Dynamic land use and land cover changes and their effect on forest resources in a coastal village of Matemwe,Zanzibar, Tanzania

Recent land cover change estimates show overall decline of tropical forests at the regional and global scales caused by multiple social, cultural and economic factors. There is an overall concern on the prevailing land use practices, such as shifting cultivation and extraction of forest materials as agents of forests losses, but also new, emerging land uses are threatening tropical forests. Understanding of the long-term development and driving forces of forest changes are needed, especially at local levels where many decisions on forest policies and land uses are made. This paper addresses the importance of such information for improved estimates of forest dynamics by studying local level land cover and land use changes during the last 50–70 years in the Eastern African tropical island of Zanzibar, Tanzania. The paper discusses the role of traditional and new land uses mainly subsistence farming, tourism and government interference through tree planting, in the long-term development of the forests at the village level. The material for the study is gathered from the interpretation of archival maps and aerial photographs combined with contemporary digital aerial photographs. The analyses are based on the mapping, spatial sampling and spatio-temporal change trajectory analysis (LCTA) of forest land cover, forest land uses and settlement patterns with GIS and statistics. Six distinct forest land cover change trajectories were identified and these illustrate dynamic and heterogeneous nature of the forests. Closed forest cover has dominated throughout due to cyclical land use patterns, but over 70% of the land area has been continuously transforming between closed, semi-open and open land cover conditions. Land use turnover rates indicate that hardly any forest areas are left untouched from the forces, which remove and re-establish forest vegetation in the long run. Land cover and land use change trajectories are spatially fragmented in the studied landscape. Majority of forest loss-gain dynamics is caused by shifting cultivation, while forest losses are most dramatic along the coast, where traditional and new land uses meet and land uses pressures are highest. The study suggests that landscape change trajectory analyses, where contemporary and historical information on land uses and land cover changes are spatially linked, can provide valuable aspects into local level forest land use planning and management strategies. For the case study, the findings suggest the following key forest management strategies for consideration: (1) establishment of a protected forest/scrubland in participation with the local stakeholders, especially the farmers, (2) promotion of areas for permanent agricultural practices, while simultaneously introducing management controls in the traditional slash-and-burn farming areas, and (3) promoting new livelihood opportunities for the farmers, who have traditionally been dependent on forest resources, meanwhile introducing alternatives for fuel wood for cooking.     

Carbon Sequestration and Conservation of Tropical Forests Under Uncertainty

Concern for global warming has focused attention on the role of tropical forests in the reduction of ambient CO₂ levels and mitigation of climate change. Deforestation is a major land use change in the tropics, with forest resources undergoing degradation through the influence of logging and conversion to other uses. Land use change is a product of varied local and regional resource use policies. Management of forest resources is one such major temporal factor, influencing resource stability and the carbon pool. Under a given management policy, both the long period of forest growth, and the slow turnover and decay of the carbon pool, enhance the relevance of stand level management policies as cost-effective mechanisms mitigating climate change. Apart from regional level uncertainties like the nature of land use and the estimation of carbon storage in vegetation and soil, the carbon flux of tropical forests is greatly influenced by uncertainty in regenerative capacity of forests and in harvest and management policies. A case study from India is used to develop a transition matrix model of natural forest management, and to explore the economic implications of maintaining and expanding existing carbon sinks. The study further explores the significance of investments in additional carbon sinks in plantation forests, given continued uncertainty in natural forest management.     

