Method and device for fine estimation of carbon sink capacity of street trees

Abstract

The present application relates to the technical field of street tree carbon storage estimation, and provides a street tree carbon sink capacity fine estimation method and device, the method comprising: obtaining first period street tree data and second period street tree data; based on a target diameter at breast height-height model, according to human management factors, the first period street tree data and the second period street tree data, the street tree biomass of the target area is estimated, the first period street tree and the second period street tree carbon storage are obtained; based on the first period street tree and the second period street tree carbon storage and the road characteristics of the target area, the street tree carbon sink parameters are calculated to evaluate the street tree carbon sink capacity of the target area; wherein the road characteristics include at least one of the greening length of each street in the target area, the plant distance between adjacent trees, the total greening length of all streets and the total road area of all streets; the street tree carbon sink parameters include at least one of the carbon fixation amount, the carbon sink, the carbon fixation density and the carbon sink density. The method improves the prediction accuracy of street tree carbon sink capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of street tree carbon storage estimation, and particularly relates to a street tree carbon sink capacity fine estimation method and device. BACKGROUND

[0002] Tree height and diameter at breast height are the most basic and important factors in forestry production investigation, and as the volume factor of standing timber, they are important indexes for calculating forest stock, biomass and carbon storage, and measuring forest growth potential and forest site quality. However, urban street trees are not only affected by common factors such as natural environment and genetic characteristics during growth, but also closely related to human management factors. These factors can affect the growth of street trees and further affect the carbon sequestration function of street trees.

[0003] At present, most tree height growth models usually directly predict the tree height of forest trees with diameter at breast height as the only independent variable. The carbon storage data of street trees calculated according to the model cannot reflect the growth difference of diameter at breast height-tree height in different environments, resulting in inaccurate statistical results of street tree carbon sink capacity and difficulty in evaluating the environmental benefits of urban trees. SUMMARY

[0004] The present application provides a street tree carbon sink capacity fine estimation method and device to solve the defect that the carbon storage data of street trees calculated by the tree height growth model in the prior art cannot reflect the growth difference of diameter at breast height-tree height in different environments, resulting in inaccurate statistical results of street tree carbon sink capacity, and improve the prediction accuracy of street tree carbon sink capacity.

[0005] The present application provides a street tree carbon sink capacity fine estimation method, comprising:

[0006] Obtaining first period street tree data and second period street tree data; the first period street tree data and the second period street tree data are collected at different time points in the target area;

[0007] Estimating the biomass of street trees in the target area based on a target diameter at breast height-tree height model, the first period street tree data and the second period street tree data according to human management factors, to obtain the carbon storage of first period street trees and second period street trees; wherein the target diameter at breast height-tree height model is determined based on a biological mathematical model; the human management factors include at least two of street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road construction shading and vertical structure;

[0008] The tree carbon sink parameter is calculated based on the carbon storage of the first period and the second period of the street trees and road features of the target area, so as to evaluate the tree carbon sink capability of the target area; wherein the road features include at least one of the greening length of each street in the target area, the spacing between adjacent trees, the total greening length of all streets and the total road area of all streets; and the tree carbon sink parameter includes carbon density and carbon sink.

[0009] According to the method for fine estimation of tree carbon sink capability, the first period of tree data and the second period of tree data are obtained by:

[0010] The sampling streets are obtained by randomly sampling the streets in the target area.

[0011] The first period of tree data is obtained by measuring each tree on each sampling street; and the measurement of each tree includes measurement of tree species name, tree height, diameter at breast height and spacing between adjacent trees.

[0012] The second period of tree data is obtained by measuring each tree on each sampling street after a target time interval.

[0013] According to the method for fine estimation of tree carbon sink capability, the target area includes a city.

[0014] The sampling streets are obtained by randomly sampling the streets in the target area.

[0015] The roads in the target area are divided according to the city road grade division condition, to obtain urban expressways, urban main roads, urban secondary roads and urban branch roads.

[0016] The urban branch roads are divided according to the road network density and the road width, to obtain new urban branch roads.

[0017] The sampling streets are obtained by randomly sampling the urban expressways, the urban main roads, the urban secondary roads and the new urban branch roads.

[0018] According to the method for fine estimation of tree carbon sink capability, the biological mathematical model includes a linear model, a logarithmic model and an allometric model.

[0019] The target diameter at breast height-height model is constructed by the following steps:

[0020] For each biological mathematical model, the target evaluation index is calculated based on the sample height data and the sample diameter at breast height data according to the biological mathematical model, to obtain an index calculation result; and the target evaluation index includes a determination coefficient R 2at least one of the Akaike information criterion (AIC), the Bayesian information criterion (BIC), the Deviance Information Criterion (DIC), the Akaike information criterion (AIC), the root mean square error (RMSE), and the mean percentage error (MEP);

[0021] The target diameter at breast height-height model is determined based on a maximum value in the index calculation result.

[0022] According to the method for fine estimation of carbon sink capacity of street trees, the biomass of street trees in the target region is estimated based on the target diameter at breast height-height model, the human management factors, the first period street tree data and the second period street tree data, to obtain the carbon storage of the first period street trees and the second period street trees.

[0023] The human management factors are used as dummy variables of the target diameter at breast height-height model to construct a dummy variable diameter at breast height-height model.

[0024] The total biomass of each street tree is calculated based on the dummy variable diameter at breast height-height model and the first period street tree data and the second period street tree data.

[0025] The carbon storage of the first period street trees is obtained based on the total biomass and a preset carbon content rate.

[0026] According to the method for fine estimation of carbon sink capacity of street trees, the human management factors include street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road construction light shielding and vertical structure.

