scholarly journals A sub-canopy structure for simulating oil palm in the Community Land Model (CLM-Palm): phenology, allocation and yield

2015 ◽  
Vol 8 (11) ◽  
pp. 3785-3800 ◽  
Author(s):  
Y. Fan ◽  
O. Roupsard ◽  
M. Bernoux ◽  
G. Le Maire ◽  
O. Panferov ◽  
...  
Keyword(s):  
Oil Palm ◽  
Net Primary Production ◽  
Leaf Growth ◽  
Canopy Structure ◽  
Field Measurements ◽  
Fruit Yield ◽  
Small Scale ◽  
Area Index ◽  
Community Land Model ◽  
Site Variability

Abstract. In order to quantify the effects of forests to oil palm conversion occurring in the tropics on land–atmosphere carbon, water and energy fluxes, we develop a new perennial crop sub-model CLM-Palm for simulating a palm plant functional type (PFT) within the framework of the Community Land Model (CLM4.5). CLM-Palm is tested here on oil palm only but is meant of generic interest for other palm crops (e.g., coconut). The oil palm has monopodial morphology and sequential phenology of around 40 stacked phytomers, each carrying a large leaf and a fruit bunch, forming a multilayer canopy. A sub-canopy phenological and physiological parameterization is thus introduced so that each phytomer has its own prognostic leaf growth and fruit yield capacity but with shared stem and root components. Phenology and carbon and nitrogen allocation operate on the different phytomers in parallel but at unsynchronized steps, separated by a thermal period. An important phenological phase is identified for the oil palm – the storage growth period of bud and "spear" leaves which are photosynthetically inactive before expansion. Agricultural practices such as transplanting, fertilization and leaf pruning are represented. Parameters introduced for the oil palm were calibrated and validated with field measurements of leaf area index (LAI), yield and net primary production (NPP) from Sumatra, Indonesia. In calibration with a mature oil palm plantation, the cumulative yields from 2005 to 2014 matched notably well between simulation and observation (mean percentage error = 3 %). Simulated inter-annual dynamics of PFT-level and phytomer-level LAI were both within the range of field measurements. Validation from eight independent oil palm sites shows the ability of the model to adequately predict the average leaf growth and fruit yield across sites and sufficiently represent the significant nitrogen- and age-related site-to-site variability in NPP and yield. Results also indicate that seasonal dynamics of yield and remaining small-scale site-to-site variability of NPP are driven by processes not yet implemented in the model or reflected in the input data. The new sub-canopy structure and phenology and allocation functions in CLM-Palm allow exploring the effects of tropical land-use change, from natural ecosystems to oil palm plantations, on carbon, water and energy cycles and regional climate.

scholarly journals A sub-canopy structure for simulating oil palm in the Community Land Model: phenology, allocation and yield

2015 ◽  
Vol 8 (6) ◽  
pp. 4545-4597
Author(s):  
Y. Fan ◽  
O. Roupsard ◽  
M. Bernoux ◽  
G. Le Maire ◽  
O. Panferov ◽  
...  
Keyword(s):  
Oil Palm ◽  
Leaf Growth ◽  
Canopy Structure ◽  
Field Measurements ◽  
Fruit Yield ◽  
Growth And Yield ◽  
Percentage Error ◽  
Area Index ◽  
Carbon And Nitrogen ◽  
Community Land Model

Abstract. Land surface modelling has been widely used to characterize the two-way interactions between climate and human activities in terrestrial ecosystems such as deforestation, agricultural expansion, and urbanization. Towards an effort to quantify the effects of forests to oil palm conversion occurring in the tropics on land–atmosphere carbon, water and energy fluxes, we introduce a new perennial crop plant functional type (PFT) for oil palm. Due to the modular and sequential nature of oil palm growth (around 40 stacked phytomers) and yield (fruit bunches axillated on each phytomer), we developed a specific sub-canopy structure for simulating palm's growth and yield within the framework of the Community Land Model (CLM4.5). In this structure each phytomer has its own prognostic leaf growth and fruit yield capacity like a PFT but with shared stem and root components among all phytomers. Phenology and carbon and nitrogen allocation operate on the different phytomers in parallel but at unsynchronized steps, so that multiple fruit yields per annum are enabled in terms of carbon and nitrogen outputs. An important phenological phase is identified for the palm PFT – the storage growth period of bud and "spear" leaves which are photosynthetically inactive before expansion. Agricultural practices such as transplanting, fertilization, and leaf pruning are represented. Parameters introduced for the new PFT were calibrated and validated with field measurements of leaf area index (LAI) and yield from Sumatra, Indonesia. In calibration with a mature oil palm plantation, the cumulative yields from 2005 to 2014 matched perfectly between simulation and observation (mean percentage error = 4 %). Simulated inter-annual dynamics of PFT-level and phytomer-level LAI were both within the range of field measurements. Validation from eight independent oil palm sites shows the ability of the model to adequately predict the average leaf growth and fruit yield across sites but also indicates that seasonal dynamics and site-to-site variability of yield are driven by processes not yet implemented in the model. The new sub-canopy structure and phenology and allocation functions now allow exploring the effects of tropical land use change, from natural ecosystems to oil palm plantations, on carbon, water and energy cycles and regional climate.

