Mueller calculus: Difference between revisions

Revision as of 04:52, 28 August 2013

Leaf Area Index (LAI) is a dimensionless quantity that characterizes plant canopies. It is defined as the one-sided green leaf area per unit ground surface area (LAI = leaf area / ground area, m² / m²) in broadleaf canopies.^[1] In conifers, three different definitions for LAI have been used:

Half of the total needle surface area per unit ground surface area ^[2]
Projected (or one-sided, in accordance the definition for broadleaf canopies) needle area per unit ground area
Total needle surface area per unit ground area Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.

LAI ranges from 0 (bare ground) to over 10 (dense conifer forests)Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park..

Interpretation and application of LAI

File:LAI Respiration.gif

LAI is used to predict photosynthetic primary production, evapotranspiration and as a reference tool for crop growth. As such, LAI plays an essential role in theoretical production ecology. An inverse exponential relation between LAI and light interception, which is linearly proportional to the primary production rate, has been established:Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.

P = P_{\max} (1 - e^{- c \cdot L A I})

where P_max designates the maximum primary production and $c$ designates a crop-specific growth coefficient. This inverse exponential function is called the primary production function.

Determining LAI

LAI can be determined directly by taking a statistically significant sample of foliage from a plant canopy, measuring the leaf area per sample plot and dividing it by the plot land surface area. Indirect methods measure canopy geometry or light extinction and relate it to LAI.^[3]

Direct methods

Direct methods can be easily applied on deciduous species by collecting leaves during leaf fall in traps of certain area distributed below the canopy. The area of the collected leaves can be measured using a leaf area meter or an image scanner and image analysis software. The measured leaf area can then be divided by the area of the traps to obtain LAI. Alternatively, leaf area can be measured on a sub-sample of the collected leaves and linked to the leaf dry mass (e.g. via Specific Leaf Area, SLA cm²/g). That way it is not necessary to measure the area of all leaves one by one, but weigh the collected leaves after drying (at 60–80 °C for 48 h). Leaf dry mass multiplied by the specific leaf area is converted into leaf area.
Direct methods in evergreen species are necessarily destructive. However, they are widely used in crops and pastures by harvesting the vegetation and measuring leaf area within a certain ground surface area. It is very difficult (and also unethical) to apply such destructive techniques in natural ecosystems, particularly in forests of evergreen tree species. Foresters have developed techniques that determine leaf area in evergreen forests through allometric relationships.
Due to the difficulties and the limitations of the direct methods for estimating LAI, they are mostly used as reference for indirect methods that are easier and faster to apply.

Indirect methods

File:Hemiphoto monarch habitat1.jpg

A hemispherical photograph of forest canopy. The ratio of the area of canopy to sky is used to approximate LAI.

Indirect methods of estimating LAI in situ can be divided in two categories: (1) indirect contact LAI measurements such as plumb lines and inclined point quadratsPotter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.; and (2) indirect non-contact measurements. Due to the subjectivity and labor involved with the first method, indirect non-contact measurements are typically preferred. Non-contact LAI tools, such as hemispherical photography, Hemiview Plant Canopy Analyser from Delta-T Devices, the CI-110 Plant Canopy Analyzer [1] from CID Bio-Science, LAI-2200 Plant Canopy Analyzer [2] from LI-COR Biosciences and the LP-80 LAI ceptometer [3] from Decagon Devices, measure LAI in a non-destructive way. Hemispherical photography methods estimate LAI and other canopy structure attributes from analyzing upward-looking fisheye photographs taken beneath the plant canopy. The LAI-2200 calculates LAI and other canopy structure attributes from solar radiation measurements made with a wide-angle optical sensor. Measurements made above and below the canopy are used to determine canopy light interception at five angles, from which LAI is computed using a model of radiative transfer in vegetative canopies. The LP-80 calculates LAI by means of measuring the difference between light levels above the canopy and at ground level, and factoring in the leaf angle distribution, solar zenith angle, and plant extinction coefficient. Such indirect methods, where LAI is calculated based upon observations of other variables (canopy geometry, light interception, leaf length and width,^[4] etc.) are generally faster, amenable to automation, and thereby allow for a larger number of spatial samples to be obtained. For reasons of convenience when compared to the direct (destructive) methods, these tools are becoming more and more important.

