Sugar palm (Arenga pinnata (Wurmb) Merr.) for livelihoods and biodiversity conservation in the orangutan habitat of Batang Toru, North Sumatra, Indonesia: mixed prospects for domestication

Endri Martini1, James M. Roshetko1,2, Meine van Noordwijk1, Arif Rahmanulloh1, Elok Mulyoutami1, Laxman Joshi1 and Suseno Budidarsono1 (1)World Agroforestry Centre (ICRAF), Jl. CIFOR, Situ Gede, Sindang Barang, Bogor, West Java, Indonesia (2)Winrock International, Jl. CIFOR, Situ Gede, Sindang Barang, Bogor, West Java, Indonesia

Email address: endri.martini@gmail.com Abstract: Domestication of desirable forest resources in agroforestry is expected to contribute to

community based forest conservation efforts, but there may be an optimum level of domestication in this respect. Aren or sugar palm (Arenga pinnata (Wurmb) Merr.) is a multipurpose tree that provides livelihoods for local people and food for other biota in the landscape. However, its domestication is still limited in many places, such as in Batang Toru Forest Block, an area of high conservation value, including habitat for the Sumatran orangutan (Pongo abelii). Options for aren management were prioritized as part of a landscape-scale conservation study by comparing domestication levels in the area. Data on economic indicators and ecological knowledge were gathered through interviews with key farmers, focus groups and transect walks. Four representative villages were selected for the study, that is, (i) two villages with no domestication of aren; and (ii) two villages with aren cultivation in rubber-based land-use systems. Cost-benefit analyses suggested that in a rich biodiversity area, such as Batang Toru, although aren was one of the sources of local livelihoods, additional investment for domestication beyond cultivation was not an option considered by farmers. Farmers still perceived wildlife as an efficient mode of aren regeneration, supported by the coexistence of people and other biota in the area. It appears the value of aren for local people's livelihoods and conservation can be enhanced by increasing its stocking density. There is also scope for improving market access and share of end-user value received by farmers.

Keywords: natural regeneration; enrichment; planting; cost and benefit analysis

Introduction Biodiversity conservation in densely populated parts of the humid tropics requires new solutions in the trade-offs between conservation and local livelihoods (Brown, 2002). One entry point in analyzing such trade-offs is to focus on agricultural systems that directly link livelihoods and biodiversity conservation (Cromwell, 1999; Scherr and McNeely, 2008). Such systems may focus on the domestication of wild species that can meet the economic needs of local people (income diversification, risk spreading, efficient labor, and land use) and contribute to biodiversity conservation (Michon and de Foresta, 1997; Belcher et al., 2005). Tree domestication provides a powerful incentive for subsistence farmers to diversify their farms with indigenous trees that provide economic returns and environmental services, including biodiversity conservation (Schroth et al., 2004; McNeely 2004). Native multipurpose trees may therefore be a stabilizing element

in the interface of (and gradient between) human use and biodiversity conservation (Kang and Akinnifesi, 2000).

Domestication of a species is driven by increased utilization by humankind (Roshetko and Evans, 1999), through an iterative dynamic process that spans a continuum from the wild to the genetically transformed state (Simons and Leakey, 2004). Clement (1999) focused on genetic changes in populations as a basis for stages of domestication. Based on different interpretations of the concept of plant domestication, Wiersum (1997a) distinguished two hierarchical levels in domestication, i.e. the biological aspects of human control over the reproduction of organisms and the social dimensions of resource access that make it worthwhile for individuals or communities to engage. In the biological sense, domestication refers to the processes operating at species or population level, i.e. the cultivation and gradual adaptation of a species' morphological and genetic characteristics for specific uses as well as specific environments. Cultivation in the sense of altering the

location or growth habit of a crop may precede domestication in a genetic sense. In the combined social plus biological sense, domestication refers to processes operating at agro-ecosystem level.

In Indonesia, aren or sugar palm (Arenga pinnata (Wurmb) Merr.) is a multipurpose tree species widely used by different ethnic groups, particularly in North Sulawesi, South East Sulawesi, North Sumatra, West Java, Central Java, East Java, East Kalimantan and West Kalimantan (Mogea et al., 1991). Aren is also identified as a priority species for human livelihood in Indonesia and Thailand (Gunasena and Roshetko, 2000). The vernacular nomenclature comprises about 150 local names for Indonesia alone (Heyne, 1987), showing the importance of aren in local livelihoods. Different ethnic groups utilize aren differently, mainly dependent on their socio-economic (religion, cultural) background, the availability of other natural resources (including fuel-wood for sugar processing), and market opportunities (Mogea et al., 1991). Within an ethnic and cultural context, aren utilization also varies with elevation.

Aren’s products are not only the sugary sap from its flower stalks but also its edible fruits and fibers for building material and household utensils. The socio-economic importance of aren and other palm species for the rural poor is described by Dalibard (2007). Aren contributes to both the livelihoods of people and the diets of wild animals, including species of high conservation value: Tonkean macaque (Macaca tonkeana) (Pombo et al., 2004), babi rusa (Babyrousa babyrussa) (Clayton, 1996), bees (Apis cerana) (Erwan, 2006), palm civets (Paradoxurus hermaphroditus Pallas), and Sumatran orangutan (Pongo abelii) (Sitaparasti, 2007). The year-round availability of fruits and high density (8.8 trees/ha) of A. pinnata in human-modified habitats offer a stable source of calories for Tonkean macaques; this is particularly critical in degraded environments (Riley, 2007). Animals play an important role in aren natural regeneration; in many areas farmers believe that the best aren planters are the palm civets (Mogea et al., 1991).

