CN106034973B - Disaster prevention control method for fir artificial forest - Google Patents
Disaster prevention control method for fir artificial forest Download PDFInfo
- Publication number
- CN106034973B CN106034973B CN201610373753.6A CN201610373753A CN106034973B CN 106034973 B CN106034973 B CN 106034973B CN 201610373753 A CN201610373753 A CN 201610373753A CN 106034973 B CN106034973 B CN 106034973B
- Authority
- CN
- China
- Prior art keywords
- forest
- fir
- stand
- density
- disaster prevention
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
- A01G23/00—Forestry
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Forests & Forestry (AREA)
- Environmental Sciences (AREA)
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Abstract
the invention provides a fir artificial forest disaster prevention control method, which relates to the field of forest management and comprises the steps of investigating sample plots of fir artificial forests to be planned and carrying out disaster prevention control on the fir artificial forests by utilizing a pre-established disaster prevention harvest prediction density control chart, so that the forest stand stability and stress resistance are improved, and better harvest, disaster prevention and reduction are realized. The method can carry out the accumulated quantity harvest prediction on the formulated cutting and breeding scheme, integrate the prediction result and the operation target, and carry out real-time adjustment on the density of the fir artificial forest, so that reasonable forest stand density can be formed in each development stage of the fir forest until the fir forest is harvested by cutting at the end, the productivity of the fir individual is fully exerted on the premise of avoiding disasters, the space is utilized to the maximum extent, and the better operation target is achieved.
Description
Technical Field
the invention relates to the field of forest management, in particular to a fir artificial forest management method for preventing crown fire, snow disaster or wind disaster.
Background
china fir (Cunninghamia lancelata) is native to China, widely distributed in 16 provinces in south China, and is a fast-growing tree species cultivated by artificial forests. The planting history of fir has been over 1000 years. The planting area of the plant reaches 9,215,000hm2, and the plant occupies 28.53 percent of the forest area in China. Further, it is estimated that 25% of commercial materials are from fir wood forest. Therefore, it is an important biological resource in our country.
However, based on climate factors and improper management modes, the fir forest is seriously damaged due to natural disasters such as wind fall, snow disaster and the like which commonly exist in the fir forest. For example, in 2005, typhoon "dawei" reached south island of the sea, about 163,333 hectares of forests suffered from wind droops, of which 60% were artificial forests. In contrast, snow disasters generally occur rarely in subtropical regions. However, in 2 months of 2008, about 18,000,000 hectares of artificial forests are subjected to ice and snow weather in subtropical regions of China, causing an economic loss of 57,300,000,000 yuan.
A fire is another natural disaster that threatens the forest in addition to wind falls and snow disasters. Crown fire comes rapidly and intensely, is difficult to suppress, and can cause serious economic loss and ecological damage. It is reported that crown fire accounts for 60% of the total burning area in northeast catalonia, spain, however, crown fire accounts for only 7% of the total number of fires occurring.
At present, the fir artificial forest adopts a felling operation mode mainly for felling by two persons. The breeding mode includes final felling and intermediate tending felling. Compared with afforestation density, intermediate tending intermediate felling is an effective means for adjusting forest stand density and further achieving an operation target. However, the arrangement of forest nurturing intermediate cuts on a time scale under a certain objective is usually quantified. Similarly, fixed rotation periods and intermediate cutting arrangements based on experience are adopted, and the fixed modes are not suitable for specific operation targets and forest land conditions, so that the aim of preventing natural disasters of the artificial forest can not be achieved.
the best and most reliable method of determining specific goals and site conditions forest management practices is generally based on experimentation. However, the varying ground quality and operational goals of different tests themselves can lead to long-term observations and limited generalization of test results, which also makes the tests unsatisfactory.
Disclosure of Invention
The invention aims to overcome the problems in the prior art and provide a fir artificial forest disaster prevention control method, which utilizes a crown fire occurrence potential curve chart and a stem stability curve chart to not only formulate a felling and breeding scheme for preventing fire, wind and snow disasters of the fir artificial forest, but also estimate the storage amount harvested by the felling and breeding scheme, synthesizes the estimated result and an operational target to regulate the density of the fir artificial forest in real time, so that reasonable forest density can be formed in each development stage of the fir forest until the fir forest is harvested at the last, the productivity of the fir individual is fully exerted, the space is utilized to the maximum extent, and a better operational target is achieved.
In order to achieve the purpose of the invention, the invention provides a disaster prevention control method for a fir forest, which comprises the following steps:
Measuring the area of the fir forest to be planned, and obtaining the stand density value and the average dominant wood height value of the fir forest through the sample plot survey of the fir forest to be planned;
obtaining a disaster prevention control mode of the artificial fir forest according to a pre-established disaster prevention harvest estimated density control chart for expressing forest stand density and superior tree height and the obtained forest stand density data and superior tree height data of the artificial fir forest;
According to the obtained disaster prevention control mode of the artificial fir forest, the artificial fir forest is cut and raised, the stability and stress resistance of the forest stand are improved, and better harvest, disaster prevention and reduction are realized.
the disaster prevention harvest estimated density control map is a two-dimensional map with the average dominant wood height as an abscissa and the forest stand density as an ordinate, and comprises a disaster prevention expression model and a density control decision model which are built into the two-dimensional map.
