Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: E017
DOI: https://doi.org/10.24326/ICDSUPL2.E017
Published online: 19 April 2023
ICDSUPL, 2, E017 (2023)
Probability of completion of the regeneration process in shelterwood management system in polish forests
Radosław Kanabus1*
1 Department of Forest Management Planning, Dendrometry and Forest Economics; Warsaw University of Life Sciences, Nowoursynowska 166, 02-787 Warszawa, Poland
* Corresponding author: radoslaw_kanabus@sggw.edu.pl
Abstract
A forest management unit (FMU) is a management planning unit which contains stands distinguished based on similar production possibilities (e.g. site type). In Polish forestry, the shelterwood management unit (SMU) group stands managed by partial shelterwood cutting (PS), group shelterwood cutting (GS) and stepwise shelterwood cutting (SS) (with a regeneration period of up to 40 years). Forecasting stand development in these FMUs is more difficult than in the clear-cutting FMUs due to the presence of stands with the young generation (in regeneration class or to be regenerated). This part of the stands transitions to one of the lower age classes depending on the age of regeneration after the clearing cuts. Until now, it has not been known what the probability of completion of the regeneration process is and what it depends on. In this study, it was decided to find out what influences the probability of completion of the regeneration process and what this probability is depending on the type of cutting used. The data used to do this were collected by the Forest Management and Geodesy Bureau in line with Forest Management Instructions (2003, 2012), in respect of 64 Polish forest districts located within 14 regional directorates of the State Forests, and with a view to forest management plans being developed and made available by the General Directorate of State Forests. Specifically, data from forest management plans elaborated in 2009 and 2010 were used, as were in essence repeat data (from Plans elaborated for the same Districts 10 years later – in 2019 and 2020). The empirical completion of the regeneration process was estimated by overlapping the vector map of stands of Forest Districts with a 100 x 100 m grid of sample plots. Probabilities were calculated using logistic regression according to the type of cutting applied (partial, group, stepwise), the mean age or mean height of regeneration and the adopted regeneration period (up to 10 years and more than 10 years). The relationship between the mean height of regeneration and the mean age of regeneration was checked. Based on the calculated probability, theoretical distributions of stands in age classes and regeneration height were made and compared with the distributions determined based on empirical data. No correlation was found between the maximum age/height of regeneration or the age/height of the dominant species in the regeneration (with the highest proportion) and the probability of completion of the regeneration process. Also, the compactness and the dominant species of the parent stand and the level of area coverage by regeneration did not influence the completion of the regeneration process. The completion of the regeneration process was influenced by the average age of regeneration and the average height of regeneration. There was also a fairly strong relationship between these characteristics. For PS it was R2=0.79, for GS R2=0.72 and for SS R2=0.73. The probability of completion of the regeneration process differed between the types of SMU and was different among stands with an assigned regeneration period of up to and above 10 years. With a regeneration period of up to 10 years, it was initially about 0.23 for GS and did not depend on the average age, for PS it was about 0.23 at an average age of 1 year and increased to 0.52 at an average age of 40 years. In SS, it was initially 0.13 and increased to 0.74 with an average age of 40 years.
How to cite
R. Kanabus, 2023. Probability of completion of the regeneration process in shelterwood management system in polish forests. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.E017