The Batang Toru forest area in North Sumatra is recognized as the largest remaining orangutan population outside national parks (Wich et al., 2003); hence, it is the focus of conservation efforts. The long-term de facto cohabitation of this landscape by people and orangutans is no guarantee for continued survival of orangutans, but offers opportunities for seeking conservation solutions that do not exclude people from the landscape. Conservation–livelihoods enhancement work in the Batang Toru area identified aren, durian (Durio zibethinus), rubber (Hevea brasiliensis) and cocoa (Theobroma cacao) as four species that contribute significantly to human livelihoods and can directly or indirectly contribute to the protection of orangutan habitats (Roshetko et al., 2007).

Interestingly, despite the importance of aren for local livelihoods, very few farmers in Batang Toru actively propagate or domesticate the species. Similar findings have been reported from other parts of Indonesia (Mogea et al. 1991; Smits and Widawati, 1999). The perception that aren trees are still abundant in the landscape may be a

reason for farmers’ reluctance to put in more effort for aren cultivation. Farmers may also have other economic considerations. Thus, this study was conducted to document the current practices in aren utilization and domestication in the Batang Toru area, to investigate farmers’ motivations in aren domestication, and to assess contribution of aren utilization and domestication for livelihoods and biodiversity conservation. Options for aren domestication development were prioritized as part of a landscape-scale conservation study by comparing aren domestication practiced in the area.

II. Methodology II.1. Species information of Aren sugar palm Aren (Arenga pinnata, syn. Arenga saccharifera) is a large palm that belongs to the Arecaceae family. The trunk is single and covered with a black, fibrous, hessian-like material. The leaves are 6–12 m long and 1.5 m broad, pinnate, with the pinnae in 1–6 rows, 40–70 cm long and 5 cm broad. The male inflorescence, in a dense cluster of 4 ft long is purple and has an unpleasant odor. The female inflorescences are longer than the male and ripen very slowly into glossy, brown, plum sized fruit. Male inflorescence is tapped for its sugary sap with a production of 5 to 40 liters of sap per day per inflorescence. Aren is often found in well-drained, tropical Asian landscapes with ample sun and water (usually near a river). The species grows best at high altitudes (500–800 masl) with precipitation above 1200 mm/year, 7–10 rainy months and average temperature around 25 ºC (Soeseno, 2000). II.2. Site description and selection of study villages Batang Toru is located in North Sumatra, Indonesia, and has a high orangutan conservation value. It covers approximately 105,000 ha in three districts—North Tapanuli, South Tapanuli and Central Tapanuli (Figure 1)—with an elevation of 200–1500 masl and annual precipitation of 1500–3000 mm. The dominant vegetation is primary rainforest. The Batang Toru area was selected for this study for two reasons.

1. The area provides habitat for a population of at least 400 Sumatran orangutan at the southern-most extremity of the species’ range (Singleton, 2004; Sitaparasti, 2007).

2. Aren is commonly cultivated and has strong cultural relevance to the dominant Batak tribe in the area (Roshetko et al., 2007).

[FIGURE 1]

Tree management of aren in Batang Toru is primarily based on natural regeneration and extractive management. Efforts to domesticate aren are uncommon in the area. However, over the last decade some farmers in Arse subdistrict (South Tapanuli) have collected aren seedlings from the wild and replanted in their fields. Four villages were selected for this study to represent type of aren domestication efforts in the area .

Figure 1. Study areas in Batang Toru, North Sumatra, Indonesia (Source: ICRAF Spatial Unit Analysis (2010))

1. Two villages where aren planting is practiced:

Lumban Lobu and Pagaran Tulason; both are located in Arse subdistrict and have predominately Moslem populations.

2. Two villages where there is no practice of aren planting: Paran Julu (Sipirok subdistrict, South Tapanuli) with a predominately Moslem population; and Hutagurgur village (Sibabangun subdistrict, Central Tapanuli) with a predominantly Christian population.

II.3. Data collection and synthesis Data were collected regarding: (i) utilization of aren in the local socio-economy; (ii) current efforts of aren domestication; and (iii) environmental services potential of aren based on local knowledge. Data were collected from primary and secondary sources between 23 November and 6 December 2008. Discussions with extension officers and traders in Sipirok were held to obtain information on: i) use and value of aren in the local socio-economy; and ii) other potential uses of aren. Semi-structured interviews were also conducted with 5–10 key persons per village to identify garden management systems and economic value at plot level.

In-depth interviews on the productivity of the plots were conducted with plot owners. Land-use economic values (revenues, costs, net present value and return to labor) were calculated based on input/output data of the plots where the aren inventory was conducted. A rapid plot inventory was conducted to describe types of land use. At least two representative rectangular plots were

sampled per village. Direct observation was made to validate the information obtained through interviews. Additional focus groups were held in villages that harvested aren products daily, that is, Paran Julu village (for sugar) and Hutagurgur village (for tuak). Secondary data were gathered from various published and unpublished sources before and after primary data collection from stakeholders.

Domestication levels in this study were defined by modifying the categories of indigenous tree utilization and management practices that were proposed by Wiersum (1997b). From Wiersum (1997b) tree utilization categories, we add more detail definition on tree regeneration (i.e. seedling production and planting), tree maintenance (e.g. thatch removal, pruning) and tree genetic selection (i.e. selection and production of improved quality germplasm). We classified the domestication levels in this study as wild, enriched, planted and domesticated (Table 1).

