scholarly journals Carbon Storage of some Rubber Trees (Hevea brasiliensis) Clones in HEVECAM’s Plantations in South Cameroon

2021 ◽  
Author(s):  
Menoh A Ngon René ◽  
Tsoata Esaïe ◽  
Tsouga Manga Milie Lionelle ◽  
Owona Ndongo Pierre-André
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Carbon Storage ◽  
Rubber Tree ◽  
Tree Height ◽  
Allometric Equation ◽  
Morphological Parameters ◽  
Area Index ◽  
Significant Difference ◽  
Total Tree

The objective of this work was to estimate the quantity of carbon stored by four main clones of rubber tree cultivated in South Cameroon: GT 1, PB 217, PR 107 and RRIC 100. The forest inventory method was used to measure trees morphological parameters, the latter used to calculate carbon storage using the allometric equation of Wauters et al., (2008). The main morphological parameters measured were: leaf area index (LAI), circumference (C), diameter at breast height (DBH) and total tree height (h). Comparing the morphological parameters of clones two by two using a Dunn test, we observe significant differences in the circumference, the diameter and even very significant in the leaf area index, but not in the height. The clones GT 1, PR 107, PB 217, and RRIC 100 stored on average: 111.05 tC / ha, 150.18 tC / ha, 165.25 tC / ha, and 187.25 tC/ha respectively. A significant difference was established between the means of carbon storage of the clones GT 1 and PB 217 (p = 0.0488) on one hand and, that of the clones GT 1 and RRIC 100 (p = 0.0240), on the other hand. These results are an estimation of models, further research can be undertaken for exact measurements.

Seed size as a factor in the growth of subterranean clover (Trifolium subterraneum L.) under spaced and sward conditions

1957 ◽  
Vol 8 (4) ◽  
pp. 335 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Seed Size ◽  
Seed Weight ◽  
Agricultural Research ◽  
Incident Light ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Area Index ◽  
Significant Difference

The significance of seed weight in the growth of subterranean clover (Trifolium subterraneum L) , of the Bacchus Marsh strain, has been assessed under both spaced plant and sward conditions at the Waite Agricultural Research Institute. Under conditions of spacing, plants of three widely separated seed size grades were grown a t a density of 1 per 25 sq. links. The dry weights of the plants were proportional to seed weight from the time of sowing (in May) till the end of October – over almost the entire growing period of the crop. Three sets of swards were grown a t a density of 25 plants per sq. link, each sward being planted with seed of one of the three sizes. Dry weight was proportional to seed weight in the early part of the season but when the swards reached a leaf area index of about 4 (i.e. when there were 4 sq. links of leaf surface on 1 sq. link of ground), a reduction in growth rate occurred. This critical leaf area index was reached first in "large seed" swards, followed later by "medium seed" and finally by "small seed" swards. Thus there was a period in which the swards were growing at different rates, and in which the dry weights came to parity, so that on the final sampling occasion (in December) there was no significant difference between the dry weights of the swards from the three seed sizes. It is concluded that a t a leaf area index of about 4, interception of incident light energy is complete.

scholarly journals DIEBACK, LEAF AREA INDEX AND YIELD OF YOUNG EUCALYPT CLONES PLANTATION IN THE BRAZILIAN SAVANNAH REGION

2018 ◽  
Vol 41 (3) ◽  
Author(s):  
Geraldo Gonçalves dos Reis ◽  
Frederico de Freitas Alves ◽  
Maria das Graças Ferreira Reis ◽  
Felippe Coelho de Souza ◽  
Diogo Sena Baiero ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Soil Water ◽  
Leaf Area ◽  
Water Deficit ◽  
Tree Height ◽  
Low Fertility ◽  
Limiting Factor ◽  
Soil Water Deficit ◽  
Area Index ◽  
Brazilian Savannah

ABSTRACT Eucalypt has been widely planted in Brazil, in the savannah region, which is characterized by high soil water deficit and low fertility. Dieback, leaf area index (LAI) and yield of young stands of 16 eucalypt clones were studied in Vazante, MG, Brazil (17º36’09"S and 46º 42’02"W). It was determined for each clone: a) the proportion of the tree height with dieback symptoms in the apical terminal (HWD%) and the proportion of trees with dieback (NWD%), at 13 months (end of the first dry season); b) the LAI at 13 and 21 months, and c) the yield at the age of 13, 19 and 25 months. HWD% reached 5-9%, and NWD%, 50-80%, for the five most susceptible clones, when the soil water deficit reached 508 mm in the year. LAI varied from 0.61 to 1.56, at 13 months, and from 2.31 to 3.48 at 21 months, presenting inverse relationship with dieback. The least susceptible clones to dieback achieved the highest yield up to 25 months of age. There was interaction between dieback and fertilizer levels only for three clones. There was a positive correlation (p < 0.001) between the LAI at the age of 13 months and the periodic monthly increment from 0 to 11 months, and from 11 to 19 months. The difference in dieback susceptibility among clones allows the selection of genotypes for regions where the soil water deficit is a major limiting factor.

