Releases of carbon to the atmosphere from degradation of forests in tropical Asia

1991 ◽  
Vol 21 (1) ◽  
pp. 132-142 ◽  
Author(s):  
R. A. Houghton
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Forest Biomass ◽  
Terrestrial Ecosystems ◽  
Tropical Asia ◽  
South And Southeast Asia ◽  
Net Flux ◽  
The Difference ◽  
Annual Flux

The net annual flux of carbon from south and southeast Asia as a result of changes in the area of forests was calculated for the period 1850 to 1985. The total net flux ranged from 14.4 to 24.0 Pg of carbon, depending on the estimates of biomass used in the calculations. High estimates of biomass, based on direct measurement of a few stands, and low estimates of biomass, based on volumes of merchantable wood surveyed over large areas, differ by a factor of almost 2. These and previous estimates of the release of carbon from terrestrial ecosystems to the atmosphere have been based on changes in the area of forests, or rates of deforestation. Recent studies have shown, however, that the loss of carbon from forests in tropical Asia is greater than would be expected on the basis of deforestation alone. This loss of carbon from within forests (degradation) also releases carbon to the atmosphere when the products removed from the forest burn or decay. Thus, degradation should be included in analyses of the net flux of carbon from terrestrial ecosystems. Degradation may also explain some of the difference between estimates of tropical forest biomass if the higher estimates are based on undisturbed forests and the lower estimates are more representative of the region. The implication of degradation for estimates of the release of carbon from terrestrial ecosystems is explored. When degradation was included in the analyses, the net flux of carbon between 1850 and 1985 was 30.2 Pg of carbon, about 25% above that calculated on the basis of deforestation alone (with high estimates of biomass), and about 110% above that calculated with low estimates of biomass. Thus, lower estimates of biomass for contemporary tropical forests do not necessarily result in lower estimates of flux.

scholarly journals Changes in carbon fluxes and pools induced by cropland expansion in South and Southeast Asia in the 20th century

2011 ◽  
Vol 8 (6) ◽  
pp. 11979-12012 ◽  
Author(s):  
B. Tao ◽  
H. Tian ◽  
G. Chen ◽  
W. Ren ◽  
C. Lu ◽  
...  
Keyword(s):  
Southeast Asia ◽  
South Asia ◽  
20Th Century ◽  
Forest Biomass ◽  
Terrestrial Ecosystems ◽  
Carbon Fluxes ◽  
Ecosystem Model ◽  
Natural Forests ◽  
Legacy Effect ◽  
South And Southeast Asia

Abstract. A process-based ecosystem model, the Dynamic Land Ecosystem Model (DLEM), was applied to evaluate the effects of cropland expansion on terrestrial carbon fluxes and pools in South and Southeast Asia in the 20th century. The results indicated that cropland expansion in both regions has resulted in a release of 18.26 Pg C into the atmosphere in the study period. Of this amount, approximately 23 % (4.19 Pg C) was released from South Asia and 77 % (14.07 Pg C) from Southeast Asia. More land area was converted to cropland but less carbon was emitted in South Asia than in Southeast Asia, where forest biomass and soil carbon are significantly higher. Carbon losses in vegetation, soil organic matter, and litter carbon pools accounted for 15.09, 2.01, and 1.60 Pg C, respectively. Significant decreases in vegetation carbon occurred across most regions of Southeast Asia due to continuous cropland expansion and depletion of natural forests. Our study also indicated that it is important to take into account the land use legacy effect when evaluating the contemporary carbon balance in terrestrial ecosystems.

