Template: Veg Cover
Description: Leaf Area Index
Variables with their units and descriptions are found below. If a group is specified in the Group-Required column, the variable is required within that group. Variables without a group and marked required are required for every group. Some variables are marked required / optional with a prefix (e.g., “Optional-a”, “Required-b”). For these variables, only one of the variables with the same prefix should be reported. The Multiple column indicates whether multiple entries of the group are allowed at a tower site.
LAI Variables
| Variable | Group-Required | Multiple | Units | Description |
|---|---|---|---|---|
| LAI | Required | M | m2 m-2 | Vegetation (Plant, Leaf, Green) Area Index Leaf Area Index (or other Vegetation Area Index as indicated in LAI_TYPE) at the tower site. Calculated as one half the total leaf area (the one-sided leaf area) per unit ground surface area. |
| LAI_TYPE | Required | M | LIST(LAI_TYPE) | Vegetation (Plant, Leaf, Green) Area Index type Use predefined list to indicate type of Vegetation Area Index. Note that Leaf Area Index is one type of Vegetation Area Index type. See predefined list for definitions. |
| LAI_CANOPY_TYPE | Required | M | LIST(LAI_CANOPY_TYPE) | Vegetation (Plant, Leaf, Green) Area Index canopy type Use predefined list to indicate the type of canopy being described by the LAI measurement. Use Total for non-forest ecosystems. For forest ecosystems, use Total if not reporting separate Overstory and Understory LAI measurements. |
| LAI_SPP | Optional-a | M | Scientific name | Vegetation (Plant, Leaf, Green) Area Index species (taxa) Vegetation species being described by the measurement. To enter a plant species, use the scientific name (Genus species Author or Genus Author). Please refer to www.theplantlist.org for current scientific names and authors. If the measurement includes all vegetation present, do not enter a value. Do not use SPP if reporting VEGTYPE. |
| LAI_VEGTYPE | Optional-a | M | LIST(VEGTYPE) | Vegetation (Plant, Leaf, Green) Area Index vegetation type Use the predefined list to indicate the type of vegetation being described by the measurement (e.g., Grass, Evergreen Tree, Deciduous Tree, etc). If vegetation type is not in predfined list, enter “Other/Not in list” and describe briefly in Approach. If the measurement includes all vegetation present, do not enter a value. Do not use VEGTYPE if reporting SPP. |
| LAI_STATISTIC | Required | M | LIST(STATISTIC) | Vegetation (Plant, Leaf, Green) Area Index statistic The statistic for the measurement reported. Use predefined list (e.g., mean, min / max, standard deviation, etc). If appropriate, report the type of statistic (e.g., spatial for spatial standard deviation) in STATISTIC_TYPE. |
| LAI_STATISTIC_TYPE | Optional | M | LIST(STATISTIC_TYPE) | Vegetation (Plant, Leaf, Green) Area Index statistic type The type of statistic reported if appropriate (e.g., spatial). Use predefined list. |
| LAI_STATISTIC_NUMBER | Optional | M | integer number | Number of observations used to determine Vegetation (Plant, Leaf, Green) Area Index statistic Number of observations (samples / replicates) used to calculate the STATISTIC for the reported measurement. |
| LAI_CLUMP | Optional | M | decimal number | Foilage element clumping index for Vegetation (Plant, Leaf, Green) Area Index measurement Foliage element clumping index is used to correct optical data estimates of LAI. Use this variable only if the method specified in LAI_METHOD supports clumping correction. For conifers, use needle clumping within shoot. |
| LAI_METHOD | Optional | M | LIST(LAI_METHOD) | Vegetation (Plant, Leaf, Green) Area Index methodology Method used to quantify the Vegetation (Plant, Leaf, Green) Area Index. Use predefined list. If method is not present, select “Other” and give additional details in LAI_APPROACH. |
| LAI_APPROACH | Optional | M | free text | Vegetation (Plant, Leaf, Green) Area Index measurement approach Report additional details used to quanity Vegetation (Plant, Leaf, Green) Area Index. |
| LAI_DATE | Required-b | M | YYYYMMDDHHMM | Vegetation (Plant, Leaf, Green) Area Index measurement date Please report the date at the precision known. Allowed reporting precisions are YYYY, YYYYMM, YYYYMMDD, and YYYYMMDDHHMM. For measurements conducted during a campaign or for temporal averages, use DATE_START and DATE_END instead of DATE. |
| LAI_DATE_START | Required-b | M | YYYYMMDDHHMM | Start date of Vegetation (Plant, Leaf, Green) Area Index measurment Start date of a measurement campaign or start date of a temporal average. Please report the date at the precision known. Allowed reporting precisions are YYYY, YYYYMM, YYYYMMDD, and YYYYMMDDHHMM. Do not use DATE_START if DATE is used. |
