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An accurate investigation is needed to determine if the selected location, the tree species, and the applied treatments can support a successful seedling establishment and outplanting performance to ensure the success of large-scale tree-planting initiatives. To shed light on the growth pattern of the trees used in the Green Belt Project plantations in the Mongolian steppe, we analysed the biomass allocation in the stem and roots of Ulmus pumila in terms of ring width, considering different management techniques involving irrigation and fertilisation. We found that the root and shoot ring width of U. pumila followed a bell-shaped curve and reached maximum values after three or four years from seedling outplanting. Moreover, our data confirm that increasing watering regimes may enhance plant growth, especially the root system, while fertilisation did not show a positive effect independently of the fertilisation type (i.e. NPK and compost). Our data allowed us to develop a predictive regression model that could be used with other species and in different environmental conditions to forecast stem and root tree growth and to simulate afforestation performances in different climatic conditions. [ABSTRACT FROM AUTHOR]

Amid urbanization, studying leaf functional traits of woody plants in urban environments is essential for understanding how urban green spaces function and how they can be effectively managed sustainably. In this study, we investigated the effects of different growing conditions on the morpho-physiological traits of Populus laurifolia and Ulmus pumila across five contrasting urban sites. The leaf area (LA), leaf length (LL), leaf width (LW), leaf biomass (LB), specific leaf area (SLA), leaf chlorophyll concentration, chlorophyll fluorescence parameters, leaf water potential at predawn (Ψpd) and midday (Ψmd), leaf performance index (PIabs), and phenotypic plasticity index (PPI) were compared across five contrasting urban sites. The soil chemical and physical properties were also compared between sites. There were significant differences in soil physicochemical characteristics between sites. We found significant effects of site on most of the morpho-physiological traits measured, except for Ψmd. The leaf chlorophyll concentration of P. laurifolia and U. pumila varied significantly between sites. The Ψpd was significantly different between years and sites. In U. pumila, the mean PPI for morphological traits (0.20) was lower than that for physiological traits (0.21). In conclusion, we revealed significant variations in the morpho-physiological traits of P. laurifolia and U. pumila across the five urban sites. Hence, long-term, large-scale studies are recommended to examine how diverse species respond to different urban growing conditions and to include other ecologically important plant traits for a better understanding of urban trees in a changing environment. [ABSTRACT FROM AUTHOR]

The selection of tree species resistant to drought, cold, salt and other natural and anthropogenic stressors is important for the success of afforestation processes especially when these take place in desert and semi-desert regions of Mongolia. The seven woody species (Tamarix ramosissima, Ulmus pumila, Elaeagnus moorcroftii, Hippophae rhamnoides, Caragana microphylla, Armeniaca sibirica, Amygdalus pedunculata) were grown under four different watering regimes and nine years of continuous monitoring conducted on the growth performances. All measured growth traits (root collar diameter, stem height, and survival rate) showed significant differences between treatments and species. The best performance of stem height and root collar diameter was observed in T. ramosissima and E. moorcroftii whereas A. pedunculata presented be lowest values. Ulmus pumila, E. moorcroftii and T. ramosissima showed the highest survival rate compared with all other species. However, control plants showed a 0% survival rate in 2016. Date presented here suggest that native species are characterized by the best adaptive characteristics compared to non-native species, which species are the best candidates to be used for afforestation processes of desert and semi-deserts areas.

We measured the basal diameter, height and crown size of saxaul trees, and used survival curve and static life table in defining population structure and dynamics of H. ammodendron. The static life-table proved that population size in the first three age classes had high range of variation, seedlings, juveniles and small trees, and had a high rate of mortality. Because, considerable number of individuals was in the early life stage of H. ammodendron, the deficit of seedlings and high mortality of seedlings and juveniles are most considerable problems. The results suggest that studied populations of H. ammodendron are depleted, and efforts are required to minimize uncontrolled exploitation and overgrazing.

Although afforestation is one of the best solutions for combating desertification, it requires intensive management. To minimize management efforts in plantations in arid area, it is crucial to select suitable tree species, i.e. those with a high adaptability to xeric environments. In this study, we investigated key tree traits related to drought adaptation in Populus sibirica Hort. ex Tausch and Ulmus pumila L., planted in the Korea-Mongolia Green Belt Plantation in Lun soum, Mongolia. We found that U. pumila had a smaller leaf size and smaller specific leaf area (SLA) than P. sibirica. In addition, the water use efficiency (WUE) of U. pumila (carbon isotope-based) was significantly higher than that of P. sibirica. Although biomass production was ∼2.5 times higher in P. sibirica than in U. pumila due to the differences in leaf area, there were no statistically significant differences in the photosynthetic characteristics on an area basis. These results indicate that U. pumila has a higher adaptive potential to dry conditions than P. sibirica due to its small leaf size, low SLA, and high WUE.

