Although deforestation rates in the Brazilian Amazon are well known, the extent of the area affected by forest degradation is a notable data gap, with implications for conservation biology, carbon cycle science, and international policy. We generated a long-term spatially quantified assessment of forest degradation for the entire Brazilian Amazon from 1992 to 2014. We measured and mapped the full range of activities that degrade forests and evaluated the relationship with deforestation. From 1992 to 2014, the total area of degraded forest was 337,427 square kilometers (km2), compared with 308,311 km2 that were deforested. Forest degradation is a separate and increasing form of forest disturbance, and the area affected is now greater than that due to deforestation.

https://science.sciencemag.org/content/sci/369/6509/1378.full.pdf

Long-term forest degradation surpasses deforestation in the Brazilian Amazon

Uncovering the spatial variability of recent deforestation drivers in the Brazilian Cerrado.

Increasing trend of native forests conversion into farmlands can adversely influence the soil quality. Such impacts on soil attribute must be studied in more details in order to protect or improve the present status of soil quality. Consequently, a large-scale study was conducted to investigate the impacts of deforestation on soil quality indicators. For this purpose, two neighboring land uses of dry farming, which have been converted from sparse forest, and a sparse forest were selected. Topsoil samples (0–15 and 15–60 cm) were collected from three sites of each land use and their designated physical and chemical properties were analyzed with standard methods. Analyzing the obtained data revealed that deforestation and, therefore, dry farming significantly increases soil pH, electrical conductivity (EC), bulk density (BD) and soil erodibility factor (K-factor) but tend to reduce SOC, total porosity (TP), saturated hydraulic conductivity (Kₛ), mean weight aggregate diameter (MWD), and geometric mean aggregate diameter (GMD). Furthermore, aggregates with sizes ≥2 mm were more prevalent in the sparse forest soils, while the dry farming soils consisted of more aggregates with sizes <2 mm. In both studied land uses and among all examined soil properties, only calcium carbonate equivalent (CCE), SOC and Kₛ at 0–15 cm depth substantially differ from those of 15–60 cm depth. Our results further indicated that SOC content of all primary particles has reduced at depth of 0−60 cm as a result of 60 years dry farming. Among the primary particles, the OC associated with sand including particulate organic carbon (POC) had the largest value in both land uses. Long-term cultivation led to reduce OC in macro-aggregates and a surge in OC in micro-aggregates, demonstrating aggregate hierarchy. Our overall observations show that forest clearance and subsequent cultivation practice, due to land degradation, has a significant negative impact on soil quality index, as such, a drop of 44.5 % of SQI was occurred.

Deforestation and cultivation of sparse forest impacts on soil quality (case study: West Iran, Baneh)

Silviculture derives from the word Silvis. Silvics is the study of the life history and general characteristics of forest trees and crops, with particular reference to environmental factors, as the boisic for the practice of Silviculture.
Silviculture has even variously defined as:
1.	Dand Smith (1962) the art of producing and tending, a forest, the application of the knowledge of Silvics in the treatment of a forest, the theory and practice of controlling forest establishments, composition and growth. 
2.	It is also defined as the art and science of cultivating forest crops or that branch of forestry which deals with the establishment, development care and regeneration of stands. 
The subject of Silvicultural practice consists of the various treatments of forest stands that may be applied to maintain and enhance their productivity. The duties of the forester with respect to Silviculture are to analyze the natural and economic factors of significance on each stand under his care and to derive and apply treatment most appropriate to the objective of management.
Silviculture occupies a position in forestry that is comparable or analogous to that of agronomy in agriculture. This is because it is concerned with the technical details of crop production. It is an applied science that rest ultimately upon this more fundamental natural and social sciences.

