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This study aimed to determine the growth and carbon storage of planted Haloxylon aphyllum in the Aralkum Desert in Kazakhstan. Six sites afforested in 2000, 2005, 2009, 2010, 2013, and 2017 were selected. The root collar diameter (cm) and height (m) were measured for all H. aphyllum in 30 m×44 m plots. Biomass accumulation (g m-2) and carbon storage (C g m-2) were calculated using allometric equations and the carbon concentration data of Haloxylon species. The diameters varied from 2.5 cm to 4.3 cm and the height varied from 106.2 cm to 223.7 cm. The growth of H. aphyllum was not linearly related to the afforestation year or soil properties. Tree growth might have been influenced by variations in the microclimate, such as temperature, precipitation, and dust storms. The mean total biomass accumulation was 20.57 g m-2 and ranged from 2.42 g m-2 to 64.53 g m-2. The mean carbon storage was 9.70 C g m-2 and ranged from 1.12 C g m-2 to 30.61 C g m-2. These biomass and carbon storage estimates were smaller than those reported for other Central Asian deserts, but afforestation enabled the generation of vegetative cover and consequently, carbon sequestration in the manmade Aralkum Desert.

Afforestation of the desiccated Aral Sea Bed is needed for the rapid introduction of vegetation and rehabilitation of the soil environment. The present study aimed to detect the soil amelioration effect by afforestation of the Aral Sea Bed with respect of changes in topsoil properties and enzyme activities. In August and November 2018, soils were sampled from the barren areas and from areas afforested in 1991, 2005, 2009, 2010, and 2013. The exchangeable base cation concentrations (Ca2+, K+, Mg2+, and Na+), cation exchange capacity (CEC), plant-available P concentration, electrical conductivity, pH, and enzyme activities (acid phosphatase, β-glucosidase, and N-acetyl-glucosaminidase) were analyzed in the surface soil (0–10 cm). Base cation concentrations, CEC, and electrical conductivity decreased following afforestation possibly because of root absorption. The observed increase in soil pH could be affected by both root absorption and decomposition of plant residues. Enzyme activities, which are early indicators of soil recovery, might have been increased by afforestation through the release of nutrients from litter and root exudates. Our findings indicate that the establishment of vegetation through afforestation can provide supportive microenvironments for plants and microorganisms by decreasing soil salinity and activating soil microbial enzymes; these effects of afforestation are amplified over time.

Climate change is likely to decrease surface water availability in Central Asia, thereby necessitating land use adaptations in irrigated regions. The introduction of trees to marginally productive croplands with shallow groundwater was suggested for irrigation water-saving and improving the land’s productivity. Considering the possible trade-offs with water availability in large-scale afforestation, our study predicted the impacts on water balance components in the lower reaches of the Amudarya River to facilitate afforestation planning using the Soil and Water Assessment Tool (SWAT). The land-use scenarios used for modeling analysis considered the afforestation of 62% and 100% of marginally productive croplands under average and low irrigation water supply identified from historical land-use maps. The results indicate a dramatic decrease in the examined water balance components in all afforestation scenarios based largely on the reduced irrigation demand of trees compared to the main crops. Specifically, replacing current crops (mostly cotton) with trees on all marginal land (approximately 663 km2) in the study region with an average water availability would save 1037 mln m3 of gross irrigation input within the study region and lower the annual drainage discharge by 504 mln m3. These effects have a considerable potential to support irrigation water management and enhance drainage functions in adapting to future water supply limitations.

