scholarly journals Seasonal and drought‐related changes in leaf area profiles depend on height and light environment in an Amazon forest

2019 ◽  
Vol 222 (3) ◽  
pp. 1284-1297 ◽  
Author(s):  
Marielle N. Smith ◽  
Scott C. Stark ◽  
Tyeen C. Taylor ◽  
Mauricio L. Ferreira ◽  
Eronaldo Oliveira ◽  
...  
Keyword(s):  
Leaf Area ◽  
Light Environment ◽  
Amazon Forest

scholarly journals Amazon forest carbon dynamics predicted by profiles of canopy leaf area and light environment

2012 ◽  
Vol 15 (12) ◽  
pp. 1406-1414 ◽  
Author(s):  
Scott C. Stark ◽  
Veronika Leitold ◽  
Jin L. Wu ◽  
Maria O. Hunter ◽  
Carolina V. de Castilho ◽  
...  
Keyword(s):  
Leaf Area ◽  
Carbon Dynamics ◽  
Forest Carbon ◽  
Light Environment ◽  
Amazon Forest

Morphology of young sugarcane stalks produced at different stages of crop development

2008 ◽  
Vol 59 (2) ◽  
pp. 149 ◽  
Author(s):  
B. Salter ◽  
G. D. Bonnett ◽  
R. J. Lawn
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Leaf Length ◽  
Light Environment ◽  
Sucrose Content ◽  
Leaf Lamina ◽  
Crop Development ◽  
Breadth Ratio ◽  
Morphological Differences ◽  
Plant Crop

Sugarcane suckers are tillers that appear late in crop development. They dilute the sucrose content of the harvested cane at the mill, reducing grower profitability. Suckers appear to have different morphology from other sugarcane stalks. Experiments were established to quantify some of these morphological differences, to determine whether these differences were conserved across a vegetatively propagated generation, and to investigate the influence of the mature stalk to which the sucker is attached on sucker morphology. Experiments were established in northern Queensland, Australia, using cvv. Q117, Q138, and Q152 to compare suckers with young primary stalks in a plant crop and/or young ratoon stalks. Leaf lamina length, breadth, area, height to last fully expanded leaf, internode diameter, and growth measurements were taken. Suckers had broader leaves, resulting in a smaller leaf length/breadth ratio, longer leaf sheaths, and lower specific leaf area at least for the first 3 leaves. Sucker stalks were thicker than normal stalks. Sucker growth was highly variable, but some were able to outgrow young primary stalks in a plant crop. When mature stalks, to which suckers were attached, were removed, the leaves produced by suckers were more similar to leaves on normal stalks with larger length/breadth ratio. The morphological differences were not carried over into plants arising from the buds on suckers. Although the reasons for these morphological differences are unknown, it is likely that the transfer of some factor(s) from the stalks to which suckers are attached, and/or an altered light environment within the canopy, may contribute to the morphology of sucker shoots.

scholarly journals Estimativa de Albedo e Índice de Área Foliar na Amazônia (Albedo Estimate and Leaf Area Index in Amazonia)

2011 ◽  
Vol 4 (1) ◽  
pp. 22 ◽  
Author(s):  
Ailton Marcolino Liberato
Keyword(s):  
Remote Sensing ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Scientific Literature ◽  
Thematic Mapper ◽  
Amazon Forest ◽  
Geometric Correction ◽  
Landsat Images ◽  
Area Index ◽  
Landsat 5 Tm

Propôs-se, neste trabalho, estimar dados de albedo e Indice de Área Foliar (IAF) à superfície terrestre usando-se o sensor Thematic Mapper (TM) do satélite Landsat 5 e compará-lo com valores disponíveis na literatura científica. A região de estudo esta localizada no estado de Rondônia. Para a realização do estudo obtiveram-se quatro imagens orbitais do satélite Landsat 5 – TM, na órbita 231 e ponto 67, nas datas 13/07/2005, 13/05, 30/06 e 16/07 do ano de 2006, a que correspondem os dias Juliano 194, 133, 181 e 197, respectivamente. As correções geométricas para as imagens foram realizadas e geradas as cartas de albedo e IAF. O algoritmo SEBAL estimou satisfatoriamente os valores de albedo e IAF de superfícies sobre áreas de floresta (exceto para IAF) e pastagem.Palavras-chave: sensoriamento remoto, vegetacao, Floresta da Amazonia. Albedo Estimate and Leaf Area Index in Amazonia ABSTRACTThis study objectives the assessment of albedo and Leaf Area Index (LAI) data at surface using  images from Thematic Mapper (TM) sensor onboard Landsat 5 satellite, and  compare the results with values available in the scientific literature. The study area is located in the State of Rondônia. To carry out the study four orbital TM - Landsat images were obtained in the path 231 and row  67, for the dates of 07/13/2005, 06/30 and 07/16 of  2006 year, which correspond to the days 194, 181 and 197, respectively. The geometric correction for images was performed and maps of albedo and IAF were generated. The algorithm SEBAL estimated, satisfactorily, the values of albedo and IAF on the surface pasture and forest (except for LAI).Keywords: remote sensing, vegetation, Amazon Forest.

