According to Order No. 480 "On Forest Pathological Examinations" issued by the Ministry of Natural Resources and Ecology, the purpose of these inspections is to identify and register diseases, pests and other pathological forest damages, as well as assess the sanitary and forest pathological state of green spaces.
The essence of the forest pathological examination
The essence of this process is to establish the causes and places of occurrence of diseases and pests of the forest and plantation groups that have impaired stability, identify the causes of drying out and weakening of the stands along with an assessment of their sanitary and forest pathological condition, as well as to monitor the occurrence and spread of diseases and forest pests.
Based on the checks conducted, information is revealed to predict the development of places of occurrence of threats, determine specific types of plant diseases and implement protective procedures.
The list of measures of forest pathological examination includes the work of prophylactic (organizational, technical, forestry, forest cultural, sanitary and health and biotechnical) types, as well as fighter and protective procedures.
Forest pathological surveys of forest stands are planned and implemented as an independent type of measures, which are included in the annual production plan developed by forestries, regional centers (stations) and inter-district engineers.
Verification methods: remote, terrestrial and combined. Remote research is used in sparsely populated areas where information can be obtained using space or aerial photography.
Terrestrial forest pathological surveys are carried out in places where forestry is conducted especially intensively, in locations of especially valuable species and in areas where ground transport can take place. Verification of such methods is carried out by a selective examination of parts of the territory.
Types of analysis
According to the order "On forest pathological examinations", the following types of checks are distinguished, depending on the tasks assigned to the forms of their conduct:
- operational current;
- control;
- inventory;
- forest pathological;
- expeditionary;
- reconnaissance;
- detailed forest pathology.
Each of these species is distinguished by the peculiarities of planning and conducting surveys in individual sections of forest areas.
Operational Ongoing Surveys
The procedure for conducting examinations of the forest pathological type in the form of operational current checks includes an analysis of various groups of stands. The objectives of this study are the following types of checks:
- Examination of the area for diseases, pests, other forest damage, as well as verification of air and ground alarms to alert you to hazards.
- Inspection of places of origin and accumulation of diseases and pests that have been identified or are under control in a detailed or reconnaissance surveillance.
- Checking plantations, areas and nurseries that are subject to afforestation for the presence of diseases or pests, determining the places of their distribution and the degree of threat of damage to future plants.
- Forest pathological examination of forest stands that were damaged by windfalls, fires, insects or other factors of anthropogenic or natural origin.
- Verification of plantations for further reconnaissance control and supervision.
- Conducting a survey of plantations for which stability is impaired for any reason, if an application for verification was received from the leskhoz or management of a territorial type of farm in order to carry out sanitary-improving, destructive or protective measures in the future.
Acts of forest pathological examinations in the Tver region and other regions are drawn up by specialists of leshozes, forest protection and forestries who are authorized to do this by internal acts of the subject or municipality.
Control checks
Conducting forest pathological examinations in the form of control checks has a definite purpose. This analysis is carried out to assess the status of foci of forest damage, as well as to monitor the number and condition of the population of insects that damage plants.
Inspection is carried out before insects leave for wintering and after leaving it, as well as before the start of measures for the extermination of pests and after them. The specialists of the forest protection department are involved in this work.
Inventory surveys
Forest pathological surveys of plantations of an inventory nature are carried out to assess the records and condition of places of occurrence and accumulation of diseases, pests and other damage to forests that act or die out due to the influence of certain reasons.
During the inspection, the foci are divided into those that require forest protection measures and those that do not need it. The survey is carried out by specialists of leshozes, forest protection or forestry in the framework of their authority.
Forest pathological examinations
The act of forest pathological examination, conducted through examination, is drawn up to establish the causes of diseases and pests, as well as to assess their condition. In addition, the examination allows you to determine the types of harmful or dangerous organisms that caused damage to the forest, if necessary, and also decide on the need for forest protection measures.
Due to the fact that the examination is a complex procedure, high-level experts in the field of forest protection, scientific workers and teachers of secondary or higher educational institutions are involved in its implementation.
Expeditionary surveys
The act of forest pathological examination, drawn up during the conduct of expeditionary type checks, fixes an assessment of the state of damage to large-scale forests. The purpose of such actions is to solve the intractable tasks of forest protection, planning and systematizing large-scale measures for the protection of green spaces, which are associated with the management and use of forests.
Such surveys are also carried out to conduct other types of work that affect the condition and stability of the inspected territories. To carry out operations of this type, employees of territorial forestry management bodies are involved.
The volumes of the planned operational current and inventory checks should be carried out in accordance with the general situation in the forest pathological field in each individual forestry and the region as a whole.
