In the field of forest planning, we are using GIS and GNSS techniques to obtain accurate, real and pertinent information quickly. SC FOREST DESIGN SRL has rich experience in the field since 2004, not only in the classical forest planning activity, but in the research and development of digital products for the spatial management information for forestry.
Description of activities and specific procedures for the forest inventory and planning
I. Preparatory works
The starting date of the preparatory works is 7 days from the date of signing the contract.
The fieldwork for forest inventory will be designed on prior documentation and general recognition and consists of:
1.1. Documentation and general recognition of the forest and documentation on site conditions and vegetation in the analyzed area
The aim is to provide first information on geology, specific forms of relief, climatic peculiarities, main soil types, intra and extracurricular stages, basic forest types, types of indicator plants, natural regeneration conditions, land degradation, etc. . Refer to previous management, works with implications for forest management, evidence of previous management, etc. It will also draw up the provisional ecological scheme of the resort and forest types in the studied area.
1.2. Procurement and analysis of cartographic material (plans, satellite imagery, orthographic aerial images).
In order to execute the requested service, SC Forest Design will consult the materials provided by the beneficiary:
Forest maps in analog format
Basic topographic plans (trapezoidal) with scale 1: 5000, equipped with data specific to the forest management
Cartographic layout of topographical plans
Geological map and pedological map.
In order to have a detailed and updated cartographic support, we will use high-resolution aerial images, exemplified in the figures below.
Fig 1. Identification of affected trees and windthrows
Fig 2. Identification of valuable species and threats
Fig 3. Identification of changes in forest boundaries
3. Procurement of data from previous managements: will be obtained from the beneficiary.
Also during the preparatory works, the test surfaces for relascopic inventories will be placed on the cartographic material using a geometric grid and they will be introduced in GPS, together with the plot and subplot boundaries, in order to transpose them in the field.
It will also proceed to the analysis of the aspects elaborated in the design theme by the administrator / owner.
The preparatory works will be completed by holding the first Planning Conference (endorsement of the design theme) within a maximum of one month from the signing of the contract.
2. Field works
2.1. Collection of field data
It is a broad phase through which information is obtained regarding the resort and the forest vegetation, representing the so-called "plot description" or "description of the planning units". All determinations will be performed in compliance with the Technical Norms for forest management. In this stage, special attention will be paid to the aspects regarding:
- knowledge of natural vegetation conditions;
- knowledge of the characteristics of the current tree;
- the productive potential of the resort;
- production and protection capacity
- collecting data on biodiversity in order to prepare the presentation report and the environmental report and / or the appropriate assessment study.
2.2. Materialization of the plot and sub-plot
Once the land is covered, the boundaries of the newly appeared sub-plot as well as the boundaries of the sub-plot and the unmodified / existing plot will be materialized with red paint documents. Also, there is the obligation to remake with paint ("refreshed") the (witness) landscaping terminals. The beneficiary will receive at the reception of the field works a list with the condition of the terminals in order to restore / reinstall the damaged or missing ones.
Where the materialization on the trees of the plot boundaries is no longer distinguished, and the orographic or arboretum conditions do not allow the reconstruction in the field, this limit is materialized by tracing, using GNSS technologies.
2.3.Plot description
It is made using standard forms, which record ecological, dendrometric, forestry and phytosanitary characteristics of landscaping interest, as well as indicating the measures needed in the next decade for each landscaping unit, taking into account the arbor and the functions assigned to it. . For the study and description of a stand, determinations will be made regarding: the fundamental type of forest and its current character, the tree elements with all the related tax elements, the proportion of species, production class, consistency, semintis, proposed works, etc., according technical norms in force.
2.4. For each tree element, as well as for the entire tree, the volume is determined by inventories, as follows:
1) The exploitable stands with the consistency between 0.1 and 0.4 or with the surface of maximum 3 ha, which are to be harvested in full (by final or cleared cuttings), will be inventoried tree by tree. Where development documents have recently been drawn up, no new inventories will be made in the arrangement, taking the data from the district documents. If the inventory taken from the bypass is more than one year old, the corresponding current increases will be added.