[0027] Before the dummy variable diameter at breast height-height model is constructed by using the human management factors as dummy variables of the target diameter at breast height-height model, the method further comprises:

[0028] The human management factors are subjected to significant correlation analysis to obtain an analysis result, and the analysis result is filtered based on a significant influence threshold to obtain human management factors with significant results.

[0029] According to the method for fine estimation of carbon sink capacity of street trees, after the carbon storage of the first period street trees is obtained, the method further comprises:

[0030] The biomass of street trees in the target region is estimated based on an allometric equation constructed based on traditional forest investigation, the first period street tree data and the second period street tree data, to obtain new carbon storage of street trees.

[0031] The evaluation result of carbon sink capacity of street trees is obtained based on the carbon storage of the first period street trees and the second period street trees and the new carbon storage of street trees.

[0032] The application also provides a device for fine estimation of carbon sink capacity of street trees, comprising:

[0033] a data acquisition module configured to acquire first period street tree data and second period street tree data, the first period street tree data and the second period street tree data being collected at different time points in a target area;

[0034] a biomass estimation module configured to estimate street tree biomass in the target area based on a target diameter at breast height-height model, human management factors, the first period street tree data and the second period street tree data, to obtain first period street tree carbon storage and second period street tree carbon storage, wherein the target diameter at breast height-height model is determined based on a biological mathematical model, and the human management factors include at least two of street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road construction light shielding and vertical structure;

[0035] a carbon sink capacity estimation module configured to calculate street tree carbon sink parameters based on the first period street tree carbon storage and the second period street tree carbon storage and road features of the target area, to evaluate street tree carbon sink capacity of the target area, wherein the road features include at least one of greening length of each street in the target area, spacing between adjacent trees, total greening length of all streets and total road area of all streets, and the street tree carbon sink parameters include carbon density and carbon sink.

[0036] The application further provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the street tree carbon sink capacity fine estimation method when executing the computer program.

[0037] The application further provides a non-transitory computer readable storage medium, which stores a computer program executable by a processor to implement the street tree carbon sink capacity fine estimation method.

[0038] The application further provides a computer program product, which includes a computer program executable by a processor to implement the street tree carbon sink capacity fine estimation method.

[0039] The street tree carbon sink capacity fine estimation method and device provided by the application estimate street tree biomass in a target area based on a target diameter at breast height-height model, human management factors, first period street tree data and second period street tree data, to obtain first period street tree carbon storage and second period street tree carbon storage, and calculate street tree carbon sink parameters based on the street tree carbon storage and road features of the target area, to evaluate street tree carbon sink capacity of the target area, thereby improving the prediction accuracy of street tree carbon sink capacity. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to make the technical solutions in the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort.

[0041] Figure 1 is one of the flowcharts of the street tree carbon sink capacity fine estimation method provided by the present application.

[0042] Figure 2 is a street tree breast height-diameter height scatter plot provided by the present application.

[0043] Figure 3 is the second flowchart of the street tree carbon sink capacity fine estimation method provided by the present application.

[0044] Figure 4 is a structural schematic diagram of the street tree carbon sink capacity fine estimation device provided by the present application.

[0045] Figure 5 is a structural schematic diagram of the electronic device provided by the present application. DETAILED DESCRIPTION

[0046] In order to make the technical solutions in the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort.

[0047] The technical solutions of the street tree carbon sink capacity fine estimation method and device of the present application will be described below. Figures 1-4

[0048] Figure 1 is one of the flowcharts of the street tree carbon sink capacity fine estimation method provided by the present application, as shown in the figure, the method comprises the following steps: Figure 1

[0049] Step 110, acquiring first period street tree data and second period street tree data; the first period street tree data and the second period street tree data are collected at different time points in the target area.

[0050] In this step, the target area includes cities, towns or other artificially planned areas with diversified road systems and street trees.

[0051] ​​In this step, the first period street tree data and the second period street tree data each include but are not limited to the name of the street tree, the height of the street tree, the diameter at breast height, and the distance to the adjacent tree.

[0052] In this embodiment, the same time point can be a time range measured in days, months, seasons, or years. For example, a period of time can be ten years.

[0053] In this embodiment, the above street tree data is obtained by measuring each tree in the sampled street tree.

[0054] The following is described by taking A City as an example. The sampled streets are determined by randomly sampling or uniformly sampling the streets in the target area of A City, and the sampled street trees are randomly sampled near the sampled streets, and the first period street tree data is obtained by measuring each tree in the sampled street trees. Ten years later, the sampled streets or the areas near the sampled streets are sampled, and the second period street tree data is obtained by measuring each tree in the sampled street trees.

[0055] Step 120, based on the target diameter at breast height-height model, the first period street tree data and the second period street tree data are estimated according to the human management factors, and the first period street tree and the second period street tree carbon storage are obtained; wherein the target diameter at breast height-height model is determined based on a biological mathematical model; the human management factors include at least two of the tree spacing, the tree pool side length, the adjacent tree species, the tree trunk whitening, the tree pool anti-treading protection, the road construction shading and the vertical structure.

[0056] In this step, the biological mathematical model includes but is not limited to linear model, logarithmic model, allometric growth model and other commonly used and biologically meaningful basic models. The biological mathematical model is used as a reference model for the dummy variable model for studying the influence of the management measures of A City on the relationship between the height and the diameter of the street trees.

[0057] In this step, by constructing the diameter at breast height-height model of the street trees in the main urban area of A City with the human management factors as the dummy variables, the carbon storage of the street trees in the main urban area of A City is estimated by the model, and the influence of the human management factors in the urban environment on the diameter and the height of the street trees is analyzed.