Soil salinity is a key factor to limiting agricultural products throughout the world, especially in arid and semi-arid areas, since it intervenes with plant morpho-physiology, resulting in reduced growth and development, as well as disruption of ion homeostasis. This work examined the effects of salinity stress on the mono-cropping of T. pratense, F. arundinacea, and M. sativa and CaSO4 and MgSO4 on the mixed-cropping of T. pratense and F. arundinacea under saline conditions. Plants were assessed by dry weights, physiological parameters (photosynthesis rate, SPAD, SLA), forage quality, and ion concentrations. The biomass of all mono species decreased under salinity, except M. sativa, and mixed cropping was affected less than mono-cropping. The values of the mono-cropping of SPAD were decreased in the long term, and SLA was higher than the control in mixed cropping, with the photosynthesis rate of mono-cropping being higher in medium salinity in the long-term; moreover, CaSO4 and MgSO4 enhanced the photosynthesis rate of mixed cropping. Overall, we concluded that M. sativa is tolerant to medium salinity, and mixed cropping plus MgSO4 and CaSO4 were efficient under salinity stress. [ABSTRACT FROM AUTHOR]

Planting trees is considered a crucial factor in mitigating the increase in carbon emissions in the atmosphere by generating plant biomass. In addition to advancing our understanding of how tree biomass is allocated in desert environments, we explore potential variations in biomass partitioning based on the irrigation regimes (4, 8, and 12 L h−1) supporting the growth of these trees. Specifically, this study compares the pattern of biomass distribution between above-ground and belowground organs of 11-year-old trees (U. pumila, E. moorcroftii, and T. ramosissima) planted in a desert site in Mongolia. An interesting result of this study is the demonstration that biomass partitioning among roots of different diameter classes differs between the tree species tested, suggesting that each tree species establishes its own type of root/soil interaction. The differences in biomass partitioning in roots could determine specificity in the strength of anchorage and efficiency of nutrition for the trees. We also demonstrate that the presence of plantations influences certain chemical properties of the desert soil, with differences depending on the tree species planted. In addition to presenting a method for planting trees in desert sites, this study underscores that a reliable evaluation of atmospheric carbon sequestration in trees must necessarily include root excavation to obtain an accurate measurement of biomass stored in belowground structures. Assessing the overall biomass produced by these trees allows us to determine the potential for carbon sequestration achievable through plantations established in desert sites. [ABSTRACT FROM AUTHOR]

Climate challenges impose the need for successful afforestation strategies which will increase the amount of carbon sequestered from the atmosphere. In practice, this means evaluation of suitable plant species and management practices for the long-term effects to prove beneficial. In the present study we employed a clasmometric approach to look into biomass partitioning in two tree species, Populus sibirica and Ulmus pumila, which have been included in the formation of the Green Belt project in Asia. Comparing the total biomass comprised of the above ground (AG) and below ground (BG) biomass of trees grown in different irrigation and fertilization regimes, we aim to better understand where the two species invest more biomass as a tool to deal with the environmental challenges. The results suggest that these two tree species prioritize different aspects of development when faced with various challenges. U. pumilia tends to be more resistant to drought making it favorable for the semi-arid and arid regions. P. sibirica is more sensitive to the lack of water but shows greater potential in terms of biomass production (especially AG biomass) and, therefore, overall higher C-sequestration. The fertilization treatments made no significant impact on tree development on Mongolian steppe soil. [ABSTRACT FROM AUTHOR]

Afforestation practices are useful tools for rehabilitating degraded lands in many parts of the world, as well as in Mongolia for protecting soil, water resources, and the potential of carbon sequestration to mitigate climate change. And so, regular investigation was conducted to determine the response and adaptation of Populus sibirica, Ulmus pumila, and Hippophae rhamnoides in terms of growth characteristics and leaf morpho-physiological traits to suggest and select effective and sustainable afforestation methods to suit Mongolia's conditions. We measured the root collar diameter (RCD), height growth, leaf area (LA), specific leaf area (SLA), leaf biomass (LB), chlorophyll concentration and leaf water potential (ψ) of the selected species. Results showed that P. sibirica (135.3±6.81cm) height growth, stem, root and total biomass were higher among the studied species, but leaf and branch biomass was higher in U. pumila (93.46±5.10cm). However, leaf morphological parameters and chlorophyll content was higher for P. sibirica (330.56±56.81µg/ml) compared with other species. Leaf water potential was found lower for U. pumila and higher in H. rhamnoides. Therefore, we suggest that U. pumila is more adaptable to low mean annual precipitation regions, requiring less water and H. rhamnoides provide good financial source for local community as they yield fruits. Our findings are relevant to ensuring the sustainability of afforestation programs in semiarid conditions in Mongolia. [ABSTRACT FROM AUTHOR]

The environmental restoration of the semi-arid steppe of Mongolia is currently being addressed by creating new plantations able to protect the soil from the advancement of desertification and to improve the economy of the population living there. The success of these interventions relies on a high survival rate and good long-term growth performance of the transplanted trees. In the present work we analyzed stem height and root collar diameter (RCD) over 10 years for two native tree species (Populus sibirica and Ulmus pumila) grown with different water regimes and fertilizers. The investigated duration is sufficiently long to provide a reliable indication of the adaptation of these tree species to the steppe's harsh environmental conditions. Results suggest that both species could be used for environmental restoration projects, although P. sibirica requires the support of additional irrigation to achieve the best growth performance. U. pumila, on the other hand, shows good growth performance even with rainfall as the only water source. However, the higher water use by P. sibirica trees seems to be compensated by a more rapid ground cover compared to U. pumila. The addition of fertilizers to the soil before transplantation does not improve the growth performance of either species. [ABSTRACT FROM AUTHOR]