Device for measuring diameter at breast height of tree

Abstract

The utility model relates to the technical field of standing tree measuring equipment, in particular to a tree diameter at breast height measuring device, which comprises a diameter at breast height ruler for measuring the diameter at breast height of a trunk and a length-variable fixing device for fixing the diameter at breast height ruler, and a fixing rod is detachably connected below the fixing device. One end of the fixing device is fixedly provided with an accommodating box for accommodating the DBH ruler; one end of the DBH ruler extends out of the accommodating box and is fixedly connected with one end, far away from the accommodating box, of the fixing device; the fixing device can be connected end to end around a trunk to be measured through length change. Compared with the prior art, the fixing device capable of driving the DBH ruler to surround the trunk by one circle is arranged, so that the technical problems that an existing tree DBH measuring device is troublesome to use and the labor intensity of operators is increased on the premise that the DBH numerical value is accurately measured are solved.

Description

Technical Field

[0001] This utility model patent relates to the technical field of standing tree measurement equipment, specifically a device for measuring the diameter at breast height of trees. Background Art

[0002] The diameter at breast height, also known as trunk diameter, refers to the diameter of the trunk of a tree at breast height above the ground. When the cross-section is deformed, the average of the maximum and minimum values ​​is measured. Different trees have different breast heights, and different countries have different regulations on the diameter at breast height. In my country and most countries, the breast height is set at 1.3 meters above the ground. The diameter at breast height is an important indicator to measure the growth status of trees, and its measurement is widely used in ecology, forestry, agronomy and other fields.

[0003] The conventional method of measuring the diameter at breast height is to use a breast diameter ruler. The structure of the breast diameter ruler is similar to that of a conventional tape measure. The difference is that the scale on the breast diameter ruler not only indicates the measured trunk circumference, but also indicates the trunk diameter at breast height corresponding to the trunk circumference. However, the existing breast diameter ruler requires a person to first select a tree trunk at a height of 1.3 meters, then use the breast diameter ruler to wrap around the trunk and then read the number. For trees with a larger breast diameter or trunks with thorns that are difficult to measure directly, the breast diameter ruler is inconvenient to operate. Usually, one person needs to fix one end of the breast diameter ruler, and another person needs to pull the other end around the trunk to measure the tree's breast diameter, which is manpower-consuming.

[0004] There are some solutions to the above problems. Existing solutions are shown in the Chinese patent "A tool for measuring the diameter of trees at breast height in forestry" (application number CN202320132422.9, publication time 20230718): A tool for measuring the diameter of trees at breast height in forestry, comprising a vertical pole, a tool box fixedly connected to the top of the vertical pole, and a movably connected claw for radially clamping the two sides of the trunk on the side of the tool box close to the trunk, and the end of the claw away from the trunk extends into the tool box. A tape measure is also provided in the tool box, and the two ends of the tape measure are respectively fixedly connected to the two claws. The tape measure is printed with scale marks indicating the distance between the two claws. A first opening for the middle part of the tape measure to extend is provided on the side of the tool box away from the trunk; in the vertical direction, the vertical distance from the center of the claw to the bottom of the vertical pole is 1.3 meters. This patent only requires pulling the belt to make the claws clamp the two sides of the tree trunk, and the trunk's diameter at breast height can be obtained through the scale markings, which solves the technical problem of the existing technology that it is necessary to first determine the 1.3-meter point and then manually pull the breast diameter ruler around the main trunk at the measurement point to measure the trunk's diameter at breast height, which is cumbersome to operate.