[0058] Specifically, the biological mathematical model includes linear model, logarithmic model and allometric growth model; the target diameter at breast height-height model is constructed by the following steps:

[0059] (1) For each biological mathematical model, based on the biological mathematical model, the target evaluation index is calculated according to the sample height data and the sample diameter data, and the index calculation result is obtained; the target evaluation index includes the determination coefficient R 2, at least one of Akaike information criterion AIC, root mean square error RMSE and mean percentage error MEP; determine the target diameter at breast height-tree height model target based on the maximum value of the indicator calculation results.

[0060] It should be noted that the tree height growth model can reflect the law of tree height changing with the diameter at breast height. It is an important component of the forest growth and harvesting model system, and it is also an important method for estimating tree height, stock volume and biomass. Introducing human management factors as dummy variables into the currently known diameter at breast height-tree height growth model can construct a growth model that is more suitable for urban street trees, providing a more refined estimation method for evaluating the carbon sequestration function of street trees.

[0061] In this embodiment, the coefficient of determination (R 2 ), Akaike information criterion (AIC), root mean square error (RMSE) and mean percentage error (MPE) are used to evaluate the accuracy of the selected common models; SSE is the residual sum of squares; SEE is the standard deviation of the estimate; Adj-R 2 is the adjusted coefficient of determination; R 2 , RMSE is the most commonly used indicator of regression model, among which the coefficient of determination R 2 The closer the value is to 1, the better the model fitting accuracy, the higher the proportion of dependent variables that can be explained, the smaller the RMSE value, the smaller the difference between the predicted value and the observed value, and the higher the model prediction accuracy; MPE is an accuracy index reflecting the average tree height estimate. The smaller the absolute value, the more reliable the prediction result; AIC is an indicator that comprehensively reflects the model fitting accuracy and complexity. The smaller the value, the higher the model quality.

[0062] Figure 2 The scatter plot of DBH-tree height of street trees provided by the present invention is Figure 2 In the embodiment shown, a scatter plot of the DBH-tree height of street trees is drawn in combination with field survey data. It can be found that the tree heights of the street trees in City A are concentrated in the range of 10-15m, and the DBH is in the range of 20-35cm; the overall tree height increases with the increase of the DBH, and the growth rate shows a trend of first increasing and then decreasing; there is a nonlinear correlation between the two, and the data of the DBH and tree height are approximately normally distributed.

[0063] (2) Determine the target DBH-tree height model based on the maximum value of the indicator calculation results.

[0064] In this embodiment, the model with the highest fitting accuracy is selected from the selected accuracy models as the basic model of tree height and diameter at breast height of street trees, that is, the target diameter at breast height-tree height model, which improves the prediction performance of the diameter at breast height-tree height model.

[0065] In this embodiment, the tree species, diameter at breast height, tree height of the street trees in the two surveys and the trunk biomass of the street trees are estimated by the tree species allometric equation method and then converted into carbon storage.

[0066] This embodiment introduces the factor of human maintenance into the growth process of urban street trees, and uses radial growth detection to monitor the growth changes of street trees in City A over a period of ten years. It establishes a more accurate and targeted growth model that is different from traditional forest types, providing a scientific reference for the scientific planning, planting, maintenance, and carbon sequestration function evaluation of urban street trees.

[0067] Step 130: Calculate street tree carbon sink parameters based on the carbon storage of the first-phase street trees and the second-phase street trees and the road characteristics of the target area to evaluate the street tree carbon sink capacity in the target area; wherein the road characteristics include at least one of the greening length of each street in the target area, the spacing between adjacent trees, the total greening length of all streets, and the total road area of ​​all streets; and the street tree carbon sink parameters include carbon density and carbon sink.

[0068] In this step, the spatial heterogeneity of the carbon storage and carbon sequestration capacity of street trees in City A can be analyzed at different scales based on the characteristics of the urban structure.

[0069] In this example, the carbon storage in the target area is calculated using the following formula:

[0070]

[0071] Among them, C entire is the carbon storage in the target area, C j is the carbon storage of a sampled street, C i is the carbon storage of a single tree; green is the green length of a single sampling street; L entire is the total green length of all sampled streets; l sample is the distance between adjacent trees;

[0072] In this embodiment, the carbon sink in the target area is calculated using the following formula:

[0073] C sink =C y -C x ;

[0074] Among them, C sink is the carbon sink in the target area; Cx is the carbon density of the target area after an interval of ten years; C y is the carbon density of the target area after an interval of ten years; C

[0075] In this embodiment, the carbon sink density of the target area is calculated by the following formula:

[0076]

[0077] wherein C density is the carbon sink density of the target area; S area is the total area of all roads.

[0078] Taking the target area A city as an example, the carbon storage, carbon sink, carbon storage density, and carbon sink density of the research area are calculated, and spatial heterogeneity analysis is performed according to each administrative region of A city.

[0079] The sidewalk tree carbon sink capacity fine estimation method provided by the embodiment of the application estimates the biomass of the target area sidewalk trees according to the target diameter-height model, the first period sidewalk tree data, and the second period sidewalk tree data, obtains the first period sidewalk tree carbon storage and the second period sidewalk tree carbon storage, and calculates the sidewalk tree carbon sink parameters according to the sidewalk tree carbon storage and the road characteristics of the target area, so as to evaluate the sidewalk tree carbon sink capacity of the target area and improve the prediction accuracy of the sidewalk tree carbon sink capacity.

[0080] In some embodiments, obtaining the first period sidewalk tree data and the second period sidewalk tree data comprises:

[0081] (1) randomly sampling from the streets in the target area to obtain the sampling streets.

[0082] In this embodiment, the sampling roads can be selected in the research area according to the stratified sampling principle.