Potentials for aren domestication were evaluated through strengths, weaknesses, opportunity and threats SWOT analysis from both the livelihoods and conservation perspectives. Rapid Assessment of Agroforestry Practices and Technology (RAFT) analytical framework (Joshi and van Noordwijk, 2009) was used to describe potential effective agroforest management practices.

Table 1. Definition of domestication levels modified from Wiersum (1997b) to classify aren domestication in Batang Toru, North Sumatra, Indonesia

Table 2. Characteristics of study villages in Batang Toru, North Sumatra, Indonesia

Village Village area (ha)

Altitude (masl)

Temp (ºC)

Annual precipitation (mm)

Topo-graphy

Religion of inhabitants

Total households

Paran Julu 484 900–1200 13–26 2000–3000 Hilly 80% Moslem; 20% Christian

245

Pagaran Tulason

311 800–900 15–26 2000–3000 Flat 100% Moslem

21

Lumban Lobu 382 800–900 15–26 2000–3000 Flat 100% Moslem

82

Hutagurgur 3571 100–600 26–32 2000–3500 Hilly 100% Christian

135

Source: BPS North Sumatra, 2006; BPS Tapsel, 2006; BPS Tapteng, 2006.

III. Findings III.1. Aren’s utilization in the local socio-economy The Batang Toru landscape has a wide range of biophysical characteristics and diverse social conditions that influence how local people use the natural resources in the area. Based on observations and discussions with local people, aren utilization in Batang Toru varied between different religious groups, that is, Moslem and Christian, and was affected by the varying biophysical characteristics of the landscape.

From a biophysical perspective, elevation played a major role in how people utilized aren in Batang Toru. All villages had approximately the same annual precipitation (2000–3000 mm) and soil characteristics. Elevation, mean temperature and topography vary among villages. Hutagurgur, the only village located in the lowlands, differs the most from other villages (Table 2). At

lower elevations (below 200 masl) aren produces less sap than at higher elevations (more than 200 masl), thus, at lower elevations aren is less utilized. Of the four villages, elevation and temperature in Paran Julu is the most conducive for aren productivity.

From a socio-economic perspective, results from

interviews with village heads and other key informants confirmed that livelihoods in all four villages were based on on-farm and off-farm activities (Figure 2). Off-farm activities included share-cropping, traditional textile (ulos) production, drivers of public transportation. On-farm sources of income were derived primarily from the several land-use systems.

a) Rice systems: average 0.5–1 ha/HH (household), irrigated or semi-irrigated. This land-use system is found in all four villages where rice cultivation is important for food security.

Domestication level

Wiersum (1997b) category

Seedling production

Tree planting

Tree maintenance

Genetic selection

Note

Wild Uncontrolled procurement of wild tree products

None None None None Uncontrolled, open access gathering or controlled gathering of wild tree products. No tree maintenance is practiced.

Enriched Controlled utilization

None Yes Yes None Systematic collection of wild tree products with protective tending of valued tree species; and selective cultivation of valued trees by artificial in-situ regeneration

Planted Purposeful regeneration

Yes Yes Yes None Cultivation of wild tree species in artificially established plantations

Domesticated Domestication Yes Yes Yes Yes Cultivation of domesticated tree crops in intensively managed plantations

b) Aren-based agroforestry systems: plots of 1–2 ha/HH, typically 1–2 km from settlements. Number of aren trees in the systems varied from 10 to 50 trees/ha. Common associated tree species encountered in the system were durian, petai (Parkia speciosa) and various timber tree species of the Lauraceae family (for example, Litsea sp.). Most of the tree species in the gardens were from natural regeneration. This land-use system is most common in Paran Julu.

c) Rubber-based agroforestry systems: characterized by irregular spacing and a diverse mix of tree species (primarily fruit and timber). Each household owned 1–4 ha. Rubber and various fruit species dominated the system; some timber trees were also present. Most of the rubber agroforests were over 30 years-old with 100–200 mature rubber trees/ha, being around 40% of total trees.

d) Rubber monocultures: regularly spaced rubber plantations, occasionally mixed with a few cinnamon trees. The holding size was 1–4 ha/HH. Rubber spacing was commonly 3 m x 6 m. Clonal planting material or a mix of clonal and local seedlings were used in monoculture systems. Clonal planting materials were provided free by the district Estate Crop Office to facilitate the development of smallholder rubber systems. Rubber monocultures were only found in Pagaran Tulason and Lumban Lobu villages.

e) Other less-common land-use systems in the study area included mixed tree-based systems (dominated by cocoa, candlenut, and vegetables); secondary forests; and small monoculture systems with cocoa, candlenut or vegetables as the crops.

Figure 2. Main sources of household income in the four study villages based on data from focus group discussions with key informants in Batang Toru, North Sumatra, Indonesia

Culturally, all four villages in this study were

dominated by the Batak tribe. The three villages of Paran Julu, Lumban Lobu and Pagaran Tulason were primarily inhabited by the Batak Angkola sub-tribe, while Hutagurgur was inhabited by the Batak Toba sub-tribe. In Batak culture, aren plays a unique and important role. In Moslem areas, aren flower sap is used to produce sugar, while in Christian areas aren sap is processed to prepare tuak, an alcoholic beverage. However, not all Moslem farmers in Batang Toru processed aren sap for sugar

because sugar production requires ample firewood. Similarly, not all Christian farmers produced tuak, as not all farmers have the expertise to tap aren flowers.