| LAI_DATE_END | Optional | M | YYYYMMDDHHMM | End date of Vegetation (Plant, Leaf, Green) Area Index measurment End date of a measurement campaign or end date of a temporal average. Please report the date at the precision known. Allowed reporting precisions are YYYY, YYYYMM, YYYYMMDD, and YYYYMMDDHHMM. Do not use DATE_END if DATE is used. |
| LAI_DATE_UNC | Optional | M | days | Uncertainty in the Vegetation (Plant, Leaf, Green) Area Index measurement date, start date, and/or end date If uncertainty in the start date differs than end date, report the uncertainty for start date here in DATE_UNC and the uncertainty for end date in Comments. |
| LAI_COMMENT | Optional | M | free text | Vegetation (Plant, Leaf, Green) Area Index comments |
LAI CANOPY TYPE Options (back to top)
| Option | Definition |
|---|---|
| Total | Total canopy. Use for non-forest ecosystems or for forest ecosystem if not reporting Overstory and Understory measurement. |
| Overstory | Overstory canopy |
| Understory | Understory canopy |
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LAI METHOD Options (back to top)
| Option | Definition |
|---|---|
| ACCUPAR | AccUPAR from Decagon Devices |
| Litterfall | Collection of leaves in litterfall traps |
| SUNSCAN | SunScan from Delta-T Devices |
| SPECTRAL | Relation between spectral reflectance and direct measurements |
| Direct | |
| Hemispherical photo | Analog or digital hemispherical photography (DHP) |
| LAI_2000 | LI-COR LI-2000 |
| LAI_2200 | LI-COR LI-2200 |
| Lidar | Use LAI_APPROACH to describe details of Lidar method used |
| Other | Use LAI_APPROACH to describe the method used |
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LAI TYPE Options (back to top)
| Option | Definition |
|---|---|
| LAI | Leaf Area Index (includes all the leaves) |
| PAI | “Plant Area Index (includes leaves, stems and other parts of the plants)” |
| GAI | Green Area Index (includes only green leaves) |
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STATISTIC Options (back to top)
| Option | Definition |
|---|---|
| Minimum | Minimum value |
| 1st Percentile | Quantile at 1% of distribution |
| 5th Percentile | Quantile at 5% of distribution |
| 10th Percentile | Quantile at 10% of distribution |
| 25th Percentile | Quantile at 25% of distribution |
| Median – 50th Percentile | Median – Quantile at 50% of distribution |
| 75th Percentile | Quantile at 75% of distribution |
| 90th Percentile | Quantile at 90% of distribution |
| 95th Percentile | Quantile at 95% of distribution |
| 99th Percentile | Quantile at 99% of distribution |
| Maximum | Maximum value |
| Mean | Average (mean) value of sample population |
| Standard Deviation | Standard deviation may be reported from a sample population that consists of individual or aggregated samples (observations). If the distinction is important, specify in Comments. |
| Measurement Uncertainty | Report uncertainty as a plus or minus value in the measurement units. For example, enter 1.5 for +/- 1.5 units. Uncertainty may be reported from the instrument’s specifications, determined empirically, or estimated by the tower team. Please describe such details in Approach. For uncertainty values that are better described by a range, a percent, or other, please enter information in Comments. |
| Single observation | Single observation |
| Expert estimate | Estimate made by expert familiar with site |
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STATISTIC_TYPE Options (back to top)
| Option | Definition |
|---|---|
| Spatial | The statistic indicated is a metric that describes the spatial component of the sample population. For example, use spatial for the standard devation of samples (observations) that represents different locations at the site for the same time period. |
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VEGTYPE Options (back to top)
| Option | Definition |
|---|---|
| Grass | |
| C3 Grass | |
| C4 Grass | |
| Grass / Graminoid | Grasses, Sedges, Rushes, and other grass-like monocots (member of order Poales) |
| Crop | |
| Herbaceous Crop | |
| Woody Crop | |
| Tree | |
| Deciduous Tree | Trees that shed their entire canopy seasonallly. Drought or cold avoidence are common reasons for deciduousness. |
| Evergreen Tree | Trees that do not seasonally shed their full canopies. |
| Shrub | |
| Herb / Forb | |
| Annual Herb / Forb | |
| Perennial Herb / Forb | |
| Aerenchymatous Plants | |
| Liana / vine | |
| Succulant | Cactus, Euphorbs, including CAM |
| Non-vascular | Moss, lichen |
| Other/Not in list | Only use this option if a major vegetation group is not included already included in the predefined list. If an existing vegetation group is not specific enough, use the existing vegetation option and add details in Approach (rather than using the “Other/Not in list” option). |
| No vegetation | Bare ground, water, or rock. Use only with SPP_PERC_O and SPP_PERC_U |
| Water | Water (perennially submerged ground) |
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