[0083] Taking the target area A city as an example, according to the history, culture, and economic development factors of A city, a plurality of ring road systems of A city are selected for sampling; the selected main urban areas should meet the above characteristics, and six representative urban areas of A city are mainly selected as the key research areas; the sampling streets are selected in the five ring road systems according to the random sampling principle: sampling points are uniformly selected at intervals of 2 kilometers, streets are selected nearby for sampling, and more than 200 sampling streets are counted in nearly 1000 roads in the six urban areas of A city.

[0084] (2) measuring each sidewalk tree of each sampling street to obtain the first period sidewalk tree data, and each measurement includes measuring the tree species name, tree height, diameter at breast height, and distance between adjacent trees.

[0085] Specifically, according to the field investigation, most of the roads have only one tree species and two rows of trees, and in the rare case that only two tree species exist on a street, 5 trees of each tree species are selected for measurement; if there are multiple tree species near the street trees, 10 street trees can be randomly selected for each sample street; for each tree, the species name is recorded, and the tree height, diameter at breast height and distance from the adjacent trees are measured to obtain the first period of street tree data.

[0086] (3) In the case that the target region passes through the target time interval, the street trees of the sample street are measured per tree, and the second period of street tree data is obtained.

[0087] In this embodiment, according to the inventory period of the forest resource monitoring second-class survey, the sample street determined in the first survey is measured per tree again after an interval of ten years to obtain the second period of street tree data.

[0088] It should be noted that due to the changes in roads and street trees caused by urban planning and construction during the period, other streets are measured nearby.

[0089] In this embodiment, the time interval of the second field investigation of city A is set to 10 years, and the sample street of the initial investigation year is measured per tree again; during the period, due to the changes in roads and street trees caused by urban planning and construction, other streets are measured nearby; at the same time, the human management factor investigation of street trees is added in the second field investigation; for example, 7 kinds of on-site surveyable and determinable human management elements such as tree trunk whitening, tree pool anti-treading protection device, building shading, tree vertical structure, tree spacing, tree pool side length and adjacent tree species are selected for statistics, and the longitude and latitude of the survey sample point are recorded by using a handheld GPS (Garmin631csx); this survey has a total of more than 200 sample roads, and nearly 700 effective data are obtained; the GPS data can be displayed on the corresponding image of the sample street or sample street tree to mark the image sampling time and geographical position.

[0090] The street tree carbon sink capacity fine estimation method provided by the embodiment of the present application can obtain sample streets by randomly sampling from the streets in the target region; the first period of street tree data is obtained by measuring per tree of the street trees of each sample street; in the case that the target region passes through the target time interval, the second period of street tree data is obtained by measuring per tree of the street trees of the sample street, which provides reliable data support for subsequent acquisition of the street tree carbon storage of the target region.

[0091] In some embodiments, the target region includes a city; the sample streets are obtained by randomly sampling from the streets in the target region, including:

[0092] (1) According to the urban road grade division condition, the roads in the target region are divided to obtain urban expressway, urban main road, urban secondary road and urban branch road.

[0093] In this embodiment, on the selected sampling points, according to the urban road grade division regulation, the road grades in the city center area of A city involved in the municipal district range are divided by using ArcGISpro (19.1.0) software, wherein Road1 is a first-class road, that is, the urban expressway including the second ring to the sixth ring; Road2 is a second-class road, that is, the urban main road; Road3 is a third-class road, that is, the urban secondary road; and Road4-6 is a fourth-class road, that is, the urban branch road.

[0094] (2) According to the road network density and the road width, the urban branch road is divided to obtain a new urban branch road.

[0095] According to the road network density and the road width, the urban branch road is divided into Road4, Road5 and Road6 three grades.

[0096] (3) Random sampling is performed on the urban expressway, the urban main road, the urban secondary road and the urban branch road to obtain a sampling street.

[0097] In this embodiment, according to the random sampling principle, the sampling streets are selected in the different road grade systems of the five rings of A city: sampling points are uniformly selected at intervals of 2 kilometers, and streets are selected nearby the sampling points for sampling, and more than 200 sampling streets are counted in the roads of all levels in the center area of A city.

[0098] The street tree carbon sink capacity fine estimation method provided by the embodiment of the application divides the roads in the target region according to the urban road grade division condition to obtain urban expressway, urban main road, urban secondary road and urban branch road. Then, the urban branch road is divided according to the road network density and the road width to obtain a new urban branch road. Finally, random sampling is performed on the urban expressway, the urban main road, the urban secondary road and the urban branch road to obtain the sampling street. The effective sampling of the urban street is realized by comprehensively considering the objective variables such as urban thermal environment and human factors, and high-quality street tree data can be obtained.

[0099] In some embodiments, based on the target diameter at breast height-height model, the first period street tree biomass and the second period street tree biomass of the target region are estimated according to the human management factor, the first period street tree data and the second period street tree data, to obtain the first period street tree and the second period street tree carbon storage.

[0100] (1) Taking the human management factor as a dummy variable of the target diameter at breast height-height model, a dummy variable diameter at breast height-height model is constructed.

[0101] It should be noted that the tree height growth model can reflect the law that the tree height changes with the change of the diameter at breast height, is an important part of the forest growth and yield model system, and is also an important method for estimating tree height, volume and biomass; In this embodiment, the artificial management and protection factors are introduced as dummy variables into the known diameter at breast height-tree height growth model, so that a growth model more suitable for urban street trees can be constructed, and a more accurate estimation method for evaluating the carbon sink function of street trees is provided.

[0102] For example, the artificial management and protection factors can be road building shading, tree pool anti-treading protection, tree trunk whitening and tree pool side length; the target diameter at breast height-tree height model is a logarithmic model; the above four factors are introduced into the diameter at breast height-tree height growth model, and the influence of the four factors on the growth relationship of the trees is further analyzed.

