Firewood, twigs, leaves, crop residue, and dung are the primary sources of solid biomass energy used for cooking by over 2.5 billion people [1
]. Lack of access to electricity and use of modern cooking solutions are widely-used indicators of energy poverty and the focus of global efforts, such as the United Nations’ Sustainable Deployment Goal target 7.1 [2
]. National-level energy security policy and research are increasingly aligned with sustainable development concepts, including diversification, resilience, and environmental/climate friendliness [4
]. Key issues for developing country energy security are unequal access and risks, including volatility of international markets [6
]. With less than one percent of the population with access to electricity during the early 1990s, Ethiopia has dramatically improved access to electricity to over 40% [7
]. Like many developing countries, the improvement has been uneven, with urban residents enjoying a 90% rate of electricity access while rural areas estimate between 5% and 25% access, leaving approximately 90% of total energy needs met with biomass [1
]. Household demands for biomass as fuel in rural Ethiopia results in less biomass available for other productive uses, such as fodder for animals or fertilizer to increase crop productivity [9
]. Recent evidence from the Nile Basin of Ethiopia indicates that burning dung has measurable negative impacts on crop productivity, but this can be countered by increased availability of firewood from on-farm trees to replace dung as a household fuel that, instead, can be applied as fertilizer, thereby increasing yields [10
Indicators of physical access to modern energy sources are associated with the concept of an energy ladder where households will switch to electricity or fossil fuels as the most modern fuel available for purchase within their means [11
]. Other quantitative energy poverty measures traditionally emphasize the concept of a deficit where a household’s economic access to a sufficient amount of fuel for basic needs is calculated in a similar way and correlated with conventional consumption-based measures of poverty, such as the poverty line [12
]. Instead, recent policy-relevant empirical studies of household fuel choice emphasize contextual factors that reveal a large role for cultural preferences in cooking methods and diverse reasons for using or stacking different fuel sources [13
]. For example, Ruiz-Mercado found that an open fire used for cooking also serves as a gathering spot for social interactions, healing, or spiritual practices and practical purposes, such as drying clothes [14
]. Wood fires for cooking were found to be preferred by wealthier urban households in Ethiopia, as is the case in Italy or other countries that enjoy grilled foods, even for those with access to modern alternatives [15
]. Focusing on the agency of the energy poor, local context and household preferences can be coherently considered in research on how energy relates to wellbeing [16
]. This focus on the relation of energy to immediate environment, agency, and the circumstances of the household has been widely researched in cooler climates where poor quality energy-inefficient housing compounds issues of high cost and limited access to preferred sources of energy for vulnerable households. This concept of fuel poverty has underlined the importance of considering the environmental context of the household, including the quality of the dwelling space as key to drawing links between energy-focused policies and programs with resulting wellbeing outcomes [17
Biomass on farms in rural settings has diverse and integral uses, such as fertilizing fields, fodder for animals, and constructing shelter. When households are forced to burn biomass for cooking or heating at the expense of their livelihood or shelter, at rates contrary to their longer-term wellbeing, household energy insecurity may contribute significantly to increasing vulnerability. Some direct wellbeing impacts of this energy related vulnerability are extensively studied including poor health outcomes due to indoor pollution, particularly associated with burning crop residue and dung, along with inefficient open fires for cooking [18
]. Poor health, lower productivity, and missed education outcomes correlated with energy poverty are explored in many studies [19
]. Time spent collecting biomass from depleted environmental sources reduces the time available for children to obtain an education or, particularly, for women who bear the major burden of collection to contribute in other meaningful ways to the household’s livelihood and wellbeing [20
The long-term cumulative effects of these negative outcomes coupled with the associated over-exploitation of the environment to meet energy requirements interact in a negative feedbacks cycle resulting persistent poverty in degraded areas [21
]. By contrast, a positive feedback cycle is identified in a recent paper from the World Bank, concluding that the effects on poverty of environmental quality are greater than the effects of environmental quality on income alone so that poor households would actually disproportionately benefit from improvements in environmental quality [22
]. Particularly relevant for Sub-Saharan Africa, what remains largely understudied are the potentially negative medium-term effects on household wellbeing and resilience of burning biomass that could have otherwise been employed to building livelihood assets, supporting household wellbeing, and improving the immediate environment [23
On-farm trees are commonly planted worldwide to meet household fuel, fiber, and food requirements with a capacity to promote longer-term desirable outcomes of resilience and well-being, such as food security [25
]. Notably, on-farm trees have been largely understudied compared with annual crops or intact forests [28
]. An analysis of Earth satellite imaging demonstrated that more than 43% of global agricultural land in 2010 had more than 10% tree cover and failure to include these trees in global environmental monitoring efforts may lead to a significant undercounting of biomass and environmental services, such as carbon sequestration [31
]. A systematic review of articles from 1950 to 2015 identified only 74 papers that have examined the relationships among trees, livelihoods, and food production, and only nine studies that have investigated longer-term datasets covering more than seven years [32
]. Furthermore, the authors found weak empirical evidence for, and few studies on, the effects of trees on desirable livelihood and food security outcomes, beyond production and income [32
]. As a result, the policy relevance for identifying alternative pathways that could promote the use of trees in sustainable development policies and programs has been limited.
