Comercialização internacional de Créditos de Carbono : regulamentos e problemáticas

Orientador : Prof. Dr. Paulo de Tarso Pires de LaraCo-orientadora : Me. Jaqueline de Paula HeimannMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências Agrárias. Curso de Especialização em Projetos Sustentáveis, Mudanças Climáticas e Mercado de CarbonoInclui referênciasResumo : O Protocolo de Quioto foi o grande propulsor global de projetos ambientais. Ao estabelecer metas de redução de emissões de GEEs aos países desenvolvidos, este Tratado Internacional iniciou um novo ciclo de desenvolvimento, estimulando a adoção de métodos sustentáveis aliados ao crescimento econômico. Para atingir esse objetivo, criou diversos mecanismos, dentre os quais o MDL – Mecanismo de Desenvolvimento Limpo, que se destacou no cenário nacional. Tal mecanismo estabeleceu uma nova forma de compensação por países desenvolvidos, através da compra de certificados de redução de carbono, gerados por projetos sustentáveis implantados nos países em desenvolvimento. Com este mecanismo, surgiu um novo mercado econômico: O Mercado de Créditos de Carbono. Tais Créditos já têm sido internacionalmente transacionados e ganharam, com o Acordo de Paris, ratificado também pelo Brasil em 2016, mais um incentivo. Considerando a complexidade trazida pelas transações internacionais, ao envolverem dois sistemas jurídicos distintos, e a abstração de seu objeto de negociação, este trabalho teve por objetivo abordar os elementos jurídicos da omercialização internacional das Reduções Certificadas de Carbono e suas problemáticas, com ênfase nas discussões acerca da natureza jurídica dos Créditos de Carbono e dos diferentes instrumentos jurídicos a serem utilizados em sua comercialização. Esta analise deixou evidente a necessidade de complementar da legislação vigente para que um mercado de carbono nacional e internacional seja (re)estruturado, oferecendo uma base sólida para a comercialização dos Créditos de Carbono. Foi, por fim, sugerido o enquadramento legal dos Créditos de Carbono como Valores Mobiliários a ser negociado na Bolsa de Valores, o que garantiria confiabilidade e segurança jurídica aos investidores estrangeiros, além de possibilizar o desenvolvimento de um plano tributário que incentive este mercado

Planejamento florestal otimizado considerando áreas mínimas e máximas operacionais de colheita