[0103] Specifically, the base model is selected as a logarithmic model, and taking the introduction of the tree trunk whitening dummy variable at the parameter a as an example, the model form is as follows:

[0104] H=(a+t×T)×lnD+b;

[0105] Wherein, H is the tree height; D is the diameter at breast height; a and b are general parameters of the model; t is a dummy variable for distinguishing tree trunk whitening, and T is a whitening condition introduction parameter; when the tree trunk is whitened, T=1, and when the tree trunk is not whitened, T=0.

[0106] In this embodiment, the street tree measurement data is classified according to the tree trunk whitening, ground anti-treading device, building shading and tree pool side length, and a dummy variable diameter at breast height-tree height model is established. After introducing the corresponding dummy variable at a suitable position of the model, the accuracy of the diameter at breast height-tree height growth model of the street tree is obviously improved.

[0107] (2) Based on the dummy variable diameter at breast height-tree height model, the total biomass of each street tree is calculated according to the first period street tree data and the second period street tree data.

[0108] For example, the carbon density and carbon sink distribution characteristics of the central urban street trees of A city can be quantitatively analyzed from three different angles of urban-rural gradient division, road grade division and administrative region division.

[0109] In this embodiment, the sampling street trees include Fraxinus, Sophora japonica, Ginkgo, Populus and Firmiana, the diameter at breast height data and tree height data of each tree species are determined through the target diameter at breast height-tree height model, and the individual tree species biomass is calculated by using the allometric growth equation of the tree species; the biomass of each tree species is calculated according to the following allometric growth equation formula:

[0110] B 梣属 = 2.1893 + 3.2949 x 10 -2 D 2 H;

[0111] B 国槐 = 0.714 + 0.029D 2 H;

[0112] B 银杏 = -0.684 + 0.090D 2 H;

[0113] B 杨属 = 0.015 x (D 2 H)1.032;

[0114] lgB 梧桐 = -1.161443 + 0.913291lg(D 2 H));

[0115] Wherein, B is total plant biomass, D is diameter at breast height (diameter of the trunk at 1.3 meters of height), and H is tree height.

[0116] In this embodiment, if a single-species allometric equation is not established for a certain tree species, an allometric equation of a species in the same genus or the same family is used; if the allometric equation of the species in the same genus or the same family is still lacking, the following generalized growth equation is used:

[0117] B = 0.11 x D 2.47 ;

[0118] In this embodiment, the above generalized equation is applicable to tree species such as Koelreuteria paniculata, Pinus bungeana, Salix matsudana, Ailanthus altissima, Ulmus pumila and Acer truncatum.

[0119] (3) Obtain the carbon storage of the first period of street trees and the second period of street trees according to the total plant biomass and the preset carbon content rate.

[0120] In this embodiment, the carbon storage of each sampling road is calculated by measuring the diameter at breast height of each tree in the sampling location, and then the carbon storage of the street trees in the urban area is selected as the sum of the carbon storage of the individual tree species in the sampling location.

[0121] Specifically, the individual carbon storage in the sampling location is calculated by the following formula:

[0122] Individual carbon storage = carbon content rate x individual biomass;

[0123] Wherein, the carbon content rate can be set according to user requirements, for example, the reference value of the carbon content rate is 0.5.

[0124] The fine estimation method for street tree carbon sink capacity provided by the embodiment of the application combines field investigation and model estimation, constructs a diameter at breast height-height model suitable for multiple urban street trees in city A, and introduces human management and protection factors, thereby improving the estimation accuracy of the diameter at breast height-height model.

[0125] In some embodiments, human maintenance factors include street tree spacing, tree pit side length, neighboring tree species, whitewashing of tree trunks, anti-trampling protection of tree pits, road building shading and vertical structure; before constructing a dummy variable diameter at breast height-tree height model with human maintenance factors as the dummy variables of the target diameter at breast height-tree height model, the method also includes: performing a significant correlation analysis on the human maintenance factors to obtain analysis results, and screening the analysis results according to the significant impact threshold to obtain new human maintenance factors.

[0126] In this embodiment, after determining the target DBH-tree height model, the dummy variable of the human management factor is incorporated into the DBH-tree height growth model. First, SPSS (Statistical Package for the Social Sciences) is used to verify whether the seven management measures have a significant correlation with the distribution of tree height and DBH of street trees.

[0127] In this embodiment, the data were analyzed using the Mann-Whitney test, confirming that the installation of ground anti-trampling protection nets and building shading had a significant effect on the growth distribution of the diameter at breast height of street trees (P<0.01).

[0128] In this embodiment, the data were analyzed using the KW test, confirming that different tree pit side lengths had a significant effect on the DBH distribution of street trees (P<0.05).

[0129] Research has found that human interference in urban ecosystems has caused an increase in soil bulk density, a decrease in porosity, a change in soil texture, a decrease in soil organic matter content, a decrease in effective water content, obstructed plant root extension, and poor breathing, which has reduced plant growth potential. Setting up anti-trampling protection nets in tree pits can effectively reduce the damage to the root environment of street trees caused by human interference, protect the growth environment, promote the absorption of nutrients by the roots, and thereby affect the growth changes of street trees' diameter at breast height and tree height.

[0130] Street trees in urban habitats suffer from the disturbance of pests and diseases at night. Whitewashing the surface of the trunks can fill the cracks in the bark, destroy the breeding ground for pests and diseases, kill mites and other forest pests, and reduce the incidence of pests and diseases. At the same time, due to the influence of the urban heat island effect, the climate in the central urban area is hot in summer and cold in winter. Whitewashing can effectively prevent the trunks from being burned or frozen. Therefore, whitewashing the trunks can reduce the interference of pests and diseases or physical damage to street trees, which is more conducive to the growth of diameter at breast height and tree height.

