HYDROLOGICAL REGIME AND GROWTH OF PINE STANDS IN CONDITIONS OF DRAINAGE RECLAMATION SYSTEMS

• Main Authors: V. Yu. Yukhnovskyi, R. M. Prokopchuk
• Format: Article
• Language: English
• Published: Ukrainian National Forestry University 2018-03-01
• Series: Науковий вісник НЛТУ України
• Subjects: reclamation; drainage channels; water table; pine stands; productivity; height
• Online Access: https://nv.nltu.edu.ua/index.php/journal/article/view/1432

A retrospective analysis of the formation and development of drainage reclamation in Volyn Polissya was carried out. The growth of pine plantations within the controlled drainage system and under the control was simulated. The data of samples and materials of the database of plantations growing on drained and control plots were used for modelling of height dynamics and changes in stocks with age. Dynamics of heights and stocks are described by the models of the polynomials of the second degree and the exponent equations. It was established that by the middle of the 3rd age class, the height of plantations on drained areas exceeds the height of plantations under the control of 2.1 m. Starting from the 3rd age class, pine stands on drained areas sharply increase the growth and at the age of quantitative ripeness, the difference in heights reached 3.0 m. Pine plantations in land reclamation areas pass into the upper class of productivity. The difference between the average heights in the 5th age class is 2.7 m. The effect of drainage is traced after 30 years, when the root system penetrates deeper horizons. The growth of roots on the control sites close to the surface of the water table is inhibited. At the same time, the soil saturated with oxygen stimulates the growth processes of the wood plants between the drainage channels, which lead to an increase in the productivity of the plantings. Comparative analyses of changes in planting stock shows that in the fourth age class the stock of pine stands on drained areas exceeds 15 %, and at the age of quantitative maturation this difference reaches 21 %, which makes 89 m3∙ha-1 and is a significant argument for the use of drainage reclamation in the wetlands of Volyn Polissya. The analysis of the hydrological regime of the drainage system "Strashevo" for the 14-year period showed that the water table during 2010–2017 sharply decreased reaching a stable value of 124–140 cm, whereas by 2009 it had fluctuated within the limits of 61–83 cm. The prolonged and significant decrease in water table leads to the declining of plantations, therefore, to ensure optimal hydrological regime of forest areas it is necessary to sluice channels or reconstruction of the drainage system in the system of bilateral action.