scholarly journals Bamboo, climate change and forest use: A critical combination for southwestern Amazonian forests?

AMBIO ◽  
2019 ◽  
Vol 49 (8) ◽  
pp. 1353-1363 ◽  
Author(s):  
Evandro Ferreira ◽  
Risto Kalliola ◽  
Kalle Ruokolainen
Keyword(s):  
Forest Fires ◽  
Clonal Plant ◽  
Anthropogenic Disturbances ◽  
Dry Season ◽  
Border Zone ◽  
Fuel Load ◽  
Mass Mortality Event ◽  
Forest Use ◽  
Amazonian Forests ◽  
Better Than

AbstractAbout 160 000 km2 of forests in the border zone between Brazil and Peru are dominated by semi-scandent bamboos (Guadua spp.). We argue that both predicted decreased precipitation during the dry season and widespread anthropogenic disturbances will significantly increase the distribution and biomass of bamboos in the area. Seasonal dryness favours the growth of evergreen bamboos in relation to trees that shed their leaves during the dry season. Disturbance can be beneficial for the bamboo because, as a clonal plant, it is often able to recover more rapidly than trees. It also withstands dry season better than many trees. The bamboo life cycle ends in a mass mortality event every 28 years, producing potential fuel for a forest fire. Presently, natural forest fires hardly exist in the area. However, in the projected future climate with more pronounced dry season and with increased fuel load after bamboo die-off events the forests may start to catch fire that has escaped from inhabited areas or even started naturally. Fires can kill trees, thus further increasing the fuel load of the forest. As a result, the landscape may start to convert to a savanna ecosystem.

Comparison of dry season urea supplements containing salt, sulfur or molasses for steers grazing native pasture in the dry tropics of northern Queensland

1981 ◽  
Vol 21 (112) ◽  
pp. 457 ◽  
Author(s):  
SR McLennan ◽  
PJ Dunster ◽  
PK O'Rourke ◽  
GM Murphy
Keyword(s):  
Compensatory Growth ◽  
Dry Season ◽  
Feeding Period ◽  
Post Feeding ◽  
Dry Tropics ◽  
Native Pasture ◽  
One Year ◽  
Better Than

The effects of feeding dry season supplements of salt and urea (NaU), salt, urea and sulfur (NaUS) and molasses and urea (MU) on the liveweight of steers grazing native pasture in northern Queensland were studied over four years. Liveweight during the feeding period was improved (P < 0.05) by each supplement in three years out of four, with a mean level of response of 49 g/d. The supplements gave similar results in two years while in one year NaU and MU were better than NaUS (P < 0.05) and in another NaUS was better than NaU (P < 0.05). Compensatory growth by unsupplemented animals after the feeding period eroded liveweight responses to supplements in most cases. Blood sulfate level was not affected by treatment, nor was it related to liveweight in either the feeding or post-feeding periods. Mean levels for unsupplemented animals were 15.8 and 21.2 �g/ml for the feeding and post-feeding periods, respectively. Salivary Na:K ratios exceeded 18:1 throughout the year for unsupplemented and NaUS groups, indicating sodium sufficiency.

Prediction for Burned Area of Forest Fires Based on SVM Model

2014 ◽  
Vol 513-517 ◽  
pp. 4084-4089 ◽  
Author(s):  
Dao Wen Xie ◽  
Shi Liang Shi
Keyword(s):  
Forest Fires ◽  
Fuel Load ◽  
Burned Area ◽  
Support Vector ◽  
Machine Model ◽  
Guangzhou City ◽  
Svm Model ◽  
Forest Fuel ◽  
Using Data ◽  
Fuel Moisture Content

Forest fire spreading is a complex burning phenomenon, and it is difficult to build a general spreading model for the fires occurred in different area over the world, even in the same country. Accordingly, predicting the burned area of forest fires is also a challenging task. In this work, five attributes (i.e. forest fuel moisture content, forest fuel inflammability, forest fuel load ,slope and burning time) are selected as input to predict burned area of forest fires occurred in the area of Guangzhou City in China. Next, using Data Mining (DM) technique, an SVM (Support Vector Machine) model was built and applied to deal with this type of a regression task, predicting burned area. Results showed that the selection of input attributes was reasonable, and the proposed SVM model was suitable for prediction of burned area, with higher precision, better generalization. This work provided a new way to deal with predictions for burned area of forest fires.