[0131] Moreover, photosynthesis of plants cannot be separated from light conditions, and good light conditions can promote photosynthesis and stimulate cell division and growth, thereby affecting diameter at breast height and tree height; when designing a tree pool for a street tree, sufficient growth space should also be left for the street tree according to different tree species, so as to store more water and nutrients, so that the root system can fully grow and develop, therefore, the size of the side length of the tree pool also affects the growth of the diameter at breast height and the tree height of the street tree.

[0132] In addition, the same tree species are often planted on the roads in the central urban area of A city, and the condition of adjacent tree species belonging to different species is extremely rare, and the influence of the spacing and vertical structure on the tree height and diameter at breast height of the street tree is not significant; in summary, the diameter at breast height-tree height growth model in the embodiment includes four factors of road building shading, tree pool anti-treading protection, tree trunk whitening and tree pool side length, and further analyzes the influence of the four factors on the growth relationship of the tree.

[0133] The street tree carbon sink capacity fine estimation method provided by the embodiment of the application further improves the estimation accuracy of the diameter at breast height-tree height model by performing significant correlation analysis on human management factors and screening the analysis results according to a significant influence threshold to obtain new human management factors.

[0134] In some embodiments, after obtaining the first period street tree carbon storage, the street tree carbon sink capacity fine estimation method further includes:

[0135] (1) The allometric equation based on the traditional forest survey is used to estimate the biomass of the street trees in the target area according to the first period street tree data and the second period street tree data, and the second period street tree carbon storage is obtained.

[0136] The similarities and differences between the carbon sink estimation results obtained by using the allometric equation based on the traditional forest survey and the carbon sink estimation results obtained by using the diameter at breast height-tree height relationship optimization model established according to the growth relationship of the street trees in A city are compared.

[0137] Through fitting and testing of the diameter at breast height-tree height model by using 112 street tree data, it is found that the fitting model has good verification results and high prediction accuracy, and the R 2 , MPE, AIC and RMSE model accuracy parameter values of the diameter at breast height-tree height model with the dummy variable are better than those of the traditional diameter at breast height-tree height allometric growth model, and the street tree carbon sink estimation results of A city are more accurate.

[0138] (2) The street tree carbon sink capacity evaluation results are obtained based on the first period street tree carbon storage, the second period street tree carbon storage and the new street tree carbon storage.

[0139] It should be noted that the analysis and discussion of the traditional breast diameter-height model is often focused on the analysis of environmental factors and its own genetic characteristics factors, and the existing common growth model is difficult to establish a unique relationship between artificial management factors and street tree growth, but as an important part of urban forest, artificial management and urban habitat play a crucial role in the growth process of street trees; the artificial management measures of street trees in the field investigation are counted, the influence on the growth conditions of diameter and height is analyzed respectively, the trunk whitening, ground anti-treading device, building shading and tree pool side length are selected as dummy variables to introduce the corresponding parameter position of the model, the artificial management factor dummy variable model is constructed, the street trees of different management types are combined, and the universality of the breast diameter-height growth model of street trees is improved.

[0140] In addition, the embodiment combines the road greening length with the allometric equation, calculates the carbon storage and carbon sink distribution of the street trees in the city A from three different angles based on the structural characteristics of the city, and analyzes the spatial heterogeneity thereof; the growth detection method of the street trees can be used to determine the growth rate of the trees, and a more accurate and targeted growth model can be established by combining objective variables such as urban thermal environment and human factors, so as to provide a reference for scientific selection, planning planting, maintenance management and carbon sink function evaluation of the street trees in the city in the future.

[0141] The street tree carbon sink capacity fine estimation method provided by the embodiment of the present application estimates the carbon sink of the street trees in the target region through the allometric equation constructed by the traditional forest investigation, and compares with the dummy variable breast diameter-height model with the introduction of artificial management factors, so as to realize the comparative analysis of the traditional breast diameter-height model and the target breast diameter-height model.

[0142] Figure 3 is the second flowchart of the street tree carbon sink capacity fine estimation method provided by the present application, in which Figure 3In the embodiment shown, a sampling survey method is used to measure each street tree in the main urban area of ​​City A to obtain measurement data on diameter at breast height, tree height, and adjacent tree spacing (first phase street tree data). Ten years later, each street tree in the same street is measured again to obtain second phase street tree data. An investigation is conducted on the human management factors of street trees in the main urban area of ​​City A, and the diameter at breast height-tree height model with the highest accuracy is selected from multiple biological mathematical models as the basic biological model. The carbon storage of street trees in the first and second phases is calculated using the diameter at breast height-tree height allometric growth equation model, and then the carbon storage of street trees in the first and second phases is obtained. The carbon sink of street trees in City A under the traditional model was obtained; the human management factor was introduced as the dummy variable of the basic biological model, and a dummy variable breast diameter-tree height model was constructed to calculate the carbon storage of street trees in the first and second periods, and then the carbon sink of street trees in City A under the target model was obtained; at the same time, the carbon sink of street trees in City A was classified from three perspectives: urban-rural gradient, road grade, and administrative division, and the spatial heterogeneity of street trees was analyzed; the carbon sink parameters of urban street trees under the traditional model and urban street trees under the target model were combined, and through model accuracy comparison, a more accurate estimation result of the carbon sink of street trees in City A was obtained to evaluate the carbon sink capacity of urban street trees.

[0143] The following describes the device for finely estimating the carbon sequestration capacity of street trees provided by the present invention. The device for finely estimating the carbon sequestration capacity of street trees described below and the method for finely estimating the carbon sequestration capacity of street trees described above can be referenced to each other.

