Increasing Tree Cover Research Articles

Changing Patterns of Tree Cover in a Tropical Highland Region and Implications for Food, Energy, and Water Resources

Abstract The Blue Nile Highlands of Ethiopia are a densely populated, predominantly rural region dominated by smallholder crop-livestock mixed farming systems. Population growth, coupled with low productivity, have long posed a threat to natural forest ecosystems in the region, as trees have been removed for fuel wood and to clear area for grazing or crop production. In recent years, however, there has been a trend to replace cropland with eucalyptus plantations. This change has major implications for the hydrology, soils, and agricultural economy of the region. This study examines changes in tree cover for a highland area at the center of the Blue Nile Highlands. Landsat imagery from 1986-2017 is applied to characterize changing tree cover patterns over space and time. We find that total tree cover in this highland region has shifted dramatically over the past 30 years. Between 1987 and 1999 there was dramatic loss of tree cover, particularly in areas of natural vegetation at high and low elevation. This period coincided with the fall of the Derg government and the transition to the current political system. In the period since 1999 there has been an increase in tree cover, with rapid gains in recent years. This increase has taken two distinct forms: regrowth in previously forested areas, due in part to active conservation measures, and the establishment of eucalyptus plantations in mid-elevation zones. The ecological and economic implications of these two types of tree cover—protected forest vs. woodlot plantations—are quite distinct, with plantation forestry providing biomass energy at a cost to food production and water resources. Effective monitoring of these changes is important for the ongoing development and implementation of effective land use policy in the region.

Transborder political ecology of mangroves in Senegal and The Gambia

Abstract Existing studies of mangroves in Senegal and The Gambia have found net increases in mangrove tree cover at the national scale, but these do not accord with local accounts and explanations of loss. This paper utilizes remote sensing analysis and political ecology frameworks to assess local accounts of mangrove wood trafficking across the border between The Gambia and southern Senegal, which were encountered in conducting qualitative field research. The remote sensing results demonstrate overall increases in mangrove cover in The Gambia and in the Sine Saloum and Low Casamance estuaries in Senegal between 1988 and 2018, but also highlight greater declines in mangrove cover in Low Casamance in the 1990s—a period of heightened regional political conflict—and in particular areas of the estuary near the Gambian and Guinea-Bissauan borders. Focusing on political ecology’s attention to multiple scales of analysis, this paper addresses divergent interpretations of mangrove changes in the region, and how local accounts of destruction may not be fully captured by the scale of observation and analysis in remote sensing. The paper argues for greater attention to spatial and temporal variation in studies of mangrove dynamics, and greater consideration for how these patterns may result from confluences of political, social, and natural factors.

Tree Cover on Cattle Farms in the Southeast Region of Guatemala

Often livestock activity is related to deforestation and loss of natural resources such as soil and water quality and quantity. The strategies that come from this perception seek the minimization of livestock effect of greenhouse gas emissions into the environment. Silvopastoral systems is been used as an alternative to increase tree cover on livestock farms, mitigate the effects of climate change, and make farmers more resilient to these. Tree cover plays an important role inside of this system, they can help with the optimization of the land use on the farm and it provides socioeconomical and environmental benefits to the farmers. Therefore, the objective of this study was to characterize livestock farms and the floristic composition of tree cover in the southeast region of Guatemala. This region belongs to the dry corridor of Central America and present high vulnerability to drought. Thirty farms were selected using seven criteria, on each farms a socioeconomical survey was applied to recollect biophysical, socioeconomical and productive information. Two groups of farms were identified: 1) farms with high level technological innovation (HLTI) and 2) farms with low level of technological innovation (LLTI). Tree data were obtained from individuals with diameter above breast height (DBH) of >5 cm. Composition, richness and abundance of tree species were evaluated using Q-Hill Diversity Index. Seven land uses were identified: scattered trees in paddocks, natural forest, agrisilvicultural systems, fodder banks, forest plantations, riparian forest and living fences. Study area were 790 ha in which there were 143 plots distributed randomly, living fences were present in 1.691 km (169.1 ha) with 44 transects. A total of 4,678 trees, from 37 families and 83 species, were found in the area. The most abundant families were Fabaceae and Pinaceae. The most common tree species for timber were Pinus spp and Quercus spp and for non-timber were Gliricidia sepium and Acacia pennatula. It was found that 77.27% of the total inventory is dominated by ten species. We conclude that farmers consider tree cover of importance, this is reflected in the 29% of tree cover found inside of natural forests, 26.2% in scattered trees in paddocks and 7.9% in forest plantations. There were marked differences of richness by individuals, density of species accumulated by land use and diametrical class.