The Drought of Amazonia in 2005

2008 ◽  
Vol 21 (3) ◽  
pp. 495-516 ◽  
Author(s):  
José A. Marengo ◽  
Carlos A. Nobre ◽  
Javier Tomasella ◽  
Marcos D. Oyama ◽  
Gilvan Sampaio de Oliveira ◽  
...  
Keyword(s):  
Forest Fires ◽  
El Niño ◽  
El Nino ◽  
Dry Season ◽  
Trade Wind ◽  
Amazon River ◽  
Air Temperatures ◽  
Tropical North Atlantic ◽  
Southern Amazonia ◽  
Southwestern Amazonia

Abstract In 2005, large sections of southwestern Amazonia experienced one of the most intense droughts of the last hundred years. The drought severely affected human population along the main channel of the Amazon River and its western and southwestern tributaries, the Solimões (also known as the Amazon River in the other Amazon countries) and the Madeira Rivers, respectively. The river levels fell to historic low levels and navigation along these rivers had to be suspended. The drought did not affect central or eastern Amazonia, a pattern different from the El Niño–related droughts in 1926, 1983, and 1998. The choice of rainfall data used influenced the detection of the drought. While most datasets (station or gridded data) showed negative departures from mean rainfall, one dataset exhibited above-normal rainfall in western Amazonia. The causes of the drought were not related to El Niño but to (i) the anomalously warm tropical North Atlantic, (ii) the reduced intensity in northeast trade wind moisture transport into southern Amazonia during the peak summertime season, and (iii) the weakened upward motion over this section of Amazonia, resulting in reduced convective development and rainfall. The drought conditions were intensified during the dry season into September 2005 when humidity was lower than normal and air temperatures were 3°–5°C warmer than normal. Because of the extended dry season in the region, forest fires affected part of southwestern Amazonia. Rains returned in October 2005 and generated flooding after February 2006.

scholarly journals Assessing Changes in Ecological Quality Status of Sediment in Tri An Reservoir (Southeast Vietnam) by using Indicator of Nematode Communities

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Tran Thanh Thai ◽  
Pham Thanh Luu ◽  
Tran Thi Hoang Yen ◽  
Nguyen Thi My Yen ◽  
Ngo Xuan Quang
Keyword(s):  
Rainy Season ◽  
Dry Season ◽  
Maturity Index ◽  
Ecological Quality ◽  
Nematode Communities ◽  
Ecological Quality Status ◽  
Freshwater Habitats ◽  
Index Value ◽  
Quality Status ◽  
Better Than

Nematode communities in Tri An Reservoir (Dong Nai Province, Southeast Vietnam) were explored in the dry season (March) and pre-rainy season (July) of 2019 and analyzed to evaluate their usage as bioindicators for ecological quality status of sediment. Nematode communities consisted of 23 genera belonging to 19 families, 8 orders for the dry and 24 genera, 17 families, 8 orders for the pre-rainy season. Several genera dominated in Tri An Reservoir such as Daptonema, Rhabdolaimus, Udonchus, and Neotobrilus indicated for organic enrichment conditions. The percentage of cp3&4 and MI (Maturity Index) value in the dry season was higher than that in the pre-rainy season expressed the ecological quality status of sediment in the dry season were better than those in the pre-rainy season. Furthermore, the result revealed that MI and c-p% composition can be used to evaluate the ecological quality status of sediment efficiently. Keywords: Bioindicator, ecological quality status of sediment, freshwater habitats, maturity index, nematodes, reservoir.

scholarly journals Changes in Physiological and Relative Genes Expression Response of Mandarin Citrus (Citrus reticulata Blanco) cv Rimau Gerga Lebong (RGL) Grafted onto Different Citrus Rootstocks

