What is the relationship among ground diameter, meter diameter and breast diameter?

Ground diameter, meter diameter and DBH are all used to measure the diameter of trees (seedlings) at a certain distance from the ground, and to represent the specifications of trees and seedlings. Generally, the ground diameter is smaller than the instrument diameter, and the instrument diameter is smaller than the DBH at the height of the measuring position.

The ground diameter is usually understood as "the diameter of seedling trunk near the surface", but it is 20 cm above the ground in practical application.

The meter diameter refers to the diameter of a tree (seedling) at 1 meter from the ground, which is similar to DBH and is usually used to indicate the specifications of a tree (seedling). When the symbol φ is used to represent the cross-sectional deformity, a set of vertically intersecting data should be measured and the average of the maximum and minimum values should be taken.

The diameter of the trunk at the chest height above the ground is equivalent to the diameter of the chest height of ordinary adults. Due to the different heights of people, in order to make the measurement points consistent, the specific height of chest height is uniformly stipulated within a country, but it is not consistent in different countries. In China and most countries, the breast height is set at1.3m above the ground. This standard height is more convenient for ordinary adults to measure readings with a wheel ruler.

Extended data:

Related instructions for use:

1, there is no uniform regulation on the representation method of seedling size in China, and the same (tree) seedling can be represented by meter diameter or DBH. Specific matters should be negotiated and reached by the tree (seedling) material suppliers in advance.

2. When the meter diameter of trees (seedlings) is less than 3.0cm, the size of seedlings is generally not expressed by meter diameter in the industry, but by ground diameter. If (tree) seedlings have obvious protrusions just at the distance from the ground 1 m, the supply and demand sides of trees (seedlings) will generally negotiate to measure the height above or below the protrusions, rather than the meter diameter.

3. Measure the trunk diameter of the tree (seedling) at a height of 30cm from the ground. A set of vertically intersecting data should be measured, and the average value of the maximum value and the minimum value should be measured when the section is deformed.

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