[0005] The tool for measuring the diameter at breast height of a tree described in the above-mentioned prior art does not need to go around the tree to measure the diameter at breast height of the tree, and many diameter at breast height measuring tools in the current technical field also apply similar technical principles to solve the problems existing in traditional diameter at breast height rulers, such as the patent "A tree diameter at breast height measuring device for forest survey" disclosed with application number CN202021740227.7, the patent "Multifunctional tree diameter at breast height measuring device for forest survey for garden maintenance" disclosed with application number CN202122619500.1, etc., all use two clamping parts with adjustable spacing to clamp the two sides of the trunk to obtain the diameter of the trunk, but such a device ignores the fact that the trunk is not an ideal cylindrical shape when designed, and such a measuring device has to be debugged many times before it can measure the maximum and minimum values ​​of the tree diameter at breast height, and then take the average value to obtain a more objective and accurate diameter at breast height value. Although the traditional diameter at breast height ruler is troublesome to operate when measuring large-diameter trees, it can obtain an accurate diameter at breast height value in one measurement.

[0006] In summary, whether it is the traditional DBH ruler or the several improved tree DBH measuring devices listed above, they are all relatively troublesome to use under the premise of ensuring accurate measurement of DBH values, which increases the labor intensity of operators. Utility Model Content

[0007] The utility model is intended to provide a device for measuring the diameter at breast height of trees, which is mainly used to solve the technical problem that the existing tree diameter at breast height measuring equipment (including the diameter at breast height ruler) is relatively troublesome to use and increases the labor intensity of the operator under the premise of ensuring accurate measurement of the diameter at breast height value.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A device for measuring the diameter at breast height of a tree comprises a diameter at breast height ruler for measuring the diameter at breast height of a tree trunk, and also comprises a fixing device with a variable length for fixing the diameter at breast height ruler, wherein a fixing rod is detachably connected to the bottom of the fixing device; a accommodating box for accommodating the diameter at breast height ruler is fixed to one end of the fixing device, and one end of the diameter at breast height ruler extends out of the accommodating box and is fixedly connected to an end of the fixing device away from the accommodating box; the fixing device can be connected end to end around the trunk to be measured by changing its length.

[0010] Beneficial effects of the utility model:

[0011] When it is necessary to measure the diameter at breast height of a tree, first assemble the fixing rod and the fixing device, then place the lower end of the fixing rod against the root of the tree trunk, and measure the diameter at breast height of the tree at a fixed length. When measuring, first fix the fixing device near one end of the receiving box, then stretch the fixing device so that it surrounds the tree trunk and connects end to end, driving the diameter at breast height ruler to surround the tree trunk, and then read the value of the diameter at breast height ruler around the tree trunk to obtain the diameter at breast height of the tree trunk;

[0012] This device drives the breast diameter ruler to circle the tree trunk through a fixed device. It does not require the cooperation of multiple people to circle the tree trunk, and the breast diameter of the tree trunk can still be measured using the breast diameter ruler. At the same time, because this solution mainly uses a soft and deformable breast diameter ruler to measure the tree trunk, it can still accurately measure the tree trunk with an irregular shape (non-ideal cylinder).

[0013] In summary, this solution solves the technical problem that existing tree diameter at breast height measuring devices are relatively troublesome to use and increase the labor intensity of operators while ensuring accurate measurement of the diameter at breast height value.

[0014] Preferably, the fixing device includes a plurality of curved slides connected in sequence by sliding, wherein the ends of the curved slide at the front end and the curved slide at the rear end, which are away from each other, can be connected, the storage box is arranged at the end of the curved slide at the front end, and the end of the diameter-at-breast-length ruler extending from the storage box is fixedly connected to the end of the curved slide at the rear end. In this solution, the plurality of curved slides slide against each other to form a circular ring, and when not in use, the plurality of curved slides can be overlapped or sleeved by sliding, thereby reducing the volume of the entire fixing device and making the fixing device easy to carry. In addition, during the sliding process of the plurality of curved slides, the diameter-at-breast-length ruler can be pulled out of the storage box, circled around the tree trunk, and measured at the trunk's diameter at breast height.