Trees and other environmental assets have not been included in typical demographic, health, and poverty surveys, neglecting a very significant source of income, assets, and resilience for poor farmers [33
]. Increasingly, there have been calls to address the lack of quantitative and panel evidence by a more systematic inclusion of resilience and environmental assets in agricultural adaptation monitoring systems measuring socio-economic and wellbeing outcomes [38
]. Rather than proposing new indicators or embarking on new data collection programs, Rasmussen et al. [34
] argue that more can be done to leverage existing datasets with innovative analytical approaches that link environmental, economic, and sociocultural factors when researching sustainable agriculture. Similarly, existing representative population datasets have been suggested as the best source for monitoring socioeconomic effects of large international environmental programs [33
]. Cross-sectional data represents the primary means for monitoring socioeconomic and some health contributions of policy or programs, such as efforts related to sustainable development goals. However, this data often lack the time series dimension of panel data useful for multidimensional and econometric research on the capacity of alternative pathways to produce desirable outcomes and resilience, particularly over the medium and long-term [39
]. An integrated use of panel econometric modeling and exploratory, multivariate analysis may effectively contribute to clarify latent relationships among actors’ behavior/preferences and the local background context, evidencing more clearly the interplay between environmental sustainability and economically-resilient developmental paths. To date, this type of analysis has been limited by that lack of available longer term panels with an appropriate diversity of variables.
One of the few longer-term time series panel datasets with both on-farm trees and socioeconomic data is the Ethiopian Rural Household Survey (ERHS). Ethiopia, as a matter of national policy, is at the forefront of integrating trees into its sustainable development plans. The country is in the process of transitioning its development pathway from near total deforestation to the adoption of a new climate-resilient green economy on a strong sustainability policy, which suggests a direct link between trees and livelihood and food security outcomes, despite the limitations of the evidence base [41
]. To date, generic best practices derived from case studies, randomized control trials on test plots, and imported technology that typically drive “top-down policy” have generally focused on community forests and not provided a fully adequate evidence base that includes on-farm or other trees [42
More generally in the literature, traditional tree-oriented well-being studies have primarily focused on communal forests and the shared economic benefits [37
]. However, to date, studies of private and communal wood lots in Ethiopia have had a limited scope and have typically aimed at understanding the productive constraints in increasing yields or the potential challenges to sustainable production [50
]. Until recently, specific studies on household behaviors related to on-farm trees in Ethiopia have been limited to the rural demand for biomass or the links between agricultural investment and land tenure with permanent crops and trees [52
]. Another paper focused on tree materials from forests and farms as a source of income-generating activities for small enterprises, but did not consider how this income further contributed to livelihoods and well-being [54
]. In new research from Southern Ethiopia proposing a contextually nuanced pathway from trees to desirable food security outcomes, Baudron and coauthors [55
] found that complex biomass flows to the household rather than direct harvest from the forest contributed most to increased diet diversity. In other words, taking into account fuel requirements, exchange of different biomass products and the range of rural household capacities and assets is essential to accurate characterization of development capacity pathways. A recent mixed methods case study from Ethiopia documented the substitution of dung with firewood from on-farm trees for cooking fuel that, in turn, increased the availability and application of dung as fertilizer, resulting in subsequent crop productivity [56
]. A key research challenge remains in further articulation of the pathways that planting on-farm trees’ contribution of fuel, food, and income to a broader range of well-being and livelihood outcomes over the medium- and longer-term.