scholarly journals Evaluation of MEGAN-CLM parameter sensitivity to predictions of isoprene emissions from an Amazonian rainforest

2014 ◽  
Vol 14 (17) ◽  
pp. 23995-24041 ◽  
Author(s):  
J. A. Holm ◽  
K. Jardine ◽  
A. B. Guenther ◽  
J. Q. Chambers ◽  
E. Tribuzy
Keyword(s):  
Land Surface ◽  
Field Measurements ◽  
Leaf Temperature ◽  
Surface Model ◽  
Amazon Forest ◽  
Biophysical Parameters ◽  
Area Index ◽  
Central Amazon ◽  
Community Land Model ◽  
Environmental Controls

Abstract. Tropical trees are known to be large emitters of biogenic volatile organic compounds (BVOC), accounting for up to 75% of the global isoprene budget. Once in the atmosphere, these compounds influence multiple processes associated with air quality and climate. However, uncertainty in biogenic emissions is two-fold, (1) the environmental controls over isoprene emissions from tropical forests remain highly uncertain; and (2) our ability to accurately represent these environmental controls within models is lacking. This study evaluated the biophysical parameters that drive the global Model of Emissions of Gases and Aerosols from Nature (MEGAN) embedded in a biogeochemistry land surface model, the Community Land Model (CLM), with a focus on isoprene emissions from an Amazonian forest. Upon evaluating the sensitivity of 19 parameters in CLM that currently influence isoprene emissions by using a Monte Carlo analysis, up to 61% of the uncertainty in mean isoprene emissions was caused by the uncertainty in the parameters related to leaf temperature. The eight parameters associated with photosynthetic active radiation (PAR) contributed in total to only 15% of the uncertainty in mean isoprene emissions. Leaf temperature was strongly correlated with isoprene emission activity (R2 = 0.89). However, when compared to field measurements in the Central Amazon, CLM failed to capture the upper 10–14 °C of leaf temperatures throughout the year (i.e., failed to represent ~32 to 46 °C), and the spread observed in field measurements was not representative in CLM. This is an important parameter to accurately simulate due to the non-linear response of emissions to temperature. MEGAN-CLM 4.0 overestimated isoprene emissions by 60% for a Central Amazon forest (5.7 mg m−2 h−1 vs. 3.6 mg m−2 h−1), but due to reductions in leaf area index (LAI) by 28% in MEGAN-CLM 4.5 isoprene emissions were within 7% of observed data (3.8 mg m−2 h−1). When a slight adjustment to leaf temperature was made to match observations, isoprene emissions increased 24%, up to 4.8 mg m−2 h−1. Air temperatures are very likely to increase in tropical regions as a result of human induced climate change. Reducing the uncertainty of leaf temperature in BVOC algorithms, as well as improving the accuracy of replicating leaf temperature output in land surface models is warranted in order to improve estimations of tropical BVOC emissions.