[0015] Preferably, the fixing device includes a first curved slide, a second curved slide, and a third curved slide, which are arranged in sequence from bottom to top and are slidably connected to each other, and the accommodating box is fixed to an end of the first curved slide away from the third curved slide, and an adjusting device for controlling the length of the breast diameter ruler extending out of the accommodating box is provided on the accommodating box, and the end of the breast diameter ruler extending out of the accommodating box is fixedly connected to an end of the third curved slide away from the first curved slide.

[0016] In this solution, the first curved slide, the second curved slide, and the third curved slide can overlap each other by sliding up and down, or can be arranged in sliding circles with each other, so that the first curved slide contacts the end of the third curved slide, thereby driving the breast diameter ruler to circle the tree trunk; the driving process of the three curved slides is as follows: first, the concave surfaces of the overlapping three curved slides are attached to the edge of the tree trunk, and the breast diameter ruler is also attached to the edge of the tree trunk, and then the third curved slide is slid to stagger it with the second curved slide, and then the second curved slide is slid to stagger it with the first curved slide, thereby driving the third curved slide to move forward further along the trajectory until the end of the third curved slide contacts the end of the first curved slide; during the movement of the three curved slides, the breast diameter ruler is driven to circle the tree trunk, and then the adjusting device on the accommodating box is adjusted to tighten the breast diameter ruler so that the breast diameter ruler is close to the surface of the tree trunk, and then the length of the breast diameter ruler extended is observed to obtain the circumference and breast diameter of the tree at the measured point.

[0017] At the same time, the fixing device is composed of three arc-shaped sliders, which can be overlapped by sliding to reduce the volume of the entire device and facilitate portability.

[0018] Preferably, a slider is fixed to the upper surface of one end of the second curved slide, and a slider is also fixed to the lower surface of the other end. A sliding groove is defined in the middle of each of the first and second curved slides to accommodate the sliding of the slider. In this embodiment, the first, second, and third curved slides are stacked one on top of the other, and the sliders of the second curved slide are respectively inserted into the sliding grooves of the first and second curved slides, thereby forming a sliding connection between the three curved slides.

[0019] Preferably, the end of the slider located on the lower surface of the second curved slider, which is away from the second curved slider, extends out of the corresponding sliding groove and is fixed to a limit plate at the end; the end of the slider located on the upper surface of the second curved slider, which is away from the second curved slider, is located in the corresponding sliding groove and is threadedly connected to a screw at the end; a pressure plate is fixed to the upper end of the screw, and the pressure plate is located outside the sliding groove of the third curved slider and can press the upper surface of the third curved slider. In this solution, the function of the limit plate is to prevent the first and second curved sliders from separating during the sliding process; the function of the pressure plate is to prevent the second and third curved sliders from separating during the sliding process. At the same time, rotating the pressure plate can cause the screw to move downward, thereby causing the pressure plate to press against the surface of the third curved slider, thereby adjusting the resistance between the second and third curved sliders; when in use, the relative position between the third curved slider and the second curved slider can be adjusted first, and then the pressure plate can be rotated to fix the two or increase the resistance to relative sliding between the two, and then the relative position of the second curved slider and the first curved slider can be adjusted to push the end of the third curved slider to a farther distance to connect with the first curved slider.

[0020] Preferably, the adjustment device includes a rotating shaft disposed within the storage box, one end of the rotating shaft being rotatably connected to the inner wall of the storage box, and the other end extending out of the storage box and having a handle fixed thereto. The circumferential surface of the rotating shaft located within the storage box is fixed to the end of the diameter-at-breast-root (DBH) ruler located within the storage box. In this embodiment, rotating the rotating shaft can wind the DBH ruler onto the rotating shaft or cause the DBH ruler to be disengaged from the rotating shaft. After the first and third curved slides are unfolded and their ends are connected, the rotating shaft is rotated to wind back the excess DBH ruler extending out of the storage box, thereby tightening the DBH ruler tied to the tree trunk. The handle on the rotating shaft is then pressed to prevent the rotating shaft from rotating, and the length of the DBH ruler extending out of the storage box and the corresponding DBH value are observed.

