LBA-ECO LC-24 FOREST COVER MAP FROM MODIS, 500-M, SOUTH AMERICA: 2001

Variable tree rooting strategies are key for modelling the distribution, productivity and evapotranspiration of tropical evergreen forests

Biogeosciences ◽

10.5194/bg-18-4091-2021 ◽

2021 ◽

Vol 18 (13) ◽

pp. 4091-4116

Author(s):

Boris Sakschewski ◽

Werner von Bloh ◽

Markus Drüke ◽

Anna Amelia Sörensson ◽

Romina Ruscica ◽

...

Keyword(s):

South America ◽

Forest Cover ◽

Soil Depth ◽

Rooting Depth ◽

Dynamic Global Vegetation Model ◽

Study Region ◽

Investment Timing ◽

Evergreen Forests ◽

Below Ground ◽

Tropical South America

Abstract. A variety of modelling studies have suggested tree rooting depth as a key variable to explain evapotranspiration rates, productivity and the geographical distribution of evergreen forests in tropical South America. However, none of those studies have acknowledged resource investment, timing and physical constraints of tree rooting depth within a competitive environment, undermining the ecological realism of their results. Here, we present an approach of implementing variable rooting strategies and dynamic root growth into the LPJmL4.0 (Lund-Potsdam-Jena managed Land) dynamic global vegetation model (DGVM) and apply it to tropical and sub-tropical South America under contemporary climate conditions. We show how competing rooting strategies which underlie the trade-off between above- and below-ground carbon investment lead to more realistic simulation of intra-annual productivity and evapotranspiration and consequently of forest cover and spatial biomass distribution. We find that climate and soil depth determine a spatially heterogeneous pattern of mean rooting depth and below-ground biomass across the study region. Our findings support the hypothesis that the ability of evergreen trees to adjust their rooting systems to seasonally dry climates is crucial to explaining the current dominance, productivity and evapotranspiration of evergreen forests in tropical South America.

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Spatial and Temporal Variations of Forest Cover in Developing Countries

Sustainability ◽

10.3390/su11061517 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1517 ◽

Cited By ~ 5

Author(s):

Qianwen Duan ◽

Minghong Tan

Keyword(s):

Developing Countries ◽

South America ◽

Forest Cover ◽

European Space Agency ◽

Binary Logistic Regression ◽

Temporal Variations ◽

Global Scale ◽

Forest Area ◽

Binary Logistic Regression Model ◽

African Countries

An understanding of changes in forest cover and the drivers of forest transition (FT) contributes to the sustainable management of global forests. In this paper, we used the latest global land cover data published by the European Space Agency (ESA) to investigate spatiotemporal variation characteristics of forest cover in developing countries from 1992 to 2015, and then analyzed causal factors of this variation using a binary logistic regression model. Existing studies on FT are mostly based on data from the Food and Agriculture Organization (FAO); this study improves our understanding of FT mechanisms through the use of a new dataset. The results indicate that the forest area in developing countries decreased from 21.8 to 21.3 million km2 from 1992–2015, and the rate of decline slowed after 2004. South America suffered the largest reduction in forest area (505,100 km2), whereas forest area in Africa increased slightly. By 2015, more than 80% of African countries had experienced FT, whereas only half of developing countries experienced forest expansion in South America. The variables affecting FT occurrence differed among continents. On the global scale, the remaining forest coverage and the proportion of forest exports negatively affected the likelihood of FT occurrence, whereas urbanization level had a positive effect.

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