Orientador : Prof. Dr. Julio Eduardo ArceCo-orientadores : Prof. Dr. Arinei Carlos Lindbeck da SilvaDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 27/08/2014Inclui referências ao final de cada capítuloÁrea de concentração : Manejo florestalResumo: Questões espaciais relacionadas ao padrão resultante das atividades de colheita florestal vem se tornando um importante componente do planejamento florestal. Geralmente estas questões são incluídas em cenários de planejamento através de consideração de relações de vizinhança entre talhões. A maior parte da literatura a respeito da inclusão de questões espaciais no planejamento se refere às restrições para limitar a área máxima de colheita. Restrições de área máxima de colheita são vistas como uma maneira de beneficiar a fauna e reduzir impactos ao solo florestal causado pelo maquinário. Este problema de planejamento é tratado no quarto capítulo deste trabalho, que tem por objetivo a incorporação de restrições de área máxima utilizando as abordagens URM e ARM a um cenário de planejamento florestal otimizado de uma floresta composta por 236 talhões do gênero Pinus e Eucalyptus. Inicialmente propostas para beneficiar a fauna, a fragmentação causada por restrições que limitam a área máxima de colheita podem ter um efeito negativo sobre a mesma, reduzindo a área de habitat interior. Adicionalmente, a fragmentação das áreas de colheita causa o aumento no custo das operações envolvidas nesta atividade. Neste contexto, o objetivo do capítulo 5 foi o de introduzir restrições para a formação de blocos de colheita respeitando uma área mínima determinada, avaliando os efeitos desta restrição sobre a configuração espacial dos talhões e receita advinda da floresta. No sexto capítulo, ainda sobre a ótica da formação de blocos de colheita, são estudadas alternativas para promover a agregação das áreas de colheita, através da maximização das adjacências entre talhões em um mesmo ano do horizonte de planejamento. Foram avaliados para tal fim modelos de Programação Linear Inteira Mista e modelos de Goal Programming. No último capítulo, ainda sobre a ótica da agregação das áreas de colheita, se buscou a conectividade dos talhões a serem colhidos em um mesmo ano do horizonte de planejamento. Para tal, foi aplicado um modelo baseado no problema da arborescência mínima. Os efeitos da inclusão de critérios para a formação de blocos de colheita foram avaliados com base no agendamento espacial da colheita e na alteração do VPL gerado pela floresta. Palavras chave: planejamento espacial, otimização, agregação da colheita florestalAbstract: Spatial relationships related to the pattern resulting from forest harvest activities have become an important component of forest planning. Usually, these spatial relationships are included in forest planning scenarios through the consideration of neighborhood relationships between the stands. The major part of literature regarding the consideration of spatial questions is related to limiting the maximum harvest area. Limiting the maximum harvest area is viewed as a way to benefit wildlife and reduce the impacts on the soil caused by the machinery. This planning problem is addressed in the fourth chapter of this study, which has the objective of including maximum area constraints applying URM and ARM approaches in an optimized forest planning model of a forest composed by 236 Pinus and Eucalyptus stands. Initially proposed to benefit wildlife, the fragmentation caused by the constraints that limit the maximum harvest area can have a negative impact on the wildlife, reducing the interior habitats. Additionally, the fragmentation of harvest area causes an increase in the cost of the harvesting operations. In this context, the objective of chapter 5 was to introduce constraints for blocking harvesting activities, respecting a minimum area and evaluate its effect on the spatial configuration of stands scheduled for harvesting and on the receipt coming from the forest. In the sixth chapter, still addressing the clustering of harvest activities, approaches to promote the aggregation of stands are studied. This is addressed through the maximization of adjacencies between stands in a same year of the planning horizon. For performing this analyses models of Mixed Integer Linear Programming and Goal Programming were tested. In the last chapter, still aiming for aggregating the harvesting areas, it was sought to obtain the connectivity of stands to be harvest in the same year of the planning horizon. To achieve the connectivity, a model based in the minimum spanning tree problem was applied. The effects of inclusion of the clustering criteria was evaluated based on the spatial distribution of stands scheduled for harvesting and in the variation of the NVP generated by the forest. Key words: spatial planning; optimization; clustering forest harvestin

Avaliação do tamanho de parcelas e intensidades de amostragem para a estimativa de estoque e estrutura horizontal em um fragmento de Floresta Ombrófila Mista