Principles of silviculture

In Amazonian Ecuador, land-use change from tropical rainforest to different productive purposes is leading to irreversible situations from an environmental perspective. The objective of this paper was to highlight the significance of the biological components in the soils in Amazonian Ecuador, and the importance of considering biological soil quality indexes when assessing environmental impacts in the soils of tropical Pan-Amazonian areas. Since the literature on the subject is dispersed and inaccessible, a bibliographic review was conducted, with the aim of compiling protocols and proposals for practical utilization. We compiled tables, including specific indicators from the biological point of view. We present the available methods for assessing the sustainability of Amazonian territories through the analysis of soil quality. Our contribution facilitates an edaphic perspective to be taken into account in decision-making processes for sustainable territorial development.

A Framework to Incorporate Biological Soil Quality Indicators into Assessing the Sustainability of Territories in the Ecuadorian Amazon

Soil quality index of an Oxisol under different land uses in the Brazilian savannah

A maior parte do desmatamento de vegetacao nativa na regiao MATOPIBA (MAranhao, TOcantins, Piaui e BAhia) esta relacionada a expansao das atividades de producao de commodities agricola. O monitoramento do desmatamento com o uso de dados de sensoriamento remoto e tecnicas de geoprocessamento, associados ao desenvolvimento de modelagem espacialmente explicita podem contribuir para melhor compreensao das variaveis relacionadas ao desmatamento, permitindo tambem a simulacao de provaveis trajetorias futuras deste fenomeno. Na presente pesquisa, foram construidos e simulados tres cenarios (tendencial, otimista e pessimista) de desmatamento para a regiao MATOPIBA entre 2011 e 2050 com base no desmatamento observado em 2002, 2008 e 2010. Os resultados dos cenarios simulados indicam um aumento de 10,3, 15,3 e 15,9 milhoes de hectares de desmatamento de vegetacao nativa entre 2011 e 2050 na area de estudo assumindo os cenarios otimista, tendencial e pessimista, respectivamente. Isto aumentaria o desmatamento em 55%, 82% e 85% (cenarios otimista, tendencial e pessimista, respectivamente) em relacao ao total observado de areas desmatadas ate 2010. Os resultados desta pesquisa podem contribuir com os gestores e tomadores de decisao para a definicao de estrategias para reduzir o desmatamento e para melhorar o desenvolvimento sustentado na regiao do MATOPIBA.Palavra-chave: Regiao do MATOPIBA, modelagem espacial, cenarios de desmatamento. DEFORESTATION MODELING IN THE MATOPIBA REGION ABSTRACT:Most of deforestation of native vegetation in the MATOPIBA (MAranhao, TOcantins, PIaui, and BAhia) region is related to the expansion of the production activities of agricultural commodities.The deforestation monitoring using remotely sensed data and GIS techniques, associated with the development of spatially explicit modeling can contribute to better understanding the variables related to deforestation and allows the simulation of future trajectories of this phenomenon. In this research, we proposed and simulated deforestation scenarios (trend, optimistic and pessimistic) for the MATOPIBA region between 2011 and 2050 based on deforestation observed in 2002, 2008, and 2010. This study results indicate an increase of deforestation of 10.3, 15.3, and 10.9 million hectares between 2011 and 2050 assuming the optimistic, business as usual, and pessimistic scenarios, respectively. It would increase deforestation in 55%, 82%, and 85% (optimistic, business as usual, and pessimistic, respectively) when compared to the total observed deforestation by 2010. This research results may help decision and policy makers to improve strategies to reduce deforestation and improve sustainable development in the MATOPIBA region.Keywords: MATOPIBA region, spatial modeling, deforestation scenarios.

https://periodicoscientificos.ufmt.br/ojs/index.php/nativa/article/download/5092/4643

