Future tropical forest management: mitigation and adaptation to climate change

6.1 Reducing greenhouse gas emissions from tropical forests

As indicated previously, deforestation and degradation of tropical forests are significant contributors to GHG emissions and human-induced climate change. The Paris Agreement on climate change at COP21 was a major landmark in climate policy, providing a comprehensive and inclusive framework for action with ambitious long-term targets to avoid dangerous anthropogenic global warming. Forest-based measures to reduce GHG emissions such as reducing deforestation and increasing sequestration through better management of existing forests and restoring forests were a key element in the Agreement. If fully achieved, these could cut GHG emissions by almost a third (Seymour and Busch, 2016). Over 60 countries referred to REDD+ in their Intended Nationally Determined Contributions and, as part of the Lima Paris Action Agenda, heads of government from major forest countries and partners committed to action prior to the COP meeting to promote equitable rural development, reverse deforestation, and massively increase forest restoration.

Brazil and Norway renewed their US$1 billion partnership to reduce deforestation until 2020 and Germany, Norway, and the UK announced US$5 billion to support country-based REDD+ programs between 2015 and 2020. While the focus is on results-based payments, the prospects for a global market that involves the transfer of emission reduction credits from developing to developed countries are unclear. With tropical developing countries committing to NDCs, they may want to use forest-based emission reductions for their own targets. In the short term, finance for REDD+ or other forest- related emission reduction activities may mainly come through bilateral funds (like the agreements Norway has with Brazil and Indonesia) or multilateral funds such as the World Bank's Forest Carbon Partnership Facility or the Green Climate Fund, which recently committed US$500 million to purchase REDD+ emission reductions. Commitments to reduce emissions from international aviation may create a large new market for forest-based offsets (Hamrick and Gallant, 2018).

Addressing deforestation requires a strategic, integrated approach to agriculture, forestry, and other natural resource and economic development policies. The effects of deforestation can be reduced through the following actions: (1) effective land use planning that involves local people and industries to ensure that deforestation only occurs in areas where conservation and community values will not be unduly affected, (2) enforcement of laws and regulations that prevent forest conversion, (3) education measures to ensure that communities and companies understand the value of intact forests, (4) supporting sustainable forest management efforts that enable communities to reap financial benefits from forests, and (5) providing financial incentives to countries, industries, communities, or households to encourage forest conservation.

Public policies have had a significant impact by reducing deforestation rates in some tropical countries (Smith et al., 2014). However, while the contribution from deforestation is reducing, the contribution from degradation is increasing (Federici et al., 2015). The REDD+ mechanism under the United Nations Framework Convention on Climate Change (UNFCCC) is supporting improved policies and laws, increasing measurement, and monitoring capacity and fundsto countries or communitiesto reduce deforestation. Gumpenberger et al. (2010) concluded that the protection of forests under forest conservation programs (including REDD) could increase carbon uptake in many tropical countries, mainly due to C0₂ fertilization effects, even under changing climate conditions. However, others argue that mitigation benefits from deforestation reduction under REDD+ could be reversed due to increased fire events, and climate-induced feedbacks (Arcidiacono-Barsony et al., 2011).

Reduced impact logging (RIL) can potentially halve carbon emissions by reducing logging degradation in tropical forests (Ellis et al., 2019). However, it is likely to be necessary to move beyond RIL to substantially increase carbon storage by developing more sophisticated, planned forest management schemes with silvicultural treatments that ensure regeneration establishment, post establishment release, and extended rotations of new stands. Research on rainforest silviculture has also focused on more productive forests in higher rainfall areas in the wet and semievergreen tropics, with less in montane or seasonally dry forests where much of the degradation is occurring (Del Cid- Liccardi et al., 2012).

Agricultural companies play an increasingly important role as forest clearance for agriculture shifts from small-scale farmers to agribusinesses. Global demand for agricultural products will continue to rise with increasing human population, but technological improvements can increase food and fiber supplies through increasing productivity without increased deforestation (Richards et al., 2019). Many companies have committed to deforestation- free supply chains to reduce their effects on forests. As mentioned previously, signatories to the New York Declaration on Forests (UN, 2014) committed to halving the rate of loss of natural forests globally by 2020 and striving to end natural forest loss by 2030. This would be achieved through eliminating deforestation from producing key agricultural commodities, reducing deforestation derived from other economic sectors by 2020, and supporting alternatives to deforestation driven by basic needs.

Restrictions to agricultural expansion due to forest conservation, increased energy crop area, afforestation, and reforestation may increase costs of agricultural production and food prices (Smith et al., 2015). Trade liberalization can lead to lower costs of food, but also increases the pressure on land, especially on tropical forests (Schmitz et al., 2012). Trade restrictions and tariffs, such as those currently in place between the United States and China, may also exacerbate forest conversion (Fuchs et al., 2019).

