Name: leaf area index estimation using three distinct methods in pure deciduous stands
Uploaded: 2019-08-29T13:00:00.000+00:00
Duration: 9 s
Description: Watch this Scientific Journal Video about Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands at JoVE.com

We are indebted to the editorial board of the Journal of Forestry Research for encouraging and authorizing us to use the representative results in this protocol from the article published there. We also kindly thank two anonymous reviewers for their valuable comments, which have substantially improved the manuscript. The research was funded by the Ministry of Agriculture of the Czech Republic, institutional support MZE-RO0118 and the National Agency of Agricultural Research (Project No. QK1810126).

The authors have nothing to disclose. The representative results were used from the article &#268;ern&#253; J, Haninec P, Pokorn&#253; R (2018) Leaf area index estimated by direct, semi-direct, and indirect methods in European beech and sycamore maple stands. Journal of Forest Research. doi: 10.1007/s11676-018-0809-0 (online version) based on the kind permission of the Journal of Forestry Research editorial board.

Litter traps are deemed as one of the most accurate methods for performing LAI estimation8, but they are more labor-intensive and time-consuming than the indirect methods35,64 which were incorporated into this protocol. Within the entire LAI estimation procedure using litter traps, a precise estimation of the SLA is the most critical point10 because the SLA can vary with plant species65, date...