scholarly journals Optimisation of photosynthetic carbon gain and within-canopy gradients of associated foliar traits for Amazon forest trees

2010 ◽  
Vol 7 (6) ◽  
pp. 1833-1859 ◽  
Author(s):  
J. Lloyd ◽  
S. Patiño ◽  
R. Q. Paiva ◽  
G. B. Nardoto ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Leaf Area ◽  
Amazon Basin ◽  
Photosynthetic Capacity ◽  
Carbon Gain ◽  
Amazon Forest ◽  
Forest Trees ◽  
Individual Tree ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Tree Canopies

Abstract. Vertical profiles in leaf mass per unit leaf area (MA), foliar 13C composition (δ13C), nitrogen (N), phosphorus (P), carbon (C) and major cation concentrations were estimated for 204 rain forest trees growing in 57 sites across the Amazon Basin. Data was analysed using a multilevel modelling approach, allowing a separation of gradients within individual tree canopies (within-tree gradients) as opposed to stand level gradients occurring because of systematic differences occurring between different trees of different heights (between-tree gradients). Significant positive within-tree gradients (i.e. increasing values with increasing sampling height) were observed for MA and [C]DW (the subscript denoting on a dry weight basis) with negative within-tree gradients observed for δ13C, [Mg]DW and [K]DW. No significant within-tree gradients were observed for [N]DW, [P]DW or [Ca]DW. The magnitudes of between-tree gradients were not significantly different to the within-tree gradients for MA, δ13C, [C]DW, [K]DW, [N]DW, [P]DW and [Ca]DW. But for [Mg]DW, although there was no systematic difference observed between trees of different heights, strongly negative within-tree gradients were found to occur. When expressed on a leaf area basis (denoted by the subscript "A"), significant positive gradients were observed for [N]A, [P]A and [K]A both within and between trees, these being attributable to the positive intra- and between-tree gradients in MA mentioned above. No systematic within-tree gradient was observed for either [Ca]A or [Mg]A, but with a significant positive gradient observed for [Mg]A between trees (i.e. with taller trees tending to have a higher Mg per unit leaf area). Significant differences in within-tree gradients between individuals were observed only for MA, δ13C and [P] A. This was best associated with the overall average [P]A for each tree, this also being considered to be a surrogate for a tree's average leaf area based photosynthetic capacity, Amax. A new model is presented which is in agreement with the above observations. The model predicts that trees characterised by a low upper canopy Amax should have shallow, or even non-existent, within-canopy gradients in Amax, with optimal intra-canopy gradients becoming sharper as a tree's upper canopy Amax increases. Nevertheless, in all cases it is predicted that the optimal within-canopy gradient in Amax should be substantially less than for photon irradiance. Although this is also shown to be consistent with numerous observations as illustrated by a literature survey of gradients in photosynthetic capacity for broadleaf trees, it is also in contrast to previously held notions of optimality. A new equation relating gradients in photosynthetic capacity within broadleaf tree canopies to the photosynthetic capacity of their upper canopy leaves is presented.