Allometric equations are routinely used in the estimation of biomass stocks for carbon accounting within forest ecosystems. However, generic equations may not reflect the growth trajectories of afforestation species that are introduced to degraded farmland characterized by water and nutrient limitations. Using sequential measurements of the height, basal diameter, and above- and belowground biomass of juvenile trees, we developed allometric equations for five woody species (Moringa oleifera Lam., Leucaena leucocephala Lam., Jatropha curcas L., Anacardium occidentale L. and Parkia biglobosa Jacq.) subjected to a gradient of water and nutrient availability in an afforestation trial on degraded cropland in the semi-arid zone of Benin, West Africa. For three of the species studied, the allometric relationships between basal diameter and biomass components (i.e. leaves, stems and roots) were described best by a simple power-law model (R2 > 0.93). The incorporation of species-specific height–diameter relationships and total height as additional predictors in the power-law function also produced reasonable estimates of biomass. Fifteen months after planting, roots accounted for 10–58% of the total biomass while the root-to-shoot ratio ranged between 0.16 and 0.73. The total biomass of the saplings ranged between 1.4 and 10.3 Mg ha−1, yielding 0.6–4.3 Mg C ha−1, far exceeding the biomass in the traditional fallow system. The rate of stem carbon sequestration measured ca. 0.62 Mg C ha−1 year−1. Overall, the allometric equations developed in this study are generally useful for assessing the standing shoot and root biomass of the five afforestation species during the juvenile growth stage and can help in reporting and verifying carbon stocks in young forests.

In the Sudano-Sahelian zone of West Africa, where deforestation and cropland soil degradation occur at alarming rates, the (re-)introduction of trees on degraded lands can improve and sustain farming systems and landscapes. The shoot and root morphological traits of five woody species introduced to degraded cropland were assessed with a particular focus on the survival, early establishment and growth of saplings subjected to manuring (1 kg per plant) and drip irrigation (0.5 L of water per plant per day). Functional traits of the woody above- and belowground organs of field-grown plants were monitored for the first 15 months after planting, covering two growing (rainy) seasons and one dry season. The high survival rate (>60%), combined with a very low incidence rate ( Jatropha curcas L., Leucaena leucocephala Lam. and Moringa oleifera Lam. The mortality rate of the most drought-sensitive species Parkia biglobosa Jacq. could be reduced ten-fold through supplemental irrigation during the dry season. The fast-growing L. leucocephala , M. oleifera and J. curcas had higher values for shoot-level traits than did the slow-growing Anacardium occidentale L. and P. biglobosa . Fertilization and irrigation enhanced the shoot growth of both the fast and slow growers during the dry and growing seasons. In contrast, belowground development was either increased or reduced by fertilization and irrigation during the growing and dry seasons, but the slow growers demonstrated a more plastic response to these treatments than did the fast growers. Among the studied traits, the relative growth rate of plant as a whole (i.e. shoots and roots combined) exhibited the greatest plastic response to resource availability, thus suggesting its application in screening candidate species for afforestation efforts. Overall, the five studied species were considered suitable for the afforestation of degraded croplands, while the early growth and establishment of saplings could be boosted by irrigation and a supply of manure.

Global warming is predicted to increase water scarcity in many drylands worldwide. In Central Asia, one of the most intensively irrigated dryland agricultural regions, climate change is likely to exacerbate the regional water supply–demand gaps, particularly in downstream areas. The withdrawal of degraded, highly salinized croplands from irrigated farming in favor of tree plantations that effectively utilize saline groundwater may contribute to irrigation water saving, which can generate valuable ecosystem services and provide rural income opportunities. To facilitate the spatial planning of afforestation in the lower Amudarya region, we developed a hydrological algorithm to map the spatio-temporal pattern of water supply–demand. The resulting map, based on seven-year continuous data of cropping pattern and corresponding irrigation dynamics, rainfall, and evapotranspiration at 250 m resolution, revealed the overly irrigated areas from which excess water can be redistributed to water-stressed areas. Furthermore, combining this information with spatial data on marginally productive croplands and with water requirement of tree plantations showed that 67% of these croplands are characterized by water availability sufficient for the introduction of salt-tolerant tree species. The algorithm developed is of potential use for defining the feasibility of introducing alternative (tree) crops with known growth and water use characteristics.