Tree Planting Stakeholder analysis in the Ugandan Albertine Rift

Background: Trees provide ecosystem services, for example, by preserving soil fertility and sequestering carbon. They contribute 8.7 percent to Uganda’s national economy. Due to the ecosystem services trees provide, several stakeholders in Uganda have intervened to increase tree cover in the landscape. These stakeholders include; Ministry of water and Environment, National Forestry Authority, World vision Uganda (WVU) and licensed individual tree planters in forest reserves. The success of their interventions depends on several factors. Among these factors, probably, the least studied is the influence of different stakeholders in promoting tree planting. This paper assesses the different stakeholders in tree planting in Kiryanga Sub County, Albertine rift region, Uganda. Methods: The analysis was conducted in a stakeholder workshop to identify stakeholders’ potential roles, relationships, power and influence on tree planting. The stakeholder; register, analysis-grid, and matrix were respectively used to identify and categorize stakeholders. Results: The identified stakeholders were; community leaders, Civil Society Organizations (CSOs), government institutions, individual farmers and farmer groups. Farmers, Local Government (LG) CSOs; WVU and Uganda Rural Development and Training (URDT) were important stakeholders in tree planting. The LG will provide seedlings, train, and guide and mobilize farmers during tree planting. WVU will promote regenerating trees from stumps, roots, and naturally growing tree seedlings. URDT will sensitize and train farmers in tree planting. Farmers also have to be engaged with to provide land and labour for tree planting. Conclusion: Tree planting interventions ought to be implemented after thorough understanding and engagement of these key stakeholders. Keywords : stakeholder analysis, Albertine Rift, tree planting, forest cover

Watersheds in planetary health research and action

Watersheds in planetary health research and action

MAPPING OF STRIP FOREST IN ADAMPUR RANGE (HARYANA) A GEO-INFORMATICS APPROACH

Abstract. Haryana state is an intensively cultivated state, and deficient in natural forests. One of the mandate of Haryana Forest Department (HFD) is to afforest for maintenance of environmental stability and restoration of ecological balance affected by serious depletion of forests, woodlands and water, and to increase tree cover in the state. National Forest Policy (1988) has set a goal to bring one third of Country’s area under forest and tree cover. Stock and dynamics of Trees Outside Forests (TOF) along with natural forests need to be understood holistically to appreciate the ecosystem services e.g., timber and non-wood products as tangible benefits along with services like carbon, water and weather moderation. The present study has attempted to demonstrate the utility of High Resolution Worldview-II (WV) satellite data (ortho rectified) that offeres immense scope to analyze the strip forests in Hisar district (Haryana, India). The study area Adampur Range (Hisar District) lies between the north latitudes 29°0′52.229″ to 29°25′6.746″ and east longitudes 75°14′0.266″ to 75°45′11.093″ with a total geographical area of about 1092.04 sq. km. The adopted methodology involves onscreen digitization of the strip forest areas in the Adampur range (Hisar Distirct). The ToF formation identification and delineation includes the forest land besides roads, river, streams, canals, distributaries and railway lines etc. The shape files were converted into .kml files and overlaid on the Google Earth data for validation. An attempt has been made to compare the area difference between the Haryana Forest Department (HFD) notification details with that of the digitized strip forest lands. It was observed that the surveyed forest area is found to be 1717.37 ha. against the notified forest area of 1714.45 ha. showing a difference of 2.92 ha. approximately in the studied beat boundaries.