Production efficiency of Abieslasiocarpa: influence of vertical distribution of leaf area

1992 ◽  
Vol 22 (9) ◽  
pp. 1230-1234 ◽  
Author(s):  
Scott D. Roberts ◽  
James N. Long
Keyword(s):  
Conceptual Model ◽  
Leaf Area ◽  
Production Efficiency ◽  
Light Environment ◽  
Subalpine Fir ◽  
Area Efficiency ◽  
Unit Leaf ◽  
Large Trees ◽  
Photosynthetic Production ◽  
Lower Ratio

A simple conceptual model is proposed concerning how leaf area efficiency (stemwood growth per unit leaf area) changes with leaf area for trees within a stand. Greater leaf area is generally associated with (i) improved light environment due to greater height and (ii) a lower ratio of photosynthetic to nonphotosynthetic tissue. Greater height and improved light environment result in higher photosynthetic production, which should increase leaf area efficiency. A lower ratio of photosynthetic to nonphotosynthetic tissue suggests that the ratio of respiration to photosynthesis increases, which should decrease leaf area efficiency. In relatively small trees, the influence of increased height (associated with greater leaf area) should more than offset the influence of the increased respiration:photosynthesis ratio; as a result, leaf area efficiency should increase with leaf area. In large trees, further increases in leaf area are associated with minimal increases in height, and leaf area efficiency should decline as the respiration:photosynthesis ratio increases. Predictions from this conceptual model were examined with data from stands of subalpine fir (Abieslasiocarpa (Hook.) Nutt.).

scholarly journals Variations in leaf physiological properties within Amazon forest canopies

2009 ◽  
Vol 6 (3) ◽  
pp. 4639-4692 ◽  
Author(s):  
J. Lloyd ◽  
S. Patiño ◽  
R. Q. Paiva ◽  
G. B. Nardoto ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Leaf Area ◽  
Amazon Basin ◽  
Dry Weight ◽  
Multilevel Modelling ◽  
Systematic Difference ◽  
Leaf Nitrogen ◽  
Amazon Forest ◽  
Individual Tree ◽  
Unit Leaf ◽  
Area Basis

Abstract. Vertical profiles in leaf mass per unit leaf area (MA), foliar 13C composition (δ13C) and leaf nitrogen (N), phosphorus (P), carbon (C), potassium (K), magnesium (Mg) and calcium (Ca) concentrations were estimated for 204 rain forest trees growing in 57 sites across the Amazon Basin. Data was analysed using a multilevel modelling approach, allowing a separation of gradients within individual tree canopies (intra-tree gradients) as opposed to stand level gradients occurring because of systematic differences occurring between different trees of different heights (inter-tree gradients). Significant positive intra-tree gradients (i.e. increasing values with increasing sampling height) were observed for MA and [C]DW (the subscript denoting on a dry weight basis) with negative intra-tree gradients observed for δ13C, [Mg]DW and [K]DW. No significant intra-tree gradients were observed for [N]DW, [P]DW or [Ca]DW. Although the magnitudes of inter-tree gradients were not significantly different for MA, δ13C, [C]DW, [K]DW, [N]DW, [P]DW and [Ca]DW, for [Mg]DW there no systematic difference observed between trees of different heights, this being in contrast to the strongly negative intra-tree gradients also found to exist. When expressed on a leaf area basis, significant positive gradients were observed for N, P and K both within and between trees, these being attributable to the positive intra- and inter-tree gradients in MA mentioned above. No systematic intra-tree gradient was observed for either Ca or Mg when expressed on a leaf area basis, but with a significant positive gradient observed for Mg between trees (i.e. with taller trees tending to have a higher Mg per unit area). In contrast to the other variables measured, significant variations in intra-tree gradients for different individuals were found to exist for MA, δ13C and [P] (area basis). This was best associated with the overall average area based [P], this also being considered to be a surrogate for a leaf's photosynthetic capacity, Amax. A new model is presented which is in agreement with the above observations. The model predicts that trees characterised by a low upper canopy Amax should have shallow or even non-existent gradients in Amax, with optimal intra-canopy gradients becoming sharper as a tree's upper canopy Amax increases. Nevertheless, in all cases it is predicted that the optimal within-canopy gradients in Amax should be less than is generally observed for photon irradiance. Although this is consistent with numerous observations, it is also in contrast to previously held notions of optimality.

scholarly journals Bamboos and a new perspective on nitrogen input in tropical forests

2018 ◽  
Author(s):  
Maíra CG Padgurschi ◽  
Simone A Vieira ◽  
Edson JF Stefani ◽  
Gabriela B Nardoto ◽  
Carlos A Joly
Keyword(s):  
Leaf Area ◽  
Tropical Forests ◽  
Ecosystem Functioning ◽  
N Cycling ◽  
Litter Production ◽  
Amazon Forest ◽  
Free Living ◽  
Total N ◽  
Neotropical Forest ◽  
N Input