Effect of root zone aeration on the growth and bioactivity of cucumber plants cultured in perlite substrate

Biologia ◽  
2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Jong Lee ◽  
Beom Lee ◽  
Jong Kang ◽  
Jong Bae ◽  
Yang Ku ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Bioactive Compounds ◽  
Root Zone ◽  
Antioxidant Activities ◽  
Leaf Growth ◽  
Co2 Concentration ◽  
Fruit Yield ◽  
Area Index ◽  
Antioxidant Power

AbstractThis study was aimed at investigating the growth and nutrient uptake of cucumber plants affected by forced aeration of supplying oxygen and stimulating gas exchange rate in root zone in a substrate. Five aeration levels during the growth (0, 0.5, 1.0, 1.5 and 2.0 L/min) were applied. Maximum leaf area and leaf fresh and dry weights were obtained at an aeration level of 0.5 L/min. Excessive aeration in root zone inhibited leaf area expansion, relative leaf growth rate and crop growth rate. An optimum leaf area index of 3.0 to 3.5 was estimated in range of 0 and 0.5 L/min. The highest fruit yield was measured of 1.13 kg/plant at 0.5 L/min, whereas at 2.0 L/min it was 0.62 kg/plant. Potassium concentration in petiole sap was lower at 63 days after transplanting than that at 32 days after transplanting. Ethylene concentrations increased with higher aeration values, however, CO2 concentration reduced with increased aeration. All bioactive compounds (polyphenols, flavonoids, flavanols, tannins and ascorbic acid) and the levels of antioxidant activities by ferric-reducing/antioxidant power and cupric reducing antioxidant capacity in ethanol extracts of cucumbers differed significantly in the investigated samples and were the highest at aeration level of 0.5 L/min in comparison with other samples (P <0.05). In conclusion, antioxidant status (bioactive compounds and antioxidant activities) improved with the appropriate aeration, which is effective for higher fruit yield and bioactivity. Excessive aeration inhibited root respiration, nutrients, bioactivity, and water uptake, and it resulted in the reduction of plant growth and fruit yield.

scholarly journals Influence of climate variability, fire and phosphorus limitation on the vegetation structure and dynamics in the Amazon-Cerrado border

2016 ◽  
Author(s):  
Emily Ane Dionizio da Silva ◽  
Marcos Heil Costa ◽  
Andrea Almeida Castanho ◽  
Gabrielle Ferreira Pires ◽  
Beatriz Schwantes Marimon ◽  
...  
Keyword(s):  
Climate Variability ◽  
Vegetation Structure ◽  
Carbon Allocation ◽  
Net Primary Production ◽  
Field Measurements ◽  
Phosphorus Limitation ◽  
Area Index ◽  
Soil P ◽  
Structure And Dynamics ◽  
Nutritional Limitation

Abstract. Climate, fire and soil nutritional limitation are important elements that affect the vegetation dynamics in areas of forest-savanna transition. In this paper, we use the dynamic vegetation model INLAND to evaluate the influence of climate variability, fire and phosphorus limitation on the Amazon-Cerrado transitional vegetation structure and dynamics. We assess how each element affects the net primary production, leaf area index and biomass and compare the simulations of aboveground biomass to observed biomass map. We used two climate datasets – the 1960–1990 average seasonal climate and the 1948 to 2008 interannual climate variability, two regional datasets of total soil P content in soil, based on regional (field measurements) and global data and the INLAND fire module. Our results show that climate interannual variability, phosphorus limitation and fire occurrence gradually improve simulated vegetation types and these effects are not homogeneous along the latitudinal/longitudinal gradient showing a synergistic effect among them. In terms of magnitude, the effect of fire is stronger, and is the main driver of vegetation changes along the transition. The nutritional limitation, in turn, is stronger than the effect of climate variability acting on the transitional ecosystems dynamics. Overall, INLAND typically simulates more than 80 % of the biomass variability in the transition zone. However, in many places, the biomass is clearly not well simulated indicating that important soil and physiological factors in the Amazon-Cerrado border, such as lithology and water table depth, carbon allocation strategies and mortality rates, still need to be included in the model.

scholarly journals Small-Scale Forest Structure Influences Spatial Variability of Belowground Carbon Fluxes in a Mature Mediterranean Beech Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 255 ◽  
Author(s):  
Ettore D’Andrea ◽  
Gabriele Guidolotti ◽  
Andrea Scartazza ◽  
Paolo De Angelis ◽  
Giorgio Matteucci
Keyword(s):  
Spatial Variability ◽  
Forest Structure ◽  
Net Primary Production ◽  
Beech Forest ◽  
Environmental Drivers ◽  
Root Production ◽  
Small Scale ◽  
Co2 Efflux ◽  
Area Index ◽  
C Cycle

The tree belowground compartment, especially fine roots, plays a relevant role in the forest ecosystem carbon (C) cycle, contributing largely to soil CO2 efflux (SR) and to net primary production (NPP). Beyond the well-known role of environmental drivers on fine root production (FRP) and SR, other determinants such as forest structure are still poorly understood. We investigated spatial variability of FRP, SR, forest structural traits, and their reciprocal interactions in a mature beech forest in the Mediterranean mountains. In the year of study, FRP resulted in the main component of NPP and explained about 70% of spatial variability of SR. Moreover, FRP was strictly driven by leaf area index (LAI) and soil water content (SWC). These results suggest a framework of close interactions between structural and functional forest features at the local scale to optimize C source–sink relationships under climate variability in a Mediterranean mature beech forest.