[0021] Preferably, a first baffle is fixed to the end of the first curved slide close to the storage box, and a second baffle is fixed to the end of the third curved slide where it connects with the first curved slide. A through slot is formed on the first baffle, and the end of the diameter-at-breast-roots ruler extending from the storage box passes through the through slot and is fixed to the side of the second baffle away from the third curved slide. The opposing surfaces of the first baffle and the second baffle can contact each other as the third curved slide moves. In this solution, the purpose of providing the first baffle and the second baffle is that when the ends of the first and third curved slides approach each other, the first baffle can prevent the second baffle from continuing to move forward. The contact between the two indicates that the first, second, and third curved slides have formed a ring. When the first and second baffles contact, the surfaces of the diameter-at-breast-roots ruler fit together. During use, the distance from the connection between the baffle and the diameter-at-breast-roots ruler to the surface of the tree trunk is a measurement error. The position of the zero scale of the diameter-at-breast-roots ruler can be adjusted to the edge of the second baffle. When measuring the degree, the degree at which the diameter-at-breast-roots ruler overlaps with the edge of the first baffle can eliminate the measurement error caused by the device structure.

[0022] Preferably, a sleeve is fixed to the lower surface of the first curved slide, with the sleeve opening facing downward, and the fixing rod is inserted into the sleeve from bottom to top and threadedly connected to the sleeve. In this solution, the fixing rod is detachably connected to the first curved slide, that is, the entire fixing device. When the device is needed, the fixing rod is assembled with the fixing device, and when it is not needed, the fixing rod and the fixing device are disassembled, thereby reducing the overall size of the device and facilitating portability.

[0023] Preferably, the length of the fixing rod is 1.3 meters. According to the standard for measuring the diameter at breast height of a tree trunk, the diameter at breast height is measured at a height of 1.3 meters from the ground. The length of the fixing rod is set to 1.3 meters. Each time the measurement is made, the fixing device can be directly placed against the trunk for measurement without having to repeatedly measure the measurement position. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a three-dimensional structural diagram of a tree diameter-at-breast-root (DBH) measurement device according to the utility model patent (when not in use);

[0025] Figure 2 This is an exploded view of a device for measuring the diameter at breast height of trees in this utility model patent;

[0026] Figure 3 This is a partial cross-sectional view of a housing box for a tree diameter-at-breast-height measuring device according to the utility model patent;

[0027] Figure 4 This is a three-dimensional structural diagram of a tree diameter at breast height measurement device according to the utility model patent (when in use).

[0028] The figure marks in the drawings of the specification include: fixing rod 1, sleeve 11, first arc-shaped slide 21, second arc-shaped slide 22, third arc-shaped slide 23, slider 3, limit plate 31, pressure plate 32, slide groove 33, first baffle 41, second baffle 42, accommodating box 5, breast diameter ruler 51, rotating shaft 52, trunk 6. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, a device for measuring the diameter at breast height of a tree includes a diameter at breast height ruler 51 for measuring the diameter at breast height of a tree trunk 6, and also includes a fixing device with a variable length for fixing the diameter at breast height ruler 51. The diameter at breast height ruler 51 is provided on the fixing device, and the two ends of the diameter at breast height ruler 51 are respectively installed on the two ends of the fixing device. The fixing device is stretched to drive the diameter at breast height ruler 51 to circle around the tree trunk 6 to measure the diameter at breast height of the tree trunk 6.