[0144] Figure 4 This is a schematic diagram of the structure of the device for finely estimating the carbon sequestration capacity of street trees provided by the present invention. Figure 4 As shown, the device for finely estimating the carbon sequestration capacity of roadside trees includes: a data acquisition module 410 , a biomass estimation module 420 and a carbon sequestration capacity estimation module 430 .

[0145] The data acquisition module 410 is used to acquire the first phase of street tree data and the second phase of street tree data; the first phase of street tree data and the second phase of street tree data are collected at different time points in the target area;

[0146] Biomass estimation module 420 is configured to estimate the biomass of street trees in a target area based on a target DBH-tree height model, human management factors, first-phase street tree data, and second-phase street tree data, thereby obtaining the carbon storage of street trees in the first and second phases. The target DBH-tree height model is determined based on a biomathematical model, and the human management factors include at least two of the following: street tree spacing, tree pit side length, adjacent tree species, whitewashing, tree pit anti-trampling protection, road building shading, and vertical structure.

[0147] The carbon sink capacity estimation module 430 is configured to calculate a street tree carbon sink parameter based on the first period street tree carbon storage and the second period street tree carbon storage and road features of the target region, so as to evaluate the street tree carbon sink capacity of the target region; wherein the road features include at least one of the greening length of each street in the target region, the spacing between adjacent trees, the total greening length of all streets and the total road area of all streets; and the street tree carbon sink parameter includes carbon density and carbon sink.

[0148] The street tree carbon sink capacity fine estimation device provided by the embodiment of the present application estimates the street tree biomass of the target region according to the artificial management factor, the first period street tree data and the second period street tree data based on the target diameter-height model, obtains the street tree carbon storage, and calculates the street tree carbon sink parameter based on the street tree carbon storage and the road features of the target region, so as to evaluate the street tree carbon sink capacity of the target region, thereby improving the prediction accuracy of the street tree carbon sink capacity.

[0149] Figure 5 The electronic device provided by the present application is shown in FIG. 1. Figure 5 As shown in FIG. 1, the electronic device can include a processor 510, a communications interface 520, a memory 530 and a communications bus 540, wherein the processor 510, the communications interface 520 and the memory 530 complete mutual communication through the communications bus 540. The processor 510 can call the logical instructions in the memory 530 to execute the street tree carbon sink capacity fine estimation method, which includes: obtaining first period street tree data and second period street tree data; the first period street tree data and the second period street tree data are collected at different time points in the target region; estimating the street tree biomass of the target region based on the target diameter-height model according to the artificial management factor, the first period street tree data and the second period street tree data, to obtain the first period street tree carbon storage and the second period street tree carbon storage; wherein the target diameter-height model is determined based on a biological mathematical model; the artificial management factor includes at least two of street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road building light shielding and vertical structure; calculating a street tree carbon sink parameter based on the first period street tree carbon storage and the second period street tree carbon storage and road features of the target region, so as to evaluate the street tree carbon sink capacity of the target region; wherein the road features include at least one of the greening length of each street in the target region, the spacing between adjacent trees, the total greening length of all streets and the total road area of all streets; and the street tree carbon sink parameter includes carbon density and carbon sink.

[0150] In addition, the logic instructions in the memory 530 described above can be implemented in the form of a software function unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium, includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0151] In another aspect, the present application also provides a computer program product, which comprises a computer program, the computer program can be stored on a non-transitory computer readable storage medium, and the computer program can be executed by a processor to enable a computer to execute the street tree carbon sink capacity fine estimation method provided by the above-mentioned method, the method comprising: obtaining first period street tree data and second period street tree data; the first period street tree data and the second period street tree data are collected at different time points of a target area; based on a target diameter-height model, the first period street tree data and the second period street tree data are used to estimate the biomass of the street trees in the target area according to human management and protection factors, to obtain the carbon storage of the first period street trees and the second period street trees; wherein the target diameter-height model is determined based on a biological mathematical model; the human management and protection factors include at least two of street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road construction shading and vertical structure; based on the carbon storage of the first period street trees and the second period street trees and the road features of the target area, street tree carbon sink parameters are calculated to evaluate the street tree carbon sink capacity of the target area; wherein the road features include at least one of the greening length of each street in the target area, the spacing between adjacent trees, the total greening length of all streets and the total road area of all streets; the street tree carbon sink parameters include carbon density and carbon sink.

[0152] In yet another aspect, the present application also provides a non-transitory computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the method for fine estimation of carbon sink capacity of street trees as provided above, the method comprising: obtaining first period street tree data and second period street tree data; the first period street tree data and the second period street tree data being collected at different time points in a target area; estimating, based on a target DBH-Height model, a street tree biomass of the target area according to a human management factor, the first period street tree data and the second period street tree data, to obtain first period street tree carbon storage and second period street tree carbon storage; wherein the target DBH-Height model is determined based on a biological mathematical model; the human management factor comprises at least two of street tree spacing, tree pool side length, adjacent tree species, tree trunk whitening, tree pool anti-treading protection, road construction light shielding and vertical structure; and calculating a street tree carbon sink parameter based on the first period street tree carbon storage and the second period street tree carbon storage and a road feature of the target area to evaluate a street tree carbon sink capacity of the target area; wherein the road feature comprises at least one of a greening length of each street in the target area, a spacing between adjacent trees, a total greening length of all streets and a total road area of all streets; and the street tree carbon sink parameter comprises carbon density and carbon sink.