Further, the disaster prevention expression model comprises:
a CBD threshold value curve group is established by a crown fire occurrence potential isoline equation;
An SC250 threshold value curve group established by a wind/snow disaster occurrence potential isoline equation;
where N represents stand density, CBD represents crown fire risk index, and SC250 represents stand stability index for dominant trees of the largest 250 trees per hectare.
preferably, the CBD threshold value of the CBD threshold value curve group is 0.1-0.4, and further preferably, the CBD threshold values are 0.1, 0.2, 0.3, 0.4, respectively.
Preferably, the SC250 thresholds of the SC250 threshold curve group are respectively 90-120, and further preferably, the SC250 thresholds are 90, 100, 110, 120.
Wherein the density control decision model comprises:
An RSI threshold curve group established by a relative density index isoline equation;
A dg threshold curve group is established by a forest stand average chest diameter isoline equation;
a V threshold value curve group established by a forest stand accumulation quantity isoline equation;
wherein N represents stand density, H0 represents dominant wood height, RSI represents relative density, dg represents stand mean breast diameter, and V represents stand accumulation.
Wherein, the RSI threshold (RSI (%) is 6, 8, 10, 12, 16, 20, and 24);
wherein, the disaster prevention control of the fir forest comprises:
Determining the position of a cross point of a forest stand density value and an average dominant wood height value of the fir forest in a two-dimensional map;
judging the position relation of the intersection point in a CBD threshold value curve group in the disaster prevention expression model, and formulating a fire prevention control mode;
And judging the position relation of the intersection point in the SC250 threshold curve group in the disaster prevention expression model, and formulating a wind/snow disaster prevention control mode.
wherein, the formulating fire prevention control mode comprises:
When the intersection point is positioned above the curve with the CBD threshold value of 0.1, the control mode is determined as forest stand thinning;
when the intersection point is located below the curve with the CBD threshold of 0.1, the control mode is determined to be temporarily untruffled.
Wherein, the method for controlling the wind/snow disaster prevention comprises the following steps:
when the intersection point is positioned above the curve with the SC threshold value of 90, the control mode is determined as forest stand thinning;
when the intersection is located below the curve with the SC threshold of 90, the control mode is determined to be temporarily untrue.
In particular, the disaster prevention control of the fir wood artificial forest further comprises the following steps:
according to the forest stand density value of the artificial fir forest and the position of the intersection of the average dominant wood height value, a density control decision model is used for predicting growth harvesting and disaster risks, and corresponding quantitative density control measures of different growth stages of the forest stand are made through the density control decision model, so that the stability and stress resistance of the forest stand are improved, and harvesting, disaster prevention and disaster reduction are realized.
to achieve the object of the present invention, the present invention provides in one aspect a disaster prevention harvest prediction density control chart for fir forest, obtained by the following steps;
collecting forest stand factor data including dominant tree species, canopy density, forest stand age, plant number per unit area, single tree breast diameter and single tree volume;
screening and processing the forest factor data to obtain fir artificial forest data including square average chest diameter, average height, dominant tree height, forest stand accumulation and total biomass;
establishing a disaster prevention expression model and a density control decision model by regression analysis on the obtained fir artificial forest data;
and constructing the established disaster prevention expression model and the density control decision model into a two-dimensional graph with the dominant wood height as a horizontal axis and the number of plants per hectare as a vertical axis to obtain a disaster prevention harvest estimated density control graph.
Wherein, the disaster prevention expression model comprises:
A CBD threshold value curve group is established by a crown fire occurrence potential isoline equation;
an SC threshold value curve group established by a wind/snow disaster occurrence potential isoline equation;
Wherein the density control decision model comprises:
An RSI threshold curve group established by a relative density index isoline equation;
A dg threshold curve group is established by a forest stand average chest diameter isoline equation;
a V threshold value curve group established by a forest stand accumulation quantity isoline equation;
wherein N represents the stand density, CBD represents the crown fire risk index, SC250 represents the stand stability index with the largest 250 trees per hectare as the dominant trees, H0 represents the dominant tree height, RSI represents the relative density, dg represents the mean breast diameter of the stand, and V represents the stand accumulation.
the beneficial effects of the invention are embodied in the following aspects:
1. the method provided by the invention can effectively predict and evaluate the risk of fire, wind or snow disasters of the artificial fir forest and prevent natural disasters of the artificial fir forest.
2. By utilizing the method provided by the invention, disaster prevention measures can be made, and the fir forest is felled or nursed, so that the stability and the stress resistance of the fir forest are improved, and the occurrence of fir forest disasters is effectively prevented.