对中国集体林区产权改革诸问题的认识

集体林产权改革必须尊重历史,尊重广大基本群众对土地和民生的基本诉求,切实维护他们对土地基本的权力,核心是公平,而不是效率,效率上的改革企图只能在局部成功。应当清醒地认识到这次改革目标是有限的。为此提出了4点建议:(1)尽快彻底取消林业税费。(2)加强林业产权制度、基层森林管理模式、利益分配机制的综合研究和试验。(3)林业部门主动放弃“森林”和“环境”等主导名词,而代替为“林农”、“林业”和“林区”“三林问题”新的话语。寻求少数林区作为改革试点,探索林区社会福利事业生成路径和管理模式,用以购买农民的森林所有权和林地的使用权,探索集体林区森林国有化改革的道路。(4)寻求多样化、有弹性的林业改革发展道路。     

Towards productive landscapes: Trade-offs in tree-cover and income across a matrix of smallholder agricultural land-use systems

One of the main causes of tropical forest loss is conversion to agriculture, which is constantly increasing as a dominant land cover in the tropics. The loss of forests greatly affects biodiversity and ecosystem services. This paper assesses the economic return from increasing tree cover in agricultural landscapes in two tropical locations, West Java, Indonesia and eastern Bangladesh. Agroforestry systems are compared with subsistence seasonal food-crop-based agricultural systems. Data were collected through rapid rural appraisal, field observation, focus groups and semi-structured interviews of farm households. The inclusion of agroforestry tree crops in seasonal agriculture improved the systems’ overall economic performance (net present value), even when it reduced understorey crop production. However, seasonal agriculture has higher income per unit of land area used for crop cultivation compared with the tree establishment and development phase of agroforestry farms. Thus, there is a trade-off between short-term loss of agricultural income and longer-term economic gain from planting trees in farmland. For resource-poor farmers to implement this change, institutional support is needed to improve their knowledge and skills with this unfamiliar form of land management, sufficient capital for the initial investment, and an increase in the security of land tenure.     

Agricultural development with rainforest conservation: methods for seeking best bet alternatives to slash-and-burn,with applications to Brazil and Indonesia

Forests continue to fall for agricultural purposes throughout the humid tropics, with immediate and potentially large consequences for climate change and biodiversity loss-issues of key interest to the international community. Some of the actors directly responsible for forest conversion fell trees to meet food security needs and alleviate poverty-issues of urgent interest to them and also to national policymakers. This multiplicity of groups with differing (often conflicting) interests in the multifarious goods and services produced by tropical forests complicates the search for alternative agricultural activities for forest margins since these alternatives must satisfy such divergent objectives. This paper sets out a conceptual framework for comparing the impacts of different land use systems and agricultural practices at the margins of tropical rainforests in terms of the concerns and objectives of two key interest groups: small-scale farmers seeking livelihoods at the forest margins and the ‘international’ interests in the global public goods and services supplied by tropical rainforests. This framework should be useful to a third key group, the national and regional policymakers who must consider these and other policy objectives and then decide on courses of action. The paper identifies data needs and analytical methods capable of supplying an empirical base for this conceptual framework, based on quantifiable indicators. It then presents preliminary results of the application of this conceptual framework in Indonesia and Brazil in association with a global, collaborative, multidisciplinary research program. Even using preliminary order-of-magnitude estimates (to be replaced by more precise measurements as they become available), this conceptual framework presents results in ways that allow researchers and policymakers to select clear ‘best bets’ for development, when they exist, and to assess tradeoffs and options for complementary policy action and research efforts, when they do not.     

Sustainability and forest transitions in the southern Yucatán: The land architecture approach

Consistent with the challenges of sustainability science, land architecture offers a comprehensive approach to land system dynamics useful for numerous types of assessments, ranging from the vulnerability of coupled human–environment systems to forest transitions. With antecedents in several research communities, land architecture addresses the tradeoffs within and between the human and environmental subsystems of land systems in terms of the kind, magnitude, and pattern of land uses and covers. This approach is especially cogent for changes in tropical forests, given the broad-ranging forces acting on them and the equally broad-ranging consequences of their loss. The rudiments of the land architecture approach are illustrated for changes in seasonal tropical forests in the southern Yucatán of Mexico, the pivot of which is the Calakmul biosphere reserve. Simplifying the dynamics involved, the region-wide land architecture is the collective design of stakeholders with different land-use goals that favor tradeoffs in subsystem outcomes serving better either the reserve and related programs or the smallholder farmers that populate the region. A major tradeoff involves forest cover per se, which holds implications for forest transition theory. Evidence for an incipient transition involves the scale of analysis taken. The dynamics involved hold too much uncertainty to forecast a permanent transition to more forest cover and imply that more complex but robust versions of the theory are required.     