scholarly journals Rule-based analysis of throughfall kinetic energy to evaluate biotic and abiotic factor thresholds to mitigate erosive power

2016 ◽  
Vol 40 (3) ◽  
pp. 431-449 ◽  
Author(s):  
Philipp Goebes ◽  
Karsten Schmidt ◽  
Werner Härdtle ◽  
Steffen Seitz ◽  
Felix Stumpf ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Abiotic Factors ◽  
Tree Height ◽  
Abiotic Factor ◽  
Area Index ◽  
Biotic And Abiotic Factors ◽  
Optimal Set

Below vegetation, throughfall kinetic energy (TKE) is an important factor to express the potential of rainfall to detach soil particles and thus for predicting soil erosion rates. TKE is affected by many biotic (e.g. tree height, leaf area index) and abiotic (e.g. throughfall amount) factors because of changes in rain drop size and velocity. However, studies modelling TKE with a high number of those factors are lacking. This study presents a new approach to model TKE. We used 20 biotic and abiotic factors to evaluate thresholds of those factors that can mitigate TKE and thus decrease soil erosion. Using these thresholds, an optimal set of biotic and abiotic factors was identified to minimize TKE. The model approach combined recursive feature elimination, random forest (RF) variable importance and classification and regression trees (CARTs). TKE was determined using 1405 splash cup measurements during five rainfall events in a subtropical Chinese tree plantation with five-year-old trees in 2013. Our results showed that leaf area, tree height, leaf area index and crown area are the most prominent vegetation traits to model TKE. To reduce TKE, the optimal set of biotic and abiotic factors was a leaf area lower than 6700 mm2, a tree height lower than 290 cm combined with a crown base height lower than 60 cm, a leaf area index smaller than 1, more than 47 branches per tree and using single tree species neighbourhoods. Rainfall characteristics, such as amount and duration, further classified high or low TKE. These findings are important for the establishment of forest plantations that aim to minimize soil erosion in young succession stages using TKE modelling.

scholarly journals Phenological patterns of defoliation and refoliation processes of rubber tree clones in the Colombian northwest

2020 ◽  
Vol 73 (3) ◽  
pp. 9293-9303
Author(s):  
Juan José Guerra-Hincapié ◽  
Óscar De Jesús Córdoba-Gaona ◽  
Juan Pablo Gil-Restrepo ◽  
Danilo Augusto Monsalve-García ◽  
Juan David Hernández-Arredondo ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Management Strategies ◽  
Rubber Tree ◽  
Principal Component ◽  
Canopy Openness ◽  
Area Index ◽  
The Relationship ◽  
Climatic Characteristic

The knowledge of the defoliation-refoliation process in rubber cultivation allows the development of management strategies in the production system to improve rubber yield. The objective of this study was to determine the intensity and duration of defoliation-refoliation of rubber clones FX 3864, IAN 710 and IAN 873 in the municipality of Tarazá and the FX 3864 and IAN 873 clones in the municipality of Nechí (northwestern Colombia). From October 2015 to June 2016, the measurements of the necromass were carried out in each location for each clone. The light environment was quantified, employing the hemispheric photographs technique to estimate canopy openness percentage (CO) and leaf area index. The assessed weeks were grouped by Principal Component Analysis (PCA) based on the original phenology and climatic variables. The defoliation-refoliation process was analyzed descriptively using graphical representations of the trend for the phenological variables that best described this process. The relationship between climatic and phenological variables in the period evaluated was evidenced; the rainfall was the most critical climatic characteristic in the induction of the defoliation process. The leaf area index was reduced to a minimum value in February, with values of 0.52 for IAN 710 clone in Tarazá, and 0.64 for the IAN 873 clone in Nechí, which corresponded to the highest defoliation stage in both locations. The refoliation period was short (4 to 6 weeks) and occurred during the dry season for all the clones in both places.

scholarly journals Aboveground Wood Production Is Sustained in the First Growing Season after Phloem-Disrupting Disturbance

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1306
Author(s):  
Maxim S. Grigri ◽  
Jeff W. Atkins ◽  
Christoph Vogel ◽  
Ben Bond-Lamberty ◽  
Christopher M. Gough
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Net Primary Production ◽  
Small Diameter ◽  
Growing Season ◽  
Wood Production ◽  
Area Index ◽  
C Cycling ◽  
Significant Difference ◽  
Successional Species