Two trees in Ethiopia, Eucalyptus globulus
and Ensete ventricosum
(enset), have a long history of being planted on farms. Searching for a solution to a fuel wood shortage that threatened the sustainability of the capital, Addis Ababa, the regime of Emperor Menelik II imported a variety of eucalyptus seedlings to be tested in a trial plantation in 1894–95 [57
]. Eucalyptus matures in 5–10 years, can rapidly accumulate biomass, and has been estimated to vary in fuel wood production of between 10 and 30 m3
/ha/year in Ethiopia [51
]. According to Turnbull and Booth [58
], “many people in Ethiopia are absolutely dependent on eucalyptus as a source of fuel and house building material”. In a wide-ranging review of the available literature, Davidson [59
] concludes that eucalyptus is similar to other trees in characteristics, such as shade or soil erosion, but primarily distinct because of its low nutrient uptake and that negative criticism of the high total annual water requirements is an unwarranted artifact of limited analysis that does not take into account surprisingly high rates of biomass creation as a ratio of water use. Negative criticism of eucalyptus resulted in a policy banning eucalyptus in parts of Ethiopia in the late 1990s due to concerns about negative impacts on crop yields [60
]. Although the water use can be a problem in dry contexts, it seems that the allelopathic properties of eucalyptus may have been overstated because most tests were undertaken in laboratory conditions on crop seeds or sprouts rather than in real-life farm conditions [59
The first written scientific description of enset dates from 1867 [61
], but cultural and linguistic evidence support the proposition that enset has been an important basis of the food system in the highlands of Ethiopia for thousands of years [62
]. Enset is harvested 5–8 years after planting and is a drought resistant fodder source for animals and food source for humans with nutrient characteristics similar to potatoes [63
]. Enset is a notable example of a productive asset for producing food while also a significant environmental asset protecting from soil erosion on the steep slopes where it is grown. Although once widely cultivated, the introduction of annual seed crops by Ethio-semites is speculated to have led to enset cultivation being replaced on flat land where it is easier to plow [62
Progress in sustainability science requires that the contributions of understudied productive and environmental assets vital to rural contexts, such as on-farm eucalyptus and enset trees, be included in research on livelihood and well-being outcomes of resilient development pathways. Agricultural mosaics now cover much of the world; thus, measurement and modelling approaches that take trees, permanent crops, and a diversity of smallholder land uses into account are required to achieve local sustainable governance of these landscapes and resources [64
]. Little space is available to extend agriculture without greater deforestation, and improving empirical information is critical to supporting alternative sustainable development pathways that meet the increasing demand for food, energy, and water—without further environmental damage [68
]. On-farm trees are concurrently productive and environmental assets, found worldwide, with the capacity to promote longer-term desirable outcomes of resilience and well-being such as food security [24
]. Notably, on-farm trees have been largely understudied compared with annual crops or intact forests [28
]. Environmental assets, such as trees, are undercounted, their contributions underestimated, and unintentional costs over the long-term are largely unarticulated in the conventional evidence base for development and agricultural policy: this undervaluation is the result of standard agro–socio–economic research and indicators that habitually concentrate on short-term production and consumption [70
]. The research presented in this paper is intended to contribute novel insights to the growing literature on how to value on-farm trees to wellbeing and resilience from a unique 20-year panel dataset in a rural agricultural mosaic context.
In this paper, we investigate the potential contribution of on-farm trees to increase not only the amount of biomass available to rural Ethiopian households but also the capacity of on-farm trees to directly and indirectly transform this biomass to increase assets that practically improve livelihoods and wellbeing. From a broader perspective, we are also interested if there is evidence that planting more on-farm trees has the capacity to avert a vicious cycle of environmental degradation with associated poor wellbeing outcomes, and rather set rural households on a pathway for resilience and sustainability. The purpose of the work is to explore the relationships between local environment, assets, and wellbeing. Specifically the research will explore the relationship between on farm tree planting, home biomass management, and two socially important development outcomes. We provide a rather large amount of descriptive data about the study area to provide the necessary context for model development and interpretation of the econometric results.