Disadvantages of methods

The disadvantage of the direct method is that it is destructive, time consuming and expensive, especially if the study area is very large.

The disadvantage of the indirect method is that in some cases it can underestimate the value of LAI in very dense canopies, as it does not account for leaves that lie on each other, and essentially act as one leaf according to the theoretical LAI models.^[5]

References

FAO: calculation of primary production
Non-Existence of an Optimum Leaf Area Index for the Production Rate of White Clover Grown Under Constant Conditions
Law, B.E., T. Arkebauer, J.L. Campbell, J. Chen, O. Sun, M. Schwartz, C. van Ingen, S. Verma. 2008. Terrestrial Carbon Observations: Protocols for Vegetation Sampling and Data Submission. Report 55, Global Terrestrial Observing System. FAO, Rome. 87 pp.
W.W. Wilhelm, K. Ruwe, M.R. Schlemmer (2000)“Comparisons of three Leaf Area Index Meters in a Corn Canopy” Crop Science 40: 1179-1183
LAI Definition of University of Giessen, Germany

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

↑ Watson, D.J., 1947. Comparative physiological studies on the growth of field crops: I. Variation in net assimilation rate and leaf area between species and varieties and within and between years. Annals of Botany, 11: 41-76.
↑ Chen, J.M., and Black, T.A. (1992): Defining leaf area index for non-flat leaves. Agricultural and Forest Meteorology 57: 1–12
↑ Breda, N, (2003). Ground-based measurements of leaf area index: A review of methods, instruments and current controversies. Journal of Experimental Botany, 54, 2403–2417
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A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang
↑ W.W. Wilhelm, K. Ruwe, M.R. Schlemmer (2000), "Comparisons of three Leaf Area Index Meters in a Corn Canopy” Crop Science 40:1179-1183

[1] Watson, D.J., 1947. Comparative physiological studies on the growth of field crops: I. Variation in net assimilation rate and leaf area between species and varieties and within and between years. Annals of Botany, 11: 41-76.

[2] Chen, J.M., and Black, T.A. (1992): Defining leaf area index for non-flat leaves. Agricultural and Forest Meteorology 57: 1–12

[3] Breda, N, (2003). Ground-based measurements of leaf area index: A review of methods, instruments and current controversies. Journal of Experimental Botany, 54, 2403–2417

[4] One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting

In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang

Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules

Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.

A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang

[5] W.W. Wilhelm, K. Ruwe, M.R. Schlemmer (2000), "Comparisons of three Leaf Area Index Meters in a Corn Canopy” Crop Science 40:1179-1183

[1]

[2]

[3]

[4]

[5]

