Grunnflatarmál og stofnþéttleiki Skógræktarverkfæri

Reiknivél fyrir grunnflatarmál, stofnþéttleika og meðal-DBH

Calculate basal area, stem density, and average DBH (QMD) from fixed plot and BAF angle-gauge surveys.

Keep DBH, BAF, and QMD in a shared forestry vocabulary while switching between metric / imperial and mm / cm / in.

Supports fixed plot and BAF surveys Shows QMD as the primary average DBH Shares by URL, CSV, JSON, and print

Inntak

Settings
Settings

Niðurstaða

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Basal area / area
—
Stem density
—
Average DBH (QMD)
—
QMD
Total tree count
—
Trees
Point count
—
Niðurstöður raða
Arithmetic mean DBH
—
Arithmetic mean DBH

Warnings

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Trees Basal area Stem density Arithmetic mean DBH QMD
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Survey methods supported

Fixed plot

Use known plot area and DBH lists to calculate basal area per area and stem density.

BAF angle gauge

Use in-tree DBH lists and BAF to estimate basal area per area and stem density from point samples.

Average DBH is QMD

The primary average DBH is QMD, or quadratic mean diameter. Arithmetic mean DBH is shown as a secondary check when tree-level diameters are present.

Examples

Inntak / Úttak

How to use

  1. Switch the survey mode between fixed plot and BAF.
  2. Veldu einingakerfi, DBH-einingu og annað hvort flatarmál reits eða BAF eftir ham.
  3. Enter the DBH list for each plot or point. You can separate values with newlines, commas, semicolons, or spaces.
  4. Skoðaðu grunnflatarmál, stofnþéttleika og QMD og notaðu síðan afritun, CSV, JSON, deilislóð eða prentun þegar þörf krefur.

Algengar spurningar

Is average DBH the arithmetic mean?

Aðalmeðaltalið sem þetta tól sýnir er QMD. Aritmetískt meðaltal DBH er aðeins sýnt sem aukaskoðun þegar þvermál einstakra trjáa eru til staðar.

Can BAF alone estimate stem density?

Já. Þegar DBH-gildi eru skráð metur tólið stofnþéttleika út frá útvíkkunarstuðli hvers trés sem fellur inn.

Should DBH be measured at 1.3 m or 4.5 ft?

Hvort tveggja er í lagi svo lengi sem þú notar sama mælingastaðalinn fyrir öll gildin sem þú slærð inn. Tólið leiðréttir ekki sjálfkrafa hæðarstaðla.

Do you handle slope correction or boundary-tree rules?

Nei. Tólið safnar aðeins saman tölunum eftir talningu á vettvangi.

Can I share large row data through a URL?

Yes, but the URL can become long. Use JSON export and import for larger surveys.

Glossary

DBH

Diameter at Breast Height. Tree diameter measured at breast height.

Basal area

The cross-sectional area of tree stems at breast height.

Stem density

The number of trees per unit area.

QMD

Quadratic Mean Diameter. An average DBH derived from basal area and stem density.

BAF

Basal Area Factor. The factor used in angle-gauge surveys.

Fixed plot

A tally method using a plot with a known area.

Formulas

tree basal area = π × (dbh / 2)^2

basal area per area = Σ tree basal area / sample area

stem density = tree count / sample area

QMD = sqrt(4 × basal area per area / (π × stem density))

BAF row basal area = in-tree count × BAF

BAF row stem density = Σ (BAF / tree basal area)

Athugasemdir

  • DBH measurement height standards vary by country and stand. Make sure all values were measured using the same standard.
  • Fylgdu talningarreglum þínum fyrir mörkatré þegar þú notar BAF.
  • QMD is the primary metric. It may not match arithmetic mean DBH.
  • Do not put private stand names or trial-plot names into share URLs or notes.
  • Niðurstaðan er samantektargildi, ekki endanlegur grundvöllur löglegra, vottunar- eða stjórnunarákvarðana.