Paran Julu was the village most dependent on aren: approximately 12% of households (30 of 245 households) relied on aren as their primary source of income. The remaining households (88%) had off-farm activities and paddy rice as the primary source of income. Aren was an important and productive crop in Paran Julu because: i) the local biophysical conditions in the village were suitable for aren; and ii) the existence of natural forests (home for seed dispersal agents and source of firewood) close to the village (4 km from the settlement).

In Paran Julu, farmers tapped aren twice a day, mainly for sugar production; only trees within 1–2 km from the settlement were tapped. Farmers reported that they needed about 1 m3 of firewood per week to process aren sap into sugar. Thus, farmers needed good accessibility to tree gardens or forests to secure sufficient firewood. Weekly sugar production in Paran Julu varied from 10 to 30 kg sugar/household. Farmers also harvested aren thatch (ijuk) and fruit (kolang-kaling) annually. Sometimes, the long distance from aren gardens to the village made farmers reluctant to harvest thatch and aren fruit. In such cases, farmers harvested thatch and fruits, only if there was an urgent need for cash in the family. Although aren was an important source of income in Paran Julu, no domestication efforts had evolved. Farmers in Paran Julu still depended on natural regeneration for aren propagation; and civets (Paradoxurus sp.) were considered to be the best aren planter.

In Lumban Lobu and Pagaran Tulason villages, both located far from the forests (more than 10 km), aren trees were considered only a secondary source of income. Before the 1990s, the primary sources of on-farm income in Lumban Lobu and Pagaran Tulason were coffee, candlenut and aren. Tapping rubber was the primary source of livelihoods in both villages at the time of this study. Firewood from rubber trees and other native vegetation was used to process aren sap into sugar. Farmers without sufficient firewood of their own bought from other farmers, at about USD 10 per m3. Farmers in Lumban Lobu and Pagaran Tulason harvested thatch more regularly compared to their peers in Paran Julu. The two former villages are closer to roads. Farmers believed that regular thatch harvesting improves aren growth. Farmers normally started harvesting aren sap and fruit when aren trees reached 8–10 years of age. Some farmers believed harvesting aren fruits reduced sap production.

Compared to the other three villages, Hutagurgur village was unique owing to its location at a low elevation and its dominant Christian population (Table 2.). The village is located 10–20 km from the nearest natural forest. Rubber had been cultivated in the village for the last 50 years and had become the main source of income for the villagers. Secondary sources of livelihoods in Hutagurgur were fruit trees, primarily durian, petai, langsat (Lansium domesticum), and cocoa. Aren was a tertiary source of livelihoods.

Also unique to Hutagurgur was that farmers fermented aren sap to produce tuak, a local alcoholic beverage sold in traditional cafés (lapo). Tuak was consumed daily and also in traditional ceremonies. Occasionally, farmers harvested aren fruits and thatch for sale. Because of Hutagurgur’s location in the lowlands, aren sap production was only 5–10 liters per flower per day compared to 20–30 liters per flower per day in the other three villages. Hence, only a few people in this village processed aren sap for sugar production. The sap from a single tree was used either to prepare tuak or sugar, but not both. The four study villages had different livelihood strategies that influenced how local people utilized and managed aren trees. Generally, aren contribution to local livelihoods in Batang Toru can be classified into four product types. 1) Sugar: trees tapped daily to provide weekly income;

aren contributed 50% of weekly household income; producers lived near the forest and had easy access to firewood for producing sugar.

2) Thatch (ijuk): leaves harvested no more than twice a year to provide yearly income; aren contributed less than 10% of yearly income of farmers.

3) Alcoholic beverage (tuak): trees tapped daily to provide weekly income; aren contributed 40–50% of weekly income of farmers, who were mostly Christians.

4) Aren fruit (kolang-kaling): harvested to provide yearly income; aren contributed 20% of yearly income; demand for fruit was highest during the annual Ramadan (fasting) month; primary markets were Sumatra and Java.

III.2. Aren domestication practices in Batang Toru Transect walks, direct observations and interviews with key informants were used to collect data. From four domestication levels defined for this study (Table 1.), only three levels were encountered in Batang Toru—wild, enriched, and planted (Table 3). Harvesting and post-harvest techniques in the study villages were relatively similar to those described by Mogea et al. (1991) for other locations in Indonesia. Tapping began when aren trees were 8–10 years old, continuing until the age of 25 years. No specific pest and disease control was practiced in Batang Toru because pests and diseases were not yet seen as a problem in the landscape.

The most intensive domestication was practiced

in Pagaran Tulason, where farmers produced their own seedlings and also collected wildlings to plant at regular spacings (8 m x 8 m). In a slightly less intensive practice, farmers in Lumban Lobu simply collected wildings from the forests to plant in natural gaps in the forest and other selected locations. In both Pagaran Tulason and Lumban Lobu, farmers removed the thatch regularly (every 3–4 months) to simulate aren stem growth. Aren cultivation in Arse subdistrict was similar to that in Lumban Lobu. In Paran Julu and Hutagurgur, where aren trees were still abundant in the surrounding forest, farmers did not plant

aren. Tree management practices in the two villages were similar while the final products from aren sugar were different: sugar in Paran Julu and tuak in Hutagurgur.

The tree species diversity in aren plots varied with intensity of aren domestication (Table 4). In a tendency, plots with increasing intensity of aren domestication (from wild to planted) showed a decrease in the number of accompanying tree species in the same plot. Around 50% of the total tree species encountered regenerated naturally, the remaining species were deliberately planted. All the species planted had economic value, for example, cacao, durian, cinnamon (Cinnamomum burmanii), jackfruit (Artocarpus heterophyllus), petai, langsat and aren.