[0153] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0154] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software plus necessary universal hardware platforms, and of course can also be realized by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0155] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for fine estimation of carbon sequestration capacity of street trees, characterized by: include: Obtain the first phase of street tree data and the second phase of street tree data; The first phase of roadside tree data and the second phase of roadside tree data are collected at different time points in the target area; The different time points are time ranges measured in years, the target area includes cities, and the roads in the cities include urban expressways, urban trunk roads, urban secondary trunk roads, and urban branch roads, which are classified based on urban road grade classification conditions; The biomass of street trees in the target area is estimated based on a target DBH-tree height model, human management factors, the first phase street tree data, and the second phase street tree data, to obtain the carbon storage of street trees in the first phase and the second phase. The target DBH-tree height model is determined based on a biomathematical model. The human management factors include street tree spacing, tree pit side length, neighboring tree species, whitewashing of tree trunks, anti-trampling protection of tree pits, road building shading, and vertical structure. Calculating street tree carbon sequestration parameters based on the carbon storage of the street trees in the first and second phases and the road characteristics of the target area to assess the street tree carbon sequestration capacity of the target area; wherein the road characteristics include at least one of the greening length of each street in the target area, the spacing between adjacent trees, the total greening length of all streets, and the total road area of ​​all streets; and the street tree carbon sequestration parameters include carbon density and carbon sink; Biomathematical models include linear models, logarithmic models, and allometric models; The target DBH-tree height model is constructed by the following steps: For each biomathematical model, the target evaluation index is calculated based on the biomathematical model according to the sample tree height data and the sample diameter at breast height data to obtain the index calculation result; the target evaluation index includes the determination coefficient R 2 , at least one of Akaike Information Criterion AIC, root mean square error RMSE and mean percentage error MEP; Determining the target DBH-tree height model based on the maximum value among the index calculation results; The target DBH-tree height model is used to estimate the biomass of the street trees in the target area according to human management factors, the first phase street tree data, and the second phase street tree data. The carbon storage of the street trees in the first phase and the street trees in the second phase is obtained, including: Performing a significant correlation analysis on the human-induced maintenance factors to obtain analysis results, and screening the analysis results according to a significant impact threshold to obtain new human-induced maintenance factors; A dummy variable DBH-tree height model is constructed with the human management factor as the dummy variable of the target DBH-tree height model.

2. The method for fine estimation of carbon sequestration capacity of street trees according to claim 1 is characterized in that: The obtaining of the first phase of roadside tree data and the second phase of roadside tree data includes: Randomly sampling streets within the target area to obtain sampling streets; Each street tree on each sampled street is measured to obtain the first phase of street tree data, wherein the measurement of each tree includes measuring the tree species name, tree height, diameter at breast height, and the spacing between adjacent trees; When the target area passes the target time interval, each roadside tree on the sampled street is measured to obtain the second phase of roadside tree data.

3. The method for fine estimation of carbon sequestration capacity of street trees according to claim 2 is characterized in that: The randomly sampling streets within the target area to obtain the sampled streets includes: Dividing the urban branch roads according to road network density and road width to obtain new urban branch roads; Random sampling is performed on the urban expressways, urban main roads, urban secondary roads and urban branch roads to obtain the sampled streets.

4. The method for fine estimation of carbon sequestration capacity of street trees according to claim 1 is characterized in that: The biomass of the street trees in the target area is estimated based on the target DBH-tree height model according to human management factors, the first phase street tree data, and the second phase street tree data, and the carbon storage of the street trees in the first phase and the second phase street trees is obtained, which also includes: Calculate the total biomass of each street tree based on the dummy variable DBH-tree height model according to the first phase street tree data; The carbon storage of the first phase of street trees is obtained based on the total plant biomass and the preset carbon content. A significant correlation analysis is performed on the human management and maintenance factors to obtain analysis results, and the analysis results are screened according to a significant impact threshold to obtain new human management and maintenance factors.

5. The method for fine estimation of carbon sequestration capacity of street trees according to claim 1 is characterized in that: After obtaining the first phase of roadside tree carbon storage, the method further includes: The allometric growth equation constructed based on the traditional forest survey is used to estimate the biomass of the street trees in the target area according to the first phase street tree data and the second phase street tree data to obtain a new street tree carbon storage; An evaluation result of the carbon sequestration capacity of the street trees is obtained based on the carbon storage of the first and second phase street trees and the new street tree carbon storage.

6. A device for finely estimating the carbon sequestration capacity of roadside trees, using the method for finely estimating the carbon sequestration capacity of roadside trees as claimed in claim 1, characterized in that: include: A data acquisition module is used to acquire the first phase of roadside tree data and the second phase of roadside tree data; The first phase of roadside tree data and the second phase of roadside tree data are collected at different time points in the target area; a biomass estimation module for estimating the biomass of street trees in the target area based on a target DBH-tree height model, human management factors, the first phase of street tree data, and the second phase of street tree data, to obtain the carbon storage of street trees in the first phase and the second phase; wherein the target DBH-tree height model is determined based on a biomathematical model; and the human management factors include at least two of street tree spacing, tree pit side length, neighboring tree species, whitewashing of tree trunks, anti-trampling protection of tree pits, road building shading, and vertical structure; A carbon sequestration capacity estimation module is used to calculate the carbon sequestration parameters of street trees based on the carbon storage of the first-phase street trees and the second-phase street trees and the road characteristics of the target area, so as to evaluate the carbon sequestration capacity of street trees in the target area; wherein, the road characteristics include at least one of the greening length of each street in the target area, the spacing between adjacent trees, the total greening length of all streets and the total road area of ​​all streets; the street tree carbon sequestration parameters include carbon density and carbon sink.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the method for fine estimation of carbon sequestration capacity of street trees as claimed in any one of claims 1 to 5 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for fine estimation of carbon sequestration capacity of street trees as claimed in any one of claims 1 to 5 is implemented.

Images