6.2 Tropical forest management for adapting to climate change

Policy on tropical forests and global climate change has so far focused mostly on mitigation, with less emphasis on how management activities may help forest ecosystems adapt to this change (Keenan, 2015). With a certain degree of human-induced climate change locked in to the climate system, and likely future larger-scale changes, adaptation measures will be needed to maintain the productive capacity and resilience of tropical forests. Adaptation options can be anticipatory or reactive, and either planned or autonomous (Prowse and Scott, 2008). They can aim to build resistance to change (e.g. to protect rare, high-value species in a specific location, or a plantation forest that is close to rotation age), or to promote resilience to enable forests to respond to future change while maintaining or providing for the recovery of important ecological processes (Millar et al., 2007).

Climate change assessment and planning needs to shift from simply projecting impacts to evaluating adaptation options. For agriculture and land use in general, there has been a shift in thinking from designing prescriptive adaptation options to identifying management principles as a basis for generating locally specific options. These principles focus on system resilience, such as redundancy, flexibility, and cross-scale awareness. Adaptation options for forests often reflect what is considered currently to be good risk management practice (Innes et al„ 2009; Keenan and Nitschke, 2016). This approach is likely to be effective under moderate climate change (Dovers, 2009) but could limit planning for transformational changes (Smith et al., 2011). A longer-term view can provide pathways for adaptation options under more extreme levels of climate change as they emerge in the future (Barnett et al., 2014; Wise et al., 2014).

Adaptation decisions need to consider both the biophysical capacity of forests to respond to climate change and the vulnerability and adaptive capacity of the human societies that depend on forests (Keenan, 2015). Communities and livelihoods are exposed to multiple stressors, and climate risk management strategies need to consider the full set of hazards and risks and compounding socioeconomic stressors in an integrated way. Many consider that other pressures and threats to tropical forests are more pressing and immediate than the long-term implications of climate change. In a survey of tropical forest managers, Guariguata et al. (2012) found that respondents perceived that natural and planted forests are at risk from being affected by climate change. However, they were unsure of the value of investing in adaptation. Climate change ranked below other threats to forests such as commercial agriculture and unplanned logging. Long-term forest planning and management was not a key consideration given other major drivers of forest loss and degradation.

In a study of communities impacted by drought in the forest zone of Cameroon, Bele et al. (2013) identified adaptive strategies such as community- created firebreaks to protect their forests and farms from forest fires, the culture of maize and other vegetables in dried swamps, diversifying income activities or changing food regimes. However, these coping strategies were incommensurate with the rate and magnitude of change being experienced and, therefore, no longer seen as useful. Some adaptive actions, while effective, were resource-inefficient and potentially translated pressure from one sector to another or generated other secondary effects that made them undesirable.

The diversity of conditions in the tropics, the range of potential threats and impacts, and the diversity of human interactions with tropical forests means that adaptation options will need to vary according to location, climate, and the nature of future risks. Adaptation is a process best addressed at local levels, with organizations, communities, businesses, households, or individuals considering their future climate risks and the benefits and costs of different risk management options (Ciurean et al., 2013). This local action will still require coordination across jurisdictions and levels of government, particularly in information provision and management of cross-boundary issues, for example in flood risk, fire management, or species conservation.

Proposed measures to address climate change impacts on biodiversity conservation including addressing preexisting stressors on biodiversity, better preparing for the effects of major natural disturbances, significantly improving off-reserve conservation efforts (including fostering appropriate connectivity), and enhancing the existing reserve system by making it more comprehensive, adequate, and representative (Lindenmayer et al., 2010). For production forest managers, landowners, and producers, adaptation actions in forest management can be grouped into broader land management options, site- specific silvicultural practices, building social and community skills, and policy and planning options (Keenan, 2017).

However, the adaptation options decided on, and the weight adaptation given in decision-making, will in large part depend on cost. There is a risk that some longer-term adaptation options that may limit for instance storm, drought, or pest risks will be substituted by shorter-term or more limited measures (Andersson and Keskitalo, 2018). Adaptation policy or strategy decisions in forest will also be influenced by similar factors to those for other decisions. Adaptation options need to be framed in a way that actors in forestry see as relevant, the focus in the industry, and the nature of available options (Mackay et al., 2017). The nature of institutions, laws, and policies, land tenure, and forest ownership arrangements in different countries will impact on policy design for adaptation and on the willingness to implement options for longer- term adaptation (Keenan et al., 2019).