@@ Line 1: / Line 1: @@
-The name of the writer is Figures but it's not the most masucline title out there. One of the things she loves most is to do aerobics and now she is trying to earn money with it. I am a meter reader but I plan on altering it. Years in the past we moved to North Dakota and I love each day living here.<br><br>Feel free to visit my web site: [http://www.article-galaxy.com/profile.php?a=165109 std testing at home]
+'''Leaf Area Index (LAI)''' is a [[dimensionless quantity]] that characterizes plant [[Canopy (forest)|canopies]]. It is defined as the one-sided green leaf area per unit ground surface area (''LAI = leaf area / ground area, m<sup>2</sup> / m<sup>2</sup>'') in [[broadleaf]] [[Canopy (forest)|canopies]].<ref>Watson, D.J., 1947. Comparative physiological studies on the growth of field crops: I. Variation in net assimilation rate and leaf area between species and varieties and within and between years. Annals of Botany, 11: 41-76.</ref>  In [[conifers]], three different definitions for LAI have been used:
+*Half of the total needle surface area per unit ground surface area <ref>Chen, J.M., and Black, T.A. (1992): Defining leaf area index for non-flat leaves. Agricultural and Forest Meteorology 57: 1–12</ref>
+*Projected (or one-sided, in accordance the definition for broadleaf canopies) needle area per unit ground area
+*Total needle surface area per unit ground area {{Citation needed|date=March 2013}}
+LAI ranges from 0 (bare ground) to over 10 (dense conifer forests){{Citation needed|date=March 2013}}.
+== Interpretation and application of LAI ==
+[[Image:LAI Respiration.gif|thumb|right]]
+LAI is used to predict photosynthetic [[primary production]], evapotranspiration and as a reference tool for [[crop]] growth. As such, LAI plays an essential role in [[theoretical production ecology]]. An inverse exponential relation between LAI and light interception, which is linearly proportional to the primary production rate, has been established:{{Citation needed|date=November 2007}}
+:<math>P=P_\max \left(1-e^{-c\cdot LAI}\right)</math>
+where ''P''<sub>max</sub> designates the maximum [[primary production]] and <math>c</math> designates a crop-specific growth [[coefficient]]. This inverse exponential function is called the '''primary production function'''.
+== Determining LAI ==
+LAI can be determined directly by taking a [[statistically significant]] [[sample (statistics)|sample]] of foliage from a [[Canopy (ecology)|plant canopy]], measuring the leaf area per sample plot and dividing it by the plot land surface area. Indirect methods measure canopy geometry or light extinction and relate it to LAI.<ref>[http://jxb.oxfordjournals.org/content/54/392/2403.full Breda, N, (2003). Ground-based measurements of leaf area index: A review of methods, instruments and current controversies. Journal of Experimental Botany, 54, 2403–2417]</ref>
+===Direct methods===
+Direct methods can be easily applied on [[deciduous]] species by collecting leaves during leaf fall in traps of certain area distributed below the canopy. The area of the collected leaves can be measured using a leaf area meter or an [[image scanner]] and image analysis software. The measured leaf area can then be divided by the area of the traps to obtain LAI. Alternatively, leaf area can be measured on a sub-sample of the collected leaves and linked to the leaf dry mass (e.g. via [[Specific leaf area|Specific Leaf Area]], SLA cm<sup>2</sup>/g). That way it is not necessary to measure the area of all leaves one by one, but weigh the collected leaves after drying (at 60–80 °C for 48 h). Leaf dry mass multiplied by the [[specific leaf area]] is converted into leaf area.<br />
+Direct methods in [[evergreen]] species are necessarily destructive. However, they are widely used in crops and pastures by harvesting the vegetation and measuring leaf area within a certain ground surface area. It is very difficult (and also unethical) to apply such destructive techniques in natural ecosystems, particularly in forests of [[evergreen]] tree species. Foresters have developed techniques that determine leaf area in [[evergreen]] forests through [[Tree allometry|allometric]] relationships.<br />
+Due to the difficulties and the limitations of the direct methods for estimating LAI, they are mostly used as reference for indirect methods that are easier and faster to apply.
+===Indirect methods===
+[[File:Hemiphoto monarch habitat1.jpg|thumb|A [[Hemispherical photography|hemispherical photograph]] of [[Canopy (forest)|forest canopy]]. The ratio of the area of canopy to [[sky]] is used to approximate LAI.]]