Tropical Forests Natural History, Diversity, and Potentiality as Theatres of Human Adaptation and Negotiation

2019 ◽  
Author(s):  
Patrick Roberts
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Homo Sapiens ◽  
Terrestrial Ecosystems ◽  
Black Pepper ◽  
Wood Products ◽  
Tropical Rainforests ◽  
Cultural Significance ◽  
Seasonally Dry ◽  
Dry Tropical Forests

The above quote by the German poet, novelist, and painter Herman Hesse highlights the cultural significance of forests in nineteenth- and twentieth-century western culture as the ‘natural’ contrast to growing urban populations and industrial expansion. Hesse’s focus on the ‘ancient’ element of these environments is certainly valid in a tropical context, given that tropical forests are some of the oldest land-based environments on the planet, existing for over one thousand times longer than Homo sapiens (Upchurch and Wolf, 1987; Davis et al., 2005; Ghazoul and Shiel, 2010; Couvreur et al., 2011). This antiquity also makes them one of the richest and most diverse terrestrial ecosystems on the planet (Whitmore, 1998; Ghazoul and Shiel, 2010). Tropical rainforests, for example, contain over half of the world’s existing plant, animal, and insect species (Wilson, 1988). A significant portion of the developed world’s diet today originated in tropical forests—including staples such as squash and yams, spices such as black pepper, cinnamon, cloves, and sugar cane, and fruits including bananas, coconuts, avocados, mangoes, and tomatoes (Iriarte et al., 2007; Roberts et al., 2017a). Tropical forests also often provide ample freshwater for their inhabitants. However, despite popular perceptions of forests, and specifically tropical forests, as uniform, they are, in fact, highly variable across space and time. In tropical evergreen rainforests productivity is often primarily allocated to wood products, meaning that edible plants and animals for human subsistence have been considered lacking, or at least more difficult to extract, relative to more open tropical forest formations (Whitmore, 1998; Ghazoul and Shiel, 2010). Similarly, while evergreen tropical rainforests generally receive significant precipitation and freshwater, seasonally dry tropical forests are subject to sub-annual periods of aridity. Therefore, while archaeologists and anthropologists have tended to see ‘tropical forest’ as a uniform environmental block, it is important to explore the diversity within this category.

Hebrew script for Jewish languages

2021 ◽  
Vol 24 (1) ◽  
pp. 149-165
Author(s):  
Peter T. Daniels
Keyword(s):  
Southeast Asia ◽  
The Other ◽  
Jewish Communities ◽  
Sacred Texts ◽  
South And Southeast Asia ◽  
The Difference ◽  
Medieval Hebrew

Abstract That “script follows religion” is well known. Missionary activities by Christian, Manichaean and Islamic, and Buddhist and Hindu proselytizers brought literacy, in alphabetic, abjadic, and abugidic scripts respectively, to previously non-literate communities in Europe, Asia and Africa, and South and Southeast Asia respectively. Judaism, however, did not proselytize; instead, it “wandered,” bringing Jewish communities throughout Europe and a good part of Asia, to lands that were already literate thanks to those earlier missionaries. Jewish languages emerged when diaspora communities adopted vernaculars altered on the basis of the culture-languages Hebrew and Aramaic. Such communities treasured their Hebrew and Aramaic literacies and often wrote the vernaculars using Hebrew script. The Hebrew letters denote consonants only, but the Jewish languages usually have more than 22 consonants and a number of vowels. Medieval Hebrew scholars devised vowels marks, used almost exclusively in sacred texts, but most Jewish languages barely use them. Unlike the other missionary scripts, Hebrew-script orthographies were often influenced by the indigenous orthographies they encountered. Exploring those influences needs an abbreviated account of the development of Hebrew orthography from its second-millennium bce forebears. A few examples follow of the adaptations of Hebrew script to Jewish languages, and various commonalities are found among such adaptations that probably emerged independently with little contact between speakers of the various languages. The question arises as to whether similar divergences and commonalities are found in other scripts spread in Scriptural contexts. That they are generally not reflects the difference between scripts arriving in non-literate versus literate surroundings.

scholarly journals Inter-comparison and assessment of gridded climate products over tropical forests during the 2015/2016 El Niño

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170406 ◽  
Author(s):  
C. Burton ◽  
S. Rifai ◽  
Y. Malhi
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Congo Basin ◽  
Wide Range ◽  
Spatio Temporal ◽  
The Impact