Small scale CO2 fluxes in a rainfed maize field under N fertilization

2020 ◽  
Author(s):  
Györgyi Gelybó ◽  
Réka Deli ◽  
Márton Dencső ◽  
Bernadett Kósa ◽  
Viktória Mateika ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Water ◽  
Field Measurements ◽  
Vegetation Period ◽  
N Fertilization ◽  
Small Scale ◽  
Material Transport ◽  
Sowing Time ◽  
Area Index ◽  
Maize Field

&lt;p&gt;Carbon-dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) fluxes in the soil-plant-atmosphere system contain bidirectional material transport with organic and inorganic sources and sinks, and various pathways. Proportion of irrigated fields in the total area of Hungarian arable lands is low, and incase of a rainfed field water and CO&lt;sub&gt;2&lt;/sub&gt; fluxes are only driven by meteorological factors. In this study we focused on maize under different fertilization treatments to see the plot scale variability of CO&lt;sub&gt;2&lt;/sub&gt; fluxes and connected parameters.&lt;/p&gt;&lt;p&gt;The site is a multifactorial sowing time-fertilizer-maize variety field experiment near Martonv&amp;#225;s&amp;#225;r. Two treatment plots were selected for the measurements with contrasting 60 kg N ha&lt;sup&gt;-1&lt;/sup&gt; and 180 kg N ha&lt;sup&gt;-1&lt;/sup&gt; fertilizer treatments and no other factors were considered in the present study. We performed synchronized observations of (i) CO&lt;sub&gt;2&lt;/sub&gt; fluxes: soil respiration (Rs; EGM-5 gas analyser + SRC-1 chamber, PPSystems); leaf scale photosynthesis (A; CIRAS-3 portable photosynthesis system, PPSystems)), (ii) soil temperature and soil water content, (iii) plant parameters: root growth (CI-600, CID-Bioscience), plant height, leaf area index (Accupar LP-80 ceptometer, Li-Cor). Data on the above parameters comprise several spatial replicates to explore spatial heterogeneity in case of a maize field managed in accordance with the typical Hungarian practice. The average applied N amount in the country is around 100-105 kg ha&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;Field measurements for CO&lt;sub&gt;2&lt;/sub&gt; fluxes and biotic and abiotic drivers were performed six times in the vegetation period to establish relationship among them. Data were analyzed to optimize the labour intensive protocol for this experimental setup. Photosynthesis varied within the vertical canopy as reflected by measurements on five leaves per plant. Soil respiration was more dependent temporally on soil water availability than on temperature.&lt;/p&gt;

Comparing direct and indirect methods of assessing canopy structure in a northern hardwood forest

2004 ◽  
Vol 34 (3) ◽  
pp. 584-591 ◽  
Author(s):  
Anne G Rhoads ◽  
Steven P Hamburg ◽  
Timothy J Fahey ◽  
Thomas G Siccama ◽  
Richard Kobe
Keyword(s):  
Large Scale ◽  
Canopy Structure ◽  
Hardwood Forest ◽  
Small Scale ◽  
Northern Hardwood Forest ◽  
Ice Storm ◽  
Area Index ◽  
Northern Hardwood ◽  
Visual Damage ◽  
Hemispherical Photographs