The early growth stage is critical in the response of trees to climate change and variability. It is not clear, however, what climate metrics are best to define the early-growth sensitivity in assessing adaptation strategies of young forests to climate change. Using a combination of field experiments and modelling, we assessed the climate sensitivity of two promising afforestation species, Jatropha curcas L. and Moringa oleifera Lam., by analyzing their predicted climate&ndash, growth relationships in the initial two years after planting on degraded cropland in the semi-arid zone of Benin. The process-based WaNuLCAS model (version 4.3, World Agroforestry Centre, Bogor, Indonesia) was used to simulate aboveground biomass growth for each year in the climate record (1981&ndash, 2016), either as the first or as the second year of tree growth. Linear mixed models related the annual biomass growth to climate indicators, and climate sensitivity indices quantified climate&ndash, growth relationships. In the first year, the length of dry spells had the strongest effect on tree growth. In the following year, the annual water deficit and length of dry season became the strongest predictors. Simulated rooting depths greater than those observed in the experiments enhanced biomass growth under extreme dry conditions and reduced sapling sensitivity to drought. Projected increases in aridity implied significant growth reduction, but a multi-species approach to afforestation using species that are able to develop deep-penetrating roots should increase the resilience of young forests to climate change. The results illustrate that process-based modelling, combined with field experiments, can be effective in assessing the climate&ndash, growth relationships of tree species.

Our study addressed biomass dynamics in traditional and newly introduced Jatropha curcas production systems in Burkina Faso, West Africa. Five prevailing J. curcas systems included interplanting with annual crops, intensely managed plantations, afforestation of abandoned land, plantings along contour stone walls, and traditional living fences. Measurements of stem diameter, tree height (n = 670) and above- and below-ground biomass (n = 157) enabled the development of generic allometric models relating shoot and root biomass with stem diameter. The relations showed very good fits (R 2 > 0.9) for all studied systems, except afforestation sites which largely perished. Considering system-specific height-diameter (HD) relationship improved the model performance for living fences where trees allocated more biomass in the height rather than diameter growth. Self-propagation in living fences results in variable stand density, tree age, and consequently shifting HD relations. Therefore these models would benefit from local calibrations should they be applied elsewhere. We argue that for the other systems the developed generic equations are applicable subject to accounting for the tree ontogenetic stages deduced from HD relations. In this respect, the allometric models for juvenile trees are most robust whereas overall validity range of the equations can be improved with more observations of large-size trees.

Agroforestry is often an economically viable land-use option for the environmental rehabilitation of salinized cropping areas in irrigated drylands, but afforestation initiative at the farm level is subject to various socio-political constraints. We analyzed the factors that affect farmer decisions with respect to the agroforestry adoption using an ex ante approach through Ethnographic Decision Tree Modeling (EDTM). Constraints on agroforestry adoption were identified via a review of legal documents, focus-group discussions, and a farm survey in northwest Uzbekistan. The findings highlighted the importance of farmer perceptions of risk with respect to decision making surrounding the adoption of alternative land uses. The EDTM analysis allowed determining those policy incentives for afforestation that could directly influence the decision-making process of potential participants. In particular, there is a need for increased land-use flexibility, improved land tenure and tree plantation proprietorship secur...

