Search Results (8)

Jujube (Ziziphus jujuba Mill.) is one of the three traditional woody crop species in China, where it originated from the middle and lower reaches of the Yellow River. Jujube is considered one of the oldest cultivated fruit trees species in the world, as its utilization can be traced back to more than 7000 years ago. The jujube has important nutritional, economic, and ecological values, hence it is well received by both planters and consumers. At present, jujube cultivation has spread to more than 48 countries and provides a pathway for Chinese farmers to produce a lucrative cash crop. Jujube is regarded as a superfruit of the future due to its excellent nutritional profile. Social progress and economic shifts leading to the improvement of living standards influence the value of jujube to consumers, who have gradually shifted toward functional foods, while at the same time, consumer desires and environmental pressures change the breeding goals for new jujube varieties. In this review, we summarize the origin, classification, and historical, as well as modern, uses of jujube. We also provide some advice on the establishment of breeding objectives in this new period of jujube development. This review aims to provide useful references for researchers new to jujube, to guide shareholders in the jujube industry, and to formulate breeding objectives for the modern development of elite jujube cultivars. Full article

Compared to agricultural environments, afforestation sites are more complex, often presenting issues such as undulating and uneven terrain. These conditions lead to instability in hole digging depth and plant spacing during continuous movement, and the hole shape may not meet expectations. Additionally, the hydraulic system exhibits slow response speed and long steady-state time, affecting the quality of sapling planting. To address these issues, this paper designs an intelligent planting control system for intermittent hole digging under continuous dynamic movement, based on a large tree planter. The focus is on studying the dynamic accuracy of the hole digging cylinder to resolve the instability of plant spacing and planting depth in actual planting processes. Firstly, a motion trajectory model of the intermittent hole digging mechanism is established to obtain the relationship between the displacement trajectory of the rotating cutter and the displacements of the floating cylinder and the hole digging cylinder. Secondly, a mathematical model of the electro-hydraulic servo system is established to control the dynamic accuracy of the hole digging operation. Finally, a Simulink simulation model of the system is established to analyze the performance indicators of the hydraulic system during operation using step and sinusoidal excitation signals. The test results show that the displacement of the hydraulic piston rod can ensure a linear extension trend within the range of 0 to 0.4 m, and the extension distance of the hole digging cylinder in the planting system is 0 to 0.35 m, ensuring linear change within this stroke. When the system’s extension command is 1 V, the actual output is 0.6 m, with a relative error of less than 10% compared to the simulation value, indicating that the control strategy can effectively improve the dynamic performance of the system. When the hydraulic system is in a steady-state extension state at 50 to 58.6 s, the relative error with the simulation value is 7.3%, meeting the “double ten indicators” requirement. The research results clearly verify the superior performance of the proposed intelligent control system, and the proposed control strategy has great potential in practical applications, promising to improve afforestation quality by stabilizing planting spacing and planting depth. Full article

Green Infrastructure (GI) is rooted in ecology and cuts across multiple disciplines, including landscape architecture, environmental sciences, planning, policy, and engineering. Likewise, the definition of this concept also cuts across disciplines, which creates ambiguity around what GI is and what makes up GI in practice—for example, mistaking bioswales for regular tree planters or green space within communities in which they are installed. We undertook a systematic literature review of 38 peer-reviewed articles for this study using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method to identify and synthesize the different disciplinary definitions of GI in the literature. This study also presents the types of GI systems mentioned in the peer-reviewed articles while identifying other benefits apart from the primary benefit of GI installation, which is stormwater management. The analysis revealed three clusters of GI definitions: (I) Interconnected natural areas and other open spaces, (II) Strategically planned natural and semi-natural areas, and (III) Decentralized systems and techniques. However, we got rid of the third cluster during the analysis because GI is known to be a decentralized system, and the definition region could not be tracked. These clusters represent a spectrum, one of which employs the structure of natural systems already in place to support human goals (bio-inclusivity). The other includes living systems as components within engineered solutions to achieve objectives (bio-integration). This review points to the need for an encompassing definition that cuts across disciplines with a consensus on the adoption and concise categorization of GI types and the multiple benefits they provide to humans and ecosystems. A consensus definition helps clear misconceptions and improve the understanding of GI, potentially improving receptivity towards these solutions within communities from a community member perspective. Full article

Agrotechnological procedures related to forest management, including planting, are burdensome and the energy expenditure of the people working is very high. Nowadays, planting is usually carried out manually, and sometimes with the use of planters coupled to universal tractors. Occasionally, planters mounted on high-power carriers are used, and usually the seedlings are removed from their cassettes and placed manually into the planter’s storage unit. In connection with the above, the prototype of a mobile automatic device for performing forest regeneration tasks and afforestation of post-agricultural and reclaimed areas (RoboFoR) was designed. The main task of this vehicle is planting forest tree seedlings with a covered root system, which are collected directly from their nursery cassettes. This study presents the structure, principle of operation and results of operational tests of the seedling storage and feeding unit. It was found that the unit achieved the expected work efficiency. However, imperfections in the system related to the non-centralized distribution of seedlings in containers and the high variability of biometric characteristics of the seedlings were also identified. A new solution for this unit was proposed, which will increase the reliability of collecting the seedlings. A new solution requires greater computational power of the control unit as well as equipping the sensor system with a technologically advanced root neck detection system. The new concept also assumes the possibility of independent movement of each gripper. Full article

