Measurement of breast diameter
There are also different opinions about the height of DBH, such as 1.2m, 1.3m, etc. The following excerpts are for your appreciation. Male seedlings of Populus tomentosa
Trunk diameter measured at1.3m above the ground.
The diameter of the seedling trunk is from the soil mark on the seedling trunk ground up to1.3m.
examination
Measure with standard measuring tools.
Trunk diameter measured at1.3m above the ground.
If the measured part is swollen or the trunk shape is not round, measure the normal starting position of the trunk of the upper seedling, and the reading is accurate to 0. 1cm.
Terrestrial carbon measurement method
Correct use of DBH ruler is very important to ensure the continuity of measurement data; All standing trees should be numbered and labeled with aluminum nails (aluminum only). Don't nail all the nails into the tree to ensure that the tree has room to grow. Nails can only be nailed to the depth that can fix the label. Bring a worker or pole with a height of1.37m to ensure that the DBH position of the target wood can be accurately determined. If none of the above tools are available, you can use a strong stick (at least 2cm in diameter). Field investigators should first lean the measuring pole against the tree to indicate the position of DBH. The placement method of measuring rod depends on the slope of the ground and the shape of the tree; If the object tree branches at breast height, two branches need to be measured and recorded in the data table as two trees; If the object tree has fallen, but it is still alive, put the measuring rod at the root of the tree to measure the DBH, just like when the tree grows upright. If there are still green leaves on the tree, it is considered as a living tree, even if there are only 1 or 2 leaves on the tree, it is considered as a living tree. There is a hook at one end of the DBH ruler. Press the hook into the bark, and then pull the measuring rope to the right.
Sichuan provincial local standards
Sichuan province bill of quantities valuation quota (2009) stipulates that "DBH (trunk diameter)" should be the diameter of trunk at the height of ground1.2m.. Generally, it starts from the left, pulls out to the right, and surrounds the torso. Even if the tree surveyor is left-handed. When the DBH ruler goes around the tree and returns to the end with the hook, it should be placed above the hook. The DBH ruler must not face outwards, and the side with numbers must face outwards. If the object is inclined, it must surround the DBH ruler according to the natural inclination angle of the object, not the angle parallel to the ground.
Use DBH ruler correctly Use DBH ruler correctly Use DBH ruler correctly Use DBH ruler correctly Be sure to pull it to the right. The DBH ruler must form a correct angle with the inclination of the tree. Don't put the DBH ruler in an abnormal position on the trunk. DBH measures the positions of irregular and regular trees.
If there are vines or vines on the tree to be measured in the nested fixed sample plot, do not prune the vines in order to clean up a place where the object tree is to be measured. If possible, push the vines away from the trunk and put the DBH ruler around the vines. If the vines are too big to push away from the trunk, pull them on the front of the tree with the back of DBH ruler. This method can be used to estimate the DBH of the object tree intuitively. Cutting off vines on trees to measure trees can only be used as a last resort, because with the passage of time, repeated measurements in this way will interfere with the natural dynamic succession of sample plots and cause differences between sample plots and surrounding forests. For other natural organisms (including fungi, epiphytes, fungal growth and termite nests, etc.). ) found in the object tree, also should follow this standard. A set of vertical cross data should be measured, but it is not necessary to measure DBH below 5 cm. If trees grow on a slope, they should be measured from the upper part of the slope to the breast height. If the height of the measured tree is scarred or bifurcated, which can't reflect the situation of the standing tree normally, you can find another normal part to measure the trunk diameter up or down, but you must record the height of the measurement place for data analysis.