resources' tangible benefits. This study aimed to determine and compare net benefits (in Ethiopian Birr (ETB) per ha) from the closed and open Boswellia papyrifera forestlands. Production and household surveys were carried out in Jijike and Siye tabias of Abergelle woreda in northern Ethiopia. Data on costs and benefits of frankincense production were collected from firms trading the product. Net benefits from forestlands and croplands were determined using the Net Present Value criterion. The estimated mean frankincense productions were 127 kg/ha/yr for closed forestland and 84.54 kg/ha/yr for open forestland. A significant difference ( p < 0.05) was observed between per tree mean frankincense yield of closed and open sites. The average grass harvest from closed area was 2851 kg/ha/yr. The financial Net Present Values were 8622 ETB/ha for closed and 6468 ETB/ha for open forestlands. These values were by 4574 ETB and 2005 ETB higher than the sum of NPV from crop and crop residuals of a hectare of cropland in the study area of the two sites, respectively. Exporting frankincense could generate foreign exchange of 53.28 and 39.05 USD/ha/yr from closed and open sites, respectively. Rural households earn about 74% of the annual total revenue (ETB/ha) from closed and open area as wage for tapping and collecting frankincense and using of grass. Sensitivity analysis showed that managing degraded Boswellia papyrifera forestland as closed area always generates a higher NPV than the open one in case of changes in discount rate and prices of inputs and outputs. Thus, managing the forest through closed areas is a competitive land-use alternative and provides higher net benefits than both open forestland and agricultural croplands.

The effect of tapping for frankincense on sexual reproduction in Boswellia papyrifera

Summary In the Horn of Africa, frankincense (an aromatic hardened wood resin) is obtained by tapping Boswellia papyrifera. World‐wide, frankincense is of great economic and social importance as an important element of incense and perfumes. The production is declining as a result of poor natural regeneration of the Boswellia woodlands, possibly as a result of the low production of viable seeds. We hypothesize that this is because of the current intensive tapping regime, which might favour allocation of carbohydrates for synthesis of resin at the expense of allocation for generative growth. Investigations were carried out at sites in different agro‐ecological zones with annually tapped trees and with trees that had not been tapped for several years. Seed viability and germination success were determined for 200 randomly collected seeds in each site. For three stands, the sexual reproduction (number of flowers, fruits and seeds) was determined for different sized trees subjected to three experimental tapping intensities (no, normal and heavy tapping). At the stand level, non‐tapped trees produced three times as many healthy and filled seeds as tapped trees. Germination success was highest in stands with non‐tapped trees (&gt; 80%) and lowest for those with tapped trees (&lt; 16%). At the tree level, sexual reproduction decreased with increasing tapping regime irrespective of tree size. Overall, large trees tended to produce slightly heavier seeds than small trees, and seeds from non‐tapped trees were heavier than those from tapped trees. In the stands where tapping was prohibited changes in tapping regimes had the greatest effect on sexual reproduction. Trees subjected to annual tapping always showed the lowest sexual reproduction. Synthesis and applications. Tapping for frankincense results in limited flower and fruit production, and low production of mainly non‐viable seeds in B. papyrifera. We argue that tapping causes competition for carbohydrates between frankincense production, and fruit and seed setting. Consequently, the current tapping regimes will cause tree exhaustion and eventually a decline in vitality. Tapping may potentially reduce natural regeneration of the species. New tapping regimes are suggested that include periods of time in which tapping is prohibited in order for trees to recover and replenish their stored carbon pool, and a reduction in the number of tapping points per tree. This is important in view of the long‐term sustainability of frankincense production, an internationally highly valued resource.