Introduction

Globally there are more than 1250 bamboo species¹ that covering 36 million ha of land, which are distributed in the tropical and sub-tropical belt between 46⁰cNorth and 47⁰c south, latitude at elevation as high as 4000 m above sea level. Ethiopia has the greatest bamboo resources in Africa and represents a significant proportion of Africa’s total bamboo resources. The country has more than 1 million hectares of bamboo which is 67 % of African bamboo assets and over 7 % of the world's region covered by bamboo. In Ethiopia, there are two bamboo species namely highland bamboo (Oldeania alpina) and lowland bamboo (Oxytenanthera abyssinica).

It additionally has extraordinary potential for commercialization and can drive country improvement². It very well may be used at all degrees of modern movement from little specialties-based businesses to present-day exceptionally coordinated plants (mash, paper and dress, furnishings, flooring) as a substitute for conventional hardwoods). Two native bamboo in particular high country bamboo and lowland bamboo species are dispersed in the south, south-west, and central parts of Ethiopia. These assets are to a great extent tracked down in four districts, in particular Benishangul-Gumaz, Oromia, Southern Countries, and Amhara. There has been a general instinct that Ethiopia has 1 million hectares of bamboo assets, yet the volume and spot of asset circulation insights aren't very much investigated.

Accordingly, research shows that agroforestry (a land use system that combines trees/shrubs and other perennials with crops and/or animals) can contribute substantially in this direction through its multiple benefits and ecosystem services. Agroforestry provides a set of innovative practices that are designed to enhance productivity in a way that often contributes to climate change mitigation through enhanced carbon sequestration³, and also strengthens the system’s ability to cope with adverse impacts of changing climate conditions⁴. In addition, agroforestry options may provide a means for diversifying production systems and increasing the ‘sustainability’ (allowing farmer’s ability to continue) of smallholder farming systems⁵.

In Ethiopia, bamboo resources constitute one of the largest non-timber forests products identified to be a suitable complement to timber usages such as building and construction, pulpwood, flooring, panel products and furniture^6,7. In comparison with forest timber species, bamboo has a short gestation period of five years and has huge range of socio-economic and environmental benefits⁸. In many parts of SSA, bamboo is currently being promoted for forest plantation developments to reduce the natural forests for timber and wood fuels^9-11. Notwithstanding, researchers will concur that sole bamboo manor advancements might influence adversely on food security with the exception of they are apparently settled on corrupted lands. This makes the integration of bamboo into indigenous cropping systems (via agroforestry) ergonomically interesting and necessary to meet both socioeconomic and environmental needs. While experiences from Asia and other countries demonstrate that the integration of bamboo within agricultural systems is a suitable approach for increased productivity of food crops and non-food biomass^12,13, there is limited available data to verify the suitability of the technology in Ethiopia (and Africa in general) and elucidate the ecological principles by which the system works. In addition, the current state of knowledge on bamboo agroforestry offers very little guidance as to how investments into the land use system may contribute to sustainable rural development in Ethiopia. Here, we reviewed the potential socioeconomic and environmental benefits of bamboo agroforestry and accentuate implications on sustainable development in Ethiopia.

Development

Overview of bamboo production and distribution in Ethiopia. Ethiopia is the country in the African Landmass with the biggest area of natural bamboo stands. It has been assessed that around 67 % of African bamboos are settled down in Ethiopia. Moreover, it has also been estimated that about 7 % of all bamboo resources in the world are found in this country. There are only two local types of bamboo in Ethiopia, highland (O. alpina) and lowland bamboo, O. abyssinica (sympodial bamboo). O. abyssinica are tracked down and dissipated in the south, southwest, and central parts of Ethiopia⁵.

Highland bamboo. Accordingly, the highland bamboo (O. alpina) grows naturally and plantation in the south, south-west, central, and north-west highlands of Ethiopia with an altitude ranging between 2200 m to 4000 m a.s.l. and yearly precipitation is over 600 mm during the stormy season isn't under 90 days. The average diameters of the height of highland bamboo are 8 cm and 17 m, consequently¹⁴. High-country bamboo (O. alpina) is found in the Awi zone of the Amhara Provincial State and is utilized as construction material for houses, walls, furniture, and bee colonies in the towns.