Land use transitions: Socio-ecological feedback versus socio-economic change

The concept of land use transition highlights that land use change is non-linear and is associated with other societal and biophysical system changes. A transition in land use is not a fixed pattern, nor is it deterministic. Land use transitions can be caused by negative socio-ecological feedbacks that arise from a depletion of key resources or from socio-economic change and innovation that take place rather independently from the ecological system. Here, we explore whether the sources of land use transitions are mostly endogenous socio-ecological forces or exogenous socio-economic factors. We first review a few generic pathways of forest transition as identified in national case studies, and evaluate the varying ecological quality of expanding forests associated with these pathways. We then discuss possible explanatory frameworks of land use transitions. We use the case of the recent forest transition in Vietnam as an illustration. Socio-ecological feedbacks seem to better explain a slowing down of deforestation and stabilization of forest cover, while exogenous socio-economic factors better account for reforestation. We conclude by discussing the prospects of accelerating land use transitions in tropical forest countries.     

A model of shifting cultivation: can soil conservation reduce deforestation?

Shifting cultivators manage soil not only by adjusting soil use on already‐cleared lands, as in continuous cultivation, but also by clearing forests to obtain new fertile soils. This study examines the crucial link between on‐farm soil conservation and deforestation in shifting cultivation by modeling forest clearing as an investment in soil for a private farmer. More generally, by doing so the study attempts to integrate deforestation and soil conservation models which have been separately developed in the literature. Our policy goal is to arrest tropical deforestation—as destruction of global commons—caused by land degradation in shifting cultivation while improving the well‐being of poor shifting cultivators. Our integrated approach enables joint policy analyses of deforestation and land degradation. Three welfare‐enhancing policies are considered. The first is agricultural and nonagricultural subsidies affecting farm and nonfarm income opportunities. The second is fiscal and tenure policies affecting discount rates. Our question is whether the link between forest clearing and soil fertility alters the outcomes of these two standard macroeconomic policies commonly found in the literature. The third policy (or program) is various soil conservation measures affecting soil regeneration and erosivity on already‐cleared lands. This article examines a very important question which has received little attention in previous theoretical works: can soil conservation reduce deforestation? This study confirms anti‐deforestation effects of the promotion of nonfarming activities—a common and often emphasized finding in previous works—among shifting cultivators. More importantly, it also demonstrates that improving various soil conservation measures not only discourages forest clearing among shifting cultivators but also tends to have greater effects on forest protection than promoting nonfarming activities. Contrarily, agricultural price subsidy or technological progress gives rise to the opposite outcome, and lowering the farmer's discount rate or improving tenure security encourages him/her to clear more forests just to accumulate soil.     

Land use and climate change in the UK

This paper reviews the relationships between land use and climate change. It explores how land use decisions will be affected by future changes in the climate, but also the feedbacks from land use change to the global climate system through greenhouse gas (GHG) fluxes. Past changes in land use were characterised by decreasing areas of agricultural use and increasing areas of forested and urbanised land. This has led to UK land use being a net sink for GHGs, mostly due to forestation. However, existing forests have on average passed their age for maximum net removals of carbon from the atmosphere. In the next decade at least, net removals from UK forests are likely to decrease significantly.Longer term scenarios of future land use change are consistent in their expectation of further declines in the agricultural area used for food production – offset to some extent by increased bioenergy cropping – along with increases in forested and urban areas. These trends are broadly consistent with the observed past land use change, but are calculated from various assumptions about future changes in drivers rather than by extrapolation from the past. Socio-economic and technological changes are likely to be the most important drivers for land use, with climate change having a smaller influence. The land use changes represented in these scenarios would likely reduce GHG emissions and enhance carbon sinks. These trends would be reinforced by small future changes in the climate, but large climatic changes are likely to cause net GHG fluxes to switch from being a sink to a source. Land use change will also be moderated by potential policy goals that seek to reduce GHG emissions from land and/or increase the size of land-based sinks. This includes strategies to reduce carbon and nitrogen emissions through increased efficiency, afforestation and biofuel production.     