On-farm eucalyptus trees over time significantly contribute to an increase in dwelling value. The generalized two-step least squares (GTSLS) random effects model resulted in a strong effect of on-farm eucalyptus trees that accounts for the largest variation in dwelling value once the time constant median value of dwellings in the village is controlled (see Table 11
). The overall
for the model is 0.342 with a Wald
value of 1730.66 and probability >
equal to 0.000. The causal direction of the correlation of eucalyptus tree planting and dwelling value indicated in the cross-lagged model above is confirmed with the significant results of a first stage of the G2SLS regression for all variables at a p
-value of 0.04 or less except for the number of rooms (see supplemental materials
). This resulting second stage partial estimation of the number of eucalyptus trees can be described in a qualitative sense as mature eucalyptus trees that have survived at least five years. The resulting coefficient of 0.25 of the standardized log value for the contribution of these mature trees therefore explain essentially 25% of the variability in dwelling value accounted for in the model. In other words, planting eucalyptus trees accounts for about 9% of the dwelling values reported in the ERHS dataset.
The other time constant variables included in the model explain variation in dwelling value in line with expectations. A higher number of rooms indicates a higher dwelling value with a significant coefficient of 0.12. By contrast, female-headed households reported a significantly lower dwelling value, with a negative coefficient of −0.94. Larger household size and higher levels of crop residue also positively contributed to dwelling value, with coefficients of 0.09 and 0.034, respectively.
After inclusion of the instrumental variables in the first stage, the number of enset trees no longer significantly contributed to dwelling value with a p-value of 0.28. This is consistent with the descriptive statistics above that would indicate that wealthier households may have more enset trees and higher reported dwelling values, but enset is primarily planted to meet food requirements while eucalyptus is planted to meet energy and construction needs. Using seedlings as an instrument effectively controlling for the endogeneity is consistent with the descriptive statistics that indicate richer households at any one moment have a higher probability of more on-farm trees, but households did not need to be wealthy in the first place to plant trees. Later in the discussion, we will pick up this theme of access to seedlings and contribution of on-farm trees to increased dwelling value.
On-farm trees may substitute as a preferred source of energy and allow for more crop residue to be used as fodder for livestock (see Table 12
. Overtime, increased availability of dung as fertilizer may increase crop productivity. The pathway between on-farm trees and increased TLU may involve more related variables but it still provides significant results from the GTSLS Model 2.
The first-stage results indicate strongly significant instruments for the endogenous variable crop residue at a p
-value < 0.001, for inclusion of eucalyptus trees, household size, longitude, and self-reported collection of crop residue and dung (see Table 13
). Only household size and longitude were significant in the first stage for predicting female-headed households (see Table S4 in supplementary material
Trees on farms contribute to household-level energy security that, over time, allows biomass that is not burnt for cooking and heating to be transformed through more productive uses into valuable assets that support sustainable livelihoods and wellbeing. This development pathway logic is consistent with research demonstrating how poor households access forest resources to improve shelter or obtain assets [96
]. In a similar way to how household assets may be used to cope with risks, the forest itself is used as an environmental asset that provides a safety net of alternative resources during times of shocks such as droughts that affect rural agricultural livelihoods [98
We demonstrate with two econometric models how on-farm trees significantly increased the value of rural Ethiopian households’ two most valuable private assets, their dwelling and livestock. The model results indicate strong significant correlations for tree variables, R-squared values above 0.3, and highly significant Wald chi-squared tests that support the validity for the proposed models. Reverse step-wise regression eliminated many variables that were likely multicollinear and added little additional information to the bottom-line relationship of trees to household level energy security and assets. A direct pathway to increased dwelling value where on-farm timber from eucalyptus is used to repair and improve the home is consistent with self-reported descriptive statistics and modeled results. The number of eucalyptus trees on a farm is the largest predictor of dwelling value after the initial time constant control variable. Inclusion of female headed households resulted a negative coefficient with dwelling value improvement in the model results perhaps reflecting the overall challenges for female headed households to build assets.
A second indirect pathway demonstrated in a first stage of the regression a significant contribution of eucalyptus trees to increased availability of crop residue that in turn is the largest determent of increased livestock values represented by the Tropical Livestock Unit variable. This is consistent with the self-reported importance of crop residue for animal fodder for these rural households. Recent work by Baudaron et al. [55
] follows a similar pathway logic from biomass to assets to wellbeing. They investigated the impact on food security related to distance to forests and found that the biomass flows as fodder and fertilizer the likely mechanism behind the positive relationship identified relating forest access to increased dietary diversity. Although the logic is similar, it is important to note that their conclusions were drawn from identified association of food security-related outcomes with spatial proximity to a natural forest, and our results focus on the results of econometric modeling of outcomes for on-farm trees.