2) The other exploitable stands that will be included in the ten-year plan will be STATISTICLY inventoried
SHAPE, SIZE, MATERIALIZATION AND BOUNDARIES OF TEST SURFACES
- The shape of the test surfaces. Statistical inventories are made by circular test surfaces, in which the measurements are made with the block.
- The size of the test surfaces. The circular test surfaces used have, in horizontal plane, the size of 500 m2
- Number of test surfaces. The number of circular test areas is determined using the tables in the Forest Management Guide (Annex 20, Vol. II), taking into account a tolerance (∆) of 10%, a probability of coverage (P) of 90% and a value of the coefficient of variation of the volume of 35%, as well as the surface of the subplot.
The number of circles (test surfaces) and the distance between them corresponding to a coefficient of variation of 35% is considered to ensure a satisfactory accuracy for determining the volume. A higher coefficient of variation implies more surfaces (circles), respectively more labor.
Fig 7. Example of taking inventory data with the help of its own application, GIS compatible
The head of the inventory team, in the execution of the works, receives from the design engineer a sketch that includes:
and plot and subplot boundaries;
interior topographic details;
terminal location;
details on the trees (composition, age, tree elements, consistency;
inventory process;
the sample area, in the case of partial inventories, the number and distance between them;
the grid of the location of the test surfaces, in relation to the slope.
CALCULATION OF VOLUMES
The diameters recorded in the putt sheets are centralized by species in centralized formulations. All inventory data entered in the files are processed by the computer in order to calculate the volume. Consecrated calculation programs are used, using the regression equations of the series of volumes published in the specialized literature.
For young trees or not included in the ten-year harvest plan
They will be inventoried using simplified (relascopic) procedures. The relascopic procedure (Bitterlich) allows the determination of the base area per hectare of a tree on the principle that it, expressed in square meters, is proportional to no. of shafts whose base diameters exceed the sides of a certain critical angle.
When performing inventories by relascopic procedures we use the simplified Bitterlich device.
LOCATION AND MATERIALIZATION OF TEST SURFACES
The test surfaces are placed at the office, on the sketch of the sublot, after a square grid, by automatic generation, using specific GIS programs. The location is made after measuring the plot and sub-plot boundaries with the GPS and the analytical determination of the surfaces. The area of any planning unit will be determined obligatorily and exclusively based on the limits resulting from measurements or vectorization, applying the numerical method - the analytical procedure, performing the actual calculations being performed automatically, using various software applications.
NUMBER OF TEST SURFACES
It is determined with the help of the following elements whose values are inscribed in the Forest Management Guide, in relation to:
- tolerance (∆) and probability of coverage (P);
- the size of the sample surface;
- the value of the coefficient of variation of the volume;
- the area of the subplot.
The sketch (s) of the subplots with the test surfaces are loaded in GPS.
The transposition in the field of this location is done with the help of a Garmin GPS, after the loading has been done in the device.
The number of soundings for non - exploitable stands shall be determined in relation to the coefficient of variation and the accuracy of ± 15% within the meaning of a probability of coverage of 80%. The coefficient of variation is determined according to the homogeneity class and the surface of the stand. Considering that the average number of trees in a survey is between 20-40, often 30-40, and that the trees generally fall into homogeneity classes 1 and 2, the average number of surveys we perform in the field corresponds coefficient of variation of 30%, according to the Forest Planning guide.
Basically, with the help of specific computer programs, introducing for each market the slope, the species (tree elements), the origin (regeneration mode), no. of trees and average height, the density and volume per hectare are obtained, as well as the proportion of species.