Knowing but not knowing: Systematic conservation planning and community conservation in the Sierra Norte of Oaxaca,Mexico

Systematic conservation planning (SCP) seeks to propose new reserves through a scientifically rigorous process using databases and research selection algorithims. However, SCP exercises have been criticized for “knowing but not doing”, i.e. not implementing the proposed reserve. But there is an additional problem that can be called “knowing but not knowing”, knowing things from databases, but not knowing crucial contextual information about community-based social processes that have supported the high forest cover and biodiversity detected. Examined here is how a common property region of the Sierra Norte of Oaxaca, Mexico has maintained high forest cover in the absence of public protected areas, while multiple SCP exercises have advocated for the creation of public protected areas in communal tropical montane cloud forests and pine forests as strategies for biodiversity conservation and resilience to climate change. Methods included archival research, review of community documents, focus group interviews, semi-structured interviews, participant observation, land use transects, and GIS analysis and remote sensing. Conservation in the region originally occurred because of low population densities, steep slopes and a lack of agricultural subsidies, supported by locally adapted agricultural practices. In the 1990s, a transition from passive to active conservation took place with land use zoning plans, community conservation rules, community forestry enterprises and payments for environmental service programs that consolidated a trend towards high, unthreatened forest cover. Today, the study communities have an average of 88.3% forest cover, with 61% of that in informal conservation based on community land use zoning and rules and another 14% governed by forest management plans approved by the Mexican government. We argue that truly systematic conservation plans would seek to understand how communities in the region are already managing forests for conservation. It is pointless and uninformed to advocate for top-down conservation interventions of forests that are already robustly conserved and resilient to climate change due to community action.     

Land Cover in a Managed Forest Ecosystem: Mexican Shade Coffee

Managed forest ecosystems like shade coffee supply valuable ecological services. Yet little is known about the drivers and characteristics of clearing in such systems. We present a spatial econometric analysis of land cover in a shade coffee region in southern Mexico. We find that plots close to large cities are less likely to be cleared all other things being equal—the opposite of the pattern usually observed in natural forests. In addition, we find that membership in coffee-marketing cooperatives, farm size, and certain soil types are associated with tree cover, while proximity to small town centers is associated with clearing.     

Diverse local regulatory responses to a new forestry regime in forest communities in the Bolivian Amazon

Over the last decade, important land and forest governance reforms have taken place in many tropical countries, including the devolution of ownership rights over land and forests, decentralization that created mechanisms for forest dwellers to participate in decision making in lowest tiers of governments. These reforms have resulted in an intensive academic debate on governance and management of forests and how actors should be involved. An important but understudied element in this debate is the ways in which communities cope with new legislation and responsibilities. Property rights bestowed by the government leave many aspects undecided and require that local forest users devise principles of access and allocation and establish authority to control those processes. We studied 16 communities in the northern Bolivian Amazon to evaluate how forest communities develop and control local rules for resource access and use. We found that the first requirement to community rule design, enforcement, and effective forest management is the opportunity to, and equity of, access to forest resources among members. Under the newly imposed forestry regulations, communities took matters in their own hands and designed more specific rules, rights and obligations of how community members could and should use economically important resources. The cases suggest that communities hold and maintain capacity to prepare their own ownership arrangements and related rules, even if they are strongly conditioned by the regulatory reforms. Very specific local histories, that may differ from community to community, influence strongly how specific ideas are being shaped, which in northern Bolivia resulted in notable local differences. The results suggest that new regulatory regimes should create appropriate conditions for communities to define adequate or at least convenient forestry institutions that assure an acceptable level of collective coexistence according to each particular communal history.     