2021 ◽  
Author(s):  
Farida Yulianti ◽  
Afifuddin Latif Adiredjo ◽  
Lita Soetopo ◽  
Sumeru Ashari
Keyword(s):  
Gene Expression ◽  
Water Deficit ◽  
Stomatal Density ◽  
Block Design ◽  
Physiological Responses ◽  
Dry Season ◽  
Relative Gene Expression ◽  
Gene Expressions ◽  
Relative Gene ◽  
Better Than

Background: RGL mandarin is one of the important mandarin citrus varieties in Indonesia. The tolerance of RGL mandarin citrus to water deficit can be induced by the rootstock. This study aimed to characterize the physiological responses and transcriptional gene expression of RGL mandarin citrus grafted onto three rootstock genotypes during the dry and the rainy seasons.Methods: Three-years-old mandarin citrus trees cv. Rimau Gerga Lebong (RGL) grafted onto three citruses (JC, Cit and K) were planted at the experimental field of the ICISFRI. The experiment was conducted with a randomized block design and each scion-rootstock combination contained five replications. All of the physiological and relative gene expression parameters observed were conducted at the last of the dry season (September 2019) and the mid of the rainy season (January 2020). Water deficit was induced by no watering plants during the dry season.Result: The results of physiological responses and relative gene expression analyses showed that RGL-Cit combination had better than RGL-JC combination and RGL-JC combination had better than RGL-K combination. RGL-Cit combination showed less wilt than RGL-JC and RGL-K combinations. The RGL-Cit combination had the highest stomatal density, stomatal aperture, stomatal conductance and photosynthetic rate in the dry season. Different plant combinations showed different gene expressions. RGL-JC and RGL-K combinations were upregulated in almost all the primers related to drought responses tested in the dry season. RGL-Cit combination only upregulated the PIP1, PIP2 and ACS2 and unregulated the others in the dry season. Therefore, citrumelo seems to be a valuable type of rootstock.

scholarly journals Wie oft brannte der Walliser Wald im 20. Jahrhundert? | Forest fire occurrences in Canton Valais in the 20th century

2004 ◽  
Vol 155 (10) ◽  
pp. 437-440 ◽  
Author(s):  
Urs Gimmi ◽  
Matthias Bürgi ◽  
Thomas Wohlgemuth
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Temporal Variability ◽  
Extreme Event ◽  
Public Awareness ◽  
The Past ◽  
Research Activities ◽  
Swiss Canton ◽  
Historical Database ◽  
Forest Use

In August 2003, a disastrous fire destroyed some 300 ha of forest near Leuk in the Swiss Canton of Valais. This extreme event heightened, for a time at least, public awareness of forest fires and triggered various research activities. Forest fires play an important part in the forest dynamics of the Valais. In this article we present a historical database, which contains data on outbreaks of fire over the past 100 years. The temporal variability of forest fires is analysed and possible relations to climate change and changes in forest use discussed. Three of the largest fires are presented as case studies (Ochsenboden in July 1921, Aletschwald/Riederhorn in May 1944 and Pfynwald in July 1962). Although wide areas of forest have been burnt in past fires, no outbreak in the last 100 years reached the extent of the forest fire of Leuk in 2003.

scholarly journals Fragmentation disrupts the seasonality of Amazonian evergreen forests

2021 ◽  
Author(s):  
Matheus Nunes ◽  
José Luís Camargo ◽  
Grégoire Vincent ◽  
Kim Calders ◽  
Rafael Oliveira ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Light Availability ◽  
Canopy Structure ◽  
Dry Season ◽  
Atmospheric Conditions ◽  
Terrestrial Lidar ◽  
Evergreen Forests ◽  
Large Trees ◽  
Climate Interactions ◽  
Amazonian Forests

Abstract Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial, which limits our understanding of future ecosystem function with a changing environment. Here, we use biweekly terrestrial LiDAR surveys spanning wet and dry seasons in Central Amazonia to show that plant phenology of old-growth forests varies strongly across strata but that this seasonality is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we found that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests shed their leaves and branches. By contrast, the understory greens-up with increased light availability driven by the upper canopy loss alongside more sunlight radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures on forest edges exacerbated the upper canopy losses of large trees throughout the dry season, and the understory seasonality in these light-rich environments was disrupted as a result of the altered canopy structure. These findings demonstrate the plant-climate interactions controlling the seasonality of wet Amazonian forests and show that forest fragmentation will aggravate forest loss under a hotter and drier future scenario.

