Scientific fundamentals of the establishment of the silvicultural demonstration plot "Borshchovychi"

Abstract

In the State Forest Enterprise "Lviv" the scientific demonstration plot "Borshchovychi" was created for the study of various methods of Scots pine management. The scheme of section placement in a stand of fresh hornbeam-oak-pine forest with different options for cutting intensity was proposed. In particular, five 50 × 80 m sections with 15-m buffer zones in between were laid evenly over the area of the taxation unit. All trees in each section were numbered and their taxation indexes were measured. A total of 5.416 trees were counted, of which 4.870 were Scots pine trees. We calculated silvicultural and taxation indicators of stands in each section. They differ slightly from each other. Thus, the shares of Scots pine in the standing volume ranges from 86.9% in the fifth section to 98.6% in the first section. The average diameter varies between 11.2-12.0 cm. The values of the average height are in the range of 10.8-11.5 m. The total growing stock of stands in the sections varies between 149.1-188.2 m3/ha. The density of the stand in the sections was 2398-3075 pieces/ha. Pine trees are characterized by a significant variability in trunk diameter. This is indicated by the values of the coefficients of variation, which are approximately equal in all sections and range from 30.15 to 32.75%. Moreover, pine trees are approximately evenly distributed in the degree of thickness (without a clear concentration in a particular degree of thickness). Despite the significant variability of tree diameter, the results of the experiment indicate a high accuracy, because the error value in any of the sections with a maximum of 1.10% does not exceed the allowable value. Organizational and technical indicators of thinning in each of the sections are outlined. The first section is the control section, where no measures are planned. The number of trees designated for thinning, and the volume of the different thinning intensities (20% ‒ in the second and fourth sections; 40% ‒ in the third and fifth sections) are calculated. Thus, 349 trees (mainly the undergrowth specimens of Scots pine) are cut in the second section; 440 trees, including 363 Scots pine trees are cut in the third section; 183 trees, including 167 Scots pine trees, are cut in the fourth section and 298 trees, including 223 Scots pine trees, are cut in the fifth section. The selection of these trees on the sample plots was carried out according to their condition, Kraft class, category of technical quality and method of cutting (low thinning ‒ in the second and fourth sections; high thinning or thinning from above ‒ in the third and fifth sections). Stand characteristics of each section before and after the cut were calculated. It was found that low thinning has no significant effect on the main stand characteristics of the stand after cutting, in particular on the average diameter and average height of the stand. Contrarily, high thinning has a significantly greater impact on taxation indicators of the stand after the intervention. From the totality of the trees left in the sections, future crop trees (65-72 pcs) of the main tree species (mainly Scots pine, less sessile oak) were identified, with a volume share of 9.5-12.0% of the total growing stock. On the future crop trees, the branches in the lower part of the crown were pruned, which will ensure the formation of a well-tapered trunk and high-quality wood in the future.

Keywords

• pine stands
• low thinning
• high thinning
• intensity of cutting
• future crop trees
• research on long-term observation plots