世界森林生态系统概评

世界森林生态系统包括热带、亚热带、温带森林,北方针叶林以及其他有林地。由于人类社会经济活动,森林生态系统遭受了规模巨大的损失,表现出非完整性特征,并使森林火灾发生的频数增加,强度加大。目前全球有60%多的森林面积受到人类经济活动的干扰和影响,工业化国家绝大部分的森林是处于“半自然”状态下,或转变为人工林,发展中国家森林覆盖率下降,从而改变了森林生态系统提供的商品和服务。     

The institutional drivers of sustainable landscapes: a case study of the ‘Mayan Zone’ in Quintana Roo, Mexico

Research on the dynamics of tropical forest land use and cover change (LUCC) has focused on the three scenarios: (1) deforestation/degradation; (2) settled, degraded areas in recovery, and (3) sparsely settled, expansive, intact forest. Through examination of a central Quintana Roo, Mexico case study we propose a fourth scenario of a ‘sustainable landscape’: an inhabited, productively used, forested landscape that nonetheless shows little change or net gains in forest cover over the last 25 years. We use Landsat images to demonstrate a low incidence of net deforestation, 0.01% for the 1984–2000 period, the lowest recorded deforestation rate for southeastern Mexico. Institutional innovations such as an agrarian reform process that established large common property forests for non-timber forest product extraction, and later innovations such as sustainable forest management institutions have driven the outcome of low net deforestation, added to multiple organizational processes that promote sustainable land use.     

Land use changes to cash crop plantations: crop types,multilevel determinants and policy implications

Cash crop plantation has recently become an expanding global phenomenon. Characterizing the dynamics of cash crop plantations and the corresponding determinants should provide critical references for land use policy. Using aerial photos and geographic information system, this paper investigated the trends of four types of cash crops (tea, fruit, mulberry and nursery) and their relations to other land use changes within Hangzhou region in subtropical China. Results showed that the total cash crop cultivated surface increased by 541.3 ha from 2004 to 2014. Most of the new tea and fruit plantations were established in places previously used as forest and woodland. Mulberry and nursery mainly expanded by replacing paddy, woodland and forest. By combining household survey, geospatial techniques and multilevel regression, multilevel determinants of cash cropping probability and cash crop expansion were quantified. At the parcel level, tea and fruit plantations inclined to occur on hilly land with gentle slope. Mulberry and nursery plantations were likely to be observed in flat areas with low elevation. Parcels covered by high quality soils and with convenient communications experienced greater cash cropping probability. At the household level, households constituted of female and old-aged labor or with low agricultural labor intensity demonstrated high probability of tea and mulberry plantations. Conversely, households constituted of middle-aged labor or with high agricultural labor intensity tended to grow more fruit and nursery. Besides, wealthier households were prone to establish fruit and nursery plantations but were reluctant to involve in tea and mulberry cropping. At the village level, population density was a significant determinant of cash cropping probability, but was an insignificant determinant of cash crop expansion. Greater occurrence of cash cropping was observed in villages with higher proportion of migrant labor and leasing land. Distance to county road and distance to provincial road were identified as negative determinants. Policy was evidenced to be of significant influence on cash cropping probability and cash crop expansion. We argue that a balance should be achieved between cash cropping promotion and natural resources protection in formulating the local land use policy.     