scholarly journals Forecasting Season Onsets in Kapuas District Based on Global Climate Model Outputs

Agromet ◽  
2018 ◽  
Vol 32 (1) ◽  
pp. 1
Author(s):  
Laode Nurdiansyah ◽  
Akhmad Faqih
Keyword(s):  
Forest Fires ◽  
Canonical Correlation ◽  
Prediction Models ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Dry Season ◽  
Global Climate Models ◽  
International Research Institute ◽  
Cluster 2

Predictions of the rainy and dry season onsets are very important in climate risk management processes, especially for the development of early warning system of land and forest fires in Kalimantan. This research aims to predict the rainy and dry season onsets in two cluster regions in Kapuas District, Central Kalimantan. The prediction models used to predict the onsets are developed by using seasonal rainfall data on September-October-November (SON) periods as predicted by five Global Climate Models (GCMs). The model uses Canonical Correlation Analysis (CCA) method available in the Climate Predictability Tool (CPT) software developed by the International Research Institute for Climate and Society (IRI), Columbia University. The results show that the predictors from HMC and POAMA models produce better canonical correlations (r = 0.72 and 0.89, respectively) compared to BCC (r=0.46), CWB (r=0.62), and GDAPS_F (r=0.67) models. In the development of models for predicting the dry season onsets, the predictors from CWB and POAMA models perform better canonical correlation results (r = 0.73 and 0.76, respectively) compared to BCC (r=0.53), GDAPS_F (r=0.64), and HMC (r=0.46) models. In general, the model validations showed that CWB, GDAPS_F, and POAMA models have better predictive skills than BCC and HMC models in predicting onsets of the rainy and dry seasons (with Pearson correlations (r) ranging between 0.30 and 0.75). Experiments on those five models for the predictions of rainy season onset in 2013 showed that the predicted onsets occurred on the range of 8 September to 22 October in Cluster 1 and on 3 to 7 October in Cluster 2. For the predictions of the dry season onsets in 2014, the models predicted the occurrences from 6 to 25 May in Cluster 1 and from 21 to 25 March in Cluster 2.

scholarly journals Trace gas and particle emissions from open biomass burning in Mexico

2011 ◽  
Vol 11 (14) ◽  
pp. 6787-6808 ◽  
Author(s):  
R. J. Yokelson ◽  
I. R. Burling ◽  
S. P. Urbanski ◽  
E. L. Atlas ◽  
K. Adachi ◽  
...  
Keyword(s):  
Forest Fires ◽  
Large Fraction ◽  
Trace Gases ◽  
Dry Season ◽  
Dry Forest ◽  
Southern Mexico ◽  
Carbonaceous Particles ◽  
Airborne Measurements ◽  
Combustion Sources ◽  
Reactive Trace Gases

Abstract. We report airborne measurements of emission factors (EF) for trace gases and PM2.5 made in southern Mexico in March of 2006 on 6 crop residue fires, 3 tropical dry forest fires, 8 savanna fires, 1 garbage fire, and 7 mountain pine-oak forest fires. The savanna fire EF were measured early in the local dry season and when compared to EF measured late in the African dry season they were at least 1.7 times larger for NOx, NH3, H2, and most non-methane organic compounds. Our measurements suggest that urban deposition and high windspeed may also be associated with significantly elevated NOx EF. When considering all fires sampled, the percentage of particles containing soot increased from 15 to 60 % as the modified combustion efficiency increased from 0.88 to 0.98. We estimate that about 175 Tg of fuel was consumed by open burning of biomass and garbage and as biofuel (mainly wood cooking fires) in Mexico in 2006. Combining the fuel consumption estimates with our EF measurements suggests that the above combustion sources account for a large fraction of the reactive trace gases and more than 90 % of the total primary, fine carbonaceous particles emitted by all combustion sources in Mexico.

Sign in / Sign up

Export Citation Format

Share Document