scholarly journals Tropical montane cloud forest: environmental drivers of vegetation structure and ecosystem function

2015 ◽  
Vol 32 (5) ◽  
pp. 355-367 ◽  
Author(s):  
Timothy J. Fahey ◽  
Ruth E. Sherman ◽  
Edmund V.J. Tanner
Keyword(s):  
Leaf Area ◽  
Carbon Fixation ◽  
Cloud Forest ◽  
Climatic Conditions ◽  
Environmental Drivers ◽  
Nutrient Concentrations ◽  
Shoot Biomass ◽  
Height Ratio ◽  
Area Index ◽  
Multiple Stems

Abstract:Tropical montane cloud forests (TMCF) are characterized by short trees, often twisted with multiple stems, with many stems per ground area, a large stem diameter to height ratio, and small, often thick leaves. These forests exhibit high root to shoot ratio, with a moderate leaf area index, low above-ground production, low leaf nutrient concentrations and often with luxuriant epiphytic growth. These traits of TMCF are caused by climatic conditions not geological substrate, and are particularly associated with frequent or persistent fog and low cloud. There are several reasons why fog might result in these features. Firstly, the fog and clouds reduce the amount of light received per unit area of ground and as closed-canopy forests absorb most of the light that reaches them the reduction in the total amount of light reduces growth. Secondly, the rate of photosynthesis per leaf area declines in comparison with that in the lowlands, which leads to less carbon fixation. Nitrogen supply limits growth in several of the few TMCFs where it has been investigated experimentally. High root : shoot biomass and production ratios are common in TMCF, and soils are often wet which may contribute to N limitation. Further study is needed to clarify the causes of several key features of TMCF ecosystems including high tree diameter : height ratio.

Relationship Between Leaf Area Index and Atmospheric Cooling of Tree Species

2019 ◽  
Vol 42 (3) ◽  
pp. 203-208
Author(s):  
S. K. Gupta ◽  
◽  
Jeet Ram ◽  
Hukum Singh ◽  
◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Mangifera Indica ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Strong Positive Correlation ◽  
Evergreen Species ◽  
Terrestrial Environment ◽  
Area Index ◽  
Effective Measure

Presence of tree canopy is known to strongly influence ambient temperature and other micro-climatic conditions underneath. Therefore, planting trees with close or dense crown can be used as effective measure to provide thermal cover to species of flora and fauna adapted to shady and cooler environment. The cooling produced by a tree is exclusively the combined results of physical and physiological functions of its canopy. Tree canopy is one of the most important, physiologically active components that establish interaction between the terrestrial environment and the atmosphere which regulates various bio-physiological processes. Leaf Area Index (LAI) is one of the most reliable indicators of growth and vigour of a tree. We compared LAI and corresponding understory temperature of a few isolated trees of Ficus benjamina, Mangifera indica, Anthocephalus chinensis, Lagerstroemia floribunda and Peltophorum africanum belonging to evergreen, semi-deciduous and deciduous nature to establish the relationship between the two parameters. A great variation in LAIs of deciduous and semi-deciduous species was observed on account of leaf shedding and fast development of crown after emergence of new leaves whereas the variation was lesser in evergreen species. A strong positive correlation was found between LAI and cooling produced by A. chinensis, L. floribunda and P. africanum whereas no linear relation was established in case of M. indica and F. benjamina.

scholarly journals Response of Soil Temperature, Moisture, and Spring Maize (Zea mays L.) Root/Shoot Growth to Different Mulching Materials in Semi-Arid Areas of Northwest China

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 453
Author(s):  
Haidong Lu ◽  
Zhenqing Xia ◽  
Yafang Fu ◽  
Qi Wang ◽  
Jiquan Xue ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Soil Water ◽  
Leaf Area ◽  
Growth Period ◽  
Soil Water Storage ◽  
Shoot Biomass ◽  
Growth Stages ◽  
Plastic Film ◽  
Area Index ◽  
Spring Maize

Adaptive highly efficient mulching technologies for use on dryland agricultural ecosystems are crucial to improving crop productivity and water-use efficiency (WUE) under climate change. Little information is available on the effect of using different types of mulch on soil water thermal conditions, or on root/shoot trait, leaf area index (LAI), leaf area duration (LAD), yield, and WUE of spring maize. Hence, in this study, white transparent plastic film (WF), black plastic film (BF), and maize straw (MS) was used, and the results were compared with a non-mulched control (CK). The results showed that the mean soil temperature throughout the whole growth period of maize at the 5–15 cm depth under WF and BF was higher than under MS and CK, but under BF, it was 0.6 °C lower than WF. Compared with CK, the average soil water storage (0–200 cm) over the whole growth period of maize was significantly increased under WF, BF, and MS. WF and BF increased the soil water and temperature during the early growth stages of maize and significantly increased root/shoot biomass, root volume, LAI, LAD, and yield compared with MS. Higher soil temperatures under WF obviously reduced the duration of maize reproductive growth and accelerated root and leaf senescence, leading to small root/shoot biomass accumulation post-tasseling and to losses in yield compared with BF

scholarly journals Production of lettuce in NFT hydroponic system at different planting seasons and irrigation regimes