[0031] The fixing device includes a first curved slide 21, a second curved slide 22, and a third curved slide 23. The first curved slide 21, the second curved slide 22, and the third curved slide 23 are arranged in sequence from bottom to top and are slidably connected to each other. After the first, second, and third curved slides 23 are slid and unfolded, they can form a ring, and the diameter of the ring is larger than the maximum diameter of the group of tree trunks 6 to be measured;

[0032] A slider 3 is fixed to the upper surface of one end of the second curved skateboard 22, and a slider 3 is also fixed to the lower surface of the other end. A sliding groove 33 for accommodating the sliding of the slider 3 is opened in the middle of the first curved skateboard 21 and the second curved skateboard 22; the first curved skateboard 21, the second curved skateboard 22, and the third curved skateboard 23 are stacked up and down, and the slider 3 of the second curved skateboard 22 is respectively inserted into the sliding groove 33 of the first and second curved skateboards 22, so that the three curved skateboards form a sliding connection with each other.

[0033] The end of the slider 3 located on the lower surface of the second curved slider 3 away from the second curved slider 22 extends out of the corresponding sliding groove 33 and the end is fixed with a limit plate 31; the end of the slider 3 located on the upper surface of the second curved slider 3 away from the second curved slider 22 is located in the corresponding sliding groove 33 and the end is threadedly connected to a screw, and the upper end of the screw is fixed with a pressure plate 32, and the pressure plate 32 is located outside the sliding groove 33 of the third curved slider 23 and can press the upper surface of the third curved slider 23; the function of the limit plate 31 is to prevent the first and second curved sliders 22 from separating during the sliding process; the function of the pressure plate 32 is to prevent the first and second curved sliders 22 from separating during the sliding process 2. The third curved slide 23 separates during the sliding process. At the same time, the pressure plate 32 is rotated to move the screw downward, thereby pressing the pressure plate 32 against the surface of the third curved slide 23, thereby adjusting the resistance between the second and third curved slides 23. When in use, the relative position of the third curved slide 23 and the second curved slide 22 can be adjusted first, and then the pressure plate 32 can be rotated to fix the two or increase the resistance to relative sliding between the two, and then the relative position of the second curved slide 22 and the first curved slide 21 can be adjusted to push the end of the third curved slide 23 to a farther distance to connect with the first curved slide 21.

[0034] In some embodiments, the installation method of the breast diameter ruler 51 and the fixing device is as follows: a accommodating box 5 is fixed to one end of the first curved skateboard 21 away from the third curved skateboard 23, and a rotating shaft 52 is provided in the accommodating box 5. The lower end of the rotating shaft 52 is rotatably connected to the bottom wall of the accommodating box 5, and the other end extends out of the accommodating box 5 and is fixed with a handle. One end of the breast diameter ruler 51 is fixed to the circumference of the rotating shaft 52, and the accommodating box 5 is open on the side, and the other end of the breast diameter ruler 51 extends out of the accommodating box 5 from the side opening; rotating the rotating shaft 52 can roll the breast diameter ruler 51 on the rotating shaft 52 or make the breast diameter ruler 51 fall off from the rotating shaft 52.

[0035] When in use, first put the concave surfaces of the three overlapping arc-shaped slides against the edge of the trunk 6, and the breast diameter ruler 51 also against the edge of the trunk 6, then slide the third arc-shaped slide 23 to make it staggered with the second arc-shaped slide 22, and then slide the second arc-shaped slide 22 to make it staggered with the first arc-shaped slide 21, thereby driving the third arc-shaped slide 23 to move forward further along the trajectory until the end of the third arc-shaped slide 23 contacts the end of the first arc-shaped slide 21; during the movement of the three arc-shaped slides, the breast diameter ruler 51 is driven to circle the trunk 6, and then the rotating shaft 52 is rotated to rewind the excess breast diameter ruler 51 extending out of the accommodating box 5, so that the breast diameter ruler 51 tied to the trunk 6 is tightened, and then the handle on the rotating shaft 52 is pressed to prevent the rotating shaft 52 from rotating, and observe the length of the breast diameter ruler 51 extending out of the accommodating box 5 and the corresponding breast diameter value.