The changes in the relative biomass allocation to roots in juvenile stands of fast-growing ( Leucaena leucocephala Lam., Moringa oleifera Lam., and Jatropha curcas L.) and slow-growing ( Anacardium occidentale L. and Parkia biglobosa Jacq.) afforestation species are driven mainly by ontogeny rather than resource availability. However, silvicultural management aiming at increasing availability of water and particularly nutrients enhances biomass production in all species. Understanding the patterns of biomass allocation among tree species in response to ontogeny and to variation in resource availability is key to the successful restoration of degraded land using forest plantations. This study assessed the effects of resource availability and ontogeny on biomass accumulation and partitioning in five semi-arid afforestation species. The aboveground and belowground biomass production of fast-growing Leucaena leucocephala Lam., Moringa oleifera Lam., and Jatropha curcas L. and slow-growing Anacardium occidentale L. and Parkia biglobosa Jacq. was monitored following the application of manure (1 kg plant−1) and/or supplemental irrigation (0.5 L per sapling daily) during the first two rainy seasons and the intervening dry season on degraded cropland in Northern Benin. Biomass accumulation in the fast-growing species was positively impacted by fertilization and irrigation during both rainy seasons. The slow-growing species responded positively to the silvicultural treatments during the dry and second rainy season. The application of fertilizer alone increased the biomass of P. biglobosa by up to 335% during the dry season. Fifteen months after planting, manure-treated L. leucocephala accumulated the most biomass (2.9 kg tree−1). The root fraction decreased with increasing tree size in all species. The comparison of root versus shoot allocation in trees of equal size indicated that the treatment-induced shifts in biomass partitioning were controlled by ontogeny, which explained 86–95% of the variation in root-shoot biomass relationships. While ontogeny was the main driver of biomass partitioning, increased resource availability induced a larger production of biomass, overall leading to greater aboveground production in all species.

We analysed the economic viability of afforestation on marginal irrigated croplands in irrigated drylands of Uzbekistan. The revenues derived from a combination of diversified agricultural production, carbon sequestration, nitrogen fixation, and avoided irrigation water use were analysed considering uncertainty associated with on-farm activities such as crop production and short-rotation forestry. At the per hectare scale variability in land-use revenues would necessitate substantial increases in carbon prices for afforestation to be as profitable as crop cultivation on marginal lands, assuming an abundant irrigation water supply. In contrast, at the farm scale the analysis results revealed that afforestation can be attractive financially even without carbon payments due to farm production constraints, variable land-use returns, and the benefits of land-use diversification. Increased carbon prices would promote carbon sequestration by motivating farmers to plant high biomass producing tree species, but would have an ecosystem service trade-off by reducing the appeal of nitrogen-fixing species that are essential for nitrogen self-sufficiency of afforestation efforts. Given the modest irrigation needs of afforestation efforts compared to the cultivation of annual crops, tree plantations could become a primary income source for farms during periods of drought. Irrigation water saved from replacing crops with trees on marginal farmland would enhance the cultivation of commercial crops on productive lands, thus increasing farm income.

Degradation of irrigated croplands in arid regions is of great environmental concern worldwide. Based on a series of field trials, afforestation with well-adapted tree species was evaluated as a viable option for the cropland rehabilitation in the lower reaches of the Amudarya River basin in Uzbekistan. Our aim was to extend available site-specific information for the entire regional landscape and provide spatially explicit guidance in support of afforestation land rehabilitation efforts. To this end, a geographic information system—based multicriteria decision-making approach has been developed for assessing the suitability of degraded irrigated cropland for introducing plantations of Elaeagnus angustifolia L. This approach utilized expert knowledge, fuzzy logic, and a weighted linear combination to produce an afforestation land suitability map. Overall, 75 287 ha of degraded croplands (18% of the irrigated cropland area) was identified as suitable for introduction of E. angustifolia. We also conclude that irrigation water supply and groundwater table depth are the critical factors determining the suitability of degraded irrigated land. These findings improve an understanding of the spatial variability of areas suitable for the initiation of agroforests and support better informed decisions on cropland rehabilitation. Copyright © 2014 John Wiley & Sons, Ltd.