Female-headed ERHS households had a strongly negative relationship with increased livestock ownership in the model results perhaps reflecting cultural norms regarding large animal ownership. The gender disparities identified in both increased dwelling value and increased livestock ownership for female-headed households should be subjects of further research.
In addition to these clearly evident pathways, there may be multiple other indirect pathways, such as using crop residue to thatch roofs or selling firewood to finance construction and repair costs to be explored in other datasets with these variables consistently measured. The enabling effect of on-farm trees to promote feedback between the widespread use of animal dung for fertilizer and the higher availability of crop residue the following year that is not quantitatively captured in either existing ERHS data but probably has an unmeasured effect on the crop residue variable in our models. In fact, increased dung availably for fertilizer has been a primary justification for rural afforestation programs and policy in Ethiopia over many years [52
]. The bottom-line finding is that having biomass above and beyond the minimum requirement for cooking and heating creates opportunity for asset creation on small farms, and on-farm trees were shown to be a popular and effective way to increase on-farm biomass availability in Ethiopia between 1989 and 2009.
ERHS households reported a preference for using dung and crop residue for productive uses as fertilizer and fodder rather than as fuel. At the same time, many households reported the use of dung and crop residue for cooking fuel, and most of this biomass was collected on their own farms. This represents a clear sign of energy insecurity when a household burns a fuel that they prefer to use for another purpose and could potentially be a robust indicator to enhance measurement of household energy insecurity to complement fuel/energy poverty measures. Recent case study research from the highlands of Ethiopia using mixed methods confirmed the continued existence of this chronic household energy insecurity as a negative feedback of biomass removal from the environment leading to less biomass being regenerated and available to the community [56
]. Firewood remained overall the most frequently used energy source for the ERHS households but was often collected in open access areas or in communal forests, as well as from on-farm sources. Households collecting in open access areas tended to collect less firewood than those with an on-farm or communal forest source. Also, this fuel collection takes more time. This was particularly evident for women collecting fuel in open access areas and likely indicates on-going environmental degradation [100
]. Households that had access to communal forests seemed to report using similar amounts of preferred fuels as those households with on-farm trees.
Communal forests have been a focus for research and policy related to meeting biomass requirements for fuel and construction by the Ethiopian government and international organizations since the 1970’s but these projects faced challenges with reported tree survival rate of less than 20% [9
]. Following this tradition, most literature relating trees to wellbeing outcomes, with specific interest in food security, has focused on communally-managed woodlots and forested areas rather than on-farm trees. Access to communal forests has been associated with greater dietary diversity [101
]. By contrast, deforestation has also been associated with poor dietary outcomes of households and children [102
]. Research from Southern Ethiopia suggests in much the same way that it is the biomass flows to the household, rather than the direct harvest of food products from the forest, that contribute to the dietary diversity [55
]. These dietary correlations are also found in the ERHS data, but with private control of on-farm trees; private tree ownership implies a similar, but distinct, capacity pathway for contributing to a wide range of livelihood outcomes. From the 20-year panel, there is a high survival rate implied by the cross-lagged data between seedlings and trees, as well as trees between rounds. Although communal forest and on-farm trees may address household energy insecurity as a pathway to improve wellbeing, on-farm trees may suffer less of the access and maintenance challenges in communal forest management.