LAI, defined as half of the total leaf surface area per unit of horizontal ground surface area1, is a key variable used in many bio-geophysical and chemical exchange models focused on carbon and water fluxes2,3,4. LAI is directly proportional to the active surface of leaves where it drives primary production (photosynthesis), transpiration, energy exchange, and other physiological attributes connected with a range of ecosystem processes in plant communities5.
Numerous approaches and instruments for performing LAI estimation have been developed, and they are currently available on the market6,7,8,9. Ground-based methods for performing LAI estimation can be grouped into two main categories: (i) direct, and (ii) indirect methods10,11,12. The first group includes methods measuring leaf area directly, while the indirect methods infer LAI from measurements of more readily measurable parameters, using radiative transfer theory (in terms of time, labour-intensiveness, and technology)13,14.
This protocol deals with the practical use of litter traps and the needle technique, as non-destructive semi-direct methods10; and the optical device plant canopy analyzer as an indirect method6,7 for performing LAI estimation on a chosen sample from temperate deciduous forest stands in Central Europe (see its structural and dendrometric characteristics in Appendix A and Appendix B).
In deciduous forests and crops, it is possible to perform non-destructive semi-direct LAI estimation using litter traps11 distributed below the canopy layer15. Litter traps provide precise LAI values for deciduous species in which LAI reaches a plateau within the growing season. However, for species that can replace leaves during the growing season, such as poplar, the method overestimates LAI11. This method assumes that the content of the traps represents the average amount of leaves that fall during a leaf-fall period in the stand16, especially during the autumn months. Traps are opened boxes or nets (Figure 1) with a predetermined sufficient size (minimum 0.18 m2, but preferably over 0.25 m2)10,17, lateral sides preventing the wind from blowing leaves into/out of the traps, and with a perforated bottom avoiding decomposition of the leaves; which are located below the canopy layer of the studied stand, however, above the ground surface11. The distribution of the traps can be either random18 or systematic in transects19 or a regular spacing grid20. The number and distribution of traps are a crucial methodological step for performing an accurate LAI estimation reflecting the unique stand structure, spatial homogeneity, expected wind speed and direction, especially in the case of sparse stands (or alleys and orchards), and the work capacity for evaluating data. The precision of LAI estimation increases with the rising frequency of traps within studied stands11,21 (see Figure 2).
The recommended frequency of collecting samples of the litter-fall from each trap is at least monthly10 and even twice per week in periods of heavy fall, which may coincide with heavy rainfall. It is necessary to prevent decomposition of the litter in the traps and the leaching of nutrients from the material during rain episodes in the case of chemical analysis. After collecting leaves in a field, a mixed sub-sample is used for estimating the specific leaf area (SLA, cm2 g-1)22, defined as the fresh projected area of leaves to its dry mass weight ratio. The rest of the collected litter is dried to a constant weight and used for calculating the dry mass of the litter as g cm-2 in the lab. Leaf dry mass on each collection date is converted into the leaf area by multiplying the collected biomass by SLA or leaf dry mass per area (LMA, g cm-2) as the inverse parameter to SLA23,24. A fresh projected area of particular leaves can be determined using a planimetric approach. The planimetric method is based on the dependency between the area of a specific leaf and the area covered by the leaf in the horizontal surface. The leaf is horizontally fixed to the scan screen, and its average is measured using a leaf area meter. Then, its area is calculated. Many leaf area meters based on different measurement principles are available on the market. Some of them include, for instance, the LI-3000C Portable Leaf Area Meter, which uses the orthogonal projection method, and the LI-3100C Area Meter, which measures leaf average using a fluorescent light source and a semi-conducted scanning camera. The next device, the CI-202 portable laser leaf area meter, codes a leaf length using a code reader. Besides them, the AM350 and BSLM101 Portable Leaf Area Meters are also commonly used for performing accurate leaf area estimation.
Furthermore, leaf area meters based on systems that analyze video exist. These leaf area meters consist of a video camera, a digitalisation frame, a screen, and a PC, including suitable software for making the data analysis such as WD3 WinDIAS Leaf Image Analysis System11. Currently, conventional scanners connected to a PC can be used for an estimating leaf area. Afterwards, the leaf area is calculated as a multiple of the number of black pixels and its size depends on the selected resolution (dots per inch &#8211; dpi), or the leaf area is measured through specific software, for instance, WinFOLIA. Finally, the total dry mass of leaves collected within a known ground surface area is converted into the LAI by multiplying by SLA and a shrinkage coefficient25 which reflects the changes in the area of fresh and dried leaves. Shrinkage depends on the tree species, water content and leaf softness. The shrinkage of leaves in length and width (what affect the projected area) is usually up to 10%26, for instance, it ranges from 2.6 to 6.8% for oak27. Sorting leaves by species for weighing and establishing the specific leaf area ratio is necessary to determine the contribution of each species to the total LAI28.
LAI determination by the needle technique is an inexpensive method derived from the inclined point quadrat method29,30,31,32. In deciduous stands, it is an alternative for performing LAI estimation without using traps10 based on the assumption that the total leaf number and their area in a tree are equal to what is collected on the soil surface after a complete leaf-fall20. A thin sharp needle is pierced vertically into the litter lying on the ground immediately after the leaf-fall10. After the complete leaf-fall, the leaves are collected from the ground onto a needle of a vertical probe, are related to the contact number and equal the actual LAI value. An intensive sampling (100-300 sampling points per studied stand per field probe) by the needle technique is required to quantify a mean contact number and to derive the LAI value correctly10,20,33.
The plant canopy analyzer (e.g., LAI-2000 or LAI-2200 PCA) is a commonly used portable instrument for performing an indirect LAI estimation by taking a measurement of the light transmission throughout the canopy7 within the filtered blue portion of the light spectrum (320-490 nm)34,35 to minimize the contribution of the light which has passed through the leaves, was scattered by the canopy and is passing through the foliage7,34. In the blue part of the light spectrum, the maximum contrast between the leaf and sky is achieved, and the foliage appears black against the sky34. Therefore, it is based on the canopy gap fraction analysis7. The instrument has been widely used for making eco-physiological studies in plant communities such as crops36, grasslands37, coniferous stands8, and deciduous stands38. The plant canopy analyzer uses a fisheye optical sensor with a FOV of 148&#176; 35 to project a hemispherical image of the canopy onto silicon detectors to arrange them into five concentric rings39 with central zenith angles of 7&#176;, 23&#176;, 38&#176;, 53&#176;, and 68&#176; 9,40,41. Five view caps (i.e., 270&#176;, 180&#176;, 90&#176;, 45&#176;, and 10&#176;) can be used to restrict the azimuth view of the optical sensor27 to avoid shading by obstacles in an open area (for the above-referenced reading) or the operator in the sensor&#8217;s FOV during LAI estimation can adjust the FOV sensor to an open area for above-canopy readings. Measurements using the plant canopy analyzer are taken above (or in a sufficiently extended open area) and below the studied canopy7. The same view caps must be used for both above and below readings to avoid biases of gap fraction estimation34. The LAI-2000 PCA produces an effective leaf area index (LAIe) as introduced by Chen et al.42, or rather an effective plant area index (PAIe) as woody elements are included in the sensor reading value. In deciduous stands with flat leaves, the LAIe is the same as the hemi-surface LAI. In the case of evergreen forest stands, the LAIe is necessary to correct for the clumping effect at the shoot level (SPAR, STAR)43, the clumping index at scales larger than the shoot (&#937;E)44, and the contribution of woody elements including stems and branches (i.e., woody-to-total area ratio),45 which cause a systematic LAI underestimation20. The clumping index on a higher spatial scale than the shoot or leaf could be quantified as an apparent clumping index (ACF), which can be estimated using the plant canopy analyzer when more restrictive view caps are used27. As these authors state that this ACF is deduced from a ratio of LAI values calculated from transmittance by different procedures for homogeneous and non-homogeneous canopies according to Lang46, we presume that this clumping index describes rather canopy homogeneity. Besides the ACF calculation, new diffuser caps that enable a more extensive application of LAI-2200 PCA in respect of weather conditions, a user menu instead of Fct codes, and the possibility to take many more measurements per file session are among the main technological upgrades compared to the former LAI-2000 PCA34,47. Measurements and subsequent internal software calculations are based on four assumptions: (1) light blocking plant elements including leaves, branches, and stems, are randomly distributed in the canopy, (2) foliage is an optically black body that absorbs all the light it receives, (3) all plant elements are the same projection to the horizontal ground surface as a simple geometric convex shape, (4) plant elements are small compared to the area covered by each ring11.