The cultivation of the biofuel crop Jatropha curcas L. in Burkina Faso may contribute to ameliorating the soil fertility of severely declining cropland through increased organic matter input and erosion control. This study addresses the potential for the soil organic carbon (SOC) sequestration in traditional and newly introduced J. curcas production systems. Five prevailing systems included interplanting with annual crops, intensely managed monoculture plantations, afforestation of abandoned cropland, plantings along contour stone walls, and traditional living fences. The SOC was analyzed in 20 paired sites of 1- to 4-year-old J. curcas plantings and adjacent cropland. Paired sites with living fences involved a longer chronosequence with 15- and 20-year-old plantings. Additionally, the contribution of J. curcas to SOC sequestration was investigated by comparing the 13C signature of the C inputs in four J. curcas sites with that of sorghum cropping. Linear regression analysis did not reveal a clear trend of SOC dynamics over time for the short-term chronosequences, nor could the isotopic tracer technique prove a contribution of 4-year-old J. curcas trees to the SOC stock. The 20-year chronosequence of J. curcas living fences exhibited a significant SOC increase of 62 ± 23 g m−2 y−1. Considering soil coverage of 1,200 m2 ha−1 by living fences (400-m hedge with a width of 3 m), 1.5 Mg SOC was sequestered. Also, changes in δ13C values indicated a contribution of C3-derived C to the SOC stock. These findings on traditional J. curcas systems indicate the potential of this biofuel crop for improving cropland soil fertility in the long run. Copyright © 2014 John Wiley & Sons, Ltd.

Afforestation is known as a low-input measure to rehabilitate marginalized irrigated croplands with a shallow, saline groundwater table. This study assessed the potential of extending afforestation to sites long-term abandoned from cropping in the lower reaches of the Amu Darya River, Central Asia. Tree survival and establishment were monitored during two growing seasons following afforestation with six tree species at two abandoned cropping sites. The sites, characterized by soil salinity and different depth to the groundwater table, received deficit irrigation of 154 mm yr−1. Afforestation was feasible with Elaeagnus angustifolia, Ulmus pumila, Morus alba, and Populus nivea x tremula given their survival rates of 75–91% on both sites after two years. N2-fixing E. angustifolia was assessed as most promising among all species evidenced by highest survival and largest above-ground biomass increment (up to 904 kg ha−1 yr−1). The principal species of the native floodplain forest, Populus euphratica and Salix...

The desiccation of the Aral Sea due to water withdrawal from contributing rivers has resulted in an unprecedented change in the region’s climate, from maritime to hot dry desert. Afforestation has been implemented on the desiccated seafloor—the Aralkum Desert—for stabilizing the exposed substrate. However, studies on the long-term status of the afforested sites are limited. Here, we examined C and N isotopic signatures in Haloxylon aphyllum plantations, as indicators of time-integrated plant response to the prevalent water and salinity constraints, in northern Aralkum, Kazakhstan. Foliar 13C composition analysis in a chronosequence of H. aphyllum plantation sites (aged 1−27 years) on the sandy substrate revealed a significant trend towards higher water-use efficiency in older plantations, possibly in response to declining water availability. A lack of correlation between plant 13C signature and soil electrical conductivity suggests no history of salt stress despite the saline environment. Furthermore, 15N enrichment in plant tissue in the water-limited Aralkum ecosystem indicates the relative openness of N cycling. There was an increase in species richness and self-propagation at the plot scale, indicating successful afforestation effort. Coupled with other approaches, isotope discrimination might elucidate mechanisms underlying stress tolerance in H. aphyllum, which could support the afforestation efforts.

The conversion of marginal croplands to tree plantations, as an option to address climate change, land degradation, and irrigation water scarcity, as well as to improve the welfare of local population requires prior analysis. This study analyzed the impacts of afforestation of marginal croplands, including potential benefits in the form of carbon sequestration rewards via the Clean Development Mechanism, on the livelihood of commercial farms and rural households by considering their interdependencies via wage-labor relations in irrigated agricultural regions of the lower reaches of the Amu Darya River, Central Asia. A dynamic nonlinear programming model was developed that jointly maximizes profit of farm and net incomes of rural households over a 15-year horizon under conditions of decreasing irrigation water availability and forestry plantations with a single seven-year rotation period. The results showed that the introduction of short-rotation plantation forestry in degraded irrigated croplands can help mitigate the repercussions of water shortages on rural livelihood, while sustaining energy needs, income, and food security. Although income and food consumption of rural households may decline from year two to six after afforestation, the subsequent increase in farm profit following the harvest of tree plantations would be transmitted to rural households through existing wage-labor payment arrangements. The incorporation of fuelwood into labor payment schemes would substitute the use of fossil fuels by rural households and thus substantially decrease their energy expenses and CO2 emissions. Furthermore, given the low irrigation water demand of trees, afforestation would increase irrigation water availability for more productive croplands.