The number of aren trees in an area depends on

the biophysical characteristics and the primary product harvested: more aren trees are required for sugar production than for tuak production. For instance, farmers needed at least 100 liters of aren sap to produce 20 kg sugar per week, while 100 liters of aren sap produced 100 liters of tuak. Hence, in this study, ‘wild’ plots were divided into two sub-categories: wild sugar and wild tuak. Between plots, the density of tappable aren trees differed among plots of different domestication levels and varied from 5 to 12 (Table 5).

The total productivity of the tree component of

plots also varied with the biophysical characteristics (Table 5). Under local management conditions, rubber trees came into production 7 years after planting, while petai and durian started producing fruit at 10–15 years. The contribution of each commodity to total household income over a 25-year period is illustrated in Figure 3. Interestingly, in all plots, kolang-kaling contributed 30–40% of the total income.

Figure 3. Contribution by commodity to income received per plot in one 25-year aren cycle by aren farmers in Batang Toru, North Sumatra, Indonesia

The economic value profitability of each plot was

calculated by including the four dominant commodities as noted in Table 5—rubber, durian, petai and aren—and by using a 25-year production cycle. Among the plots, the wild tuak plot had the highest NPV and return to labor

Table 3. Description of tree management practices at three aren domestication levels in the four study villages in Batang Toru, North Sumatra, Indonesia

Domest-ication level

Village Main products

Tree propagation

Tree spacing

Tree main-tenance

Land-use types

Wild Hutagurgur Alcoholic beverage

None Irregular, based on natural regeneration

None Mixed gardens; rubber agroforests; intensive rubber gardens

Paran Julu Sugar

Enriched Lumban Lobu

Thatch Collect and plant wild seedlings

Irregular (transplanting in gaps or other selected locations)

Remove thatch to stimulate trunk growth.

Mixed gardens; rubber agroforests; intensive rubber gardens

Planted Pagaran Tulason

Sugar and thatch

Propagate seedlings from local seed sources; collect and plant wild seedlings

Planted at regular spacing (8m x 8m)

Remove thatch to stimulate trunk growth.

Degraded land; rubber agroforests; intensive rubber gardens; mixed gardens

(Figure 4). Thus, the wild tuak plot would be the

type of management preferred by farmers. And, if compared between plots, enriched plot has the lowest NPV and return to labor.

Figure 4. Net Present Value (NPV) and return to labor per hectare for various levels of aren domestication (product combinations calculated for a 25-year aren cycle with aren production starting at 10 years old), in Batang Toru area, North Sumatra, Indonesia. Wild plots are calculated from 5 aren trees/ha, planted plots from 12 aren trees/ha, and enriched plot from 10 aren trees/ha.

Contrary to the NPV and return to labor trend shown in Figure 4, enriched and planted plots had higher revenues compared to wild tuak and wild sugar (Figure 5). However, both enriched and planted plots had higher costs compared to wild plots. Interestingly, wild tuak production

had the lowest revenue and the lowest cost but highest profit (NPV and return to labor). Moreover, the cost for wild sugar, enriched and planted plots was 10 times higher than for the wild tuak plot. With sugar production, the cost of fuelwood is more than 50% of its total cost (Table 6), although at the time of study fuelwood is a non-tradable product, that is, most farmers do not buy fuelwood for sugar production. Meanwhile, the total cost of domestication (planting, enrichment, land preparation and maintenance) was only around USD 500 for enriched and USD 600 for planted. In conclusion, NPV value depends more on the final product than on type of garden management (domestication level).

Figure 5. Revenue and total costs per hectare of each

observed plot, calculated for a 25-year aren cycle with aren production starting at 10 years old, in Batang Toru, North Sumatra, Indonesia

Table 4. Tree species composition of aren plots of different domestication levels in Batang Toru, North Sumatra, Indonesia Local name Scientific name Main

product Occurrence on aren plots of different domestication level Wild sugar Wild tuak Enriched Planted

Aren Arenga pinnata Fruit Flower sap Thatch

Natural Natural Natural Planted

Bambu Phyllostachys sp. Timber Natural - - - Cempedak Artocarpus integer Fruit Natural - - - Coklat Theobroma cacao Fruit - - Planted - Durian Durio zibethinus Fruit

Timber Planted Planted - -

Goti Alstonia angustiloba Timber - Natural - - Jambu batu Syzygium sp. Fruit

Timber - - - Natural

Karet Hevea brasiliensis Latex Fuelwood

- Planted Planted Planted

Kayu manis Cinnamomum burmanii

Bark Fuelwood

Planted - - Planted

Kopi Coffea robusta Fruit - - Natural - Langsat Lansium domesticum Fruit

Timber - Planted Planted -

Mangga Mangifera sp. Fruit Timber

Natural - - -

Medang Lauraceae Timber Fuelwood

Natural - - -

Medang labu Litsea sp. Timber Fuelwood

- Natural - -

Nangka Artocarpus heterophyllus

Fruit Planted Planted Planted -

Nangka-nangkaan

Artocarpus sp. Fuelwood Natural - - -

Petai/Parira Parkia speciosa Fruit Timber

- Planted - -

Pohon kayu Various timber species

Timber Natural Natural - -

Rambutan Nephelium lappaceum Fruit - Natural - - Salak Sallaca zallaca Fruit Natural - - - Waru Hisbiscus sp. Timber - - - Natural Total number of species naturally regenerated

8 5 2 2

Total number of species planted 3 5 4 3 Total number of species 11 10 6 5 Sample plot size (ha) 0.16 0.08 0.12 0.08

Note: ‘Natural’ means established by natural regeneration; ‘Planted’ means established by the farmers, ‘-’ means the species not encountered.