<table><tbody><tr><td>Area Meter</td><td>LI-COR Biosciences Inc., NE, USA</td><td>LI-3100C</td><td>https://www.licor.com/env/products/leaf_area/LI-3100C/</td></tr><tr><td>Computer Image Analysis System</td><td>Regent Instruments Inc., CA</td><td>WinFOLIA</td><td>http://www.regentinstruments.com/assets/images_winfolia2/WinFOLIA2018-s.pdf</td></tr><tr><td>File Viewer</td><td>LI-COR Biosciences Inc., NE, USA</td><td>FV2200C Software</td><td>https://www.licor.com/env/products/leaf_area/LAI-2200C/software.html</td></tr><tr><td>Laboratory oven</td><td>Amerex Instruments Inc., CA, USA</td><td>CV150</td><td>https://www.labcompare.com/4-Drying-Ovens/2887-IncuMax-Convection-Oven-250L/?pda=4|2887_2_0|||</td></tr><tr><td>Leaf Image Analysis System</td><td>Delta-T Devices, UK</td><td>WD3 WinDIAS</td><td>https://www.delta-t.co.uk/product/wd3/</td></tr><tr><td>Litter traps</td><td>Any</td><td>NA</td><td>See Fig. 2</td></tr><tr><td>Needle</td><td>Any</td><td>NA</td><td>Maximum diameter of 2 mm</td></tr><tr><td>Plant Canopy Analyser</td><td>LI-COR Biosciences Inc., NE, USA</td><td>LAI-2000 PCA</td><td>LAI-2200 PCA or LAI-2200C as improved versions of LAI-2000 PCA can be used, see: https://www.licor.com/env/products/leaf_area/LAI-2200C/</td></tr><tr><td>Portable Laser Leaf Area Meter</td><td>CID Bio-Science, WA, USA</td><td>CI-202</td><td>https://cid-inc.com/plant-science-tools/leaf-area-measurement/ci-202-portable-laser-leaf-area-meter/</td></tr><tr><td>Portable Leaf Area Meter</td><td>ADC, BioScientic Ltd., UK</td><td>AM350</td><td>https://www.adc.co.uk/products/am350-portable-leaf-area-meter/</td></tr><tr><td>Portable Leaf Area Meter</td><td>Bionics Scientific Technogies (P). Ltd., India</td><td>BSLM101</td><td>http://www.bionicsscientific.com/measuring-meters/leaf-area-index-meter.html</td></tr><tr><td>Portable Leaf Area Meter</td><td>LI-COR Biosciences Inc., NE, USA</td><td>LI-3000C</td><td>https://www.licor.com/env/products/leaf_area/LI-3000C/</td></tr></tbody></table>