To understand the impacts of extreme climate events, it is first necessary to understand the spatio-temporal characteristics of the event. Gridded climate products are frequently used to describe climate patterns but have been shown to perform poorly over data-sparse regions such as tropical forests. Often, they are uncritically employed in a wide range of studies linking tropical forest processes to large-scale climate variability. Here, we conduct an inter-comparison and assessment of near-surface air temperature fields supplied by four state-of-the-art reanalysis products, along with precipitation estimates supplied by four merged satellite-gauge rainfall products. Firstly, spatio-temporal patterns of temperature and precipitation anomalies during the 2015–2016 El Niño are shown for each product to characterize the impact of the El Niño on the tropical forest biomes of Equatorial Africa, Southeast Asia and South America. Using meteorological station data, a two-stage assessment is then conducted to determine which products most reliably model tropical climates during the 2015–2016 El Niño, and which perform best over the longer-term satellite observation period (1980–2016). Results suggest that eastern Amazonia, parts of the Congo Basin and mainland Southeast Asia all experienced significant monthly mean temperature anomalies during the El Niño, while northeastern Amazonia, eastern Borneo and southern New Guinea experienced significant precipitation deficits. Our results suggest ERA-Interim and MERRA2 are the most reliable air temperature datasets, while TRMM 3B42 V7 and CHIRPS v2.0 are the best-performing rainfall datasets. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals The role of earthworms in nitrogen and solute retention in a tropical forest in Sabah, Malaysia: a pilot study

2012 ◽  
Vol 28 (6) ◽  
pp. 611-614 ◽  
Author(s):  
Sarah Johnson ◽  
Arshiya Bose ◽  
Jake L. Snaddon ◽  
Brian Moss
Keyword(s):  
Pilot Study ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Direct Evidence ◽  
Terrestrial Ecosystems ◽  
Retention Mechanisms ◽  
Solute Retention ◽  
Living Organisms ◽  
Very High

Compounds of the 20 elements needed by living organisms are relatively soluble in water and therefore vulnerable to being leached and lost from terrestrial ecosystems during mineralization. Intact systems have thus acquired retention mechanisms that sequester nutrients and minimize losses. Such mechanisms should be particularly important where rainfall is very high but direct evidence of retention mechanisms in tropical forests is scarce (Snaddon et al. 2012, Turner et al. 2007).

scholarly journals Detecting tropical forest biomass dynamics from repeated airborne lidar measurements

2013 ◽  
Vol 10 (8) ◽  
pp. 5421-5438 ◽  
Author(s):  
V. Meyer ◽  
S. S. Saatchi ◽  
J. Chave ◽  
J. W. Dalling ◽  
S. Bohlman ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Spatial Scale ◽  
Tropical Forests ◽  
Spatial Scales ◽  
Forest Biomass ◽  
Airborne Lidar ◽  
Barro Colorado Island ◽  
Accurate Estimation ◽  
Old Growth ◽  
Lidar Measurements

Abstract. Reducing uncertainty of terrestrial carbon cycle depends strongly on the accurate estimation of changes of global forest carbon stock. However, this is a challenging problem from either ground surveys or remote sensing techniques in tropical forests. Here, we examine the feasibility of estimating changes of tropical forest biomass from two airborne lidar measurements of forest height acquired about 10 yr apart over Barro Colorado Island (BCI), Panama. We used the forest inventory data from the 50 ha Center for Tropical Forest Science (CTFS) plot collected every 5 yr during the study period to calibrate the estimation. We compared two approaches for detecting changes in forest aboveground biomass (AGB): (1) relating changes in lidar height metrics from two sensors directly to changes in ground-estimated biomass; and (2) estimating biomass from each lidar sensor and then computing changes in biomass from the difference of two biomass estimates, using two models, namely one model based on five relative height metrics and the other based only on mean canopy height (MCH). We performed the analysis at different spatial scales from 0.04 ha to 10 ha. Method (1) had large uncertainty in directly detecting biomass changes at scales smaller than 10 ha, but provided detailed information about changes of forest structure. The magnitude of error associated with both the mean biomass stock and mean biomass change declined with increasing spatial scales. Method (2) was accurate at the 1 ha scale to estimate AGB stocks (R2 = 0.7 and RMSEmean = 27.6 Mg ha−1). However, to predict biomass changes, errors became comparable to ground estimates only at a spatial scale of about 10 ha or more. Biomass changes were in the same direction at the spatial scale of 1 ha in 60 to 64% of the subplots, corresponding to p values of respectively 0.1 and 0.033. Large errors in estimating biomass changes from lidar data resulted from the uncertainty in detecting changes at 1 ha from ground census data, differences of approximately one year between the ground census and lidar measurements, and differences in sensor characteristics. Our results indicate that the 50 ha BCI plot lost a significant amount of biomass (−0.8 Mg ha−1 yr−1 ± 2.2(SD)) over the past decade (2000–2010). Over the entire island and during the same period, mean AGB change was 0.2 ± 2.4 Mg ha−1 yr−1 with old growth forests losing −0.7 Mg ha−1 yr−1 ± 2.2 (SD), and secondary forests gaining +1.8 Mg ha yr−1 ± 3.4 (SD) biomass. Our analysis suggests that repeated lidar surveys, despite taking measurement with different sensors, can estimate biomass changes in old-growth tropical forests at landscape scales (>10 ha).