Several methods exist for measuring forest canopies following disturbance, and the biases and differences among them are unclear. We compared techniques for measuring the northern hardwood forest's canopy structure at the Hubbard Brook Experimental Forest, New Hampshire, following the severe ice storm of January 5–10, 1998. Methods included leaf area index (LAI) using LI-COR's LAI-2000, visual damage assessments based on tree branch loss, radiation estimates from hemispherical photographs, and LAI determined from litterfall. LAI-2000 measurements were not significantly related to visual damage class estimates, but were strongly correlated with radiation estimates from hemispherical photographs and average LAI values from litterfall. LAI from the LAI-2000 and litterfall differed on a point-by-point basis, but were similar at the stand scale. The LAI-2000 has the highest precision for large-scale measurements. Visual damage estimates appear adequate for assessing large-scale patterns of disturbance intensity in the northern hardwood forest, but the LAI-2000 is more accurate at quantifying canopy structure at large plot or stand scales. Hemispherical photographs may also accomplish this, but are better suited to characterizing the distribution of canopy gaps and light availability patterns over time. Litterfall provides accurate and precise measurements of small-scale LAI patterns in deciduous forests and reveals species-specific patterns.

scholarly journals Influence of climate variability, fire and phosphorus limitation on the vegetation structure and dynamics in the Amazon-Cerrado border

2017 ◽  
Author(s):  
Emily Ane Dionizio da Silva ◽  
Marcos Heil Costa ◽  
Andrea Almeida Castanho ◽  
Gabrielle Ferreira Pires ◽  
Beatriz Schwantes Marimon ◽  
...  
Keyword(s):  
Climate Variability ◽  
Vegetation Structure ◽  
Carbon Allocation ◽  
Net Primary Production ◽  
Field Measurements ◽  
Area Index ◽  
Soil P ◽  
Structure And Dynamics ◽  
Nutritional Limitation ◽  
P Limitation

Abstract. Climate, fire and soil nutritional limitation are important elements that affect the vegetation dynamics in areas of forest-savanna transition. In this paper, we use the dynamic vegetation model INLAND to evaluate the influence of inter-annual climate variability, fire and phosphorus (P) limitation on the Amazon-Cerrado transitional vegetation structure and dynamics. We assess how each environmental factor affects the net primary production, leaf area index and aboveground biomass (AGB), and compare the AGB simulations of observed AGB map. We used two climate datasets – the 1960–1990 average seasonal climate and the 1948 to 2008 inter-annual climate variability, two regional datasets of total soil P content in soil, based on regional (field measurements) and global data and the INLAND fire module. Our results show that inter-annual climate variability, P limitation and fire occurrence gradually improve simulated vegetation types and these effects are not homogeneous along the latitudinal/longitudinal gradient showing a synergistic effect among them. In terms of magnitude, the effect of fire is stronger, and is the main driver of vegetation changes along the transition. The nutritional limitation, in turn, is stronger than the effect of inter-annual climate variability acting on the transitional ecosystems dynamics. Overall, INLAND typically simulates more than 80 % of the AGB variability in the transition zone. However, the AGB in many places is clearly not well simulated, indicating that important soil and physiological factors in the Amazon-Cerrado border, such as lithology and water table depth, carbon allocation strategies and mortality rates, still need to be included in the model.

scholarly journals Detecting Forest Degradation in the Three-North Forest Shelterbelt in China from Multi-Scale Satellite Images

2021 ◽  
Vol 13 (6) ◽  
pp. 1131
Author(s):  
Tao Yu ◽  
Pengju Liu ◽  
Qiang Zhang ◽  
Yi Ren ◽  
Jingning Yao
Keyword(s):  
Remote Sensing ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Net Primary Production ◽  
Remote Sensing Data ◽  
Forest Degradation ◽  
Observation Data ◽  
Area Index ◽  
Sensing Data ◽  
Multi Scale

Detecting forest degradation from satellite observation data is of great significance in revealing the process of decreasing forest quality and giving a better understanding of regional or global carbon emissions and their feedbacks with climate changes. In this paper, a quick and applicable approach was developed for monitoring forest degradation in the Three-North Forest Shelterbelt in China from multi-scale remote sensing data. Firstly, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Ratio Vegetation Index (RVI), Leaf Area Index (LAI), Fraction of Photosynthetically Active Radiation (FPAR) and Net Primary Production (NPP) from remote sensing data were selected as the indicators to describe forest degradation. Then multi-scale forest degradation maps were obtained by adopting a new classification method using time series MODerate Resolution Imaging Spectroradiometer (MODIS) and Landsat Enhanced Thematic Mapper Plus (ETM+) images, and were validated with ground survey data. At last, the criteria and indicators for monitoring forest degradation from remote sensing data were discussed, and the uncertainly of the method was analyzed. Results of this paper indicated that multi-scale remote sensing data have great potential in detecting regional forest degradation.

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