3. The method can also carry out the accumulated quantity harvest prediction on the formulated cutting and breeding scheme, integrates the prediction result and the operation target, and carries out real-time adjustment on the density of the artificial fir forest, so that reasonable forest stand density can be formed in each development stage of the fir forest until the fir forest is harvested at the end, the productivity of the fir individual is fully exerted on the premise of avoiding disasters, the space is utilized to the maximum extent, and the better operation target is achieved.
Drawings
FIG. 1 is a diagram illustrating a pre-estimated density control of disaster prevention harvesting according to the present invention;
FIG. 2 is a control method developed by applying a disaster prevention harvest estimated density control chart in embodiment 1 of the present invention; wherein, a represents an operation scheme for fire prevention, B represents an operation scheme for wind/snow prevention, and C represents an operation scheme for not performing disaster prevention.
Detailed Description
Example 1 construction of disaster prevention harvest estimated density control chart
1 raw data acquisition and preliminary processing
the invention utilizes the eighth national forest resource of Fujian province to clear and check data. The research sample plots of Fujian province are distributed above the intersection points of a 4 x 6km kilometer grid, are squares and have an area of 667 square meters.
There are two types of data files for each plot, namely a "sample plot data file" describing the forest stand characteristics of each sample plot and a "sample plot data file" describing each sample plot within the sample plot.
the sample data file comprises 75 survey factors, the sample wood data file comprises 11 survey factors, and the factors adopted by the invention are as follows: dominant tree species, canopy density, stand age and number of plants per unit area (N) and tree species (S), diameter (dbh) and wood volume (Velcro), as well as calculated average tree height (H250) of the 250 trees with the greatest tree height per hectare in the stand and average diameter (D250) of the 250 trees with the greatest tree height per hectare in the stand.
the dominant species refers to the species with the highest accumulation and specific gravity in the mixed forest. As the artificial fir forest in China is mainly pure forest, in order to realize the purpose of the invention, the first step is to screen pure fir forest data, so that the dominant tree species of sample plot is a precondition for screening fir, on the basis, the proportion of the sum of the breast height cross-sectional areas of fir in each sample plot to the total breast height cross-sectional area of the fir in the sample plot is calculated according to the tree species data and the breast diameter (dbh) data in the sample data file, and then the sample plot with the proportion exceeding 90% is screened.
Canopy density is the ratio of the projected area of the canopy to the area of the forest land in the stand. The invention adopts the Chinese fir pure forest which is already closed into forest, and in order to improve the accuracy of the invention, the invention further screens out the Chinese fir forest with the forest stand age of more than 10 years from the screened sample plot as the sample plot for constructing the disaster prevention harvest estimated density control chart.
after the data are screened and primarily processed, 516 fir pure forest blocks are screened out and used as fir artificial forest data, the geographic position distribution of sample plots is 23-28 degrees N and 115-120 degrees E, the forest stand origin mode mainly comprises seedling planting, germination and nature, and the proportion of artificial forest sample plots formed in the seedling planting mode is 76.13%. The age of the stand was 10(a) or more, i.e., the middle age and the same plots above accounted for 67.3% of the total. Table 1 describes fir forest data as shown in table 1.
The average tree height (H250) of the 250 trees with the maximum tree height per hectare in the forest stand is estimated from the single tree breast diameter data in the sample tree data according to H single as 1.3+ d single 2/(2.292+0.432 d single +0.031 d single 2), and the area of the sample tree is 667 square meters in the invention, so the average tree height of the 16-17 trees with the maximum height in each sample tree is taken as the H250 of the forest stand.
the average diameter (D250) of the 250 trees with the maximum tree height per hectare in the forest stand is the average diameter of the 250 trees with the maximum tree height per hectare in the forest stand selected by using the single tree breast height data in the sample tree data, namely the average diameter of the breast height of the 16-17 trees with the maximum height in each sample plot is taken as the D250 of the forest stand.
The description and calculation of various forest stand factors refer to the national forest resource continuous inventory technical Specification (2003)
TABLE 1 statistical description of fir stand factor
2 construction of disaster prevention model
2.1 construction of crown fire potential isoline equation
the fire of the crown is necessary when the fire of the crown is generated when the surface fire rises along with the lower trees (the general name of large shrubs and low trees below the crown in the forest) and then the crown layer is ignited. When the trees are the same, the main factor influencing the burning difficulty of the tree crowns is the amount of the tiny combustible substances such as twigs and thin leaves in the tree crowns, the quantitative index of the factor is the volume density (CBD) of the tree crowns, the CBD represents the mass of the available tree crown fuel in unit volume, and the calculation mode of the CBD is defined as the ratio of the leaf biomass (on average of the tree stand single plants) to the volume of the tree crowns (on average of the tree stand single plants). The forest stand density and the advantage height have an inherent relation, so that the potential of crown fire occurrence of a certain forest stand can be accurately judged by constructing an equation representing the relation between the CBD and the forest stand density and the advantage height and drawing a CBD contour line, and a specific disaster prevention and reduction management scheme can be formulated by combining a relative spacing index curve, a forest stand average diameter curve and a forest stand accumulation curve, so that the maximum operation benefit is obtained.