leaf area index estimation using three distinct methods in pure deciduous stands

Accurate estimations of leaf area index (LAI), defined as half of the total leaf surface area per unit of horizontal ground surface area, are crucial for describing the vegetation structure in the fields of ecology, forestry, and agriculture. Therefore, procedures of three commercially used methods (litter traps, needle technique, and a plant canopy analyzer) for performing LAI estimation were presented step-by-step. Specific methodological approaches were compared, and their current advantages, controversies, challenges, and future perspectives were discussed in this protocol. Litter traps are usually deemed as the reference level. Both the needle technique and the plant canopy analyzer (e.g., LAI-2000) frequently underestimate LAI values in comparison with the reference. The needle technique is easy to use in deciduous stands where the litter completely decomposes each year (e.g., oak and beech stands). However, calibration based on litter traps or direct destructive methods is necessary. The plant canopy analyzer is a commonly used device for performing LAI estimation in ecology, forestry, and agriculture, but is subject to potential error due to foliage clumping and the contribution of woody elements in the field of view (FOV) of the sensor. Eliminating these potential error sources was discussed. The plant canopy analyzer is a very suitable device for performing LAI estimations at the high spatial level, observing a seasonal LAI dynamic, and for long-term monitoring of LAI.

Average LAI values at the stand level of all studied stands in the 2013 growing season are presented in Figure 8. On all plots except A, the highest values were measured by litter traps, which serve as the reference level. Contrarily, the highest mean LAI value was estimated through the needle technique on plot A. All differences between LAI values estimated using litter traps and a plant canopy analyzer were not significant (p &#62; 0.05; Figure 8, left). On pl...

Watch this Scientific Journal Video about Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands at JoVE.com

Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

An accurate estimation of leaf area index (LAI) is crucial for many models of material and energy fluxes within plant ecosystems and between an ecosystem and the atmospheric boundary layer. Therefore, three methods (litter traps, needle technique, and PCA) for taking precise LAI measurements were in the presented protocol.

Accurate estimations of leaf area index (LAI), defined as half of the total leaf surface area per unit of horizontal ground surface area, are crucial for ...

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Environment

13.4K Views.  Research Station at Opočno. An accurate estimation of leaf area index (LAI) is crucial for many models of material and energy fluxes within plant ecosystems and between an ecosystem and the atmospheric boundary layer. Therefore, three methods (litter traps, needle technique, and PCA) for taking precise LAI measurements were in the presented protocol.

Video: Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

Modifying the Bank Erosion Hazard Index (BEHI) Protocol for Rapid Assessment of Streambank Erosion in Northeastern Ohio

Understanding the source of pollution in a stream is vital to preserving, restoring, and maintaining the stream&#8217;s function and habitat it provides. Sediments from highly eroding streambanks are a major source of pollution in a stream system and have the potential to jeopardize habitat, infrastructure, and stream function. Watershed management practices throughout the Cleveland Metroparks attempt to locate and inventory the source and rate the risk of potential streambank erosion to assist in formulating effect stream, riparian, and habitat management recommendations. The Bank Erosion Hazard Index (BEHI), developed by David Rosgen of Wildland Hydrology is a fluvial geomorphic assessment procedure used to evaluate the susceptibility of potential streambank erosion based on a combination of several variables that are sensitive to various processes of erosion. This protocol can be time consuming, difficult for non-professionals, and confined to specific geomorphic regions. To address these constraints and assist in maintaining consistency and reducing user bias, modifications to this protocol include a &#8220;Pre-Screening Questionnaire&#8221;, elimination of the Study Bank-Height Ratio metric including the bankfull determination, and an adjusted scoring system. This modified protocol was used to assess several high priority streams within the Cleveland Metroparks. The original BEHI protocol was also used to confirm the results of the modified BEHI protocol. After using the modified assessment in the field, and comparing it to the original BEHI method, the two were found to produce comparable BEHI ratings of the streambanks, while significantly reducing the amount of time and resources needed to complete the modified protocol.

Modifying the Bank Erosion Hazard Index BEHI Protocol for Rapid Assessment of Streambank Erosion in Northeastern Ohio

Streambank erosion potential can be evaluated and ranked using David Rosgen&#8217;s Bank Erosion Hazard Index (BEHI), however this protocol has significant limitations. Here we present protocol modifications to address time constraints, allow nonprofessionals to complete accurate assessments, and account for non-alluvial stream conditions in Northeast Ohio.

Understanding the source of pollution in a stream is vital to preserving, restoring, and maintaining the stream&#8217;s function and habitat it provides. ...