2020 ◽  
pp. 1042-1047
Author(s):  
Cláudio Silva Soares ◽  
Alde Cleber Silva de Lima ◽  
Jeneilson Alves da Silva ◽  
Marina Suenia de Araújo Vilar ◽  
André Luiz Pereira da Silva ◽  
...  
Keyword(s):  
Leaf Area ◽  
Arid Regions ◽  
Climatic Conditions ◽  
Growth And Yield ◽  
Leaf Biomass ◽  
Area Index ◽  
Hydroponic System ◽  
Satisfactory Performance ◽  
Irrigation Regimes ◽  
Calcium Iron

Hydroponics has drawn huge interests by Brazilians in semi-arid regions due to the lack of water and fertilizer use. The objective of this study was to evaluate the growth and yield of lettuce cultivars in the hydroponic system in two planting seasons and different irrigation regimes. The research was carried out in Campus II / UEPB and followed a 2 x 6 x 3 factorial scheme in randomized blocks, represented by two planting seasons (the summer and the winter), six lettuce cultivars (Elba, Great Lakes, Mimosa Rose, Simpson, American, Cristina), three irrigation regimes (15 min, 30 min, 45 min) and five replications. The hydroponic system used was the NFT. For nutrition, Hidrogood Fert® solution (Compound + Calcium + Iron) was applied. At the 40th day after sowing, green and dry leaf biomass, green stem biomass, leaf area, leaf area index and productivity were analyzed. After that, the variance analysis was performed by the F-test for 5% of probability and the Scott-Knott test for comparison of the averages. The high temperatures caused very small growth in the stem of the Simpson cultivars, independent of the irrigation regime used. Besides the highlight of the American cultivars, the other cultivars presented satisfactory performance in the climatic conditions of Lagoa Seca / PB.

scholarly journals Growth analysis of chickpea (Cicer arietinum L.)

1994 ◽  
Vol 51 (3) ◽  
pp. 430-435 ◽  
Author(s):  
S.S.S. Nogueira ◽  
V. Nagai ◽  
N.R. Braga ◽  
M. Do C.S.S. Novo ◽  
M.B.P. Camargo
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Matter ◽  
Growth Analysis ◽  
Climatic Conditions ◽  
Area Index ◽  
Experimental Station ◽  
Matter Production ◽  
Winter Crop ◽  
Quadratic Models

An experiment to study the growing pattern of a chickpea variety, IAC-Marrocos, was carried out at the Monte Alegre Experimental Station, SP, during 1987 and 1988. The dry matter production of all parts of the plant, as well the leaf area index, were weekly evaluated. Exponential quadratic models of regression were adjusted to total dry matter, leaf dry matter and leaf area index, and a linear model to dry matter of grain. Based on the growth analysis it was concluded that the chickpea is a rustic eatable plant that can be recommended as an alternative winter crop for similar climatic conditions as those of the experiment.

Effects of repeated fertilization on needle longevity, foliar nutrition, effective leaf area index, and growth characteristics of lodgepole pine in interior British Columbia, Canada

2005 ◽  
Vol 35 (2) ◽  
pp. 440-451 ◽  
Author(s):  
Isaac G Amponsah ◽  
Philip G Comeau ◽  
Robert P Brockley ◽  
Victor J Lieffers
Keyword(s):  
British Columbia ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Response ◽  
Lodgepole Pine ◽  
Nitrogen Concentration ◽  
Nutrient Concentrations ◽  
Area Index ◽  
Needle Longevity ◽  
Effective Leaf Area Index