Intensification of cocoa agroforestry systems as a REDD+ strategy in Cameroon: hurdles,motivations, and challenges

Tree planting and the use of inputs within cocoa agroforestry systems are key intensification pathways for enhancing the contribution of these systems to REDD+. However, scholarship on the hurdles, motivations, and challenges pertaining to intensification of these systems remains surprisingly scanty. A questionnaire addressing these knowledge gaps was administered to 461 cocoa farmers randomly selected from 10 communities in the South Region of Cameroon. The lack of technical support was identified as one of the main obstacles to tree planting and the use of inputs. The least motivating factor behind tree planting and the use of inputs was inadequate technical assistance. Limited access to credit facilities was observed as of the most important challenges to tree planting and the use of inputs. Addressing the various hurdles and challenges and promoting the least motivation factor through proper incentive mechanisms could advance REDD+ since intensification pathways within these systems increase agricultural productivity thereby enabling farmers to stay on the same land. This results in less forest being cleared and allows for the recovery of forests degaraded for the creation of these systems. In closing, we proffer incentive mechansims for promoting intensification pathways within these cocoa agroforestry systems.     

The role of land use conversion in shaping the land cover of the Central American Dry Corridor

The Central American Dry Corridor (CADC) is a trans-border region characterized by climatic and ecological continuities. It is expected to experience rising aridity and severe hydro-climatic events due to climate change. Subsistence agriculture and other rural livelihoods to which land cover is central are widely practiced in this impoverished territory of approximately eleven million people.The CADC’s land cover was profiled to determine: a) how it differs from Non-CADC areas, and b) the role of land use in shaping these differences. Spatial autocorrelation analysis using satellite data showed that forest cover is a third less prevalent in the CADC than in the Non-CADC while the share of mosaic vegetation and mosaic cropland is nearly double. A naturally prevalent cover type in the CADC, tropical dry forest (TDF), has been largely eliminated.The significantly lesser proportion of forest and greater percentage of coverage consistent with agriculture and ranching implicate land use conversion, specifically deforestation for agricultural expansion and cattle ranching, in shaping CADC land coverage. The process began in the mid-1800s when small-scale agriculturalists migrated to the region followed by large-scale export crop and beef production, primarily for international markets. Deforestation peaked after WWII, concluding by the 1990s with the conversion of most woodlands. Similar patterns now threaten forests along the Caribbean coast.Traditional land use practices cannot sustain local communities or preserve the resource base, thereby contributing to rural outmigration. Adopting sustainable practices and promoting livelihoods strategies leading to forest regeneration will be fundamental for CC adaptation in the CADC.     

Understanding recurrent land use processes and long-term transitions in the dynamic south-central United States,c. 1800 to 2006

Forests have historically been under significant land use pressures that cause periods of degradation, clearance, and recovery. To understand these changes, studies are needed that place trends in a historical landscape context and also examine recent dynamics. Here, we use historical investigation (c. 1800) and an examination of land use and land cover change between 1973 and 2006 to establish a baseline trajectory of the forested system of the south-central United States (US) plains. The study culminates in a highly detailed accounting of the processes and causes of land change between 2001 and 2006. In the study region, the forest transitioned from early low-intensity use, to clearance for farming and timber, to widespread recovery from degradation beginning in the 1930s. By 1970, the region was transitioning from recovered woodlands to an intensive regime of recurrent timber harvest and replanting. The recurring cycle inherent in intensive silviculture has been the main cause of land change for the past several decades, accounting for more than 95% of the total extent of change between 2001 and 2006. The transition to forest recovery in the south-central US was an important historical occurrence. However, the dynamic post-transition landscape needs to be better understood.     

Greenhouse gas and groundwater recharge abatement benefits of tree crops in south-western Australian farming systems

The indirect benefits of a commercial tree crop for greenhouse gas and groundwater recharge abatement are analysed. Oil mallees are introduced into a whole-farm linear programming model as a source of income, an offset to greenhouse gas emissions from the mixed sheep and cropping enterprises and as a source of groundwater recharge abatement. The profitability of oil mallees is found to be very sensitive to the discount rate, yield and price assumptions and the relative profitability of other farm enterprises (especially the wool enterprise). Under standard assumptions where oil mallees are profitable, the trees significantly reduced greenhouse gas emissions and groundwater recharge and the farm remains profitable. If farm-level policies are introduced for greenhouse gas abatement, without tree crops or some other technological change, the current farming systems would fail and be replaced by alternative land uses.