Lowland Bamboo. The plant name of lowland bamboo is O. abyssinica in Ethiopia. It is intrinsic in Ethiopia and endemic in tropical Africa¹⁵. This species is cultivated solitary in the Western piece of Ethiopia along the significant stream valleys and in the lowland boundary of Sudan. This species is cultivated solitary in the Western piece of Ethiopia along the significant waterway valleys and in the lowland line of Sudan. Lowland bamboo is found between 1100 m to 1700 m.a.s.l. and covers over 1 million hectares of land and 85 % of this area is covered by O. abyssinica. The typical width and level of a solitary bamboo is 5 cm and 7 m, consequently¹⁴. The species has huge significance for the country's society and fills the defile of cast material in pastoral areas. It is additionally usually utilized as an option for lumber in house cast, hedge, and furthermore as feed for livestock, human food, and as energy supply during the dry season¹⁶.

Environmental benefit from bamboo agroforestry. Agroforestry isn't generally completely perceived as it incorporates both spatial and time scales and numerous ideas simultaneously. In any case, this is fundamental for strategy producers to advance agroforestry. strategy bodies like¹⁷ characterize agroforestry as an aggregate name for land use frameworks and innovations where woody perennials (trees, bushes, palms, bamboo, and so on) are purposely used on the same land management units as agricultural crops and/or animals’’, the definition also supported by¹⁸. Agroforestry is the deliberate integration of woody vegetation in at least two vertical layers on land, with the bottom layer providing an agricultural product such as crops or forage/pasture which is consumed by animals¹⁹.

Accordingly, the definition of agroforestry²⁰ demonstrates a key feature of agroforestry as a land use system that is designed to meet both environmental and socioeconomic needs for land users at all levels. In any case, the accomplishment of such financial and natural advantages is regularly subject to the woody part which is the most vital of agroforestry frameworks. Below, reviewed certain socioeconomic and ecological needs in Ethiopia which could be met through bamboo agroforestry.

Land restoration and soil conservation. Accordingly, land degradation is a major biophysical problem in Ethiopia normally contributed by the removal of vegetation through unstainable agricultural practices and illegal mining operations^21,22. Like most trees, bamboo has the tendency to improve soils as it grows on marginal soils with low fertility. The significant elements of bamboo for controlling soil disintegration are its broad sinewy underground root growth, associated rhizome framework, the verdant mulch it might create on the dirt surface, its comparatively dense foliage which protects against beating rains, and its habit of producing new culms from underground rhizomes which allows harvesting without disturbing the soil²³.

Soil and water conservation. Bamboo woodlands have a broad rhizome framework, a thick litter layer, exceptionally versatile culms, and a thick covering. These qualities give bamboo woodlands a high limit with respect to disintegration control, soil and water preservation, avalanche counteraction, and security of riverbanks²⁴. Reports, the broad rhizome arrangement of bamboos lies principally in the top layers of soil, subsequently, it frequently assumes a significant part in settling soils on steep slopes and river banks²⁵. Most of the time bamboo is described by a complicated organization of rhizome underground root growth which causes them to succeed other backwoods types to really keep soil particles intact, consequently, thereby preventing soil erosion and promoting water percolation. Because of the inescapable underground root growth, extraordinarily molded leaves, and thick litter floor, the amount of stem stream rate and overhang capture of bamboo is 25 %, which significantly diminishes runoff, forestalling huge disintegration and keeping up two times as much water in the watershed²⁶, especially in the space of inclined to high measures of overflow and debased lands. On one hand, this species are evergreen plants, and thick shade and soil cover given by dead leaves reduces sprinkle separating and further creates assault limit²⁷. Thus, it is significant in getting the hydrological capability of the catchments and waterways. A greater part of bamboo species is trademarked in high-height biological systems on steep slants in zones of high seismic action, consequently, their job in soil adjustment might be basic. The over-the-ground piece of bamboo wood diminishes disintegration by precipitation capture and by protecting the dirt from wind disintegration and sun drying^2,25.