And calculating the single-wood leaf biomass according to the formula Wf single-0.0115. D single 2.0823 according to the single-wood breast diameter data in the sample wood data, wherein Wf single represents the single-wood leaf biomass in kg, D single represents the single-wood breast diameter in cm. The biomass of single tree leaves in the sample plot is averaged to obtain the average biomass of single tree leaves in the forest stand, wherein the unit is kg & tree-1.
And calculating the volume of the single-tree crown according to the single-tree breast diameter data in the sample tree data by using the formula VC single-0.005. D single 2.957, wherein VC single represents the volume of the single-tree crown and has the unit of m 3. And averaging the volumes of the single tree crowns in the sample plot to obtain the average tree crown volume of the single tree in the forest stand, wherein the unit is m 3. tree-1.
and comparing the obtained single forest stand plant average leaf biomass data with the single forest stand plant average crown volume data to obtain the crown volume density of each sample plot, wherein the unit is kg/m 3.
establishing a relation expressing the volume density of a tree crown, the density of a forest stand and the breast height sectional area BA of the forest stand by using an equation ln (CBD) ═ alpha 1+ alpha 2 · ln (BA) + alpha 3 · ln (N), wherein N is the density, alpha i (i ═ 1-3) is a regression coefficient, BA is the sum of the breast height sectional areas of the forest stands per hectare, the unit is m2/ha, and the calculation formula is that in the equation, di is the breast diameter of the ith forest stand in the forest stand and N is the number of forest stands per hectare. In the invention, BA is obtained by converting the chest height of the forest trees in the accumulated sample plot into a standard unit after calculating and accumulating. Substituting the BA data and forest stand density data into an equation to perform regression fitting according to the volume density data of various ground crowns obtained by calculation, wherein the parameter estimation method is an ordinary least square method (OLS), and obtaining a model ln (CBD) ═ 3.7395+ 0.5012. ln (BA) + 0.1998. ln (N);
a model representing the relation between the mean square diameter of the forest stand and the density and the height of the forest stand is established by using an equation, wherein dg represents the mean diameter (cm) of the forest stand, N represents the density (stem ha-1) of the forest stand, H0 represents the height (m) of the dominant forest stand, and beta i (i is 0-2) is a regression coefficient. Fitting the relation by using a full information maximum likelihood method and a SAS Institute 2011, performing parameter estimation on a process to obtain a regression coefficient beta i value, wherein the result is shown in Table 2, and the fitting effect is better (the overall accuracy of the fitting model is evaluated and calculated by using general fitting data comprising a decision coefficient (R2) and a Root Mean Square Error (RMSE) between an observed value and a predicted value);
TABLE 2 parameter estimation for models
And combining the equation with an equation ln (CBD) — 3.7395+ 0.5012. ln (BA) + 0.1998. ln (N), obtaining the set CBD threshold values of 0.1, 0.2, 0.3 and 0.4, and outputting a group of crown fire occurrence potential equivalence curves in a two-dimensional map.
2.2 construction of wind/snow disaster occurrence potential threshold value curve group
The tensile capacity of the trees of the same tree species in wind (snow) disasters mainly depends on the proportional relation between the height and the diameter of the trees, and the wind resistance stability of the trees is weakened along with the increase of the height-diameter ratio; the wind resistance stability of a forest stand mainly depends on the tensile force born by the unit area of the trunk cross section of the upper forest tree of the forest stand in wind (snow) disasters and the bending property of the stem, the quantitative index of the factor is a stability index (SC250), the calculation mode of the SC250 is defined as the ratio between H250 and D250, and the density and the advantage height of the forest stand have an inherent relation, so that the potential of wind (snow) disasters of a certain forest stand can be accurately judged by constructing an equation representing the relation between the SC and the density and the advantage height of the forest stand and drawing an SC250 contour line, and a specific disaster prevention and reduction management scheme can be formulated by combining a relative spacing index curve, a forest stand average diameter curve and a forest stand accumulation curve to obtain the maximum operation benefit.
a model representing the relation between H250 and the height of the forest stand dominant trees is established by using an equation H250-b 1-H0 + b2, and bi (i-1-2) is a regression coefficient. Substituting the H250 data and the H0 data obtained by calculation into an equation to perform regression fitting, wherein the parameter estimation method is an ordinary least square method (OLS), and a model H250-0.8095. H0+0.8616 is obtained;
Performing regression fitting by using an equation D250-c 1-dg + c2, D250 data and dg data, performing parameter estimation by using an ordinary least square method (OLS), establishing a model representing the relation between D250 and the mean breast diameter of the forest stand, wherein ci (i-1-2) is a regression coefficient, and obtaining a model D250-1.3715-dg + 1.0309;
Using the equation D250 ═ c1 · dg + c2, H250 ═ 0.8095 · H0+
0.8616, establishing an equation representing the relationship between the flexibility index (SC250) and the stand dominant wood height (H250) and the stand density to obtain beta i (i is 0-2), setting the threshold value of the SC250 to be 80, 90, 100, 110 and 120, and obtaining a wind/snow disaster occurrence potential threshold value curve group.