Turning down the heat: An enhanced understanding of the relationship between urban vegetation and surface temperature at the city scale

Guiding urban planners on the cooling returns of different configurations of urban vegetation is important to protect urban dwellers from adverse heat impacts. To this end, we estimated statistical models that fused multi-temporal very fine spatial (20 cm) and vertical (1 mm) resolution imagery, that captures the complexity of urban vegetation, with remotely sensed temperature data to assess how urban vegetation configuration influences urban temperatures. Perth, Western Australia, was used as a case-study for this analysis. Panel regression models showed that within a location an increase in tree and shrub cover has a larger cooling effect than grass coverage. On average, holding all else equal, an approximate 1 km2 increase in shrub (tree) cover within a location reduces surface temperatures by 12 °C (5 °C). We included a range of robustness checks for the observed relationships between urban vegetation type and temperature. Geographically weighted regression models showed spatial variation in the cooling effect of different vegetation types; this indicates that i) unobserved factors moderate temperature-vegetation relationships across urban landscapes, and ii) that urban vegetation type and temperature relationships are complex. Machine learning models (Random Forests) were used to further explore complex and non-linear relationships between different urban vegetation configurations and temperature. The Random Forests showed that vegetation type explained 31.84% of the out-of-bag variance in summer surface temperatures, that increased cover of large vegetation within a location increases cooling, and that different configurations of urban vegetation structure can lead to cooling gains. The models in this study were trained with vegetation data capturing local detail, multiple time-periods, and entire city coverage. Thus, these models illustrate the potential to develop locally-detailed and spatially explicit tools to guide planning of vegetation configuration to optimise cooling at local- and city-scales.

Changes in the area of optimal tree cover of a declining Afro‐Palaearctic migrant across the species’ wintering range

Land use change in sub‐Saharan Africa continues apace, but its role in driving the declines of Afro‐Palaearctic migrant birds is unknown. This is due partly to a lack of knowledge of migrants’ requirements on the wintering grounds, and of spatially explicit assessments of land cover change. We compared tree cover data derived from satellite remote sensing (available for the period 2000–2014) with distributional data from surveys in four West African countries for the Wood Warbler Phylloscopus sibilatrix, one such declining migrant, to determine the extent of, and change in, optimal tree cover. Wood Warblers were most likely to occur where tree cover per hectare was between 40 and 61% (optimal tree cover). Extrapolation to the whole of the wintering range indicated there was a 46.7% net increase in extent between 2000 and 2014. This was due to an alarming 27 683 km2 of previously closed forest being degraded from > 61% cover to between 40 and 61%, an area greater than that of the optimal tree cover that was lost. Increases in optimal tree cover were greatest in countries with greatest forest cover, such as Sierra Leone, Liberia, Côte d'Ivoire and Democratic Republic of Congo. The results suggest that loss of optimal tree cover in the wintering range might not be a key driver of population decline for Wood Warblers, but the degradation will probably impact species that rely upon dense tree cover.

The Relationship Between the Natural Environment and Individual-Level Academic Performance in Portland, Oregon

We tested the hypothesis that exposure to the natural environment is associated with improved academic performance. Specifically, we examined the association between individual-level standardized math and reading test scores and exposure to the natural environment using data from Portland Public Schools (17,918 students attending 83 schools for the math model and 19,459 students attending 90 schools for the reading model). We found that a 1- SD increase in tree cover within 200 m of a child’s home was associated with moving from the 50th percentile to the 51st percentile on math tests. A 1- SD increase in tree cover within 100 m of a child’s school was associated with moving from the 50th percentile to the 56th percentile on reading tests. Finally, a 1- SD increase in road density within 100 m of a child’s home was associated with moving from the 50th percentile to the 47th percentile on reading tests.

Is planting trees the solution to reducing flood risks?