Table 5. Table 5. Average productivity in USD of aren plots of different domestication levels based on interviews with plot owners in Batang Toru, North Sumatra, Indonesia

Price (USD/unit)*

Plots Unit Wild tuak Wild

sugar Enriched Planted

Number of tappable aren trees

n.a. Tree/ha 5 5 10 12

Number of rubber trees

n.a. Tree/ha n.a. n.a. 350 350

Production Sap production Liter/tree 7.14 10 7.14 7.14 Palm sugar 0.78 Kg/ha/year n.a. 600 857 1028 Fruits (kolang-kaling)

0.28 Kg/ha/year 1500 1500 3000 3600

Alcoholic beverage (tuak)

0.11 Bottle (600 mL)/ha/year

5000 n.a. n.a. n.a.

Thatch (ijuk) 0.22 Kg/ha/year 12.5 12.5 25 30 Rubber 0.22 Kg/ha/year n.a. n.a. 847 847 Petai 0.22 Fruit/tree/year 189 n.a. n.a. n.a. Durian 0.56 Fruit/tree/year 200 100 n.a. n.a. Annual Gross Income USD/year 1128.1 941.7 1693.7 1994.4

Note: ‘n.a.’ = not applicable; ‘*’ = the price at November 2008: USD 1 = Rp 9000

Table 6. Cost breakdown for a 25-year aren cycle by domestication level in Batang Toru, North Sumatra, Indonesia

Cost breakdown Type of expense Aren domestication types Wild tuak

Wild sugar Enriched Planted

Total cost (USD) 1,880.25 16,997.39 22,047.95 22,707.46 Fuelwood Non-tradable 0% 76% 58% 56% Labor for aren tapping Non-tradable 50% 10% 8% 10% Labor for beating the flower/pre-harvesting (mangoal-goal)

Non-tradable 9% 0.5% 0.5% 0.5%

Labor for sugar processing Non-tradable 0% 7% 7% 7% Labor for rubber tapping Non-tradable 0% 0% 16% 16% Natural fermented additive (raru) Tradable 33% 0% 0% 0% Other (equipment, fertilizers) Tradable 8% 6% 11% 11%

Note: ‘Non-tradable’ means farmers do not buy the material; ‘Tradable’ means farmers buy the material

From gender perspective, the aren-based management system was mainly dominated by men, particularly during tapping (Figure 6). Women played an important role in cooking sugar and in the production of sweetmeat (kolang-kaling) from aren fruit. In general, in Batang Toru communities men play a larger role in aren management. Women have important responsibilities in managing other land-use types located close to settlements. There is no significant change of gender roles between different aren domestication levels (i.e. wild, enriched, planted).

III.3. Landscape-level opinion on Aren’s environmental services potentials At landscape level, aren occurs in most parts of Batang Toru, from lowlands to uplands. Aren trees are still considered to be abundant, thus domestication had not been considered necessary. From discussions with key stakeholders (farmers and government officers), aren trees also provided services such as preventing erosion and providing sources of food for animals such as civets, bees, orangutans, monkeys (Macaca spp and Presbytis melalophos) and squirrels. The provisioning service is a potential source of greater conflict between animals and humans, more than has already been seen in some parts of Batang Toru (Sitaparasti, 2007). Villages located near the

Figure 6. Gender role allocation in aren-based systems in Batang Toru, North Sumatra, Indonesia forest commonly have more conflict with orangutans, which consume aren flower sap and fruit. To avoid further conflict with orangutans, the villagers usually try to block the orangutan route to the aren trees. It is important to note that villagers do not kill orangutans for disturbing aren trees, as farmers believe that the aren trees will no longer provide sap if orangutans are physically harmed or killed. Stakeholders believe that the aren root structure is good for preventing land erosion, thus aren can be used in land rehabilitation programs, particularly on steep slopes. However, aren has not yet been included as tree species for land rehabilitation program in Batang Toru landscape, one of the reasons is because there are still plenty of aren trees in the landscape.

III. 4. Strengths, Weaknesses, Opportunities and Threats (SWOT) of domesticating aren in Batang Toru

Based on the SWOT analysis of aren domestication in Batang Toru (Table 7), aren trees can be (trans-) planted in a mixed tree-based system (agroforestry) at spacings of 8 m from other tree species; with the number of aren trees ranging from 12 to 30 trees/ha. Aren can be planted with any kind of tree species, for example, durian or rubber, however, spacing between trees is an important factor for optimum production. It is best to plant aren only 3 to 5 years after planting other tree species. Based on the information received from farmers and from direct observation, the aren root system is fibrous and horizontal and has the potential to affect the growth of other tree species.

Based on the SWOT analysis of aren products (Table 8), price fluctuations may affect tree maintenance intensity—the higher the price, the higher the intensity of garden management—including intensive harvesting and processing of products. Tuak and aren sugar have the potential to provide weekly income, while thatch and kolang-kaling are sources of annual income. Another potential product from aren is ethanol for biofuel. Fuelwood stock may be the biggest constraint for sugar or

biofuel production, thus planting species that provide useful fuelwood in or near aren gardens may be useful.

