Pongamia: A Possible Option for Degraded Land Restoration and Bioenergy Production in Indonesia

Indonesia has 14 million ha of degraded and marginal land, which provides very few benefits for human wellbeing or biodiversity. This degraded land may require restoration. The leguminous tree Pongamia pinnata syn. Milettia pinnata (pongamia) has potential for producing biofuel while simultaneously restoring degraded land. However, there is limited information on this potential for consideration. This paper aims to address the scientific knowledge gap on pongamia by exploring its potential as a biofuel and for restoring degraded land in Indonesia. We applied a literature review to collect relevant information of pongamia, which we analyzed through narrative qualitative and narrative comparative methods with careful compilation and scientific interpretation of retrieved information. The review revealed that pongamia occurs naturally across Indonesia, in Sumatra, Java, Bali, Nusa Tenggara and Maluku. It can grow to a height of 15–20 m and thrive in a range of harsh environmental conditions. Its seeds can generate up to 40% crude pongamia oil by weight. It is a nitrogen-fixing tree that can help restore degraded land and improve soil properties. Pongamia also provides wood, fodder, medicine, fertilizer and biogas. As a multipurpose species, pongamia holds great potential for combating Indonesia’s energy demand and restoring much of the degraded land. However, the potential competition for land and for raw material with other biomass uses must be carefully managed.

Cananga odorata (ylang-ylang).

Cananga odorata is known as the perfume tree or ylang-ylang, and the flowers (also leaves and fruits) yield an important essential oil widely used in perfume manufacture. The essential oil also has a wide range of medicinal uses. Cananga odorata can grow to a height of about 30 m with a straight stem and drooping, brittle branches, but when grown for perfume extraction it is normally not more than 3 m high. The tree is native to Southeast Asia, however, it has been widely planted, mainly in home gardens, as an ornamental, multipurpose species. It is found naturalized or planted in many tropical and subtropical areas of the World (particularly as an occasional species in fallow forests, open forests and along forest margins), including China, Taiwan and many of the Pacific Islands. The timber is used locally for construction purposes, for canoes, and occasionally for fuelwood. The species is also known to be sold and used for folk medicine. Medicinal uses include treatment of boils, as a carminative, for treatment of cephalgia, diarrhoea, gout, malaria, eye problems, rheumatism and as an emmenagogue (Duke, 2014).

Casuarina equisetifolia (casuarina).

C. equisetifolia is a nitrogen-fixing tree of considerable social, economic and environmental importance in many tropical areas of the world. It is widely planted for reclamation of unstable coastal ecosystems in the tropics and subtropics. It is salt-tolerant and can grow on sands so is especially useful for erosion control and windbreaks along coastlines and estuaries. The wood has many uses but is renowned as a fuel. It is a truly multipurpose species, providing a range of products and services for industrial and local end-users.

Adenanthera pavonina (red-bead tree).

A. pavonina is a valuable multipurpose species (Adkins, 1994; Clark and Thaman, 1993). It is a source of food, fodder, green manure, fuel, timber, dye, decoration, medicine and other products. In the South Pacific Islands it is intercropped with spices, coffee, coconuts, or planted along borders as a windbreak in plantations or on agroforestry farms (Adkins, 1994; Clark and Thaman, 1993). Throughout the tropics and sub-tropics it is extensively cultivated as an ornamental tree along roadsides and in communal areas.