Orientador : Prof. Dr. Sebastião do Amaral MachadoCoorientadores: Prof. Dr. Afonso Figueiredo Filho, Prof. Dr. Sylvio Péllico NetoÁrea de concentração: Manejo florestalDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 30/05/2011Bibliografia: fls. 93-98O emprego da técnica de amostragem em inventários florestais se ocupa em gerar informações para o conhecimento dos resursos naturais de forma a subsidiar a tomada de decisões dos gestores, tanto na esfera pública quanto privada. Tendo em vista a importância da informação gerada pela aplicação da técnica de amostragem, esta pesquisa foi concebida com o objetivo de avaliar a influência de diferentes tamanhos de parcelas e intensidades amostrais na estimativa do estoque e parâmetros fitossociológicos. A área estudada, corresponde a um remanescente de Floresta Ombrófila Mista de 15,2 ha, localizado no Campus III – Jardim Botânico da Universidade Federal do Paraná. Para a realização da pesquisa, a abordagem metodológica adotada consistiu, inicialmente, no georreferenciamento da área de estudo e na realização do censo de todas as árvores com DAP superior a 10 cm. Todos os dados obtidos nessa etapa foram incluídos em um geodatabase. Após essa etapa foram definidos 20 variações de amostragem de área fixa com objetivo de realizar as simulações de inventário, considerando a combinação dos diferentes tamanhos de parcelas definidos (200m², 400m², 500m² e 1000m²) com as diferentes intensidades de amostragem (2%, 5%, 10% e 15%). Os resultados obtidos revelaram que existem nesta área 121 espécies florestais, distribuídas em 47 famílias e 80 gêneros, sendo que a família predominante em termos de diversidade de espécies é Myrtaceae. A área basal média por hectare para a floresta é de 22,05m²/ha e o número médio de árvores é de 601N/ha. Ao comparar os resultados obtidos pela enumeração completa, com os obtidos pelas simulações de amostragem foi possível observar que, ao considerar a floresta como um todo, os resultados gerados pela técnica de amostragem são bastante confiáveis. Entretanto, ao avaliar o resultado em nível de espécie, observou-se que esses apresentam um viés acentuado em relação ao valor paramétrico. De modo geral, o aumento da intensidade amostral apresentou estreita relação com a melhoria das estimativas por espécie. No entanto, verificou-se que ao utilizar parcelas de 200m² o coeficiente de variação, para a variável de interesse apresenta valor mais alto, ao contrário do que ocorre em parcelas de tamanhos maiores. Parcelas de 1000m² tendem a captar de forma mais precisa a variação da distribuição espacial da variável de interesse, produzindo resultados mais confiáveis do que ao utilizar parcelas de 200m², sob uma mesma intensidade de amostragem. Além disso, para a estimativa do valor de cobertura em nível de espécie, parcelas de 1000m² demonstraram ser mais precisas em detrimento das de menor tamanho. Os resultados obtidos corroboram a hipótese de que para a estimativa do estoque e de índices fitossociológicos, parcelas maiores apresentam um melhor desempenho, principalmente para spécies com grande representatividade dentro da floresta. A única situação onde a utilização de parcelas menores pode apresentar melhor desempenho é para os estimadores de espécies raras (menos de um indivíduo por hectare). Com base no exposto, é recomendável que, para a estimativa do estoque e de índices fitossociológicos, sejam utilizadas parcelas de pelo menos 1000m² e intensidade amostral tão grande quanto os recursos de tempo e dinheiro disponíveis permitirem. Palavras-chave: Inventário florestal, método de amostragem, precisão, fitossociologia, distribuição espacial, distribuição diamétrica.The use of sampling techniques in forest inventories generates information regarding natural resources, contributing to the decision making of managers in the public and private spheres. Considering the importance of information generated by the use of sampling techniques, the objective of this study was to assess the influence of different plot sizes and sampling intensities to estimate the stock and phytosociological parameters. The studied area corresponds to a Mixed Omb ophylous Forest remnant, of 15.2 ha, located in the Campus III – Jardim Botânico, which belongs to the Federal University of Paraná. The methodological approach of this study consisted initially of the georeferencing of the study area and a census, of all trees with breast height diameter (DBH) greater than 10 cm. The collected data were included in a geodatabase. After this step 20 sampling variations of fixed area were defined to perform the inventory simulations. This process considered the combination of different plot sizes (200sq.m, 400sq.m, 500sq.m and 1000sq.m) with different sampling intensities (2%, 5%, 10% and 15%). The results indicated that the area contains 121 tree species, distributed in 47 families and 80 genera. In terms of species diversity the predominant family is Myrtaceae. The average forest basal area is 22.05sq.m/ha and the average number of trees is 601N/ha. The comparison of the census results with those obtained through the sampling simulations indicated that the sampling technique is quite reliable when the forest is considered as a whole. However, when the results are evaluated at the species level, they show a strong deviation in relation to the parametric value. In general an increase in sampling intensity provided an improvement of the estimations at species level. However it was observed that for plots of 200sq.m the variable of interest presented a highest value. The opposite was observed in larger plots. Plots of 1000sq.m tend to capture more accurately the variation of the spatial distribution of the variable of interest. Thus the obtained results are more eliable than those from 200sq.m plots with the same sampling intensity. In addition, plots of 1000sq.m were more precise for the estimation of the species cover index. The results corroborate with the hypothesis that to estimate the stock of a forest and phytosociological indexes larger plots present a better performance, particularly for species of great representativity in the forest. The only situation in which smaller plots might perform better is to estimate indexes related to rare species (less than one individual per hectare). Based on this it is recommended that for estimations regarding stock and phytosociological indexes, plots of at least 1000sq.m should be used and a sampling intensity as high as time and financial resources allow

Realizing Mitigation Efficiency of European Commercial Forests by Climate Smart Forestry