Surveys, their importance and urgency should be justified accordingly. Dates of control inspections are appointed by forest protection specialists who perform detailed control and supervision. Survey plans are compiled annually. It includes checking the condition of places of occurrence and accumulation of diseases and pests.
When conducting surveys, remote and ground based methods are used. If the first method is used separately from the second, it must be re-checked.
Reconnaissance surveys
Acts of forest pathological examinations in the Tver region and other areas are compiled on the basis of checking the state of forest stands by visual observation. It can be used for preliminary study of the object of study before a detailed check. Also, this method is used to select items to account for all the details, identify parts of the territory with foci of diseases, pests and impaired resistance.
Reconnaissance surveys are carried out in the form of supervision of the state of green spaces, the degree of damage to plants by stem pests. Also, control is carried out for diseases and pests of young animals and plantings in nurseries.
Ground-based reconnaissance surveys are carried out using a sighting device, clearings, forest roads and trails. The distance between the passage lines should be from two hundred to a thousand, in taiga territories - from two to four kilometers, laying in forests of an unsettled type is carried out by compass.
Inspections are carried out on taxation type sections, which are located along the laid route. All plantations of coniferous, oak, beech types or with a predominance of ash are examined, regardless of size. Deciduous plantations are checked if the area under cultivation is from five hectares.
The degree of damage to tree crowns by insects gnawing needles and leaves is determined by eye examination in percentage (weak type damage - up to twenty five percent, medium type - up to fifty percent, strong type - up to seventy-five percent, full type - over seventy-five percent) . Also, during examinations, the type and age of the larvae is indicated.
The assessment is carried out as a percentage of the affected trees of their total number, as well as for the categories of dead and drying plants. Infestation of forest plantations by pests is determined by the specific signs of their harmful activity (drill type flour, sawdust, drops of resin, beetles, airflows and inlets on wood bark, larvae and passages under the bark).
In some cases, trees are cut down and analyzed to check the plant population and determine the composition of pest species. The presence of various diseases is established by specific signs of an external nature (fruiting mushroom bodies, characteristic types of rot, necrosis, tumors, cancer wounds, parts of drying out, etc.).
The inspection reports indicate the established types of harmful diseases and insects, the root cause of damage and weakening of stands (wind, fire, defoliation by insects).
Planted areas with a high degree of damage to trees, if this degree exceeds the size of natural decay, as well as if the diameter of pathological leaf fall trees exceeds the average volume of the stand, become foci of a certain type of disease or pest.
Detailed examination
Acts of forest pathological examinations, the forms of which are free, are compiled on the basis of a detailed detailed forest pathological type. These checks are carried out by laying test areas and conducting a detailed assessment with respect to plantations, their samples or model samples.
The purpose of a detailed check is to determine the degree of plant occupation by harmful insects, infection by various diseases and other pathological factors, as well as to further determine the prospects for the development, spread of emerging forest lesions to assess the degree of threat to future plant growth and development, and to develop protective measures.
This type of inspection is most often carried out in the autumn or early spring. At this time, stocks of wintering species of pests are taken into account, the scale of the threat to green spaces in the coming year is established. Based on the checks performed, the timing of the future survey may change, as a result of which changes are made to the schedule.
When calculating plants, a six-point scale of categories of conditions is used. The number of trees in each group is calculated as a percentage of their total number. The results are entered in a specially designed form.
If necessary, specialists carry out a detailed step-by-step analysis of the selected trees for the degree of population of pests and disease. Categories for checks are as follows:
- Healthy, without visual signs of impairment.
- Weakened.
- Extremely weak.
- Drying out.
- Shrunken.
If the examination is carried out in a nursery, it is preceded by the identification of lesions at the stage of reconnaissance verification. The degree of mortality from various infectious lodging is taken into account by counting and selecting affected seedlings, as well as excavating sowing furrows.
On one hectare of land from twenty or more excavations are carried out, two hundred fifty or more seeds and dead seedlings are collected for future analysis. Excavations are carried out diagonally on the investigated area. At the same time, special samples are laid along the excavations at the rate of one linear meter per one furrow of the sowing.
Criteria for assessing plants in nurseries
During forest pathological examination, the prevalence of diseases in nurseries is determined as the ratio of the number of affected seedlings to the entire group of registered plants. The resulting number is multiplied by one hundred.
The degree of infection of the seedlings with foliage and pine needles is evaluated on a five-point scale, where 0 - healthy trees, 1 - lesions up to twenty-five percent, 3 - lesions up to seventy percent, 4 - lesions up to one hundred percent.
An examination of the forest pathological type is a necessary procedure for the timely detection of diseases, their treatment, as well as the development of preventive and protective measures.