+Indirect methods of estimating LAI ''in situ'' can be divided in two categories: (1) indirect contact LAI measurements such
+as plumb lines and inclined point quadrats{{Citation needed|date=November 2007}}<!-- (Gower et al., 1999; Scurlock et al., 2001;
+Jonckheere et al., 2004a) -->; and (2) indirect non-contact measurements. Due to the subjectivity and labor involved with the first method, indirect non-contact measurements are typically preferred. Non-contact LAI tools, such as [[hemispherical photography]],  Hemiview Plant Canopy Analyser from Delta-T Devices, the CI-110 Plant Canopy Analyzer [http://www.cid-inc.com/ci-110.php] from [[CID Bio-Science]], LAI-2200 Plant Canopy Analyzer [http://www.licor.com/env/products/area_meters/LAI-2200/] from [[LI-COR Biosciences]] and the [http://www.decagon.com/products/instruments/ceptometer-par-lai-instruments-2/accupar-lp-80/ LP-80 LAI ceptometer] [http://www.decagon.com/ag_research/canopy/lp80.php] from [[Decagon Devices]], measure LAI in a non-destructive way. [[Hemispherical photography]] methods estimate LAI and other canopy structure attributes from analyzing upward-looking [[fisheye]] photographs taken beneath the plant canopy. The LAI-2200 calculates LAI and other canopy structure attributes from solar radiation measurements made with a wide-angle optical sensor. Measurements made above and below the canopy are used to determine canopy light interception at five angles, from which LAI is computed using a model of radiative transfer in vegetative canopies. The LP-80 calculates LAI by means of measuring the difference between light levels above the canopy and at ground level, and factoring in the leaf angle distribution, solar zenith angle, and plant extinction coefficient. Such indirect methods, where LAI is calculated based upon observations of other variables (canopy geometry, light interception, leaf length and width,<ref>{{cite journal |last=Blanco |first=F.F. |coauthors=Folegatti, M.V. |year=2003 |title=A new method for estimating the leaf area index of cucumber and tomato plants |journal=Horticultura Brasileira |volume=21 |issue=4 |pages=666–669 |doi=10.1590/S0102-05362003000400019 }}</ref> etc.) are generally faster, amenable to automation, and thereby allow for a larger number of spatial samples to be obtained. For reasons of convenience when compared to the direct (destructive) methods, these tools are becoming more and more important.
+===Disadvantages of methods===
+The disadvantage of the direct method is that it is destructive, time consuming and expensive, especially if the study area is very large.
+The disadvantage of the indirect method is that in some cases it can underestimate the value of LAI in very dense canopies, as it does not account for leaves that lie on each other, and essentially act as one leaf according to the theoretical LAI models.<ref>W.W. Wilhelm, K. Ruwe, M.R. Schlemmer (2000), "Comparisons of three Leaf Area Index Meters in a Corn Canopy” Crop Science 40:1179-1183</ref>
+==See also==
+*[[Canopy (ecology)]]
+*[[Hemispherical photography]]
+*[[Normalized Difference Vegetation Index]]
+*[[Specific leaf area]]
+== References ==
+* [http://www.fao.org/landandwater/agll/gaez/app/a6.htm  FAO: calculation of primary production]
+* [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=550583&tools=bot  Non-Existence of an Optimum Leaf Area Index for the Production Rate of White Clover Grown Under Constant Conditions]
+* Law, B.E., T. Arkebauer, J.L. Campbell, J. Chen, O. Sun, M. Schwartz, C. van Ingen, S. Verma. 2008. Terrestrial Carbon Observations: Protocols for Vegetation Sampling and Data Submission. Report 55, Global Terrestrial Observing System. FAO, Rome. 87 pp.
+* W.W. Wilhelm, K. Ruwe, M.R. Schlemmer (2000)“Comparisons of three Leaf Area Index Meters in a Corn Canopy”  Crop Science 40: 1179-1183
+* [http://www.uni-giessen.de/~gh1461/plapada/lai/lai.html LAI Definition of University of Giessen, Germany]
+{{reflist}}
+[[Category:Agronomy]]
+[[Category:Forest modelling]]
+[[Category:Remote sensing]]
+[[Category:Dimensionless numbers]]

Mueller calculus: Difference between revisions

Revision as of 04:52, 28 August 2013

Contents

Interpretation and application of LAI

Determining LAI

Direct methods

Indirect methods

Disadvantages of methods

See also

References

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Mueller calculus: Difference between revisions

Revision as of 04:52, 28 August 2013

Interpretation and application of LAI

Determining LAI

Direct methods

Indirect methods

Disadvantages of methods

See also

References

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