Agricultural mismanagement of irrigated drylands results in severe soil degradation. Afforestation is an option for ameliorating such degraded land. We evaluated the impact afforestation has on the topsoil (0–20 cm) of salinized degraded cropland in regards to salinity, aggregate stability, and soil organic carbon (SOC) stocks in Uzbekistan, Central Asia. The effects of tree plantations established under either furrow or drip irrigation were studied four years following afforestation and two years after irrigation ceased. For comparative study we also sampled fallow land, land with 80 years of tree growth, natural forest, desert ecosystems, and paddy rice fields. Initial furrow irrigation showed to be most effective in improving soil fertility after four years of afforestation; the respective plantations of Populus euphratica and Ulmus pumila showed significant levels of reduced soil salinity and increased aggregate stability and improved SOC stocks. The comparison of the long-term afforested land with the short-term equivalent suggested a C sequestration rate of 0.09–0.15 t C ha −1 year −1 . The SOC stocks of the long-term afforestation site exceeded those of the native forest. Hence, a rehabilitation of salt-affected cropland is feasible following the conversion into occasionally irrigated tree plantations, although it takes decades to reach steady-state conditions.

The establishment of forests on small-scale marginal lands in the Amu Darya Lowlands in Uzbekistan is an alternative use of land abandoned from cropping. Over four consecutive years biomass data were collected from Elaeagnus angustifolia, Ulmus pumila, and Populus euphratica plantings and complemented with data of mature trees (15–20 years) growing naturally on marginal land. These formed the basis for elaborating 20-year growth functions for these species. The potential for capital investment in the small-scale forests was assessed by considering annual fuelwood, fodder and fruit production, plus the stumpage value after 20 years. The benefit to cost ratio (BCR) and Net Present Value (NPV) were compared at 10%, 16% and 24% discount rates. At a 16% discount rate (base case), the NPV for E. angustifolia was greatest (13,924 US$ ha−1)1, followed by P. euphratica(4,096 US$ ha−1), and U. pumila (1,717 US$ ha1) showing a BCR of 7.8, 2.2 and 1.8, respectively. These suggest that afforestation is a prom...

Land degradation is a serious hindrance to agricultural development in Uzbekistan, a country striving to rebuild its agricultural sector for self-sustained production. The potential of multipurpose trees for upgrading degraded land is enormous. However, knowledge is lacking about the establishment and growth characteristics of different species, the energy content of firewood and the nutritive value of fodder. This study presents such data for 10 selected local multipurpose species grown on gleyic solonchak soil. Elaeagnus angustifolia L. and Tamarix androssowii showed superior biomass growth, respectively producing up to 11.0 and 10.4 t ha−1 of utilizable aboveground dry matter (DM). E. angustifolia showed high potential for rapid establishment evidenced by root elongation of over 100 m tree−1 at the age of 3 years. T. androssowii, Prunus armeniaca L. and Populus nigra var. pyramidalis Spach exhibited the greatest fuelwood characteristics, showing calorific values in the range of 14.4 – 16.2 MJ DM kg−1. E. angustifolia and Morus alba L. demonstrated superior fodder potential given by the crude protein content of 216 and 117 g DM kg−1. Recommendations on species selection are proposed based on various species characteristics. In assessing the potential of trees for afforestation of degraded land a reliable economic analysis of these aspects must be taken into account. When considering all characteristics concurrently, a mixture of species instead of monocrop cultivation seems to provide the best solution for improving degraded land.