3. Construction of a Density control decision model
3.1 construction of threshold Curve group for forest stand relative Density index
Establishing a model for expressing the relation between forest stand density and dominant wood height by using an equation, wherein RSI is a relative density index, and is expressed in percentage, and setting the threshold of the RSI to be 6, 8, 10, 12, 16, 20 and 24 by using a relative spacing index equation with N as a dependent variable to obtain an RSI threshold curve group;
3.2 construction of threshold Curve group for mean Breast diameter of forest stand
And (3) constructing an equation which takes N as a dependent variable and expresses the average breast diameter of the forest stand, the density of the forest stand and the height of the dominant tree to obtain threshold values of 19, 20, 21, 22, 23, 24, 25 and 26 for setting dg, and obtaining a threshold value curve group of dg.
3.3 construction of threshold Curve group for forest stand accumulation
A model for expressing the relation between the forest stand accumulation amount and the average diameter of the forest stand, the density of the forest stand and the height of the dominant trees is established by using an equation, V is the forest stand accumulation amount (m3/ha), and beta i (i is 3-5) is a regression coefficient. And performing parameter estimation on the equation to obtain a threshold curve group of the forest stand accumulation amount, wherein the set V threshold is 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400 and 450.
Finally, a disaster prevention harvest estimated density control chart is obtained, as shown in fig. 1.
The following is an example of the application of the estimated harvest density control map,
the implementation place is located in a forest farm (26 degrees to 27 degrees to 04 'N, 117 degrees to 05 degrees to 117 degrees to 40' E) of the general happy county, Fujian province. The area is mainly in southeast Wuyi mountains, and the area mainly comprises middle and low mountains, and the highest mountain Longxi mountain has the altitude of 1620m, belongs to subtropical monsoon climate, and has the characteristics of oceanic climate and continental climate, the annual average air temperature is 18.7 ℃, the annual precipitation is 1672mm, and the frost-free period is 273 d. The temperature in the environment is higher, the summer time is long, the winter is warmer, the frost is less, and the growth period is long.
application examples
1. Sample plot survey
the dominant height, the number of tree plants per hectare and the average diameter of the forest stand of the fir forest to be evaluated were measured in the fir forest to be evaluated according to the procedure of example 1, and the terrain level of the fir forest area was 22m, the reference age was 20 years, the average diameter of the forest stand was 5.42cm, and the density of the forest stand was 912 per hectare. The operation target is set to be the height of the dominant trees of 26m and the average diameter of the forest stand of 19 cm.
2. Determination of the control mode
Dividing the fir forest to be evaluated into 4 cells, and respectively taking the cells as a and considering the regulation and control of crown fire; b. considering the regulation and control of wind/snow disasters; c. the regulation and control of crown fire and wind/snow disaster are not considered.
2.1 Regulation considering crown fire
2.1.1 evaluation of crown fire Generation potential
According to the measured and calculated dominant wood height and forest stand density of the forest stand, a point corresponding to the dominant wood height and forest stand density is found in a disaster prevention harvest estimated density control chart shown in figure 1, and whether the artificial fir forest is raised to crown fire after the occurrence of the surface fire is judged according to the position relation between the point and a crown fire occurrence potential curve with 4 different CBD values.
The method is obtained according to the operating experience of fir forests for years, and the crown fire occurrence threshold is when the CBD threshold is 0.1, so when the CBD exceeds 0.1, the crown fire can occur after the forest land fires.
If the position of the corresponding point is lower than the crown fire generation potential contour line (contour line) with the CBD value of 0.1, the crown fire of the fir artificial forest is not generated, and the forest does not need to be harvested in the same year (particularly thinning).
If the position of the corresponding point is higher than the crown fire generation potential contour line (contour line) with the CBD value of 0.1, the risk of crown fire generation of the artificial fir forest on the surface is higher, the forest needs to be thinned in the current year, the thinning number is determined by finding out the number NCBD mark of each hectare corresponding to the dominant tree height of the point on the crown fire generation potential contour line (contour line) with the CBD value of 0.1, and the difference between the actual number density of the trees in the forest stand and the NCBD mark of the forest stand is the thinning strength in the current year. In order to ensure that the dominant trees of the forest stand before and after thinning are unchanged in height, the thinning technology adopts downward thinning, namely the connecting line of two points before and after cutting is vertical to a transverse shaft, and the main objects of thinning are trees which grow poorly and are in a suppressed state in the forest stand. The advantage of adopting downward thinning is: after thinning, the average diameter of the forest stand can be improved to a certain degree, but the advantage of the forest stand is high and is hardly influenced.