Bamboo for carbon sequestration. Accordingly, besides being a tool for poverty alleviation in rural areas, bamboo plantations are also a significant carbon sink and a key option to mitigate land degradation²⁸. While most wood species need many years or hundreds of years to arrive at development, bamboo typically matures in less than 10 years. This suggests high biomass mature rates and, subsequently high carbon sequestration limit²⁹, with its quick produce rate and high yearly regrowth in the wake of gathering, the bamboo woodland has a high carbon stockpiling potential, particularly when the reaped culms are changed into tough items. The expanded life expectancy of sturdy bamboo items created conceivable by present-day innovation can guarantee that the sequestered carbon won't return rapidly to the environment, in this way dragging out the carbon stockpiling by bamboo³⁰. Not just preferred soil security over arable land, bamboo might possibly sequester a significant measure of carbon in its over-the-ground biomass and subterranean soil natural carbon³¹. For this, it has been examined that the promotion of putting away carbon under a bamboo trimming framework would also build ranchers' pay.

Biodiversity functioning. The stand of species is essentially important for biodiversity conservation. In various pieces of the country, the species give living space, food, sanctuary, and destinations for proliferation to different imperiled species¹⁶.

Socio-economic contributions of bamboo in Ethiopia. In Ethiopia, rural communities have a strong bond with forests and use them for many purposes, and they make use of timber and non-timber forest products to support their livelihoods. Nowadays using forest and its products is mandatory and studies show that there will be a huge demand for wood and wood products. Bamboo can be used to share pressure and substitute other hardwood³². In general, bamboo is used for fences, houses, baskets, beehives, hats, mats, furniture, traditional sticks, and house utensils, for animal feed and agricultural tools. It is likewise utilized for medication²⁷.

However, the volume of income was miniature as it is expected since the area is endowed with natural bamboo forests and suitable conditions for establishing bamboo plantations. In addition, poor harvesting and processing are the leading factors for low benefits derived from bamboo. Hence, a lot should be done to improve the grower’s income. Bamboo plants have many traditional and cultural uses in many parts of Ethiopia and the entire world. From this, we can deduce, that bamboo has a contribution to a household’s livelihood though it is very little in amount. Another review uncovered that bamboo estate has both positive and negative monetary impacts on cultivators and conditions^33,34.

The contributions of bamboo to the household income in Ethiopia. The degree of different uses of bamboo for income generation by three different wealth categories (Rich, medium, and poor) indicated that all farmers use bamboo for house cast, fencing, kindling, grain compartments, and fodder for livestock³⁴. In southern regional states and Benishangul-Gumaz National Regional States in Ethiopia reported that bamboo accounted for 2-3 % at the national level and more than 50 % in rural areas³⁵. Likewise, bamboo pay contributed up to 11 % of the yearly money pay of the families, the least (3.4 %) at Masha and the biggest (38 %) at Banja and Bahir Dar Zuria Districts. In the present study, 19.22 % of the household income is more or less similar to these studies¹⁰.

Human consumption and Animal feed. Bamboo leaves are likely to contain much higher concentrations of nutritionally important components such as nonstructural carbohydrates and protein, as well as minerals such as phosphorus and potassium, compared to other plant parts³⁶. The leaves of bamboo can likewise have esteem as a forage supplement, especially in the colder time of year time. Around the world, local stands of bamboo are natural surroundings and scrounge for a scope of wild and homegrown livestock.

Ecological processes and component interaction within bamboo agroforestry. Interactions may occur aboveground or belowground. Competitive and complementary interaction within a bamboo agroforestry system may be dependent on the arrangement of the components, planting density, and the level of technical management³⁷. The survey of cooperation in bamboo agroforestry may require the assessment of mind-boggling natural cycles. Experimental designs with different planting spacing and densities of bamboo and crops may be crucial in defining the best cultural practices applicable to specific bamboo species and agricultural crop.