As authors have emphasized the role of communal and national forests as environmental assets that promote desirable wellbeing and resilience outcomes, we propose that on-farm trees function promote many of those same outcomes but through the transformation of environmental assets into livelihood assets even more directly related to the outcomes of interest. As put forth in the fuel poverty literature, the quality of housing has a significant impact on both the amount of fuel required, but also the enjoyment of wellbeing benefits from obtaining sufficient fuel [104
]. We find strong correlations of improved consumption, education, and diet diversity with more valuable Ethiopian homes that are in better repair. We found significant correlations of dwelling value with less risk exposure. Dwelling value and in particular livestock assets were strongly significantly correlated with improved coping to drought. In fact the promotion of common environmental assets and on-farm tress may be complimentary, rather than substitutive, goals. Recent research from a watershed management area in Ethiopia confirmed that household level trees were major contributors to achieving project goals by meeting community fuel and fodder needs while relieving pressure on existing forests and at the same time increasing productivity by increasing dung availably for fertilizer [56
As competition and policy trade-offs for management of food–energy–water resources are predicted to increase dramatically in the coming decades, broadening the evidence base through research on the links between well-being, environmental assets, and socio-ecological processes is fundamental to improving the understanding of resilience dynamics and create better-informed policies [67
]. However, intuitive, empirical evidence, similar to that presented in this study, is rare in large part because of a paucity of coherent and appropriate panel data for studying the important role of trees and environmental assets in the outcomes socio-ecological systems from existing observational datasets [33
]. For example, most households in the ERHS dataset procured their seedlings at a market. The community without a market that sold seedlings did not have many on-farm trees, with only two households reported eucalyptus trees grown from seedlings provided by the Ministry of Agriculture. Novel empirical results and identification of an alternative resilient development pathway require datasets with a diversity of variables, such as informal seedling markets, as well as a diversity of seeds and other non-industrial inputs, that more broadly represent the essential elements of rural agricultural livelihoods, markets and the foundational socio-ecological system on which they rely.
Arnold and Perssin, in their sweeping survey of research on woodfuel, concluded renewed attention to woodfuel and timber as a co-products of agriculture and agro-forestry activities is overdue [108
]. Further research on biomass as the foundation of household energy security pathways promises new insights into the role not only of seeds and seedlings, but also other environmental assets that contribute to rural livelihoods. Research that bridges productive and environmental assets should be encouraged and include a measurement of medium- and longer-term outcomes. A particularly exciting area for further investigation is the dual nature of trees and permanent crops as productive and environmental assets providing a wide range of socioeconomic benefits and environmental services [109
Taken as a whole, a broad range of positive effects on well-being, livelihoods, and resilience can be observed over the medium term, from access to seedlings to cultivation of on-farm trees. Meaningful improvement in well-being, livelihoods, and assets takes time. Female-headed households may face increased challenges regarding energy security, or asset creation in general, which requires further investigation. Additional research is required on the role of tree-oriented investment by rural households in the accumulation of assets and the observed improvements in well-being and resilience outcomes over the medium and longer term.
Our research is limited in similar ways to more general ongoing challenges of sustainability science as a whole. In our investigation, we were limited for econometric modeling to the panel data that was collected in the ERHS whose primary purpose was to characterize the productive agricultural aspects and their relation to largely consumption based food security measures. Although modules on gender, decision-making, shocks or energy use appeared in some rounds, other important sustainability information was missing almost entirely, such as data on environmental assets, environmental services, or governance of common spaces. Our use of household panel data also limited analysis of environmental and contextual issues at landscape or regional level that typically strengthen sustainability focused research. Our use of statistical tests for inclusion of variables in the econometric model is necessarily reductionist and insights potentially could be made by further investigation of some of the borderline significant variables in different approach, such as factor analysis or beginning with other environmental assets than on-farm trees. We chose to limit our focus on the core relationship of the most common trees to the most valuable assets for clarity in presentation of the main findings but certainly see the value of future investigations into a broader set of variables with more sophisticated statistical techniques, such as three-stage least squares models.
We believe this work contributes to a number of promising opportunities for future research. There is great potential for researching the comparative benefits of different trees, including native species, on farms and their benefits, but that will require a sampling frame that is able to capture a representative sample in this context where most trees are rare with most species only reported by one or two households out of 1475. Use, income, and distribution of benefits from on-farm tree products in different farming systems could potentially contribute to better understating of the cost benefit and appropriateness of policies promoting on-farm or common area tree planting in different contexts. This could also include more investigation of gender and wealth dynamics at the intra-household level. Much of the interest in biomass management research is related to agricultural and food security outcomes. The inclusion of nutritional analysis potentially could integrate these related lines of inquiry around cooking, nutrition-sensitive agriculture and nutritional wellbeing outcomes. The potential of natural assets as instruments including soil, seedlings, and seeds, requires further investigation to see the value of potential wide-spread application of these instruments in different contexts. Finally and most importantly, we believe environmental outcome-related lines of inquiry about on-farm trees such as reduced soil erosion due to larger availability of biomass or the valuation of improved environmental services at different spatial scales. Unfortunately, the data available over longer time periods, such as the 20-year ERHS panel, is limited in these respects and may require novel approaches to explore. We support calls for socio-economic datasets to include a wider variety of environmental indicators and information about trees, fiber, and permanent crops.