Studies on Phenology and Reproductive Biology of Khejri [Prosopis cineraria (L.) Druce]

Background: Khejri [Prosopis cineraria (L.) Druce] belongs to the family Leguminosae and subfamily Mimosoideae. The rural communities encourage the growth of Khejri in their agricultural fields as it improves grain yield and storage biomass production. It is the true multipurpose species and also called as ‘Golden Tree of Desert’, ‘Kalpvriksha’ of the desert, ‘King of desert’, ‘Love Tree’, and ‘Pride of the Desert’. For any tree improvement programme, knowledge of phenology and breeding system is pre-requisite, which also helps in understanding the evolutionary dynamics of a species. The range of genetic variability is controlled by reproductive system, which in turn controls the adaptive change. Pollination mechanisms affect seed set, fertility, gene flow, breeding systems, hybridization and genetic constitutions of tree populations. Methods: In this investigation during 2014-15, ten trees of [Prosopis cineraria (L.) Druce] growing at the research area of Forestry Department of CCS Haryana Agricultural University, Hisar were randomly selected and phenological observations were made on the selected trees at different phenophases. Through selfing, breeding behaviour was examined, by covering the inflorescence with muslin cloth bags before opening. Approximately, an equal number of buds were kept open in close vicinity of the covered branch. Reproductive capacity was estimated from the percentage of fruit setting in marked inflorescence. Result: In present study of Prosopis cineraria, the average fruit set under self-pollination was nil whereas it was 2.03 per cent in open natural pollination. This study confirms previous studies that Prosopis cineraria is a cross-pollinated species.

Croton guatemalensis (Euphorbiaceae) phenology at the Zoque Tropical Forest Biological Corridor

Croton guatemalensis is a threatened and multipurpose species in communities of southeastern Mexico and Central America. For the first time, its reproductive phenology and its relationship with environmental variables present in four different natural protected areas of the Zoque Tropical Forest Biological Corridor was determined. Throughout a year the flowering and fructification of the species was monitored, the local environmental variables were recorded and fruits and seeds were collected to determine, under a random design, the germination of the seeds and the growth of seedlings in the laboratory and in nursery respectively. In all cases, flowering was presented from July to April, while fructification occurred from March to September, coinciding with the months where the rains diminish considerably. In terms of seed germination, it presented a statistically significant difference between seeds from the four protected areas. The most contrasting results were presented between La Pera and Area Villa de Allende (98% ± 3.84% and 6% ± 3.84% respectively). According to the generalized linear model, soil porosity was the only variable that influenced the germination of the species (the higher the porosity, the higher the percentage of final germination, t = 2.237, P = 0.0503). Because this is the first study on the ecophysiology of C. guatemalensis in southern Mexico, the importance of it becomes relevant when providing fundamental reproductive information for the generation of strategies for conservation, restoration and forest management of the species.

The genus Agave in agroforestry systems of Mexico

<p><strong>Background:</strong> The genus <em>Agave</em> L. is recognized for its wide distribution in Mexican ecosystems. Species have been described as multipurpose as part of agroforestry systems (AFS). There has not been a systematized, detailed analysis about its richness in AFS nor their ecological, economic and cultural relevance.</p><p><strong>Questions</strong>: What is the <em>Agave</em> richness in Mexican AFS? What is their ecological, agronomical, economic and cultural relevance? What are the risks and perspectives for strengthening their role in AFS?</p><p><strong>Species studied</strong>: 31 <em>Agave</em> species in Mexican AFS.</p><p><strong>Study site and dates</strong>: AFS throughout Mexican territory. January to august 2018.</p><p><strong>Methods</strong>: Systematization of published information, scientific reports, repositories, and our fieldwork, was performed. The data base “The genus <em>Agave</em> in AFS of Mexico” was created, containing information about <em>Agave</em> richness in AFS, ecological, economic and cultural relevance, as well as the current and future perspectives of the AFS they are included in.</p><p><strong>Results</strong>: We recorded 31 species with 22 uses that were part of AFS practices (hedgerows, boundaries and live fences), in homegardens, terraces and agroforests in temperate, semiarid and sub-humid regions, managed by 12 cultural groups. The main benefits of agaves are soil retention, infiltration of water and satisfaction of socio-economic and cultural needs. The decrease of multipurpose species and functions was observed in relation with the commercialization of mezcal.</p><strong>Conclusions</strong>: There has been ample recognition of AFS as settings for conservation and use of <em>Agave,</em> as well as the importance of the knowledge and management practices associated to agave species in AFS.