The intermittent hole-digging tree-planting machine shows a periodic short-time peak load law in planting operation, and the operation process is “idling” for small loads most of the time, leading to large torque fluctuations in the transmission system, unscientific power matching, and high energy consumption. To solve the above problems, this article proposes to use a series of energy-saving flywheels in the transmission system of the tree planting machine. On the premise of obtaining holes that meet the target young tree planting requirements, the optimal power compensation strategy for the flywheel system of the tree planting machine is studied to reduce torque fluctuations in the power transmission system, use smaller power drive units, and save energy. Firstly, the nonlinear multi-body dynamics simulation model of soil cutting by the hole-digging component is established. The boundary and contact conditions are set to simulate the power consumption of the hole-digging component at three rotating speeds. Based on the simulation results, the flywheel power compensation strategy is discussed, and the torque fluctuation of the flywheel balance system is analyzed. The results showed that the higher the speed, the greater the power consumption. The power value suddenly increased from 17.82 kW (1.28 s) to 27.93 kW (1.43 s) when the speed was 220 r/min. Then, the power value rapidly decreased, and the power consumption presented a short-term peak feature. The transmission system’s maximum input power is determined as 17.82 kW according to the various simulated power consumption characteristics. The part exceeding the power consumption is compensated by the energy storage flywheel. The total compensation energy was 2382.5 J. After the flywheel system was involved, the maximum output power of the tractor power output shaft decreased by 36.2%, and the peak torque decreased from 445.7 N·m to 285.1 N·m. The power consumption obtained from the field test and simulation was similar, but the energy required to overcome peak load was jointly provided by the flywheel and the engine. The actual input power of the power output shaft during the energy release period of the flywheel system was 18.51 kW when the rotating speed of the hole-digging component was 220 r/min, and the relative error with the simulation value was 2.43%. The measured actual speed reduction of the flywheel system was 8.9%. After installing an energy storage flywheel in the transmission system of the tree planting machine, the output power of the power unit can be stabilized. Tree planting machines can be equipped with smaller power units, which can reduce energy consumption and exhaust emissions. Full article

Urban spaces are often dominated by paved surfaces and ongoing processes of densification; consequently, intensifying the urban heat island effect. In order to strengthen the liveability of urban spaces, an adequate amount of green spaces is needed. Trees in planters are an alternative greening solution; however, the lack of root space due to underground infrastructure poses a challenge. Furthermore, temporal aspects such as tree growth, tree death, and growth responses to environmental factors are frequently overlooked in projects that use trees in planters. In multiple case studies that employ the method “Research through Drawing” we analyse five selected projects, which deal in sharply contrasting ways with the temporal aspects of trees in planters. Our results show that promising approaches exist, albeit they are not described explicitly in either written or graphical form. Consequently, temporal aspects are only vaguely considered in the projects’ design concept. This results in the neglect of the further use of trees in planters in temporary projects, or in the disregard for tree death in the design and responses to it in permanent projects. Therefore, the potential of trees in planters as an alternative and complementary greening solution remain unexploited. To overcome this, a coherent temporal approach that considers growth, death of plant parts or whole plants, and that is developed as an integral part of the design concept and communicated graphically, would ensure that the involved actors and their respective tasks are well coordinated throughout the lifetime of a project. Full article

Formal tree producer associations are critical for the sustainable management of private commercial farm forests in Kenya. However, there is limited information on their current status and the key factors driving their operations in the country. This paper sought to address this informational gap by reviewing the existing literature in the country from the theoretical background of sustainable development and later validating the obtained findings with the current state of knowledge at regional and global levels. Results from document content analysis indicate that there are over 10,000 tree growing farmers organized into planting groups across the country after many years of piloting by the government and private sector players. At the national level, there are two associations. These include Kenya Forest Growers Association (KEFGA), mainly composed of large scale planters, and Farm Forestry Smallholder Producers Association of Kenya (FFSPAK), targeting small-holders. Besides these two, six major sub-national associations are seeking to improve members’ welfare by enhancing the acquisition of livelihood assets. Further, various socio-cultural, economic, and political factors affect their operations in Kenya. These associations have deployed multiple strategies to benefit their members. However, the formation of savings and credit cooperative societies (SACCOs) seems to be their preferred mode of community empowerment. In conclusion, even though these associations are still at the infancy stage, their future remains promising in-view of the observed behavioral change in their governance, which appears to favor entrenched equality and equity towards sustainable development. Full article

Climate variability and change significantly affect smallholder farmers’ food security and livelihoods in sub-Saharan Africa. Tree planting is one of the measures promoted by development programs to mitigate and adapt to climate change. Tree planting is also believed to positively contribute to livelihoods. This paper examines factors influencing smallholders’ tree planting activities in four villages in the Ziro province, Southern Burkina Faso. Furthermore, it analyses the challenges encountered and willingness to continue tree planting under current tenure arrangements. The data was obtained through key informants, household interviews, focus group discussions, and field observations. Results indicate that the majority of farmers interviewed planted Mangifera indica (50%), Anacardium occidentale (32%) and Moringa oleifera (30%). In a number of trees planted, Eucalyptus camaldulensis, Mangifera indica and Anacardium occidentale dominated. Tree planters were mainly farmers who held large and old farm areas, were literate and relatively wealthy, had favorable attitudes toward tree planting, and with considerable years of participation in a farmers’ group. The main reasons for planting trees included income generation from the sale of tree products, access to markets and local support for tree planting. Preference for agriculture, tenure insecurity and lack of sufficient land were the main reasons cited for not planting trees. Farm households that were relatively poor, had smaller workforces and smaller farm sizes were not willing to continue tree planting. To effectively engage farmers in tree planting and to make it more attractive, policies are needed that address tenure insecurity for migrants, enable better access to markets, and support fair pricing structures for wood and other tree resources. Full article