Template: Veg Cover
Description: Diameter at Breast Height
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.
DBH Variables
| Variable | Group-Required | Multiple | Units | Description |
|---|---|---|---|---|
| DBH | Required | M | cm | Tree diameter at breast height (DBH) The diameter of the primary tree trunk (stem) measured at breast heigh, 1.3 meters from the soil surface. If reporting the diameter at a different height, report the height in the DBH_HEIGHT variable. Report the minimum tree size threshold for trees to be included in DBH measurements in DBH_MIN. If possible, report DBH periodically to follow change through time. If BASAL_AREA and TREES_NUM are both reported, DBH need not be reported. |
| DBH_SPP | Optional-a | M | Scientific name | Tree diameter at breast height (DBH) 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. |
| DBH_VEGTYPE | Optional-a | M | LIST(VEGTYPE) | Tree diameter at breast height (DBH) vegetation type Use the predefined list to indicate the type of vegetation being described by the measurement (e.g., Tree, Evergreen Tree, Deciduous Tree). Not all VEGTYPE options are appropriate for DBH measurement. 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. |
| DBH_STATISTIC | Required | M | LIST(STATISTIC) | Tree diameter at breast height (DBH) 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. |
| DBH_STATISTIC_TYPE | Optional | M | LIST(STATISTIC_TYPE) | Tree diameter at breast height (DBH) statistic type The type of statistic reported if appropriate (e.g., spatial). Use predefined list. |
| DBH_STATISTIC_NUMBER | Optional | M | integer number | Number of observations used to determine tree diameter at breast height (DBH) statistic Number of observations (samples / replicates) used to calculate the STATISTIC for the reported measurement. |
| DBH_HEIGHT | Optional | M | m | Mean height at which tree diameter at breast height (DBH) was measured Report the height at which mean tree diameter was measured if different than breast height (1.3m) |
| DBH_MIN | Optional | M | cm | Minimum tree size (diameter) threshold for tree diameter at breast height (DBH) measurement The diameter at 1.3m from the soil surface (breast height) above which trees are included in the diameter at breast height (DBH) calculations. |
| DBH_APPROACH | Optional | M | free text | Tree diameter at breast height (DBH) approach |
| DBH_DATE | Required-b | M | YYYYMMDDHHMM | Diameter at Breast Height 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. |
| DBH_DATE_START | Required-b | M | YYYYMMDDHHMM | Start date of tree diameter at breast height (DBH) 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. |
| DBH_DATE_END | Optional | M | YYYYMMDDHHMM | End date of tree diameter at breast height (DBH) 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. |
| DBH_DATE_UNC | Optional | M | days | Uncertainty in the tree diameter at breast height (DBH) 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. |
| DBH_COMMENT | Optional | M | free text | Tree diameter at breast height (DBH) comments |
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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