Flood risk and associated impacts are major societal and policy concerns following widespread flooding in December 2015, which cost the UK economy an estimated £5 billion. Increasing advocacy for alternatives to conventional hard engineering solutions is accompanied by demands for evidence. This study provides a systematic review and meta‐analysis of direct evidence for the effect of tree cover on channel discharge. The results highlighted a deficiency in direct evidence. From 7 eligible studies of 156 papers reviewed, the results show that increasing tree cover has a small statistically significant effect on reducing channel discharge. Meta‐analysis reveals that tree cover reduces channel discharge (standardised mean difference −0.35, 95%CI, −0.71 to 0.00), but the effect was variable (I2 = 81.91%), the potential for confounding was high, and publication bias is strongly suspected (Egger Test z = 3.0568, p = .002). Due to the lack of direct evidence the overall strength of evidence is low, indicating high uncertainty. Further primary research is required to understand reasons for heterogeneity and reduce uncertainty. A Bayesian network parameterised with data from the meta‐analysis supports investment in integrated catchment management, particularly on infrastructure density and water storage (reservoirs), for effective responses to flood risk.

Linkages between soil carbon, soil fertility and nitrogen fixation in Acacia senegal plantations of varying age in Sudan.

BackgroundOver the last decades sub-Saharan Africa has experienced severe land degradation and food security challenges linked to loss of soil fertility and soil organic matter (SOM), recurrent drought and increasing population. Although primary production in drylands is strictly limited by water availability, nutrient deficiencies, particularly of nitrogen (N) and phosphorus (P), are also considered limiting factors for plant growth. It is known that SOM (often measured as soil organic carbon (SOC)) is a key indicator of soil fertility, therefore, management practices that increase SOM contents, such as increasing tree cover, can be expected to improve soil fertility. The objectives of this study were to investigate the effect of Acacia senegal (Senegalia senegal) trees on soil nitrogen, phosphorus and potassium (K) in relation to SOC, the potential of A. senegal for N2 fixation, and to identify possible N and P ecosystem limitations.MethodsSoil nutrient (total N, P, K and available P and exchangeable K) concentrations and stocks were determined for the 0–10, 10–20,20–30 and 30–50 cm layers of A. senegal plantations of varying age (ranging from 7 to 24-years-old) and adjacent grasslands (reference) at two sites in semi-arid areas of Sudan. At both sites, three plots were established in each grassland and plantation. The potential of A. senegal for N2 fixation in relation to plantations age was assessed using δ15N isotopic abundances and nutrient limitations assessed using C:N:P stoichiometry.ResultsSoil concentrations of all studied nutrients were relatively low but were significantly and directly correlated to SOC concentrations. SOC and nutrient concentrations were the highest in the topsoil (0–10 cm) and increased with plantations age. Acacia foliage δ15N values were >6‰ and varied little with plantations age. Soil C:N and C:P ratios did not differ between grassland and plantations and only 0–10 cm layer N:P ratios showed significant differences between grassland and plantations.DiscussionThe results indicated that soil fertility in the Sahel region is strongly related to SOM contents and therefore highlighting the importance of trees in the landscape. The higher mineral nutrient concentrations in the topsoil of the plantations may be an indication of ‘nutrient uplift’ by the deeper roots. The high foliar δ15N values indicated that N2 fixation was not an important contributor to soil N contents in the plantations. The accretion of soil N cannot be explained by deposition but may be related to inputs of excreted N brought into the area annually by grazing and browsing animals. The soil C:N:P stoichiometry indicated that the plantations may be limited by P and the grasslands limited by N.

Future impacts of the reforestation policy on the atmospheric parameters in Ireland: a sensitivity study including heat discomfort impacts on humans and livestock

The increase of temperature attributed to anthropogenic emissions is projected to continue in future climate scenarios. Protocols and policies are being put in place in several European countries to reduce both emissions and impact of human activities on climate. The Irish Reforestation policy is a good example of such protocols. Nevertheless often contemplated policies do not take into account their potential effects on the atmospheric variables. This study aims to assess the influence of the increase of vegetation cover over Ireland, on surface temperature, livestock and human heat comfort, using the Weather Research Forecast (WRF-ARW 3.7.1) model. Multi-scale numerical simulations are performed under two scenarios: (i) a “control scenario” con- sidering no change in vegetation cover with respect to the prescribed one and (ii) a “green scenario” with increased tree cover based on the introduced Irish Reforestation policy. To simulate this policy, the cropland and vegetative mo- saic is substituted with evergreen broad leaf forest, increasing the total forest area from 19.7% to 36.2% of the land in the analyzed domain. This change in vegetation cover increases the temperature over the simulated domain up to 0.7oC and, moreover, it enhances both human and livestock heat discom- fort during the day-time, with different magnitude all over the domain. It is concluded that the reforestation policy, which is introduced to mitigate the climate warming and greenhouse gas emissions, causes a further increase in temperature along with heat discomfort to both human and livestock.