According to the position relation, the forest stand is calculated to exceed the crown fire occurrence threshold, namely the position is higher than the CBD curve with the threshold value of 0.1, therefore, the method adopts downward thinning measures to ensure that the fir forest is in a safe range.
2.1.2 making management plan for preventing crown fire
In order to avoid the occurrence of crown fire in the future, a long-term operation scheme considering the risk of crown fire should be made, the disaster prevention harvest estimated density control chart shown in fig. 1 is used for judgment and decision making, the year of which the CBD of the forest stand is close to 0.1, namely the CBD threshold value of the occurrence of crown fire is calculated, and the forest age (year) is determined by referring to a Fujian province fir status index table and a status index curve chart (Mengxi, 2006) on the premise that the benchmark age location index and the forest stand dominant wood of a certain age are high. And then, establishing an intermediate cutting scheme, and thinning the artificial fir forest in some years until the main cutting of the fir forest is harvested. The intermediate cutting principle is to ensure that the total yield obtains the maximum value on the premise of preventing the occurrence of crown fire. The scheme is detailed in table 1 and line a in fig. 2.
TABLE 1 management scheme considering forest canopy fire risk
2.2 Regulation considering wind/snow disaster
2.2.1 assessment of Pre-wind/snow disaster occurrence
according to the measured and calculated dominant wood height and forest stand density of the forest stand, finding out a point corresponding to the dominant wood height and forest stand density in the disaster prevention harvest estimated density control chart shown in figure 1, and judging whether the artificial fir forest has wind/snow disasters according to the position relation of the point and a crown fire generation potential curve of 5 different SC250 values.
according to the method, the wind/snow disaster occurrence threshold is obtained according to years of fir forest operation experience, when the SC250 threshold is 90, the fir forest cannot resist the wind/snow disaster and is folded to cause loss when the SC250 exceeds 90.
that is, if the position of the corresponding point is lower than the wind/snow disaster occurrence potential curve with the SC value of 90, it indicates that the artificial fir forest does not have wind/snow disasters, and the forest does not need to be nurtured and harvested in the same year (this refers to thinning).
if the position of the corresponding point is higher than the wind/snow disaster occurrence potential curve with the SC value of 90, the risk of wind/snow disaster occurrence of the fir artificial forest is high, thinning is needed to be performed on the forest in the current year, the thinning number is determined by finding out the number NSC mark of each hectare corresponding to the dominant tree height of the point on the crown fire occurrence potential curve with the SC value of 90, and the difference between the actual number density of the trees of the forest stand and the NSC mark of the forest stand is the thinning strength in the current year. In order to ensure that the dominant trees of the forest stand before and after thinning are unchanged in height, the thinning technology adopts downward thinning, namely the connecting line of two points before and after cutting is vertical to a transverse shaft, and the main objects of thinning are trees which grow poorly and are in a suppressed state in the forest stand. The advantage of adopting downward thinning is: after thinning, the average diameter of the forest stand can be improved to a certain degree, but the advantage of the forest stand is high and is hardly influenced.
according to the position relation, the forest stand is calculated to be under a safe SC250 threshold curve, namely the position is lower than the SC250 curve with the threshold value of 90, so thinning measures are not adopted in the method.
2.2.2 planning of management plan for preventing wind/snow disaster
In order to avoid wind/snow disaster in the future, a long-term operation scheme considering the risk of wind/snow disaster should be prepared, and a simulation operation considering the risk of wind/snow disaster is performed below. The wind/snow disaster occurrence latent diagram shown in fig. 1 is used for carrying out judgment and decision, the year that the SC of the forest stand is close to 90, namely the year that the SC is close to the SC threshold value of the wind/snow disaster occurrence is calculated, and the method for determining the forest age (year) refers to a Fujian province fir status index table or status index curve diagram on the premise that the benchmark age location index and the forest stand dominant wood of a certain age are known to be high. And then, establishing an intermediate cutting scheme, and cutting and cultivating the artificial fir forest in some years until the artificial fir forest is cut and harvested mainly. The intermediate cutting principle is to ensure that the total yield obtains the maximum value on the premise of preventing wind/snow disasters. The scheme is detailed in table 2 and line B shown in fig. 2.
Table 2 management scheme considering wind/snow disaster
2.2 Regulation without taking into account disaster prevention
The wind/snow disaster occurrence latent diagram shown in fig. 1 is used for judging and deciding, and under the premise that the standing index of the reference age and the dominant trees of the forest stands of a certain age are known to be high, the method for determining the forest ages (years) refers to a Fujian province fir status index table or a status index curve diagram. And then, establishing an intermediate cutting scheme, and cutting and cultivating the artificial fir forest in some years until the artificial fir forest is cut and harvested mainly. The thinning principle is to ensure that the total yield is maximized. The scheme is detailed in table 3 and line C shown in fig. 2.