4.2.5. Topographic measurements
The works for raising the forest boundaries will be executed using GNSS technologies (Global Navigation Satellite System), as follows:
all the data resulting from the terrestrial measurements will have as reference the S42-Romania System which is based on the 1940 Krasovski ellipsoid and the 1970 Stereographic projection plan;
the GNSS equipment used is dedicated to the acquisition of data in the environment represented by the forest fund;
in the field trips will be raised in the plan: the outer limit of the forest bodies or the limit of the Production Unit, the limits of the newly constituted management units, the points represented by the control terminals;
for the topographic elevation of the external limit of the forest bodies or of the limit of the Production Unit, the determinations will be included in the precision category of +/- 1.0 m respecting the conditions
To use one of the services of the Romanian Position Determination System (ROMPOS), namely: the DGNSS service (GNSS differential) or the RTK Service (Real Time Kinematic);
To use for the conversion of coordinates from ellipsoidal coordinates (lat, long) on the GRS80 ellipsoid, the ETRS89 system (as purchased by GNSS equipment) into coordinates specific to the Stereographic 1970 projection, Krasovski 42 ellipsoid, the application will be used
The principle of positioning in the G.P.S.
- if the field conditions do not allow (justifiably) the effective crossing of certain forest boundaries, this fact will be brought to the attention of the contracting authority, and the respective limit will be taken over from the color orthophotoplan or from the basic topographic plan ;
The spatial position resulting from measurements for the forest boundaries and boundaries that were the subject of topographic measurements will be included.
4.2.6. Reception of field works
After the completion of the field works, they will be received, with delegates of the beneficiary, the relevant ministry and the provider.
4.3. Data processing and drafting of the arrangement
4.3.1. Calculation of the surfaces of the arrangement units
The area of any planning unit will be determined obligatorily and exclusively on the basis of the limits resulting from measurements or vectorization, applying the numerical method - the analytical procedure, performing the actual calculations being performed automatically, using various software applications.
4.3.2. Calculation of usable stands
In order to calculate as correctly as possible the possibility indices and the real volumes to be harvested, the rest of the exploitable stands, the pre-exploitable stands and the young ones will be inventoried by relascopic procedures.
4.3.3. Data processing with the AS program
The information taken from the field will be processed using the AS 2010 program (latest version of the application).
4.3.4. Preparation of landscaping maps
The landscaping maps will be drawn up according to the specifications in force, using as graphic primitives the points, lines and polygons resulting from the field activities and processing in the GIS application.
4.3.5. Requesting a point of view from the responsible environmental authority on the occasion of the second planning conference.
Together with the beneficiary, on the occasion of the Second Planning Conference, a point of view will be requested from the responsible environmental authority by inviting a representative of it.
4.3.6. Preparation, organization and support of the Second Planning Conference
4.3.7. Delivery to the beneficiary of the following documents:
- synthesis of the plot description;
- the ten-year plan for harvesting the main products;
- the ten-year plan of the stands for the care of the stands;
- ten-year plan of conservation works;
- ten-year plan of regeneration works;
4.4. Technical specifications regarding the realization of the Geographic Information System
The geographic information system will be fed with a geographical database, consisting of the spatial database and the descriptive database, which will be made within the contract. The two components of the geographical database (graphic primitives interdependent with the descriptive data) will characterize from a topographical and silvicultural point of view the studied area.
Thus, all spatial (graphical) and descriptive (alphanumeric) information will be stored in a single geographical database, unitary at the level of the entire Production Unit.
4.4.1. Structure and content of the geographical database
In the geodatabase the information will be stored at table level, the attributes being managed in tables based on a series of “key” concepts of relational data:
the data are organized in tables;
the tables contain rows;
all rows in a table have the same columns;
each column has a date type, such as: integer, decimal number, character, date (as a time period), raster, etc .;
the relationships are used to associate the rows from one table with the rows from another table, the relationship being made based on the information contained at the level of the same column (primary key);
series of relational and operator functions (such as SQL) are available to operate in the tables and elements of this data;
rules of relational integrity
The tables provide descriptive information for spatial objects. Tables and relationships play a key role in GIS applications.
4.4.2. Georeferencing of analog planes, initially scanned and brought in digital format
Those data provided by the contracting authority, which are not found in digital format but in analog format on paper, will be scanned in color, at a resolution of at least 350dpi, respecting the color index "Indexed Color" (256colors) and subsequently geographically referenced (georeferenced ) to the Stereographic projection plan 1970.
The format of the scanned file must be standard uncompressed TIF and the format of the georeferenced file must be uncompressed geoTIF.
Regarding the georeferencing operation, both for digital raster formats (georeferencing)