Socio-economic factors and management regimes as drivers of tree cover change in Nepal.

Despite the local and global importance of forests, deforestation is driven by various socio-economic and biophysical factors continues in many countries. In Nepal, in response to massive deforestation, the community forestry program has been implemented to reduce deforestation and support livelihoods. After four decades of its inception, the effectiveness of this program on forest cover change remains mostly unknown. This study analyses the spatial and temporal patterns of tree cover change along with a few socio-economic drivers of tree cover change to examine the effectiveness of the community forestry program for conserving forests or in reducing deforestation. We also investigate the socio-economic factors and policy responses as manifested through the community forestry program responsible for the tree cover change at the district level. The total tree cover area in the year 2000 in Nepal was ∼4,746,000 hectares, and our analysis reveals that between 2001 and 2016, Nepal has lost ∼46,000 ha and gained ∼12,200 ha of areas covered by trees with a substantial spatial and temporal variations. After accounting socio-economic drivers of forest cover change, our analysis showed that districts with the larger number of community forests had a minimum loss in tree cover, while districts with the higher proportion of vegetation covered by community forests had a maximum gain in tree cover. This indicates a positive contribution of the community forestry program to reducing deforestation and increasing tree cover.

Tracking tree canopy cover changes in space and time in High Nature Value Farmland to prioritize reforestation efforts

ABSTRACTIn High Nature Value Farmland areas such as the woodlands locally known as ‘montado’, increasing tree cover is a nature-based solution to mitigate land degradation which leads to loss of productivity and increase susceptibility to climate change. In the Mediterranean dryland areas, native tree species such as Holm-oak provide important ecosystem services. Tree cover provides shadow and food for animals, contributes to soil organic matter and protects soil from erosion, increasing water infiltration and biodiversity, thus increasing woodlands’ resilience. However, Holm-oak trees are facing high mortality rates and low natural regeneration due to both environmental and anthropogenic factors, which call for reforestation actions. Yet, because of its high costs, reforestation must focus on the most degraded areas. Tracking tree canopy cover over space and time using remote-sensing techniques could allow land managers to understand which factors promote or hinder mortality, growth and regeneration at large spatial scales, and help to prioritize areas for restoration. Most studies evaluating tree cover use a space-for-time substitution, are rarely done over time, and address small areas, thus disregarding climate effects; those performing large-scale analysis (i.e. over space) of satellite images seldom provide ground-validated information. To overcome these limitations, this study uses satellite imagery to quantify spatial and temporal changes in tree cover. This was done relating normalized difference vegetation index (NDVI) to aerial photography photointerpretation, over a precipitation gradient in a Mediterranean dryland area. Dry-season NDVI was positively related with tree canopy cover changes, both over space and time. The spatial–temporal models developed here were then validated with independent data and applied over a large area to create regional maps of changes in Holm-oak canopy cover over space and time. Thus, NDVI based-data can be used in large-scale assessments of Holm-oak canopy cover. Our findings provide an important tool to improve forest management strategies, e.g. by enabling to map and quantify tree cover decline, and to prioritize areas for reforestation, thus improving ecosystem services delivery in Holm-oak woodlands, such as improving farmland productivity and resilience to climate change.