Carbon (C) cycling processes are particularly dynamic following disturbance, with initial responses often indicative of longer-term change. In northern Michigan, USA, we initiated the Forest Resilience Threshold Experiment (FoRTE) to identify the processes that sustain or lead to the decline of C cycling rates across multiple levels (0, 45, 65 and 85% targeted gross leaf area index loss) of disturbance severity and, in response, to separate disturbance types preferentially targeting large or small diameter trees. Simulating the effects of boring insects, we stem girdled > 3600 trees below diameter at breast height (DBH), immediately and permanently disrupting the phloem. Weekly DBH measurements of girdled and otherwise healthy trees (n > 700) revealed small but significant increases in daily aboveground wood net primary production (ANPPw) in the 65 and 85% disturbance severity treatments that emerged six weeks after girdling. However, we observed minimal change in end-of-season leaf area index and no significant differences in annual ANPPw among disturbance severities or between disturbance types, suggesting continued C fixation by girdled trees sustained stand-scale wood production in the first growing season after disturbance. We hypothesized higher disturbance severities would favor the growth of early successional species but observed no significant difference between early and middle to late successional species’ contributions to ANPPw across the disturbance severity gradient. We conclude that ANPPw stability immediately following phloem disruption is dependent on the continued, but inevitably temporary, growth of phloem-disrupted trees. Our findings provide insight into the tree-to-ecosystem mechanisms supporting stand-scale wood production stability in the first growing season following a phloem-disrupting disturbance.

scholarly journals Potential and Limits of Retrieving Conifer Leaf Area Index Using Smartphone Camera Sensors

2017 ◽  
Author(s):  
Yonghua Qu ◽  
Jian Wang ◽  
Jinling Song ◽  
Jindi Wang
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Zenith Angle ◽  
Tree Height ◽  
Measuring Instruments ◽  
Conifer Forest ◽  
Area Index ◽  
Gap Fraction ◽  
Smartphone Sensors ◽  
Camera Sensors

Plant leaf area index (LAI) is a key characteristic affecting field canopy microclimate. In addition to traditional professional measuring instruments, smartphone camera sensors have been used to measure plant LAI. However, when smartphone methods were used to measure conifer forest LAI, very different performances were obtained depending on whether the smartphone was held at the zenith angle or at a 57.5&deg; angle. To validate further the potential of smartphone sensors for measuring conifer LAI and to find the limits of this method, this paper reports the results of a comparison of two smartphone methods with an LAI-2000 instrument. It is shown that both methods can be used to reveal the conifer leaf-growing trajectory. However, the method with the phone oriented vertically upwards always produced better consistency in magnitude with LAI-2000. The bias of the LAI between the smartphone method and the LAI-2000 instrument was explained with regard to four aspects that can affect LAI: gap fraction, leaf projection ratio, sensor field of view (FOV), and viewing zenith angle (VZA). It was concluded that large FOV and large VZA cause the 57.5&deg; method to overestimate the gap fraction and hence underestimate conifer LAI, especially when tree height is greater than 2.0 m. For the vertically upward method, the bias caused by the overestimated gap fraction is compensated for by an underestimated leaf projection ratio.

scholarly journals Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

2006 ◽  
Vol 131 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Libertad Mascarini ◽  
Gabriel A. Lorenzo ◽  
Fernando Vilella
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Limiting Factor ◽  
Simple Method ◽  
Area Index ◽  
Water Index ◽  
Significant Difference ◽  
Shoot System

In roses (Rosa ×hybrida L.), the bending of branches is a technique that modifies the canopy of the plant and could affect such parameters as the leaf area index (LAI), the quality of reflected light, and the water index (WI) of the plant. The measurement of spectral reflectance with remote sensors is a nondestructive, quick, and simple method to study these parameters. The aim of this paper is to quantify the modification of reflected radiation quality, the LAI and the water index of the plant with different canopies, and its impact on flowering and the number and quality of flowers produced. In R. ×hybrida `Terracotta', using the spectral crop reflectance, the red: far red ratio [red (R) = 680 nm; far red (FR) = 730 nm], percentage of blue light of reflected radiation, and vegetation indices [normalized difference vegetation index (NDVI), simple ratio index (SRI), water index (WI)] were calculated in two architectural managements: traditional (upright hedge) and bent shoot. NDVI had a greater correlation with LAI than SRI (r2 = 0.98 and 0.85, respectively), but SRI was more reliable for LAI values of 1 to 3.5. The bent shoot system compared to the traditional one decreased the R:FR ratio of reflected radiation and increased LAI and plant water content. These changes were related to a higher commercial quality of the flowers (longer flowering shoots with a larger stem diameter and fresh weight), although there was no significant difference in the number of flowers harvested. The period that showed the largest difference in the quality of the flower using the bent shoot system had a LAI of 2.8 vs. 1.8 with traditional management and a marked reduction in the R:FR of the light reflected by bent plants. The bent shoot system advanced the peak production by 1 month at the end of winter and improved the flowers at a time when sun radiation is limiting factor for production.