The establishment of woody fallow systems is an option for the improvement of degraded agricultural landscape within the ecologically deteriorated Aral Sea area in northwest Uzbekistan. Growth and development of ten tree species, differing in tolerance to drought and salinity, were studied over 24 months. To determine species suitability for afforestation, conventional diameter and height measurements were compared to Relative Growth Rate (RGR) and its underlying components, Net Assimilation Rate (NAR), Specific Leaf Area (SLA) and Leaf Weight Ratio (LWR), as well as the Crop Growth Rate (CGR) as a function of NAR and Leaf Area Index (LAI). RGRs varied between 0.46 and 2.16 mg g � 1 day � 1 and showed highly significant differences among species, but also between years, which reduces the parameter’s suitability for species selection. The same is true for NAR and SLA. CGR values ranged from 0.01 to 0.71 g m � 2 day � 1 , increased with age of the trees, and showed significant species differences. CGR correlated better with NAR (r = 0.89) and SLA (r = 0.86) than RGR. Overall CGR correlated highly with the RGRs in height and diameter (in 80% and 71% of all cases, respectively). Thus, CGR appears to be a suitable indicator complementing RGR, NAR and SLA estimates to decide on species suitability for afforestation. The intensive measurements for RGR should be done later, rather than earlier in the tree life cycle. At an early age, CGR and diameter measurements are more meaningful. A combination of estimates, not a single factor, best assesses the long-term sustainable growth under natural conditions and allows early selection of species suitable for afforestation of degraded patches in the agricultural landscape. Ranking of all parameters concurrently showed the high potential of Elaeagnus angustifolia and Populus euphratica, which matched previous rankings based on total biomass production and financial added value. # 2005 Elsevier B.V. All rights reserved.

This study analyzed the financial attractiveness of Clean Development Mechanism Afforestation and Reforestation (CDM A/R) in irrigated agricultural settings. The Net Present Value (NPV) and Internal Rate of Return (IRR) of CDM A/R were estimated by analyzing the case of Khorezm region in Uzbekistan, where a mixed-species tree plantation was established on marginal cropland. The dual purposes of carbon sequestration and production of fruits, leaves as fodder, and fuelwood were studied over a seven-year rotation period. We compared the opportunity costs of land in marginal agricultural areas between this short-rotation plantation forestry and the annual cultivation of the major crops in the region, i.e., cotton, winter wheat, rice, and maize. The analyses were performed considering different levels of irrigation water availability, from 0 to 30,000 m 3 /ha, to reflect the reality of a high variability of water supply in the region. The NPV of CDM A/R ranged between 724 and 5794 USD/ha over seven years, depending on the tree species. Among the latter, Elaeagnus angustifolia L. had the highest profits due to the annually recurring cash flows generated from fruit production. Temporary Certified Emission Reductions (tCER) ranged within 399–702 USD/ha after the assumed 7-year crediting period and would not suffice to cover initial investments and management costs of tree plantations. IRR peaked at 65% with E. angustifolia under the conventional afforestation and measured − 10% and 61% when considering only the tCER and the CDM A/R, respectively. In contrast, other species had higher IRRs in case of the CDM A/R. The total profits from tree plantations exceeded those of both cotton and winter wheat, even with the assumption that there was an optimal irrigation supply for these crops. Rice production was overall the most profitable land use option but required water input of 26,500 m 3 /ha/year, which is not consistently available for marginal croplands. We argue that the current global average price of 4.76 USD/tCER is insufficient to initiate forestry-based CDM projects but, in the absence of other incentives, can still motivate forestation of degraded croplands for land rehabilitation and the provisioning of non-timber products. Given the low irrigation needs of trees, 3–30% of the crop water demand, a conversion of degraded cropland to forested areas could save up to 15,300 m 3 /ha/year at the current tCER price. Combining the monetary value of water and carbon would enlarge the scope for CDM A/R in irrigated drylands, thus enhancing the investments in marginal land rehabilitation and strengthening the resilience of rural populations to the repercussions of climate change.