Lesson Learned From Mangrove Rehabilitation Program in Indonesia

Indonesia as an archipelagic country more than 17,504 islands with the length of coastline estimated at 95,181 km bears mangroves from several meters to several kilometers. They grow extensively in the five big islands (Jawa, Sumatra, Kalimantan, Sulawesi, Papua). At the year of 2009, Agency of Survey Coordination and National Mapping (Bakosurtanal) of Indonesia reported the existing mangrove forest area in Indonesia of about 3,244,018 ha, however Directorate General of Land Rehabilitation and Social Forestry, Ministry of Forestry (Ditjen RLPS MoF) of Indonesia at 2007 reported about 7,758,411 ha of mangrove area in Indonesia (including existing vegetated mangrove area). It was further reported that those mangroves were 30.7% in good condition, 27.4% moderate-destroyed, and 41.9% heavy-destroyed. In order to rehabilitate destroyed mangrove ecosystems, Indonesia applies at least three type of planting designs (square planting design, zig zag planting design, and cluster planting design) and eight planting techniques (“banjar harian” technique, bamboo pole technique, guludan technique, water break technique, huge polybag technique, ditch muddy technique, huge mole technique, cluster technique). Generally, in Indonesia Rhizophora spp. are used for mangrove rehabilitation and/or restoration with the spacing of 1x1 m spending varied planting cost based on the site local condition and planting technique used. The mangrove planting ranged from about Rp. 14.2 million using propagules to Rp. 18.5 million using cultured seedlings. Recently, local community used to utilizing associated mangrove aquatic fauna for supporting their daily life as well as utilizing mangrove habitat for multipurpose uses through agroforestry techniques (silvofishery, agrosilvofishery, agrosilvopastoralfishery systems). So that, the good mangrove ecosystem serves luxurious both flora and fauna species (biodiversity) as well as their abundance for significantly supporting the welfare of coastal community.


Introduction
Mangroves are a group of salt tolerant plants inhabiting inter-tidal zone between the high-water mark of spring tides and a level close to but above mean sea level in the tropical and sub-tropical regions, mostly well developed in the sheltered coast, deltas, lagoons, and estuaries. These plants and the associated microbes, fungi, plants, and animal constitute the mangrove community, in which it intercorrelated with abiotic factors constitute mangrove ecosystem. If those mangrove ecosystems are dominated by trees, we called mangrove forests. The term "mangrove" itself describes both the plants inhabiting inter-tidal zone and the community itself (Tomlinson, 1986), even ecosystem (FAO, 2005;Kusmana, 1993).
Mangrove ecosystem is an interface unique ecosystem between marine and terrestrial ecosystems characterized by high productivity and rapid cycling of nutrients (Snedaker, 1978) that contribute a major share of the energy requirements offshore ecosystems (Harger, 1982). Therefore, they are considered as important natural resource for multiple reasons, especially for the tropical countries.
The rate of disturbance and variety of the humaninduced influences on the mangrove ecosystems have been steadily increasing, so a large proportion of the World's mangrove is threatened with destruction. The main cause of the mangrove destruction as currently underway in the world can be broadly distinguished as: (1) over exploitation by the traditional users (e.g. for charcoal, pole and firewood) and uncontrolled forest concessionairs, (2) destructive actions resulting from activities generally unrelated to sustained uses of mangroves (e.g. conversion to agriculture, mining/mineral extraction, aquaculture, urban infrastructures, resettlements, etc.) (Saenger et al., 1983), and (3) pollution and natural disaster (Kusmana, 2010). So that, the conversion of mangrove areas to other uses over the past decades has been alarming.
In the developing countries, short-term economic gains in the mangrove areas (e.g. oil mining, resettlement, industrial estate, etc.) have taken precedence over the long-term generation of benefits which have both economic and natural values. However, mangroves are sensitive to outside influences and are increasingly subjected to stress or disappearance through reclamation and pollution (Snedaker, 1978).
As an archipelagic country, Indonesia consists of more than 17,504 islands (28 big islands and 17,475 small islands) with the length of coastline estimated at 95,181 km, which bears mangroves from several meters to several kilometers. According to the latest information, the mangrove vegetated area in Indonesia is amounted to 3.2 million hectares (Bakosurtanal, 2009 For centuries the Indonesian people have traditionally utilized mangroves, mainly for firewood, charcoal, tannin, dyes, food and beverages, medicine, pole and timber. The main genera used are Rhizophora, Bruguiera, Ceriops, Avicennia, Nypa and Oncosperma (Soegiarto, 1984). At the beginning, the fishing and charcoal making are generally the basic economic activities in the mangrove areas. However, in the following period a commercial scale of mangrove exploitation in Indonesia has been begun with a production of logs, charcoal and chip-woods. In the same time, the increasing of population growth and economic development in this country resulted in the destruction even disappearance of many mangroves through conversion of them to fishponds, industrial estates, transportation and recreation infrastructure, resettlement, tin mining, agricultural activities, and other uses.
The multiple role of the mangroves as a renewable resources in the coastal area in relation to serving valuable forest products and environmental services for the coastal population is well recognized in Indonesia, so that degraded mangroves must be rehabilitated and mangrove plantation should be established in some intertidal areas to enrich land productivity as well as environmental quality of the ecosystem.