[0036] In some embodiments, a first baffle 41 is fixed to one end of the first curved slide 21 close to the accommodating box 5, and a second baffle 42 is fixed to one end of the third curved slide 23 where it connects with the first curved slide 21. A through slot is provided on the first baffle 41, and the end of the breast diameter ruler 51 extending from the accommodating box 5 passes through the through slot and is fixed to the side of the second baffle 42 away from the third curved slide 23; the opposing surfaces of the first baffle 41 and the second baffle 42 can contact each other as the third curved slide 23 moves; the purpose of providing the first baffle 41 and the second baffle 42 is to ensure that when the first and third When the ends of the curved slide 23 approach each other, the first baffle 41 can prevent the second baffle 42 from moving forward. The contact between the two indicates that the first, second and third curved slides 23 have been formed into a circle; and when the first and second baffles 42 are in contact, the surface of the breast diameter ruler 51 is fitted together, and during use, the distance from the connection between the baffle and the breast diameter ruler 51 to the surface of the trunk 6 is a measurement error. The zero scale position of the breast diameter ruler 51 can be adjusted to the edge of the second baffle 42, and when measuring the degree, the degree at the edge of the breast diameter ruler 51 that overlaps with the first baffle 41 can be taken to eliminate the measurement error caused by the equipment structure.

[0037] A sleeve 11 is fixed to the lower surface of the end of the first curved slide 21 near the receiving box 5. The sleeve 11 opens downward, and a fixing rod 1 is threadedly connected from bottom to top within the sleeve 11. The fixing rod 1 is 1.3 meters high. In this embodiment, the fixing rod 1 is detachably connected to the first curved slide 21, that is, the entire fixing device. When the device is needed, the fixing rod 1 is assembled with the fixing device, and when it is not needed, the fixing rod 1 and the fixing device are disassembled, reducing the overall size of the device and making it easier to carry.

[0038] From the above, it can be seen that the technical principles of the present utility model are as follows:

[0039] The operator walks to the tree trunk 6 to be measured, then screws the fixing rod 1 into the sleeve 11 to complete the assembly of the fixing rod 1 and the fixing device, and presses the bottom of the fixing rod 1 against the ground, with the length direction consistent with the length direction of the tree trunk 6. Then, the overlapping first, second, and third curved slides 23 are slid and unfolded through the slide groove 33 and the slider 3, and circle around the measuring point of the tree trunk 6. The process is as follows: rotate the pressure plate 32 to adjust the pressure of the pressure plate 32 on the third curved slide 3, and then adjust the resistance when sliding between the third curved slide 3 and the second curved slide 3. Then, slide the third curved slide 3 and the second curved slide 3 to unfold, and then slide the second curved slide 3 and the first curved slide 3 to unfold, so that the first baffle 41 and the second baffle 42 at the end of the first curved slide 3 and the third curved slide 3 contact. In the process of sliding the second curved slide 22, because the second and third curved slides 3 have a certain resistance when sliding, the relative position of the third curved slide 23 and the second curved slide 22 is not easy to change during the sliding and unfolding of the first and second curved slides 22.

[0040] During the unfolding of the first, second, and third curved slides 23, the end of the third curved slide 23 drives the breast height ruler 51 to extend from the accommodating box 5 during continuous movement. Finally, the first and second baffles 42 come into contact, so that the breast height ruler 51 circles around the trunk 6. Then, the first baffle 41 and the second baffle 42, which are close to the trunk 6, are pressed against the surface of the trunk 6. Then, the rotating shaft 52 is rotated to roll the excess breast height ruler 51 back into the accommodating box 5, so that the breast height ruler 51 tightly surrounds the surface of the trunk 6. Then, the extended length of the breast height ruler 51 and the corresponding breast height diameter value are read.

[0041] At the same time, the rotating shaft 52 can be rotated while the three arc-shaped slides are unfolded to control the extension length of the diameter at breast height ruler 51, so that the diameter at breast height ruler 51 is always in a tensioned state, and the diameter at breast height value obtained by finally surrounding the tree trunk 6 is more accurate.