Potential Bamboo based Agroforestry systems. Bamboo-based agroforestry systems can play important roles in enhancing productivity, sustainability and resource conservation in agricultural systems³⁸. Care should however be taken to include factors needed for their successful implementation and sustainability of effects during their design stage. For instance; the general objective of the frameworks, explicit should be met, monetary and specialized capacities, market accessibility for produce and secure residency should be thought of. The triumphs of coordinating bamboo into cultivating frameworks have been accounted for by a few creators, model^39-43 (Table 3). These fast-growing plants can therefore be taken advantage of to improve the productivity of agricultural systems which are mostly considered as low in tropical Africa.

The possibility of integrating bamboo into food crop production as live stakes can also be considered. Live staking is where living trees or woody perennials are used as support for growing crops such as yam, potatoes and beans. Currently at the Crops Research Institute of the Council for Scientific and Industrial Research in Ghana, a trial where bamboo is being explored as live stakes for yam production is underway. Comparing bamboo-based systems to tree based systems, the former has the advantage of fast growth and early maturity. Within 3 to 4 years, bamboo comes into production, reaching maximum productivity in 7 to 8 years⁴⁴. In comparison to similar agroforestry systems with a tree - Acacia mangium and a shrub - Tephrosia candida, intercropping with bamboo resulted in reduced run-off and lower erosion⁴⁵. In Northern Vietnam, bamboo accounted for higher percentage of household income (7-14 %) than A. mangium and T. candida (1-10 %) in an agroforestry system⁴⁵. In Jharkhand, India, bamboo culms from agroforestry systems are good alternatives for depleting and expensive timber resources, and these culms are also available at lower prices⁴².

Aside the fast growth and early maturity, other qualities qualify bamboo as a good agroforestry component (Table 4). It must however be noted that bamboo can show promising results in agroforestry systems when each plant receives individual care⁴⁴. Like other mixed species planting systems, there is bound to be competition among the components of bamboo-based agroforestry systems. Bamboos may out-compete the agricultural or food crop components because of their higher root densities. To overcome interspecific competition in bamboo-based agroforestry systems, agricultural crops can be planted 8-9 m away from the bamboo clumps⁴⁴. In situations where shorter distances are desired⁴⁴ further recommend that bamboo roots can be spatially isolated from the crops through trenching (30-40 cm wide and 50-60 cm deep) at 5-6 m away from the bamboo clumps. To manage aboveground interactions, pruning of the bamboo canopy may be considered¹⁴.

As per⁵⁵ fitting dividing for bamboo is critical to improve creation of bamboo and related crops. Hence, a potential tradeoff is expected for bamboo-based agroforestry frameworks to streamline creation of intercrops without compromising bamboo yields. The yields of intercrops in bamboo-based agroforestry systems are higher in wider spacings as compared to closer spacings⁴². This is because the intercrops are able to utilize resources such as sunlight, soil moisture, space and nutrients better at wider spacings. Since agricultural systems cannot effectively function on impoverished soils, the focus of all agricultural systems is to improve soil fertility whilst increasing or maintaining crop yields⁵⁶. As⁴¹ put it, the nutrient pumping action of bamboo, the slow decomposition of the silicarich bamboo litter and the extremely high biomass of fine bamboo roots improve soil fertility and soil health to make bamboobased agroforestry systems successful.

Conclusion

From the above reviews, it can be concluded that the bamboo-based agroforestry systems are essential as regards socio-economic and environmental status in Ethiopia. Because of its shorter harvesting time and excellent growth and survival on any soil strata, bamboo can be included in profitable agroforestry systems, besides this, bamboo can play an important role in soil and water conservation as well as have a significant impact on various features of physical and chemical properties of soil. Besides this, the bamboo plantation also helps in better carbon sequestration and adding various types of nutrients through its litter falling into the soil. The socioeconomic and ecological importance of bamboo are not farfetched particularly with the provision of huge biomass source for renewable energy, potential for restoring degraded forestlands and also as a sustainable carbon sink. By incorporating bamboo into mixed-use agroforestry complexes, we can maximize its functionality while integrating it with other production crops. As a relatively new innovation, it is imperative that research on the socioeconomic and biophysical aspects of it is intensified, so that future developments and scaling-up can be rooted in robust scientific findings rather than the intuitions of governments and development actors.