Intensively managed tree plantations are becoming the dominant source of industrial wood supply (Payn et al., 2015) and plantation area is increasing rapidly in the tropics. These plantations usually consist of a single exotic fast growing species, often using clonal production systems that, while highly productive, might expose the estate to more risks from increased disturbance (wind or fire), pests, or disease. The short rotations (5-10 years) used in these systems provide some capacity for more rapid adaptation, with options to change species or genotypes, or vary management in response to rapidly changing conditions. Increasing diversity in tropical plantations has been proposed as a management strategy for some time to increase resilience, enhance productivity, and provide for a wider range of values (Keenan et al., 1999). Converting monospecific plantations to mixed stands may improve stand stability and reduce increasing abiotic and biotic disturbances due to climate change. However, as indicated earlier, little is known about the extent to which tropical tree species or tropical tree communities can resist increasing disturbances in the shortterm, such as water limitations due to increasing dry season intensity or length (Kunert and Cardenas, 2015).

New types of knowledge partnerships can support improved interaction between researchers and policy makers and better decision-making (Preston et al„ 2015).The USDA Forest Service has actively promoted these partnerships (Joyce et al., 2009; Nagel et al., 2017), and the experience in the tropical El Yunque National Forest (EYNF) in Puerto Rico suggests that managers are better positioned to address increasing uncertainty and surprise at multiple scales. However, ongoing commitment is required to the resources necessary for implementing adaptive, collaborative forest management, and to provide space and flexibility required to make swift adjustments in response to rapid or unexpected system changes (McGinley, 2017).

Adaptation is a continuous process of 'adapting well' to ongoing change (Tompkins et al., 2010). This requires organizational learning based on experience, new knowledge, and a comprehensive analysis of future options. This can take place through 'learning by doing' or through a process of search and planned modification of routines (Berkhout et al., 2006). However, interpreting climate signals is not easy for organizations, the evidence of change is ambiguous, and the stimuli are not often experienced directly within the organization. For example, many forest managers in Australia felt little need to change practices to adapt to climate change, given both weak policy signals and limited perceived immediate evidence of increasing climate impacts (Cockfield et al., 2011 ).To explain and predict adaptation to climate change, the combination of personal experience and beliefs must be considered (Blennow, 2012). Adaptation will be as much focused on what we are prepared to lose, and preparing as a society to address that (Barnett et al., 2016) as on what we might want to keep in a future climate.

Adaptation measures may help maintain the mitigation potential of tropical forests. For example, projects that prevent fires and restore degraded forest ecosystems also prevent release of GHGs and enhance carbon stocks. Mitigation and adaptation benefits can also contribute to sustainable development considerations (Louman et al., 2019). Broadly, however, there has been little integration to date of mitigation and adaptation objectives in climate policy. For example, there is little connection between policies supporting REDD+ initiatives and adaptation. Integrating adaptation into REDD+ can advance climate change mitigation goals and objectives for sustainable forest management (Long, 2013). Kant and Wu (2012) considered that adaptation actions in tropical forests (protection against fire and disease, ensuring adequate regeneration and protecting against coastal impacts and desertification) will improve future forest resilience and have significant climate change mitigation value. Discourses on the future of forests in the Congo Basin focus on the opportunities for forests under the REDD+ mechanism, but also recognize the need for the forests and dependent societies and sectors to adapt to potential climate risks. Different agents frame climate change adaptation and mitigation policies in the region in different ways: mitigation only, adaptation only, or an integrated approach. These framings result in differing views on costs and benefits, scale of operation, effectiveness, financial resources, and implementation mechanisms. Overall, the mitigation discourse seems to be stronger than the adaptation discourse (Somorin et al., 2012).

Adaptation is about making good decisions for the future, considering the implications of climatic and other environmental and social change. Tropical forest management will have to adaptto a changing and highly variable climate to effectively provide a role in mitigation, deliver associated ecosystem services, and provide benefits in poverty reduction (Eliasch, 2008; Keenan, 2015). In achieving this, the roles and responsibilities of different levels of government, the private sector, and different parts of the community are still being defined.

Integrated measures might support improved forest and biodiversity conservation, and mixed-species forestry-based afforestation may help maintain or enhance carbon stocks, while also providing adaptation options to enhance resilience of forest ecosystems to climate change (Smith et al., 2015). Integrated approaches between forestry and agriculture might also support both climate mitigation and adaptation policy objectives. Enhancement of soil carbon stocks and integrating trees into agricultural systems have the potential to increase productivity, diversity, and resilience to climate change (Verchot et al., 2007; Smith and Olesen, 2010). It is increasingly recognized that reducing emissions and increasing carbon stocks needs a landscape approach. At the 2018 Global Landscapes Forum, held prior to the UNFCCC COP, participants emphasized the need to engage multiple stakeholders from across different tenures and land uses and consider the multiple benefits and services that people want from the landscapes in developing climate solutions.