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay

In order to isolate and accurately determine rates of herbicide metabolism in an obligate-outcrossing dicot weed, waterhemp (Amaranthus tuberculatus), we developed an excised leaf assay combined with a vegetative cloning strategy to normalize herbicide uptake and remove translocation as contributing factors in herbicide-resistant (R) and &#8211;sensitive (S) waterhemp populations. Biokinetic analyses of organic pesticides in plants typically include the determination of uptake, translocation (delivery to the target site), metabolic fate, and interactions with the target site. Herbicide metabolism is an important parameter to measure in herbicide-resistant weeds and herbicide-tolerant crops, and is typically accomplished with whole-plant tests using radiolabeled herbicides. However, one difficulty with interpreting biokinetic parameters derived from whole-plant methods is that translocation is often affected by rates of herbicide metabolism, since polar metabolites are usually not mobile within the plant following herbicide detoxification reactions. Advantages of the protocol described in this manuscript include reproducible, accurate, and rapid determination of herbicide degradation rates in R and S populations, a substantial decrease in the amount of radiolabeled herbicide consumed, a large reduction in radiolabeled plant materials requiring further handling and disposal, and the ability to perform radiolabeled herbicide experiments in the lab or growth chamber instead of a greenhouse. As herbicide resistance continues to develop and spread in dicot weed populations worldwide, the excised leaf assay method developed and described herein will provide an invaluable technique for investigating non-target site-based resistance due to enhanced rates of herbicide metabolism and detoxification.

This manuscript describes how herbicide metabolism rates can be effectively quantified with excised leaves from a dicot weed, thereby reducing variability and removing any possible confounding effects of herbicide uptake or translocation typically observed in whole-plant assays.

In order to isolate and accurately determine rates of herbicide metabolism in an obligate-outcrossing dicot weed, waterhemp (Amaranthus tuberculatus), we ...

Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m2 yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries.

Assessment of arthropod abundance in crops is critical for investigating population dynamics and species interactions. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropods in rice.

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the ...

Evaluating Dryocosmus Kuriphilus-induced Damage on Castanea Sativa

Dryocosmus kuriphilus Yasumatsu has become a major pest for Castaneasativa since its arrival in Europe. Its galling activity results in the formation of different gall types and prevents the development of normal shoots. Repeated and uncontrolled attacks cause, besides the production of galls and the attendant gall-related reduction in leaf area, progressive corruption of the branch architecture, including the death of branch parts, and an increase in dormant bud activation. Thus far, there have been few attempts to quantify branch architecture damage. Further, the different methods for assessing infestation degree (MAID) that have been developed focus only on the galls' presence and abundance.
Using the leaf area to sapwood area relationship as a green biomass indicator, we developed in a previous study a damage composite index (DCI) that takes into account the most important branch architectural features, allowing for realistic damage assessment during the entire epidemic process. 
The aim of this study is to present this novel method and highlight differences in the damage description with respect to other broadly used indices. Results show how the DCI depicts branch damage better, especially during the epidemic peak, compared to MAID, which tend to underestimate it. We conclude by suggesting how to properly evaluate the overall impact of the pest by means of our composite damage index, the infestation degree using classic methods, and crown transparency evaluations.

Evaluating Dryocosmus Kuriphilus-induced Damage on Castanea Sativa

It is common practice to assess the damage caused by Dryocosmus kuriphilus by considering the abundance of galls alone rather than by also taking related branch corruption into consideration. We propose a composite damage index that takes into account the most important branch features, thus enabling more realistic damage assessment.

Dryocosmus kuriphilus Yasumatsu has become a major pest for Castaneasativa since its arrival in Europe. Its galling activity results in the formation of ...

A Method for Quantifying Foliage-Dwelling Arthropods

Terrestrial arthropods play an important role in our environment. Quantifying arthropods in a way that allows for a precise index or estimates of density requires a method with high detection probability and a known sampling area. While most described methods provide a qualitative or semi-quantitative estimate adequate for describing species presence, richness, and diversity, few provide an adequately consistent detection probability and known or consistent sampling areas to provide an index or estimate with adequate precision to detect differences in abundance across environmental, spatial, or temporal variables. We describe how to quantify leaf-dwelling arthropods by sealing the leaves and end of branches in a bag, clipping and freezing the bagged material, and rinsing the previously frozen material in water to separate arthropods from the substrate and quantify them. As we demonstrate, this method can be used at a landscape scale to quantify leaf-dwelling arthropods with adequate precision to test for and describe how spatial, temporal, environmental, and ecological variables influence arthropod richness and abundance. This method allowed us to detect differences in density, richness, and diversity of leaf-dwelling arthropods among 5 genera of trees commonly found in southeastern deciduous forests.

