Experimental Industrial Fellings with Undergrowth Preservation in Fir-Spruce Forests of Khabarovsk Krai

摘要

Spruce-fir forests of Khabarovsk krai have been subjected to significant overexploitation since felling was prohibited in Far Eastern ceder forests. In fact, they have replaced the ceder plantations that fell out of use, which is also confirmed by researchers from neighboring regions (Maiorova, 2012, 2021). By 2006, the portion of spruce forests used for industrial felling reached 85% of their total area. At present, the state of these forests has deteriorated so much that the portion of highly productive spruce forests is no more than 10%; in clearings they are replaced by plantations of Asian white birch, aspen, and larch. The area of artificial reforestation in spruce forests is approximately 50 000 ha each year, but the metric area and resources in these forest formations continue to decline. Since 2009, resource losses have been approximately 30 million m(3). However, if the forestry requirements for the preservation of undergrowth are followed during logging, no decrease in the area of spruce-fir forests should occur, because these forests are largely provided with undergrowth. In this regard, I have conducted studies that make it possible to assess the survivability of the preliminary-generation undergrowth during logging using different systems of machines and technological schemes for the work on the felling sites. In three forest districts of the krai, I laid out experimental plots where logging works were conducted using "shuttle " and "bypass-trail " technologies while also employing gradual and selective fellings. The results show that, when shuttle technology is used, the percentage of surviving pregeneration undergrowth does not exceed 25%, while the bypass trail technology leads to much higher values-up to 75%. The most acceptable result of the undergrowth preservation was achieved for the cutting sites where selective and gradual methods were used. Thus, the employment of the logging technologies with reduced impact or a complete transition to gradual and selective felling methods in spruce-fir forests would make it possible to achieve their sufficient natural reforestation.