Comparing the relative abilities of tree species to cool the urban environment

Increasing urbanisation poses numerous challenges to human quality of life. Cities are particularly vulnerable to the urban heat-island effect, which will be amplified by climate change. Increasing tree cover may be one of the most cost-effective ways of moderating urban temperatures. Trees cool their surroundings by casting shade, reflecting solar radiation, transpiring, and intercepting rainfall that subsequently evaporates. However, the potential of trees to reduce the urban heat-island effect is underutilised. The aim of this study was to synthesise understanding of the relative abilities of different tree species to provide urban cooling in temperate regions of the world and thereby develop a pragmatic approach for choosing those trees that have greatest potential in that regard. Based on a literature review and semi-structured interviews with leading experts, we developed a series of scenarios to illustrate the impacts of a tree’s cooling mechanisms and tree species’ attributes on components of the surface-energy balance equation. This enabled us to select parameters and propose simple equations that can be used to compare the relative abilities of tree species in relation to each of the cooling mechanisms. The parameters selected were for: transpiration – crown diameter, Leaf Area Index (LAI), canopy aspect ratio, and stomatal conductance or growth rate; reflection – albedo, crown diameter and LAI; shading – canopy aspect ratio, crown diameter, LAI and tree height. The approach is intended for use by urban planners and managers who wish to make informed decisions about which tree species to select for planting to counter the urban heat-island effect.

Socioeconomic and ecological perceptions and barriers to urban tree distribution and reforestation programs

Tree planting and reforestation initiatives in urban and peri-urban areas often use tree distribution or “giveaway” programs as a strategy to increase tree cover and subsequent benefits. However, the effectiveness of these programs in terms of increasing overall tree cover and providing benefits to low-income and disadvantaged communities has been little studied. We assess these programs by exploring community participation in, and barriers to, an urban tree distribution program in Fort Lauderdale, United States and the role socioeconomic background and tree functional types have on participation. We use a mixed-methods approach, panel data, choice experiments, and econometrics to quantitatively analyze respondent’s ranking of program options. High income, White respondents had the highest level of awareness and participation while low income, African Americans (AA) had the lowest level. Monetary rebates were perceived as positive and significant as the compensation value increased to US$8.00 - $12.00. Fruit-bearing and native tree functional types were more preferred than flowering or shade trees. Latinos, AA, and high income respondents preferred fruit trees, while White, high income preferred native trees. Overall, low income respondents perceived the greatest barriers towards participation. 20% of Broward County residents who participated in the survey were aware of the tree giveaway programs and 13% had previously participated. Findings indicate an adaptive governance mismatch between program objectives to equitably increase city tree cover via planting shade trees versus individual’s knowledge and preference for other tree types and functions. Results can be used for developing and evaluating reforestation initiatives to equitably increase tree cover and improve the governance of urban ecosystems.

Declining urban and community tree cover in the United States

Paired aerial photographs were interpreted to assess recent changes (c. 2009–2014) in tree, impervious and other cover types within urban/community and urban land in all 50 United States and the District of Columbia. National results indicate that tree cover in urban/community areas of the United States is on the decline at a rate of about 175,000 acres per year, which corresponds to approximately 36 million trees per year. Estimated loss of benefits from trees in urban areas is conservatively valued at $96 million per year. Overall, for both urban and the broader urban/community areas, 23 states/districts had statistically significant declines in tree cover, 25 states had non-significant decreases or no change in tree cover, and three states showed a non-significant increase in tree cover. The most intensive change occurred within urban areas, with tree cover in these areas dropping one percent over the 5-year period, compared to a 0.7 percent drop in urban/community areas. States/districts with the greatest statistically significant annual decline in percent urban tree cover were: Oklahoma (−0.92%/yr), District of Columbia (−0.44%/yr), Rhode Island (−0.40%/yr), Oregon (−0.38%/yr) and Georgia (−0.37%/yr). Coinciding with the loss of tree cover was a gain in impervious cover, with impervious cover increasing 0.6 percent in urban/community areas and 1.0 percent in urban areas over the 5-year period. Such changes in cover types affect the benefits derived from urban forests and consequently the health and well-being of urban residents.