We describe how to quantify leaf dwelling arthropods by sealing the leaves and end of branches in a bag, clipping and freezing the bagged material, and rinsing the previously frozen material in water to separate arthropods from the substrate for quantification.

Terrestrial arthropods play an important role in our environment. Quantifying arthropods in a way that allows for a precise index or estimates of density ...

Simulating Impacts of Ice Storms on Forest Ecosystems

Ice storms can have profound and lasting effects on the structure and function of forest ecosystems in regions that experience freezing conditions. Current models suggest that the frequency and intensity of ice storms could increase over the coming decades in response to changes in climate, heightening interest in understanding their impacts. Because of the stochastic nature of ice storms and difficulties in predicting when and where they will occur, most past investigations of the ecological effects of ice storms have been based on case studies following major storms. Since intense ice storms are exceedingly rare events it is impractical to study them by waiting for their natural occurrence. Here we present a novel alternative experimental approach, involving the simulation of glaze ice events on forest plots under field conditions. With this method, water is pumped from a stream or lake and sprayed above the forest canopy when air temperatures are below freezing. The water rains down and freezes upon contact with cold surfaces. As the ice accumulates on trees, the boles and branches bend and break; damage that can be quantified through comparisons with untreated reference stands. The experimental approach described is advantageous because it enables control over the timing and amount of ice applied. Creating ice storms of different frequency and intensity makes it possible to identify critical ecological thresholds necessary for predicting and preparing for ice storm impacts.

Ice storms are important weather events that are challenging to study because of difficulties in predicting their occurrence. Here, we describe a novel method for simulating ice storms that involves spraying water over a forest canopy during sub-freezing conditions.

Ice storms can have profound and lasting effects on the structure and function of forest ecosystems in regions that experience freezing conditions. ...

Field Measurement of Effective Leaf Area Index using Optical Device in Vegetation Canopy

Leaf area index (LAI) is an essential canopy variable describing the amount of foliage in an ecosystem. The parameter serves as the interface between green components of plants and the atmosphere, and many physiological processes occur there, primarily photosynthetic uptake, respiration, and transpiration. LAI is also an input parameter for many models involving carbon, water, and the energy cycle. Moreover, ground-based in situ measurements serve as the calibration method for LAI obtained from remote sensing products. Therefore, straightforward indirect optical methods are necessary for making precise and rapid LAI estimates. The methodological approach, advantages, controversies, and future perspectives of the newly developed LP 110 optical device based on the relation between radiation transmitted through the vegetation canopy and canopy gaps were discussed in the protocol. Furthermore, the instrument was compared to the world standard LAI-2200 Plant Canopy Analyzer. The LP 110 enables more rapid and more straightforward processing of data acquired in the field, and it is more affordable than the Plant Canopy Analyzer. The new instrument is characterized by its ease of use for both above- and below-canopy readings due to its greater sensor sensitivity, in-built digital inclinometer, and automatic logging of readings at the correct position. Therefore, the hand-held LP 110 device is a suitable gadget for performing LAI estimation in forestry, ecology, horticulture, and agriculture based on the representative results. Moreover, the same device also enables the user to take accurate measurements of incident photosynthetically active radiation (PAR) intensity.

Fast and precise leaf area index (LAI) estimation in terrestrial ecosystems is crucial for a wide range of ecological studies and calibrating remote sensing products. Presented here is the protocol for using the new LP 110 optical device for taking ground-based in situ LAI measurements.

Leaf area index (LAI) is an essential canopy variable describing the amount of foliage in an ecosystem. The parameter serves as the interface between ...