In conclusion, although current domestication efforts are limited, aren positively contributes to local people’s livelihoods and also provides a source of food for wildlife in the landscape. Further domestication efforts—particularly germplasm selection, planting and management techniques, harvesting and post-harvest management and technology—still require further work. IV. Discussion This study confirms the observations of Mogea et al. (1991) that the role of aren in local livelihoods remains valid. A recent study in the area showed that in addition to rubber, durian, cacao and kemenyan (Styrax benzoin), approximately 30% of farmers in Batang Toru also depended on aren to meet their livelihoods’ needs (Tata and van Noordwijk 2010). Despite aren’s importance to local livelihoods, in the past two decades there has been little effort by farmers to domesticate aren. This slow progress of domestication has been documented with other palm species. Byg and Balsev (2006) showed that most palms in the tropics are exploited in wild stands and are only occasionally cultivated, while only a few palms have been domesticated.

Out of 46 subdistricts in the Batang Toru landscape, only in Arse subdistrict of South Tapanuli district had farmers begun to cultivate aren by transplanting wild seedlings and planting seedlings produced on farms into a mixed-tree garden or agroforestry system. Discussion with farmers in Arse revealed some reasons why farmers cultivate aren the way they do. One motivation was the important role of aren in local livelihoods. Similar motivations of smallholder farmers to adopt agroforestry systems have been reported in the Philippines (Schurren and Snelder 2008) and Indonesia (Manurung et al. 2008).

Farmers’ aren domestication efforts in Arse subdistrict were supported by the local government. The head of Arse subdistrict in the 1990s built an aren nursery near the subdistrict office and distributed aren seedlings to nearby farmers. Simultaneously, Arse extension officers were actively promoting aren to improve local people’s livelihoods. In this context, government stimulus was important to motivate farmers to improve aren production and productivity. Simmons et al. (2002) highlighted government involvement as a key factor that influenced smallholders’ tree-planting behavior.

Our study identified three major types of aren domestication (wild, enriched and planted). Comparison of NPV and return to labor data showed that the wild type, which depends on natural regeneration of aren, was the most profitable; while the enriched type was the least profitable. However, the wild type is profitable under conditions where aren trees are still abundant and the wildlife (such as civets) are still available to help in pollination and seed dispersal. In many areas where natural vegetation has been converted to other land uses, enriched or planted types may be the better options for utilizing

Table 7. SWOT analysis by level of aren domestication in Batang Toru, North Sumatra, Indonesia Domestication level

Strengths Weaknesses Opportunities Threats

Wild • Least costly because it requires no labor for planting.

• Culturally embedded with local livelihoods.

• Usually occurs in mixed garden systems with high biodiversity that supports food security.

• Tree populations are dependent on natural regeneration.

• Gardens are becoming further from villages due to land conversion and limited natural regeneration.

• Tree production can be enhanced by regularly removing thatch at least once a year.

• Without enrichment planting of seedlings or wildlings by humans, the number of aren trees will decrease.

• Intensive fruit harvesting reduces source of seeds for natural regeneration.

Enriched • Many species from these mixed systems provide farmers with income, for example, rubber and fruit trees.

• In the extreme, systems become monocultures with low biodiversity.

• Cultivation of many valuable species to enhance income and reduce risks (the number of aren should be about 30 trees per ha).

• Aren propagation methods should be introduced to farmers.

• If farmers only depend on natural seed germination, the quality and quantity of available seedlings (wildlings) will be low.

Planted • Many species from these mixed systems provide farmers with income, for example, rubber and fruit trees.

• Tree regeneration not only depends on natural stock in the area but also nursery grown seedlings that may be from other areas.

• In the extreme, systems become monocultures with low biodiversity.

• Higher management cost per ha because of labor requirements for planting and maintenance.

• Cultivation of many valuable species to enhance income and reduce risks (the number of aren should be about 30 trees per ha).

• Mother tree selection, seed management and nursery management methods can be introduced to provide farmers with alternative income opportunities.

• The development of extensive areas of monoculture will decrease biodiversity and fragment the landscape.

Table 8. SWOT analysis by aren product in Batang Toru, North Sumatra, Indonesia Main product

Strengths Weaknesses Opportunities Threats

Alcoholic beverage (tuak)

• Require less labor and investment (no fuelwood requirement).

• 40–50% of weekly family incomes.

• Culturally embedded with local livelihoods.

• Limited market opportunity (only to non-Moslems)

• Production and marketing can be improved to increase income (tertiary source of income).

• Ethanol from aren has potential as source for biofuel.

• High tuak production may threaten sugar production in the area.

Palm sugar

• 50% of weekly family incomes. • High requirements for labor and fuelwood.

• Production system can be improved to increase income.

• Harvesting technique can also be improved. • Fuelwood species can be planted in aren

gardens.

• A decrease in fuelwood supply will increase the cost (and amount of planning) of sugar production.

Thatch • Low harvesting costs compared to sugar production.

• < 10% of yearly family incomes.

• Only harvested in gardens located near roads.

• Different biophysical characteristics result in different thatch quality.

• High market demand, sometimes with international market orientation.

• Can be harvested twice per year. • Routine thatch removal good for tree growth.

• Farmer perceptions indicate that intensive thatch harvest at productive age may reduce the sap production and moisture content.

Aren fruits (kolang-kaling)

• 20% of yearly family incomes. • Harvested once a year.

• Intensive fruit harvesting reduces source of seeds for natural regeneration.

• Demand for kolang-kaling is greatest during the annual Ramadan (Moslem) holiday.