European temperate and boreal forests sequester up to 12% of Europe's annual carbon emissions. Forest carbon density can be manipulated through management to maximize its climate mitigation potential, and fast-growing tree species may contribute the most to Climate Smart Forestry (CSF) compared to slow-growing hardwoods. This type of CSF takes into account not only forest resource potentials in sequestering carbon, but also the economic impact of regional forest products and discounts both variables over time. We used the process-based forest model 4 C to simulate European commercial forests' growth conditions and coupled it with an optimization algorithm to simulate the implementation of CSF for 18 European countries encompassing 68.3 million ha of forest (42.4% of total EU-28 forest area). We found a European CSF policy that could sequester 7.3-11.1 billion tons of carbon, projected to be worth 103 to 141 billion euros in the 21st century. An efficient CSF policy would allocate carbon sequestration to European countries with a lower wood price, lower labor costs, high harvest costs, or a mixture thereof to increase its economic efficiency. This policy prioritized the allocation of mitigation efforts to northern, eastern and central European countries and favored fast growing conifers Picea abies and Pinus sylvestris to broadleaves Fagus sylvatica and Quercus species

Food systems transformation in Indonesia: Results on baseline and stylized scenarios from GLOBIOM

As part of an effort to inform food system transformation in Indonesia and build on analytical and modelling work by BAPPENAS, FAO and others, this report contains the model description, business as usual trajectory and stylized scenarios coming from the GLOBIOM model. The report takes a food system approach where stylized scenarios follow three main policy levers, namely the healthy diets, socio-economic sustainability of agri-food supply and environmental sustainability: 1. Healthy diets – In line with the RPJMN goal of improving the quality of Indonesian diets, this axis reflects a transition towards healthier diets in Indonesia through reducing food insecurity and increasing the consumption of products that are key to a healthy diet. 2. Socioeconomic sustainability of agri-food supply – In line with the RPJMN goal of increasing food availability, this axis reflects a transition towards increased and more sustainable agricultural production that meets the needs of a growing population by increasing local agricultural production and increasing the share of domestic production in national consumption. 3. Environmental sustainability – In line with the RPJMN goals of strengthening the environment, improving climate resilience, and promoting low carbon development, this axis reflects a transition towards environmental sustainability, achieved through policies that constrain land use and reduce food loss and waste, thereby reducing GHG emissions, reducing deforestation and preserving biodiversity. One or two policy interventions are designed along each of the axes and compared in terms of the main flagship indicators: percentage undernourished, share of food calories produced domestically (%), total value added from agriculture, forest cover and GHG emissions. The scenarios modeled are: (1) ‘POU’: A target to increase food consumption towards reducing undernourishment to 2.5% by 2030 combined with a transition towards healthier diets; (2) ‘INT’: An intensification scenario leading to increased productivity on cropland through better cultivars and an increased use of water and fertilizers; (3) ‘GHG050’: A carbon tax of 50 USD/ton on agriculture and land use emissions; (4) ‘CONS’: an extension of the moratorium policy on primary forests and peatland conversion. In addition, different combinations of the individual policy interventions are made: a target on undernourishment combined with a moratorium on primary forests (CONS_POU), a moratorium on primary forests combined with agricultural intensification (CONS_INT), a target on undernourishment combined with agricultural intensification (INT_POU), and a combined moratorium on primary forests, target on undernourishment and agricultural intensification scenario (CONS_INT_POU). Model We use the Global Biosphere Management Model (GLOBIOM, Havlík et al. 2014), developed at the International Institute for Applied Systems Analysis (IIASA), to understand the effects of policy interventions on the three axes. GLOBIOM provides a national and sub-national level picture of food system performance within the agriculture and forestry sector in Indonesia, identifying and analysing synergies and trade-offs associated with policy interventions over the medium to long term, in this case 2030-2045. The model has been updated and refined using best available data and tailored to the context of Indonesia. A consistent land use-land cover map has been built using the best land cover map available, agricultural statistics and other available spatially explicit information on land use. The list of crops has been extended compared to the standard version of GLOBIOM to better represent the land use dynamics and demands for the main commodities in international markets. A comparison of the most important agricultural and land use items and indicators shows that GLOBIOM follows both the trend and absolute changes of the land use, land use dynamics, GHG emissions, production, consumption, and trade over the historical reference period of 2000-2020 well. Business as usual results GLOBIOM’s business as usual trajectory show that, due to the foreseen growth in GDP, production and value added, the percentage of undernourished decreases steadily over the time horizon, from 9% in 2020 to 5.7% in 2030 and 1.4% in 2045 under a no intervention scenario. Agricultural yields and value added measured in real terms continue to increase over the time horizon, by 13.8% in 2030 and 42% in 2045 compared to the 2020 value added. This is a lot smaller than the relative increase in real value added of 118% that GLOBIOM-Indonesia simulated over the 2000-2020 period. Regarding the flagship indicators for the environment, emissions show a decrease compared to 2020, by 17% in 2030 and by 10% in 2045. This decrease in emissions is largely due to the sharp decrease in emissions from land cover change, mostly resulting from reduced deforestation and from the reduced draining of peatlands for agricultural conversion. Primary forests decrease by 2.4% in 2030 and 3.6% in 2045 compared to the 2020. Natural land decreases by 5.8% in 2030 and 17.4% in 2045. The land from these land covers shifts to agriculture, livestock and forestry production: plantation oil palm (+6.7% in 2030 and +18% in 2045), forest plantations (+9.5% in 2030 and +25.5% in 2045), cropland (+2.4% in 2030 and +10.9% in 2045) and a small increase in grassland for livestock production (+1.1% in 2030 and +7.6% in 2045). Scenario results Based on the stylized scenarios and their comparison regarding the main flagship indicators and the three axes, the following conclusions and policy recommendations can be drawn: In the short term, to reach the goal of lower undernourishment and promoting healthier diets, it is particularly important to target and implement policy measures that directly impact consumers. Targeting consumers directly can lead to a reduction in the percentage of undernourished from 5.7% under the business as usual trajectory to 2.8% by 2030. Focusing on agricultural producers through the enhancement of yields will only lead to a reduction in the percentage undernourished to 5.3% by 2030. Intensification measures may not be effective in reducing undernourishment and promoting healthier food choices, as the increased production is partly directed towards cash crops and exports . Under the intensification scenario, production increases are concentrated in coffee and soy. Under the reduction in undernourishment scenario, production increases are observed primarily for rice, soy and sweet potatoes, crops that directly benefit consumption. Therefore, well-targeted policies towards not only reducing undernourishment but also improving diets will lead to more calorie and nutrient rich consumption patterns compared to an intensification scenario where the focus is purely on increasing agricultural production. Scenarios focused solely on the environment result in slight increases in the percentage of undernourished individuals, especially in the longer term. This is because environmental policies that limit land cover conversion or put a price on emissions from agriculture and land use activities reduce the amount of productive land available for conversion to cropland and increase production costs. Regarding the socio-economic sustainability of the agri-food system, we find that different crops will benefit from either agricultural intensification or support to consumers. Cash crops like coffee and crops used to feed livestock such as soybeans will gain in terms of value added, by respectively 59.4% and 57.4% by 2030 under an intensification scenario. On the other hand, root crops like cassava and sweet potatoes, which are healthy staple foods, will gain in value added, by respectively 25.5% and 18.4% by 2030 under a scenario with higher demand for these types of crops (POU). Under a combined scenario with both POU and intensification, both cash crops and root crops will gain in value added. At the same time, food prices go down in the INT_POU scenario, leading to cost savings for the government in case of food subsidies to meet the targeted reduction in undernourishment. Regarding environmental sustainability, a scenario focusing only on a decrease in undernourishment leads to an increase in the cropland extent and in emissions. Cropland expansion is driven by the additional demand for certain crops (+0.5mln ha compared to the base in 2030 and +0.49mln ha compared to the base by 2045). If primary forests are subject to a moratorium, other potentially biodiverse-rich land covers, like natural lands are likely to be converted more. Combining scenarios can mitigate negative emissions effects compared to a business-as-usual scenario, but may not achieve individual goals (e.g. no reduced deforestation under CONS-INT-POU). In both the short and long term, a conservation scenario is the most effective in "saving" primary forests (+1.9% or nearly 1 million hectares (0.97) by 2030 and +1.8% or 1.2 million ha by 2045) compared to a carbon tax (+0.3% or 147,000 hectares by 2030 or +1.4% or 665 thousand ha by 2045). However, a conservation scenario also leads to a reduction in natural land (-0.6% or 146,000 hectares), which is not covered by the moratorium. A conservation and intensification scenario leads to the largest gains in primary forests (+2.3% or 1.2 million hectares by 2030 and up to 2 million ha by 2045) and natural land (+1.1% or 276,000 hectares by 2030 or 786 thousand ha by 2045). When also combining these two objectives with a target on reducing undernourishment, it becomes possible to reduce emissions, particularly those caused by changes in land cover, without increasing the percentage of undernourished people. The analysis of policy interventions and its outcomes primarily focuses on the national level. However, implementing these interventions across Indonesia, being an archipelago, could lead to increased transaction costs, such as higher food distribution expenses. Currently, most of the food production occurs in Java. Initial findings from GLOBIOM suggest that targeting these food producing hotspots can yield quick wins in terms of e.g. food production and food availability. Nonetheless, regions outside of Java have the highest rates of undernourishment, indicating the need for further research to explore regional variations in meeting policy objectives

Managing Forests for Biodiversity Conservation and Climate Change Mitigation

We include biodiversity impacts in forest management decision making by incorporating the countryside species area relationship model into the partial equilibrium model GLOBIOM-Forest. We tested three forest management intensities (low, medium, and high) and limited biodiversity loss via an additional constraint on regional species loss. We analyzed two scenarios for climate change mitigation. RCP1.9, the higher mitigation scenario, has more biodiversity loss than the reference RCP7.0, suggesting a trade-off between climate change mitigation, with increased bioenergy use, and biodiversity conservation in forests. This trade-off can be alleviated with biodiversity-conscious forest management by (1) shifting biomass production destined to bioenergy from forests to energy crops, (2) increasing areas under unmanaged secondary forest, (3) reducing forest management intensity, and (4) reallocating biomass production between and within regions. With these mechanisms, it is possible to reduce potential global biodiversity loss by 10% with minor changes in economic outcomes. The global aggregated reduction in biodiversity impacts does not imply that biodiversity impacts are reduced in each ecoregion. We exemplify how to connect an ecologic and an economic model to identify trade-offs, challenges, and possibilities for improved decisions. We acknowledge the limitations of this approach, especially of measuring and projecting biodiversity loss

Forest carbon allocation modelling under climate change

Peer reviewe

Modelling the effects of climate and management on the distribution of deadwood in European forests

Deadwood is a key old-growth element in European forests and a cornerstone of biodiversity conservation practices in the region, recognized as an important indicator of sustainable forest management. Despite its importance as a legacy element for biodiversity, uncertainties remain on the drivers of deadwood potentials, its spatial distribution in European forests and how it may change in the future due to management and climate change. To fill this gap, we combined a comprehensive deadwood dataset to fit a machine learning and a Bayesian hurdle-lognormal model against multiple environmental and socio-economic predictors. We deployed the models on the gridded predictors to forecast changes in deadwood volumes in Europe under alternative climate (RCP4.5 and RCP8.5) and management scenarios (biodiversity-oriented and production-oriented strategies). Our results show deadwood hotspots in montane forests of central Europe and unmanaged forests in Scandinavia. Future climate conditions may reduce deadwood potentials up to 13% under a mid-century climate, with regional losses amounting to up to 22% in Southern Europe. Nevertheless, changes in management towards more biodiversity-oriented strategies, including an increase in the share of mixed forests and extended rotation lengths, may mitigate this loss to a 4% reduction in deadwood potentials. We conclude that adaptive management can promote deadwood under changing environmental conditions and thereby support habitat maintenance and forest multifunctionality

Forest carbon allocation modelling under climate change

Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in dynamic vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is implemented in 31 dynamic vegetation models to identify the main gaps compared to our theoretical and empirical understanding of carbon allocation. We found that a hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in examined models. The analysis revealed that although the number of carbon allocation studies over the last 10 years has substantially increased, some background processes are still insufficiently understood, and some issues in models are frequently oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilisation of non-structural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge to mechanistic description of carbon allocation in models that would integrate the impact of environmental conditions, disturbances, and seasonal variation in carbon allocation, or (iii) to improve more simplistic models by accounting for the impact of crucial factors affecting carbon allocation in particular environment

Forest carbon allocation modelling under climate change

Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is currently implemented in 31 contrasting models to identify the main gaps compared with our theoretical and empirical understanding of carbon allocation. A hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in the examined models, while physiologically more sophisticated approaches were used less often than empirical ones. The analysis revealed that, although the number of carbon allocation studies over the past 10 years has substantially increased, some background processes are still insufficiently understood and some issues in models are frequently poorly represented, oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilization of nonstructural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge of carbon allocation into defence, regeneration and improved resource uptake in order to better account for changing environmental conditions. © The Author(s) 2019. Published by Oxford University Press