Digital Leaf Physiognomy for Paleoclimate and Paleoecological Reconstruction

Reconstructing Terrestrial Paleoclimate and Paleoecology with Fossil Leaves Using Digital Leaf Physiognomy and Leaf Mass Per Area

Climate and environment strongly influence the size, shape, and toothiness (physiognomy) of plants&#39; leaves. These relationships, particularly in woody non-monocotyledonous angiosperms, have been used to develop leaf-based proxies for paleoclimate and paleoecology that have been applied to reconstruct ancient terrestrial ecosystems for the last ~120 million years of Earth&#39;s history. Additionally, given that these relationships have been documented in living plants, they are important for understanding aspects of plant evolution and how plants respond to climatic and environmental changes. To conduct these types of analyses on modern and fossil plants, leaf physiognomy must be measured accurately using a reproducible methodology. This protocol describes a computer-based method for measuring and analyzing a variety of leaf physiognomic variables in modern and fossil leaves. This method allows for the measurement of leaf physiognomic traits, in particular variables related to leaf serrations, leaf area, leaf dissection, and linearity that are used in the digital leaf physiognomy proxy for reconstructing paleoclimate, as well as petiole width and leaf area, which are used for reconstructing leaf mass per area, a paleoecological proxy. Because this digital leaf trait measurement method can be applied to fossil and living plants, it is not limited to applications related to reconstructing paleoclimate and paleoecology. It can also be used to explore leaf traits that may be informative for understanding the function of leaf morphology, leaf development, phylogenetic relationships of leaf traits, and plant evolution.

Author Spotlight: Leaf Trait Analysis for Climate and Ecology Reconstruction in Modern and Ancient Plant Communities

The protocol presented shows digital measurement and analysis of continuous leaf physiognomic traits on fossil leaves to reconstruct paleoclimate and paleoecology using the digital leaf physiognomy and leaf mass per area reconstruction methods.

Climate and environment strongly influence the size, shape, and toothiness (physiognomy) of plants&#39; leaves. These relationships, particularly in woody ...

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Here, we developed an individual-tree model of 5-year basal area increments based on a dataset including 21898 Picea asperata trees from 779 sample plots located in Xinjiang Province, northwest China. To prevent high correlations among observations from the same sampling unit, we developed the model using a linear mixed-effects approach with random plot effect to account for stochastic variability. Various tree- and stand-level variables, such as indices for tree size, competition, and site condition, were included as fixed effects to explain the residual variability. In addition, heteroscedasticity and autocorrelation were described by introducing variance functions and autocorrelation structures. The optimal linear mixed-effects model was determined by several fit statistics: Akaike&#8217;s information criterion, Bayesian information criterion, logarithm likelihood, and a likelihood ratio test. The results indicated that significant variables of individual-tree basal area increment were the inverse transformation of diameter at breast height, the basal area of trees larger than the subject tree, the number of trees per hectare, and elevation. Furthermore, errors in variance structure were most successfully modeled by the exponential function, and the autocorrelation was significantly corrected by first-order autoregressive structure (AR(1)). The performance of the linear mixed-effects model was significantly improved relative to the model using ordinary least squares regression.

Mixed-effects models are flexible and useful tools for analyzing data with a hierarchical stochastic structure in forestry and could also be used to significantly improve the performance of forest growth models. Here, a protocol is presented that synthesizes information relating to linear mixed-effects models.

Here, we developed an individual-tree model of 5-year basal area increments based on a dataset including 21898 Picea asperata trees from 779 sample plots ...

Biology

Tree Survey: Point-Centered Quarter Sampling Method

A number of methods are available for sampling forest communities. Point-centered quarter is one such method. It is used to gather information on the density, frequency, and coverage of tree species found in a forest. This information provides the ability to estimate the number of individual trees encountered, how often a certain tree occurs, how common the tree is compared to other trees, and the size of the tree. Compared to the standard plot analysis, the point-centered quarter method is more efficient, which is a major advantage. In a fixed-area plot sampling, a small portion of the total area of the forest is examined. In this small subsample, the density is determined directly by counting and identifying each tree. The ratio between size of the subplot and the overall forest size is used to determine the density for the entire forest.

A number of methods are available for sampling forest communities. Point-centered quarter is one such method. It is used to gather information on the ...

Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

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Simulating Impacts of Ice Storms on Forest Ecosystems

Field Measurement of Effective Leaf Area Index using Optical Device in Vegetation Canopy

Reconstructing Terrestrial Paleoclimate and Paleoecology with Fossil Leaves Using Digital Leaf Physiognomy and Leaf Mass Per Area

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Tree Survey: Point-Centered Quarter Sampling Method