• If harvest regulations or guidelines are not developed, kolang-kaling production might not be sustainable.

aren as a source of local livelihoods. A link between environmental conditions and land-use intensification was also observed by Snelder and Lasco (2008), who showed that in a forest-rich environment tree management is practiced but primarily in a rather passive way. In forest-deprived areas, trees are established on farms and field boundaries through intercropping and line planting.

Moreover, Byg and Balsev (2006) showed that perceptions of declining palm availability in combination with heavy reliance on palm products were positively related to palm cultivation (domestication). Thus, the stage in Batang Toru (that is, the enriched and planted practices) could be seen as a turning point for the current optimum progress of aren domestication particularly in areas where aren availability is declining, as in Arse subdistrict. From an economic perspective, optimum domestication level relates to the costs and benefits of the system. Enriched and planted plots have similar costs. However, the differences in numbers of trees between enriched (10 trees) and planted (12 trees) resulted in differences of profitability. Thus, setting the optimum number of aren trees per hectare in aren cultivation with enriched or planted types of practice is important aspect that needs to be considered in enhancing aren’s positive contribution to the local livelihood.

Aren yields multiple products that contribute positively to local livelihoods. Tree species utilized for multiple purposes are important to farmers for livelihoods’ needs (Garen et al., 2011). There are four main aren products with economic value: alcoholic beverage, sugar, thatch and sweets. Only sugar and alcoholic beverage are harvested for weekly income. Our profitability data showed that alcohol production had higher NPV compared to sugar, thus, if there is no social barrier (such as religion) to alcohol consumption and there is sufficient market, production of alcohol maybe the best option for farmers to fulfill their weekly income. Interestingly, during the 2008 world financial crisis when the global rubber price decreased, some rubber–aren farmers in Batang Toru switched from producing sugar to tuak. Farmers shifted to alcohol production that required less labor compared to sugar production. This allowed farmers to allocate more time to alternative livelihood activities to fill the gap left by reduced income from rubber.

Moreover, discussion of the role of domestication cannot be divorced from that of commercialization, since without a new market the incentives to domesticate intensively for self-use are insufficient (Leakey and Simons, 1998). Future success of domestication and commercialization depends on the benefits remaining with the farmers and their local industries and markets (Simons and Leakey, 2004). Belcher and Schreckenberg (2007) showed that the size and nature of the market are crucial factors to be considered in the commercialization of agricultural products. Goods and services that are primarily exported outside the producing region tend to have significantly larger markets. Thus, the main constraints to entering export markets, from a local or regional perspective, are on the supply side. Farmers’

biggest challenge is to increase the quality and quantity of production at competitive prices. However, in the case of aren, which is not an export commodity, advanced domestication seems unlikely unless a large, steady and lucrative domestic demand evolves.

Planting aren has the potential to provide diet for wildlife (Clayton, 1996; Pombo et al., 2004; Erwan, 2006; Sitaparasti, 2007). While beneficial from a conservation and biodiversity point of view, this may cause conflict between wildlife and farmers if local communities do not value biodiversity or lack awareness regarding the benefits of wildlife in the landscape (pollination and dispersal of aren seeds, which reduces tree regeneration costs). Cropping intensification and greater emphasis on short-term productivity can result in loss of species diversity and reduced genetic variation in farming systems (Donald, 2004; Lengkeek et al., 2006). Thus, interventions that support biodiversity and improve livelihoods should be more concerned with maximizing functional diversity than with just increasing the number of tree species found in landscapes per se (Dawson et al., 2009). However, smallholder farmers tend to choose a low-cost and low-risk practice that can contribute to their farm income (Schroth et al., 2004). Hence, Greiner et al. (2009) suggested that the design of conservation policies and programs at the regional level ought to be guided by a better understanding of the motivations and risk attitudes of farmers so as to be able to tailor and bundle incentives for maximum effectiveness and efficiency.

V. Conclusion In conclusion, farmers’ motivation to domesticate aren is influenced by environmental conditions, market opportunities, and social aspects (including government programs). From the livelihoods and biodiversity points of view, profitability analysis shows that the wild type of aren domestication practice is the optimum practice in a biodiversity-rich landscape such as Batang Toru. With the conditions in Batang Toru landscape as studied, although aren is one of the sources of local livelihoods, additional investment for domestication beyond cultivation was not the option considered by farmers as the cost or investment for intense genetic selection may exceed the benefits that can be gained. However, in converted or agriculturally intensified landscapes, where the remnant population of aren trees is limited, enriched or planted domestication levels may be optimum. To optimize the role of aren for local livelihoods and biodiversity conservation, the number of aren trees per hectare needs to be considered. From our data, a stocking density of 12 aren trees/ha seems to be the minimum for an aren agroforest to contribute to a family’s livelihood in a significant manner. Domestication efforts will benefit farmers only if supported by improved market access and share of the end-user value received by the farmers. Acknowledgements This study was funded through the Trees in Multi-use Landscapes in Southeast Asia (TULSEA) project funded

by the Federal Ministry of Economic Cooperation and Development (BMZ) and Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Initial work was conducted through the Development of Sustainable Economic Alternatives component of the USAID-funded Development of Collaborative Orangutan Habitat Protection in Batang Toru Watershed, North Sumatra, project. We appreciate the assistance and contribution of the collaborating communities and local government offices in Batang Toru, and Robert Frederick Finlayson for final language editing of the paper. We also thank two anonymous reviewers for valuable comments on the manuscript. References Belcher B., Perez MR, Achdiawan R (2005) Global

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