[0042] The above is only an embodiment of the present invention, and the commonly known specific structures and characteristics of the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, and these should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection claimed by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A device for measuring the diameter at breast height of a tree, characterized by: It includes a breast-height diameter ruler for measuring the breast-height diameter of a tree trunk, and also includes a fixing device with a variable length for fixing the breast-height diameter ruler, and a fixing rod is detachably connected to the bottom of the fixing device; a accommodating box for accommodating the breast-height diameter ruler is fixed to one end of the fixing device, and one end of the breast-height diameter ruler extends out of the accommodating box and is fixedly connected to the end of the fixing device away from the accommodating box; the fixing device can be connected end to end around the tree trunk to be measured by changing its length; the fixing device includes a plurality of arc-shaped slides that are slidably connected in sequence, and among the plurality of arc-shaped slides, the ends of the arc-shaped slide at the front end and the arc-shaped slide at the rear end that are away from each other can be connected, the accommodating box is arranged at the end of the arc-shaped slide at the front end, and the end of the diameter ruler extending out of the accommodating box is fixedly connected to the end of the arc-shaped slide at the rear end.

2. The device for measuring the diameter at breast height of a tree according to claim 1, characterized in that: The fixing device includes a first curved slide, a second curved slide, and a third curved slide. The first curved slide, the second curved slide, and the third curved slide are arranged in sequence from bottom to top and are slidably connected to each other. The accommodating box is fixed to an end of the first curved slide away from the third curved slide, and an adjusting device for controlling the length of the breast diameter ruler extending out of the accommodating box is provided on the accommodating box. The end of the breast diameter ruler extending out of the accommodating box is fixedly connected to an end of the third curved slide away from the first curved slide.

3. The device for measuring the diameter at breast height of a tree according to claim 2, characterized in that: A slider is fixed to the upper surface of one end of the second arc-shaped slide, and a slider is also fixed to the lower surface of the other end. The middle parts of the first arc-shaped slide and the second arc-shaped slide are both provided with sliding grooves for accommodating the sliding of the sliders.

4. The device for measuring the diameter at breast height of a tree according to claim 3, characterized in that: The slider located on the lower surface of the second curved slider extends out of the corresponding sliding groove at one end away from the second curved slider and a limiting plate is fixed on the end; the slider located on the upper surface of the second curved slider is located in the corresponding sliding groove at one end away from the second curved slider and a screw is threadedly connected to the end, and a pressure plate is fixed to the upper end of the screw, and the pressure plate is located outside the sliding groove of the third curved slider and can press the upper surface of the third curved slider.

5. The device for measuring the diameter at breast height of a tree according to claim 4, characterized in that: The adjusting device includes a rotating shaft arranged in the accommodating box, one end of the rotating shaft is rotatably connected to the inner wall of the accommodating box, and the other end extends out of the accommodating box and is fixed with a handle. The circumference of the rotating shaft located in the accommodating box is fixed to the end of the breast height ruler located in the accommodating box.

6. The device for measuring the diameter at breast height of a tree according to claim 5, characterized in that: A first baffle is fixed to one end of the first curved slide close to the accommodating box, and a second baffle is fixed to one end of the third curved slide where it connects with the first curved slide. A through slot is provided on the first baffle, and the end of the breast diameter ruler extending from the accommodating box passes through the through slot and is fixed to a side of the second baffle away from the third curved slide; the opposing surfaces of the first baffle and the second baffle can contact each other as the third curved slide moves.

7. The device for measuring the diameter at breast height of a tree according to claim 6, characterized in that: A sleeve is fixed on the lower surface of the first arc-shaped slide plate, with the sleeve opening downward. The fixing rod is inserted into the sleeve from bottom to top and is threadedly connected to the sleeve.

8. A device for measuring the diameter at breast height of a tree according to any one of claims 1 to 7, characterized in that: The length of the fixing rod is 1.3 meters.

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