Use of GIS for Estimating Potential and Actual Forest Biomass for Continental South and Southeast Asia

1994 ◽  
pp. 67-116 ◽  
Author(s):  
Louis R. Iverson ◽  
Sandra Brown ◽  
Anantha Prasad ◽  
Helena Mitasova ◽  
Andrew J. R. Gillespie ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Forest Biomass ◽  
South And Southeast Asia

scholarly journals Detecting tropical forest biomass dynamics from repeated airborne Lidar measurements

2013 ◽  
Vol 10 (2) ◽  
pp. 1957-1992 ◽  
Author(s):  
V. Meyer ◽  
S. S. Saatchi ◽  
J. Chave ◽  
J. Dalling ◽  
S. Bohlman ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Spatial Scales ◽  
Forest Biomass ◽  
Airborne Lidar ◽  
Barro Colorado Island ◽  
Accurate Estimation ◽  
Prediction Errors ◽  
Old Growth ◽  
Lidar Measurements

Abstract. Reducing uncertainty of terrestrial carbon cycle depends strongly on the accurate estimation of changes of global forest carbon stock. However, this is a challenging problem from either ground surveys or remote sensing techniques in tropical forests. Here, we examine the feasibility of estimating changes of tropical forest biomass from two airborne Lidar measurements acquired about 10 yr apart over Barro Colorado Island (BCI), Panama from high and medium resolution airborne sensors. The estimation is calibrated with the forest inventory data over 50 ha that was surveyed every 5 yr during the study period. We estimated the aboveground forest biomass and its uncertainty for each time period at different spatial scales (0.04, 0.25, 1.0 ha) and developed a linear regression model between four Lidar height metrics and the aboveground biomass. The uncertainty associated with estimating biomass changes from both ground and Lidar data was quantified by propagating measurement and prediction errors across spatial scales. Errors associated with both the mean biomass stock and mean biomass change declined with increasing spatial scales. Biomass changes derived from Lidar and ground estimates were largely (36 out 50 plots) in the same direction at the spatial scale of 1 ha. Lidar estimation of biomass was accurate at the 1 ha scale (R2 = 0.7 and RMSEmean = 28.6 Mg ha−1). However, to predict biomass changes, errors became comparable to ground estimates only at about 10-ha or more. Our results indicate that the 50-ha BCI plot lost a~significant amount of biomass (−0.8 ± 2.2 Mg ha−1 yr−1) over the past decade (2000–2010). Over the entire island and during the same period, mean AGB change is −0.4 ± 3.7 Mg ha−1 yr−1. Old growth forests lost biomass (−0.7 ± 3.5 Mg ha−1 yr−1), whereas the secondary forests gained biomass (+0.4 ± 3.4 Mg ha−1 yr−1). Our analysis demonstrates that repeated Lidar surveys, even with two different sensors, is able to estimate biomass changes in old-growth tropical forests at landscape scales (>10 ha).

Sign in / Sign up

Export Citation Format

Share Document