We investigated the effects of repeated fertilization (either periodically every 6 years or annual fertilization) on needle longevity and growth response in two juvenile lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stands in the interior of British Columbia, Canada. Annual fertilization decreased needle longevity by 23% at the Kenneth Creek site and by 30% at Sheridan Creek, compared with the control treatments at each site. At Sheridan, repeated fertilization significantly increased effective leaf area index, foliated shoot length, and annual shoot growth. However, none of these variables was significantly altered by repeated fertilization at Kenneth. At both locations, fertilization elevated nutrient concentrations in the current year's foliage. Annual fertilization increased nitrogen concentration in mid-crown branches of retained cohorts (1998–2002) at both study sites. Furthermore, annual nitrogen addition apparently induced or exacerbated copper and iron deficiency in these stands, especially at Kenneth Creek, which may be related to the premature loss of foliage. Nutrient imbalance may also be related to poor effective leaf area index and growth response at Kenneth Creek. Stem growth efficiency declined with annual fertilization at Kenneth Creek because of accelerated turnover of needles, increased allocation of growth to branches, and probably reduced photosynthetic capacity.

scholarly journals Simulation of soybean growth and yield under northeastern Amazon climatic conditions

2011 ◽  
Vol 46 (6) ◽  
pp. 567-577 ◽  
Author(s):  
Paulo Jorge de Oliveira Ponte de Souza ◽  
José Renato Bouças Farias ◽  
José Paulo Mourão de Melo e Abreu ◽  
Aristides Ribeiro ◽  
Edson José Paulino da Rocha ◽  
...  
Keyword(s):  
Leaf Area ◽  
Meteorological Data ◽  
Climatic Conditions ◽  
Growth And Yield ◽  
Slight Reduction ◽  
Total Biomass ◽  
Independent Data ◽  
Yield Model ◽  
Area Index ◽  
Soybean Yield

The objective of this work was to parameterize, calibrate, and validate a new version of the soybean growth and yield model developed by Sinclair, under natural field conditions in northeastern Amazon. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, PA, Brazil, from 2006 to 2009. The climatic conditions during the experiment were very distinct, with a slight reduction in rainfall in 2007, due to the El Niño phenomenon. There was a reduction in the leaf area index (LAI) and in biomass production during this year, which was reproduced by the model. The simulation of the LAI had root mean square error (RMSE) of 0.55 to 0.82 m² m-2, from 2006 to 2009. The simulation of soybean yield for independent data showed a RMSE of 198 kg ha-1, i.e., an overestimation of 3%. The model was calibrated and validated for Amazonian climatic conditions, and can contribute positively to the improvement of the simulations of the impacts of land use change in the Amazon region. The modified version of the Sinclair model is able to adequately simulate leaf area formation, total biomass, and soybean yield, under northeastern Amazon climatic conditions.

The growth of swards of subterranean clover with particular reference to leaf area

1958 ◽  
Vol 9 (1) ◽  
pp. 53 ◽  
Author(s):  
JL Davidson ◽  
CM Donald
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Substantial Reduction ◽  
Ground Surface ◽  
Subterranean Clover ◽  
Climatic Conditions ◽  
Dry Matter Production ◽  
Leaf Production ◽  
Area Index ◽  
Matter Production

An experiment was conducted to study the growth of subterranean clover (Trifolium subterraneum L.) sown at different densities; the control swards were not defoliated while others were subjected to a single defoliation at various dates. During the final month the rate of dry matter production (tops only) increased to a maximum when the leaf area index (the ratio of the area of the leaves to the area of the ground surface — L.A.I.) was about 4-5, falling by about 30 per cent. as the L.A.I. increased to 8.7. The rate of leaf production was greatest at about L.A.I. 4-5, falling to zero at L.A.I. 8.7. Climatic conditions during the growing season influenced the relationship of L.A.I. to growth; as conditions became more favorable the values of the optimum LA.1. for growth and of the ceiling L.,4.1. progressively rose. Irrespective of the density, all swards tended towards a common ceiling L.A.I. and yield by the end of the season. The effect of defoliation depended on the L.A.I. at which defoliation occurred, on the value to which the L.A.I. was reduced, and on current climatic conditions. If swards near the ceiling L.A.I. were defoliated, total dry matter production was slightly increased and there was a great increase in leaf production. On the other hand, defoliation of swards from about the optimum L.A.I. to very low L.A.I. values led to a substantial reduction in both dry matter and leaf production. It is suggested that all these effects depend on the light relationships within the sward and their influence on the balance of photosynthesis and respiration. Pasture at the optimum L.A.I. will give greater production than swards of lower or higher L.A.I.; defoliation can give greatly increased leaf production, unless L.A.I. is reduced to very low values.