The growth and development of Corchorus olitorius (L.) grown alone and intercropped with tomato (Lycopersicon esculentum (Mill.))

1987 ◽  
Vol 109 (1) ◽  
pp. 39-45 ◽  
Author(s):  
I. M. Ojeifo ◽  
E. O. Lucas
Keyword(s):  
Lycopersicon Esculentum ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Growth And Development ◽  
Morphological Characters ◽  
Corchorus Olitorius ◽  
Economic Returns ◽  
Area Index ◽  
Maximum Value ◽  
Significant Difference

SummaryTwo experiments were conducted on two varieties of Corchorus olitorius(‘NHCo 6’ and ‘NHCo 7’). The first one was on the effect of density of planting on their growth and development whilst the second was on the best planting ratio for Corchorus-tomato intercropping.There was no significant difference in morphological characters of the two varieties. The maximum value of leaf area index for the two varieties was around 3. Maximum marketable and edible yields were obtained for the two varieties at 30 × 5 cm (666600 plants/ha) and the best time for harvesting was 44 days after sowing.The best planting ratio for Corchorus-tomato intercrop was 2 rows of Corchorus and 1 row of tomato for maximum edible yield of Corchorus but for maximum economic returns, the best ratio was 1 row of Corchorus to 2 rows of tomato.

Effects of treated municipal wastewater on fluctuation trend of leaf area index and quality of maize (Zea mays)

2013 ◽  
Vol 67 (4) ◽  
pp. 797-802 ◽  
Author(s):  
Sayed Roholla Mousavi ◽  
Mohammad Galavi ◽  
Hamdollah Eskandari
Keyword(s):  
Zea Mays ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Municipal Wastewater ◽  
Clean Water ◽  
Area Index ◽  
Growing Period ◽  
Significant Difference ◽  
Treated Municipal Wastewater

The effect of primary-treated municipal wastewater (TMWW) on the leaf area index (LAI) and quality of maize (Zea mays) was studied in comparison to the clean irrigation water (control). The experiment was based on a randomized block design with four replicates, and it was conducted in a field experiment in Aligoudarz (Iran). Irrigation was applied with five different methods as treatments: T1: irrigation with clean water during whole growing period (control); T2: 75% clean water and 25% TMWW; T3: 50% clean water and 50% TMWW; T4: 25% clean water and 75% TMWW; T5: irrigation with TMWW during whole growing period. Results showed that irrigation with TMWW had a significant positive impact on all characters compared with the control. Maximum LAI was yielded on the 80th day after emergence in T4. Use of TMWW increased seed oil to 5.85%, which was 29.2% more than that in the control. Maximum values for percentage of protein, total dry matter and phosphorus concentration were obtained in T5. Maximum zinc concentration (15.93 mg kg−1) was obtained in T4; it was 8% more than the control. According to the results there was no significant difference in treatment T4 and T5.

Fast determination of light availability and leaf area index in tropical forests

2002 ◽  
Vol 18 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Laurent Cournac ◽  
Marc-Antoine Dubois ◽  
Jérôme Chave ◽  
Bernard Riéra
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Optical Sensors ◽  
Light Availability ◽  
Tree Height ◽  
Light Transmittance ◽  
Limiting Factor ◽  
Area Index ◽  
Gap Fraction ◽  
Direct Measurements

An important property of plant communities is the Leaf Area Index (LAI), which is the vertically integrated surface of leaves per unit of ground area. Leaves are the primary sites of photosynthesis and transpiration, thus the LAI, which conditions the light interception by the canopy, is directly related to carbon and water exchange with the atmosphere at the stand scale (McNaughton & Jarvis 1983). LAI also has an impact on tree growth through the interception of light. Light availability below canopies is the principal limiting factor of tree recruitment and growth in forests (Denslow et al. 1990). Several methodologies have been used for measuring LAI in the field. These can be classiffed in four categories (Marshall & Waring 1986): (1) direct measurements by litterfall collection or destructive sampling, (2) allometric correlations with variables such as tree height or tree diameter, (3) gap-fraction assessment (e.g. with hemispherical photographs), (4) measurement of light transmittance with optical sensors.

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