The importance of grass cover for mammalian diversity and habitat associations in a bush encroached savanna

In grasslands across the world, woody species are replacing grass cover. This bush encroachment can alter available food, cover, and space resources for most mammalian species; however, the specific responses of mammals to bush encroachment in African savannas remain largely unknown. We examined the fine-scale response of mammals across a gradient of bush encroachment using camera traps and a Bayesian hierarchical multi-species abundance model that estimates local relative abundance and species richness while accounting for imperfect detection. Additionally, we simulated species-specific relative abundances and species richness responses to differing bush encroachment management actions. Contrary to our expectations, the relative abundance of only one species showed a negative relationship to shrub cover and another to tree cover. However, the relative abundance of eight out of twenty-one species showed a positive association with grass cover. Mammal species richness increased with grass cover, decreased with shrub cover, and showed no clear pattern with increasing tree cover. Furthermore, our simulations suggest reducing and increasing shrub and grass cover respectively by 50% would increase species richness and local abundances for the mammal community of the area. Our results indicate grass cover exerts a strong influence on habitat use, relative abundances and species richness in bush encroached areas. Our study shows that mammal's positive response to grass cover is more important than potential negative impacts of increasing shrub cover. Consequently, recovering and maintaining adequate grass cover in savannas subject to bush encroachment is an indispensable condition to maximize mammalian diversity and abundances.

Does Certification Change the Trajectory of Tree Cover in Working Forests in The Tropics? An Application of the Synthetic Control Method of Impact Evaluation

Certification by the Forest Stewardship Council (FSC) remains rare among forest management units (FMUs) in natural tropical forests, presenting a challenge for impact evaluation. We demonstrate application of the synthetic control method (SCM) to evaluate the impact of FSC certification on a single FMU in each of three tropical forest landscapes. Specifically, we estimate causal effects on tree cover change from the year of certification to 2012 using SCM and open-access, pan-tropical datasets. We demonstrate that it is possible to construct synthetic controls, or weighted combinations of non-certified FMUs, that followed the same path of tree cover change as the certified FMUs before certification. By using these synthetic controls to measure counterfactual tree cover change after certification, we find that certification reduced tree cover loss in the most recent year (2012) in all three landscapes. However, placebo tests show that in one case, this effect was not significant, and in another case, it followed several years in which certification had the opposite effect (increasing tree cover loss). We conclude that SCM has promise for identifying temporally varying impacts of small-N interventions on land use and land cover change.

Development of the VTUF-3D v1.0 urban micro-climate model to support assessment of urban vegetation influences on human thermal comfort

With urban areas facing longer duration heat-waves and temperature extremes from climate change and growing urban development, adaptation strategies are needed to protect city residents. Examining the role that increased tree cover and water availability can have on human thermal comfort (HTC) is needed to help guide the development of thermally comfortable cities. To inform planning, modelling tools are needed that provide sufficient resolution to resolve urban influences on HTC and the ability to model important physiological processes of vegetation. To achieve this, a new micro-scale model, VTUF-3D (Vegetated Temperatures of Urban Facets) has been developed. In it, offline modelling of individual items of vegetation is performed using the MAESPA process-based tree model (Duursma and Medlyn, 2012) (a model that can model individual trees, vegetation, and soil components), and integrated into the TUF-3D (Krayenhoff and Voogt, 2007) urban micro-climate surface energy balance (SEB) model. This innovative approach allows the new model to account for important vegetative physiological processes and shading effects, using configurable templates to allow representation of any type of vegetation or water sensitive design feature. This work enables detailed calculations of surface temperatures (Tsfc), mean radiant temperature (Tmrt), and a HTC index, the universal thermal climate index (UTCI), across urban canyons. This study presents an overview of VTUF-3D. Also presented are two evaluations of VTUF-3D. The first evaluation compares modelled surface energy balance fluxes to observations in Preston, Australia (Coutts et al., 2007). The second evaluation compares spatial and temporal predictions of Tmrt and UTCI to two observed street canyons in the City of Melbourne (Coutts et al., 2015b). The VTUF-3D model is shown to perform well and is suitable for use to examine critical questions relating to the role of vegetation and water in the urban environment in support of HTC.