Leaf properties, litter fall, and nutrient inputs of Terminalia ivorensis at different tree stand densities in a tropical timber - food crop multistrata system

2000 ◽  
Vol 30 (9) ◽  
pp. 1400-1409 ◽  
Author(s):  
L Norgrove ◽  
S Hauser
Keyword(s):  
Leaf Area ◽  
Leaf Litter ◽  
Specific Leaf Area ◽  
Nutrient Concentrations ◽  
Litter Production ◽  
Food Crops ◽  
Litter Fall ◽  
Nutrient Inputs ◽  
Area Index ◽  
Tropical Timber

Tree litter fall was monitored for 2 years in two Terminalia ivorensis A. Chev. plantations in the humid tropics of southern Cameroon. The plantations were 6 and 17 years old when they were each thinned to two timber stand densities (TSD) and understorey food crops were introduced. Leaf litter was the predominant litter fraction in all treatments. Treatment means of specific leaf area for T. ivorensis ranged from 83.7 to 100.7 cm2·g-1. Litter-fall production, leaf area per tree, and leaf area index for T. ivorensis were all higher in year 2 than in year 1. There was near complete defoliation of the T. ivorensis stand by Epicerura sp. (Lepidoptera: Notodontidae) caterpillars in the month just before the start of litter-fall sampling. This is the first report of an Epicerura sp. from Cameroon. Terminalia ivorensis leaf litter production per tree, specific leaf area, and leaf litter nutrient concentrations showed few significant differences between TSD treatments. This lack of response suggests that T. ivorensis is a suitable species for growing at stand densities lower than is normal silvicultural practice in association with food crops.

scholarly journals Improving remote estimation of winter crops gross ecosystem production by inclusion of leaf area index in a spectral model

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5613 ◽  
Author(s):  
Radosław Juszczak ◽  
Bogna Uździcka ◽  
Marcin Stróżecki ◽  
Karolina Sakowska
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spring Barley ◽  
Crop Productivity ◽  
Climatic Conditions ◽  
Area Index ◽  
Gross Ecosystem Production ◽  
Ecosystem Production ◽  
Winter Crops ◽  
Remote Estimation

The hysteresis of the seasonal relationships between vegetation indices (VIs) and gross ecosystem production (GEP) results in differences between these relationships during vegetative and reproductive phases of plant development cycle and may limit their applicability for estimation of croplands productivity over the entire season. To mitigate this problem and to increase the accuracy of remote sensing-based models for GEP estimation we developed a simple empirical model where greenness-related VIs are multiplied by the leaf area index (LAI). The product of this multiplication has the same seasonality as GEP, and specifically for vegetative periods of winter crops, it allowed the accuracy of GEP estimations to increase and resulted in a significant reduction of the hysteresis of VIs vs. GEP. Our objective was to test the multiyear relationships between VIs and daily GEP in order to develop more general models maintaining reliable performance when applied to years characterized by different climatic conditions. The general model parametrized with NDVI and LAI product allowed to estimate daily GEP of winter and spring crops with an error smaller than 14%, and the rate of GEP over- (for spring barley) or underestimation (for winter crops and potato) was smaller than 25%. The proposed approach may increase the accuracy of crop productivity estimation when greenness VIs are saturating early in the growing season.

Sampling gap fraction and size for estimating leaf area and clumping indices from hemispherical photographs

2010 ◽  
Vol 40 (8) ◽  
pp. 1588-1603 ◽  
Author(s):  
Alemu Gonsamo ◽  
Jean-Michel N. Walter ◽  
Petri Pellikka
Keyword(s):  
Leaf Area ◽  
Cloud Forest ◽  
Hemispherical Photography ◽  
Biophysical Parameters ◽  
Area Index ◽  
Plant Canopies ◽  
Gap Fraction ◽  
Tropical Cloud Forest ◽  
Exotic Plantations

Hemispherical photography is becoming a popular technique for gap fraction measurements to characterize biophysical parameters and solar radiation in plant canopies. One of the crucial steps in the measurement of canopy gap fraction using hemispherical photography is determining the resolution of the sampling grid. In this work, the effects of varying resolutions of sampling grids by modifying the angle widths of zenithal annuli and azimuthal sectors were evaluated for leaf area and clumping indices computations. Sensitivity analysis was performed to test these effects using artificial photographs simulating ideal canopies with varying leaf area index and aggregation levels of foliage elements. Contrasting forest types, including natural tropical cloud forest and exotic plantations, were tested as real canopies. Results indicate that leaf area and clumping indices estimates are significantly affected by the variation of sampling grids. A new approach to solve the problem of null-gap segments, obscured completely by foliage, is proposed. However, the determination of optimal combinations of zenithal annuli and azimuthal sector angular widths that suit all canopy types remains a difficult practical problem that is often overlooked. Finally, theoretically sound gap fraction and size sampling regions were demonstrated for reliable estimates of canopy biophysical parameters.

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