TABLE 3 Regulation and control management scheme without taking disaster prevention into account
Therefore, by applying the disaster prevention harvest estimated density control chart, the disaster prevention density of the fir forest stand can be regulated and controlled only according to the data of the forest stand information without performing complex calculation on the sample plot information of the forest stand, and particularly, as long as the density of the fir forest stand in the operation process is always controlled below a disaster prevention threshold curve, the land can be fully utilized, the optimal activity of the forest can be maintained, the occurrence of natural disasters can be avoided, the spontaneous combustion withering phenomenon can not occur, a large number of timber products can be harvested, and the disaster prevention harvest estimated density control chart has wide applicability and practicability.
although the present invention has been described in detail, it is not limited thereto, and those skilled in the art can make modifications based on the principle of the present invention, and thus, various modifications made according to the principle of the present invention should be understood to fall within the scope of the present invention.
Claims (3)
1. A disaster prevention control method for a fir forest is characterized by comprising the following steps:
measuring the area of the fir forest to be planned, and obtaining the stand density value and the average dominant wood height value of the fir forest through the sample plot survey of the fir forest to be planned;
Obtaining a disaster prevention control mode of the artificial fir forest according to a pre-established disaster prevention harvest estimated density control chart for expressing forest stand density and superior tree height and the obtained forest stand density data and superior tree height data of the artificial fir forest;
According to the obtained disaster prevention control mode of the artificial fir forest, the artificial fir forest is cut and raised, the stability and stress resistance of the forest stand are improved, and better harvest, disaster prevention and reduction are realized;
The disaster prevention harvest estimated density control chart is a two-dimensional chart with the average dominant wood height as an abscissa and the forest stand density as an ordinate, and comprises a disaster prevention expression model and a density control decision model which are constructed in the two-dimensional chart;
according to the forest stand density value of the artificial fir forest and the position of the intersection of the average dominant wood height value, a density control decision model is used for predicting growth harvesting and disaster risks, and corresponding quantitative density control measures of different growth stages of the forest stand are made through the density control decision model, so that the stability and stress resistance of the forest stand are improved, and harvesting, disaster prevention and disaster reduction are realized;
The disaster prevention expression model comprises:
A CBD threshold value curve group is established by a crown fire occurrence potential isoline equation;
An SC threshold value curve group established by a wind/snow disaster occurrence potential isoline equation;
Wherein N represents the stand density, CBD represents the crown fire risk index, and SC250 represents the stand stability index with the largest 250 trees per hectare as the dominant trees;
The density control decision model comprises: an RSI threshold curve group established by a relative density index isoline equation; a dg threshold curve group is established by a forest stand average chest diameter isoline equation; a V threshold value curve group established by a forest stand accumulation quantity isoline equation;
wherein N represents the density of the forest stand, CBD represents the crown fire risk index, SC250 represents the forest stand stability index taking the maximum 250 trees per hectare as dominant trees, H0 represents the height of the dominant trees, RSI represents the relative density, dg represents the mean breast diameter of the forest stand, and V represents the accumulation amount of the forest stand;
The disaster prevention control of the fir wood artificial forest comprises the following steps:
Determining the position of a cross point of a forest stand density value and an average dominant wood height value of the fir forest in a two-dimensional map;
judging the position relation of the intersection point in a CBD threshold value curve group in the disaster prevention expression model, and formulating a fire prevention control mode;
judging the position relation of the intersection point in an SC250 threshold curve group in the disaster prevention expression model, and making a wind/snow disaster prevention control mode;
the method for formulating the fire prevention control mode comprises the following steps:
when the intersection point is positioned above the curve with the CBD threshold value of 0.1, the control mode is determined as forest stand thinning;
when the intersection point is positioned below the curve with the CBD threshold value of 0.1, the control mode is determined as temporary untwining;
when the intersection point is positioned above the curve with the SC threshold value of 90, the control mode is determined as forest stand thinning;
When the intersection is located below the curve with the SC threshold of 90, the control mode is determined to be temporarily untrue.
2. The method of claim 1, wherein the density control decision model comprises:
An RSI threshold curve group established by a relative density index isoline equation;
a dg threshold curve group is established by a forest stand average chest diameter isoline equation;
a V threshold value curve group established by a forest stand accumulation quantity isoline equation;
Wherein N represents stand density, H0 represents dominant wood height, RSI represents relative density, dg represents stand mean breast diameter, and V represents stand accumulation.