Modelagem do desmatamento na região do matopiba

Long-term studies of community and population dynamics indicate that abrupt disturbances often catalyse changes in vegetation and carbon stocks. These disturbances include the opening of clearings, rainfall seasonality, and drought, as well as fire and direct human disturbance. Such events may be super-imposed on longer-term trends in disturbance, such as those associated with climate change (heating, drying), as well as resources. Intact neotropical forests have recently experienced increased drought frequency and fire occurrence, on top of pervasive increases in atmospheric CO2 concentrations, but we lack long-term records of responses to such changes especially in the critical transitional areas at the interface of forest and savanna biomes. Here, we present results from 20 years monitoring a valley forest (moist tropical forest outlier) in central Brazil. The forest has experienced multiple drought events and includes plots which have and which have not experienced fire. We focus on how forest structure (stem density and aboveground biomass carbon) and dynamics (stem and biomass mortality and recruitment) have responded to these disturbance regimes. Overall, the biomass carbon stock increased due to the growth of the trees already present in the forest, without any increase in the overall number of tree stems. Over time, both recruitment and especially mortality of trees tended to increase, and periods of prolonged drought in particular resulted in increased mortality rates of larger trees. This increased mortality was in turn responsible for a decline in aboveground carbon toward the end of the monitoring period. Prolonged droughts influence the mortality of large trees, leading to a decline in aboveground carbon stocks. Here, and in other neotropical forests, recent droughts are capable of shutting down and reversing biomass carbon sinks. These new results add to evidence that anthropogenic climate changes are already adversely impacting tropical forests.

/pdf/the-impact-of-long-dry-periods-on-the-aboveground-biomass-in-2x1csx15md.pdf

The impact of long dry periods on the aboveground biomass in a tropical forest: 20 years of monitoring

Os estudos direcionados para quantificacao de estoques de carbono fixado por florestas naturais estao em ampla evidencia, assim como a discussao sobre a efetividade da recuperacao de areas degradadas como estrategia para reduzir os niveis de CO2 atmosferico. Neste sentido, tiveram-se dois objetivos neste artigo: i) quantificar o estoque de carbono presente na biomassa da parte aerea de um fragmento de Floresta Estacional Semidecidual Montana, pertencente ao Bioma Mata Atlântica no estado de Minas Gerais e ii) incorporar a variavel estoque de carbono na estrutura horizontal da analise fitossociologica e comparar os resultados aos obtidos pela metodologia padrao, sem utilizar essa variavel no calculo do valor de importâncias das especies. Os resultados indicam que o estoque de carbono encontrado equivale a fragmentos em estagio medio de sucessao, e que a utilizacao da variavel carbono influencia sobremaneira o valor de importância das especies. Esta metodologia serve como suporte para a escolha de especies arboreas de maior potencial para sequestrar carbono e pode subsidiar programas de restauracao de remanescentes florestais do Bioma de Mata Atlântica.

/pdf/analise-fitossociologica-e-do-estoque-de-carbono-no-estrato-53t0fi7lus.pdf

Análise fitossociológica e do estoque de carbono no estrato arbóreo de um fragmento de floresta estacional semidecidual

Selective logging activities are commonly observed in the Brazilian Amazon and are responsible for high forest impact. In this study, selective logging detection techniques and the spatiotemporal extension of forests impacted by logging activities between 2003 and 2014 in portions of the states of Mato Grosso, Para, and Rondonia were assessed using remotely sensing data. Based on results obtained, it was estimated that the overall accuracies are greater than 91% for techniques applied to detect forests impacted by selective logging in the study areas. Forests impacted by selective logging increased in Western state of Mato Grosso and Northern state of Rondonia, which indicates a stage high forest activity in these regions. In contrast, in Eastern state of Para, a decrease in forests impacted by logging activities was observed, which indicates collapsed stage of logging activities resulting from deforestation and predatory logging in that region.

/pdf/selective-logging-detection-in-the-brazilian-amazon-1dfxol39ig.pdf

Ricardo de Oliveira Gaspar

Papers

Soil quality index of an Oxisol under different land uses in the Brazilian savannah

Modelagem do desmatamento na região do matopiba

The impact of long dry periods on the aboveground biomass in a tropical forest: 20 years of monitoring

Análise fitossociológica e do estoque de carbono no estrato arbóreo de um fragmento de floresta estacional semidecidual

Selective Logging Detection in the Brazilian Amazon