Mangrove Rehabilitation and Restoration in Indonesia and Other Countries
Mangrove rehabilitation or restoration is becaming important in Souteast Asia, mainly as the effect of mangrove destruction becames apparent in the form of loss of coastal fisheries productivity, loss of livelihood of coastal communities, and loss of live and proverty in the wake of storms and tsunamis. Promotions of regeration of mangroves has been the goal of mangrove foresters in South Asia (Giesen et al., 2006). It is reported also that as a general rule, mangrove seedlings should be planted with 1 metre spacing, i.e. at a density of 10,000 per hectare. High initial mortality is not unsual, but survival rates of at least 50 percent should be expected. Typical forest density of mature mortality of planted saplings should not lead to an unsually sparse forest (Lewis and Streever, 2000). Indeed , a round of thinning may be required in years 5-10 to prevent the establishment of 'pole forests', i.e dense stands of thin, tall trees, as these may be particularly susceptible to storm demage. According to Lewis (2001), the cost of mangrove restoration usually varies from US$225 per hectare to US$216 000 per hectare, depending on the location and technique used.
Almost all countries in Southeast Asia executed mangrove rehabilitation/restoration in improving and recovering mangrove ecosystem function in their region (Table 1).

Planting Design and Tehnique
Regarding to the mangrove rehabilitation and restoration, there are three planting design commonly applied in Indonesia (Figure 1) with the spacing of 1x1 m, 1x2 m, 1.5x1.5 m, 2x2 m, and 2x3m depending on the goal of planting and local specific habitats condition. Beside at least eight planting techniques haven been applied by the various parties in planting mangrove in Indonesia (Figure 2).

Budget for Mangrove Rehabilitation
As an archipelagic country, Indonesia has the largest mangrove areas in the world (about 3,2 million ha), but about 70 % of them are destroyed. Because of the paramount important function of mangrove ecosystems, Indonesia has been spent high efforts to rehabilitate and restore degraded mangroves using several techniques to guarantee the success of planting. In oder to serve general guidance for stakeholders to participate in executing the mangrove rehabilitation/restoration, mainly for internal need institution in allocating budget, Ministry of Forestry enacted the Decree of Director General of Watershed Management and Social Forestry No. P.05/V-SET/2014 on estimate Unit Price Standard for Mangrove Rehabilitation. In general its regulation giving information such as shown on Table 2.
Beside a technical aspect (knowledge of an autecology and silvicultural technique of species to be planted), the cost budget for mangrove rehabiliation or restoration should be considered firmly. According to our experiences, there is a variation cost budget for  (Table 3 and 4). Regarding to seedling production in the nursery, the cost budget is about Rp 1,350 per an individual seedling (Table 5).
In this event, I want to describe experience for three difference cases of mangrove rehabilitation in Indonesia.    Cost for producing one seedling in the nursery 1,349 (rounded to 1,350) Note : for the spacing 0.5x0.5 m, cost for planting one seedling using Guludan Technique is Rp 101,000

Cases of Mangrove Rehabilitation Programs in Indonesia a. Case (1): Mangrove planting using Guludan Technique in coastal area of Angke Kapuk, North Jakarta
Angke Kapuk coastal area lost of about 70 % mangrove area in the periode between 1977now, because of conversion to airport, high way, urban facilities, resettlements, and fish ponds. Now, those conversion of mangrove remain only 372 hectares of degraded mangrovevegetatedland, in which about 95 hectares mainly covered by neglected fish ponds submerged by deep water ranging from one to four meters.
Some mangrove planting techniques have been applied for rehabiliting the area, i.e bamboo basket, big can or drum filled soil as a media for growing seedlings, but those techniques fail in growing seedlings. So that, at 2005 Faculty of Forestry IPB introduced Guludan Techniques (Figure 3) for mangrove planting using four to six months seedlings of bakau (Rhizophora spp) with the spacing 0.5x0.5 m. Fortunately, this planting technique success to grow mangrove seedlings well with the survival rate of more than 80 % showing the good performance of seedling growth (at 3 years old, steam diameters reached 2.5-3 cm seedling height 2.8-3 meter, and biomass 506-702 g/ind for 2 years old) ( Figure 4). Surprisingly, this technique can also facilitate natural sucession in guludan, such as Sonneratia spp, Avicennia spp, etc ( Figure 5). For constructing a Guludan of 4.5 m (width) x 6 m (lenght) x 1 m (height) planted by 200 seedlings needs a budget amounted to Rp 10,938,000 (Table 12).   From the experience of applying guludan technique, we got some lesson learns such as follows: a. Mangrove can be planted in the mineral soils b. The appropriate media for growing mangrove seedlings is the mixed soil between 60% mineral soil and 40 % mud c. In order to avoid abundant weeds, planted mangrove seedlings in the guludan should be submerged about 10-20 cm by waters d. R. mucronata seedlings show grow well at the water salinity less then 20 ppt e. More denser the spacings, more higher the height growth of seedlings and vice versa for stem diameter growth f. Spacings of 0.5 x 0.5 m resulted in the good growth of R. mucronata seedlings planted in guludan g. Lateral Root Manipulation (LRM) with the fertilization of Rock Phospat combined with Humic Substance Complex and Terabuster can be applied to improve the neglected growth of seedlings h. Planted seedlings in the guludan should be maintained until 3 years old from the weeds, snails and caterpillar. At 1970s Perum Perhutani (Forest State Company) introduced the system of Tambak Tumpangsari (Sylvofishery System) using design of empang parit (mangrove forest stand in the middle surrounded by pond channal for culturing fish/shrimp) with the ratio area in one unit fish pond about 80 % forest and 20 % pond channal. In accordance with the passage time, sylvofishery system developed to become various system such as agrosilvofishery and agrosilvofisherypastoral systems which have been applied by local coastal communities ( Figure 6).
Those kinds of techniques better to be applied for mangrove rehabilitation on the mangrove degraded areas borderline or surrounded by landless poor community. The Farmer at least obtain the net profit amounted to Rp. 4,500,000 in cultivating fish of bandeng/milk fish (Chanos chanos) for one ha fish pond using sylvofishery system (Table 12).
The profit increases if the farmer applied agrosilvofisherypastoral system for (chicken, oil palm, milk fish, fuelwood) for once harvesting period (6 months), about Rp. 12,641,000 per ha (Bapak Ginting, personal communication).