3. the method for controlling disaster prevention of fir wood artificial forest according to claim 1, wherein the estimated density control chart of disaster prevention harvest of fir wood artificial forest is obtained by the following steps:
Collecting forest stand factor data including dominant tree species, canopy density, forest stand age, plant number per unit area, single tree breast diameter and single tree volume;
screening and processing the forest factor data to obtain fir artificial forest data including square average chest diameter, average height, dominant tree height, forest stand accumulation and total biomass;
Establishing a disaster prevention expression model and a density control decision model by regression analysis on the obtained fir artificial forest data;
And constructing the established disaster prevention expression model and the density control decision model into a two-dimensional graph with the dominant wood height as a horizontal axis and the number of plants per hectare as a vertical axis to obtain a disaster prevention harvest estimated density control graph.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610373753.6A CN106034973B (en) | 2016-05-31 | 2016-05-31 | Disaster prevention control method for fir artificial forest |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610373753.6A CN106034973B (en) | 2016-05-31 | 2016-05-31 | Disaster prevention control method for fir artificial forest |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106034973A CN106034973A (en) | 2016-10-26 |
| CN106034973B true CN106034973B (en) | 2019-12-06 |
Family
ID=57171477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610373753.6A Active CN106034973B (en) | 2016-05-31 | 2016-05-31 | Disaster prevention control method for fir artificial forest |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106034973B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110889571B (en) * | 2018-09-10 | 2024-05-10 | 中国林业科学研究院森林生态环境与保护研究所 | Woodland disease (insect) base index curve group and establishing method and application thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678870A (en) * | 2013-09-24 | 2014-03-26 | 中国林业科学研究院资源信息研究所 | Growth and management interactive visualization simulation method for forest stand |
| CN104537464A (en) * | 2014-12-11 | 2015-04-22 | 北京林业大学 | Chinese fir forest felling and breeding method |
-
2016
- 2016-05-31 CN CN201610373753.6A patent/CN106034973B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678870A (en) * | 2013-09-24 | 2014-03-26 | 中国林业科学研究院资源信息研究所 | Growth and management interactive visualization simulation method for forest stand |
| CN104537464A (en) * | 2014-12-11 | 2015-04-22 | 北京林业大学 | Chinese fir forest felling and breeding method |
Non-Patent Citations (2)
| Title |
|---|
| Carlos Lo＇pez-Sa＇nchez et al.A Density Management Diagram Including Stand Stability and Crown Fire Risk for Pseudotsuga Menziesii (Mirb.) Franco in Spain.《Mountain Research and Development》.2009,第29卷(第2期), * |
| 福建杉木人工林密度控制图研制及应用;田猛等;《西北林学院学报》;20150515;第30卷(第3期);第157~163页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106034973A (en) | 2016-10-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kuyah et al. | Allometry and partitioning of above-and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes | |
| Rosset et al. | Seasonal variation in radiation and energy balances of permanent pastures at different altitudes | |
| Thimme Gowda et al. | Study on water requirement of Maize (Zea mays L.) using CROPWAT model in northern transitional zone of Karnataka | |
| Failla et al. | Spatial distribution of solar radiation and its effects on vine phenology and grape ripening in an alpine environment | |
| Matyssek et al. | Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts? | |
| Smit et al. | Sensitivity of crop yields and land resource potential to climatic change in Ontario, Canada | |
| Terjung et al. | Climatic change and water requirements for grain corn in the North American Great Plains | |
| Pereira et al. | Potato potential yield based on climatic elements and cultivar characteristics | |
| Esfandiary et al. | Wheat yield prediction through agro meteorological indices for Ardebil District | |
| Silva et al. | Agrometeorological research on forage cactus and its advances in Brazil. | |
| CN106034973B (en) | Disaster prevention control method for fir artificial forest | |
| Coughenour | Savanna—landscape and regional ecosystem model: model description | |
| Richardson et al. | Root-zone water storage and growth of Pinus radiata in the presence of a broom understorey | |
| CN110956322B (en) | Summer maize flowering phase high-temperature disaster risk prediction method under climate warming trend | |
| Lee et al. | Geostatistical analysis of regional differences in stem taper form of Pinus densiflora in central Korea | |
| Allen et al. | Applying the FAO-56 dual Kc method for irrigation water requirements over large areas of the Western US | |
| Abdolahipour et al. | Effect of time and amount of supplemental irrigation at different distances from tree trunks on quantity and quality of rain-fed fig production | |
| Moeletsi | Agroclymatic characterization of Lesotho for dryland maize production | |
| Vishnoi et al. | Study on water requirement of potato (Solanum tuberosum L.) using CROPWAT MODEL for Tarai region of Uttarakhand | |
| Trnka et al. | Evaluating drought risk for permanent grasslands under present and future climate conditions | |
| Li et al. | Study on approaches of land suitability evaluation for crop production using GIS | |
| Farrelly et al. | The use of site factors and site classification methods for the assessment of site quality and forest productivity in Ireland. | |
| da Silva et al. | Development of ecophysiological simulationmodelto estimate a potential productivity of sugar cane in Brazil and Australia. | |
| Vegesana et al. | Analysis of generic crop growth model for use in decision support systems for farmers | |
| Khanh et al. | An assessment of the carbon stocks of Melaleuca forests in the lower U Minh National Park in Ca Mau province of Southern Vietnam |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |