MODEL ANALYSIS OF THE PLANTATIONS SPRUCE PRODUCTIVITY DEPENDENT ON THE PLANTING SCHEME AND INTENSITY OF RANDOM EXTERNAL FACTORS IMPACT

Abstract

With rational forestry management, it is created special artificial forest plantations of high productivity for technically valuable species allowing the largest supply of grown wood. One of the ways to increase the supply of wood per unit of forest area is to regulate the initial density and planting pattern of trees. Using simulation methods, it is shown that in the absence of external influences, a checkerboard planting pattern is an optimal one providing a larger supply of wood as compared to a rectangular pattern. In real conditions, there are risks of  dying off for individual trees due to random external factors like gusts of wind and phytophages. Therefore, in real life the supply of wood grown under such optimal planting schemes would  be significantly lower as compared to the calculated values obtained.

In this regard, there arise problemsaimed at studying theplantings productivity dependent on the planting pattern and the intensity of tree death during the forest stand growth as a result of the random external factorsinfluence. To solve these problems, we used a simulation model of  tree communitiesdynamics, which takes into account the spatial location of each tree, in this way making it easy to simulate various forest planting schemes and remove some trees at any step of modeling. As a result of the computational experiments, the optimal values of spruce plantations initial density have been defined for different planting schemes, dependent on the intensity of theexternal factors influence. It is shown that at a certain intensity of the external factors impact, the maximum timber stock does not depend on the planting scheme, but is determined by the initial density of the forest stand.When the impactintensity increases,, the planting density also needs to be increased, in order to obtain the maximum reserve.