Background. Bamboos are typical plants in tropical forests acting as resource for different animals and influencing forest structure and dynamics, but our knowledge about their influence on ecosystem functioning remains in its infancy. Nitrogen (N) is an important macronutrient that exerts control over productivity of ecosystems. Biological Nitrogen Fixation (BNF) is one of the main N input to terrestrial systems, more specifically by free-living BNF in tropical forests. In these forests, the dominant presence of bamboo and the occurrence of free-living N-fixers in its leaf surfaces appear to play a relevant role in N cycling. Here, we explore the importance of a native bamboo to N cycle in a Neotropical forest to provide insights on bamboo’s role on ecosystem functioning. Methods. The study was conducted in a pristine montane Atlantic Forest, Brazil. We select 100 sample units (100 m² each) and counted all bamboo clumps and live culms, estimated the leaf area, the litter production and its N content. We estimated the potential N input mediated by bamboo based on available data of free-living BNF rates for this species and then we contextualized it with information about N cycling components in the study area. Results. We counted 4000 live culms ha-1 and estimated 4.3 x 104 m² ha-1 of bamboo leaf area for free-living N-fixers colonization. Considering the free-living BNF rates quantified for the same study area, the native bamboo may contribute up to 61.6 kg N ha-1 y-1 which represents a reduction in the N deficit of at least 25% in the Neotropical forest area we studied. Through its litter, the bamboo adds 9 kg N ha-1 y-1 to the system (15% of the total fixed on its leaf surface). Discussion. The bamboo’s contribution for N input we found may be explained by free-living community composition on its leaf as previously indicated by other studies, as well as by the bamboo overabundance, and thus habitat availability for colonization. Such N input represents a reduction in N deficit in the study area where the rates of symbiotic BNF (0.2 kg N ha-1y-1) are lower than values in Amazon Forest (3 kg N ha-1y-1). This native bamboo may supply N to the system probably through the decomposition of its leaves which represents a return of 15% of the total N fixed. Although it is still necessary to evaluate the characteristics of bamboo that will further elucidate its role in the functioning of the forests, our findings suggest that it closely regulates N inputs and may better explain high diversity and carbon stocks of the area.

Interactive effects of season and light environment on growth and leaf dynamics of evergreen tree seedlings in the humid subtropics

1996 ◽  
Vol 74 (4) ◽  
pp. 589-598 ◽  
Author(s):  
J. H. C. Cornelissen
Keyword(s):  
Leaf Area ◽  
Growth Rates ◽  
Leaf Size ◽  
Light Environment ◽  
Interactive Effects ◽  
Tree Seedlings ◽  
Total Leaf Area ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Total Leaf

Interactive effects of season and light environment on tree seedling growth were studied in four evergreen species in the humid subtropics of China. These species were the needle-leaved pioneer Pinus massoniana and the broad-leaved shade-tolerant Castanopsis fargesii, Sloanea leptocarpa, and Elaeocarpus japonicus. The experimental outdoor light environments, which broadly simulated those in forest gaps and clearings, were 100, 55, 33, and 18% of incident light quantity. Mean relative growth rates for both total leaf area and s tem height revealed interaction of season and light environment in Pinus, Castanopsis, and Elaeocarpus. In these species, mean relative growth rates were higher in summer in more shaded environments and in autumn in more exposed environments, but this shift was not as clear in Castanopsis. Winter growth was virtually nil in all species, although Pinus still achieved some winter stem height change. The hypothesis that late-successional rather than early-successional species would demonstrate interactions of season and light environment on growth and development was not sufficiently supported by the data. Variation in mean relative growth rates for total leaf area was due to changes in whole-plant average leaf size as well as leaf numbers. In Sloanea and Elaeocarpus seedlings in high light environments, reduced leaf size and enhanced leaf abscission rates gave rise to negative mean relative growth rates for total leaf area. The more sun-tolerant Castanopsis seedlings revealed no such leaf size response and shed few, if any, leaves in any of the light environments. These results indicate that seasonal variability in the growth response of tree seedlings to the light environment is an important factor to be taken into account in studies on gap dynamics of subtropical forests. Keywords: China, leaf area, leaf turnover, leaf size, mean relative growth rate, shade, subtropical, sun.

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