Izvorni znanstveni članak
Estimating and Modelling Harvester Productivity in Pine Stands of Different Ages, Densities and Thinning Intensities
Piotr S. Mederski
orcid.org/0000-0003-3060-4422
; Poznań University of Life Sciences Faculty of Forestry Department of Forest Utilisation ul. Wojska Polskiego 71A 60-625 Poznań POLAND
Mariusz Bembenek
orcid.org/0000-0002-9437-8439
; Poznań University of Life Sciences Faculty of Forestry Department of Forest Utilisation ul. Wojska Polskiego 71A 60-625 Poznań POLAND
Zbigniew Karaszewski
orcid.org/0000-0001-8037-021X
; Wood Technology Institute Wood Science and Application Department ul. Winiarska 1 60-654 Poznań POLAND
Agnieszka Łacka
; Poznań University of Life Sciences Faculty of Agronomy and Bioengineering Department of Mathematical and Statistical Methods ul. Wojska Polskiego 28 60-637 Poznań POLAND
Anna Szczepańska-Álvarez
; Poznań University of Life Sciences Faculty of Agronomy and Bioengineering Department of Mathematical and Statistical Methods ul. Wojska Polskiego 28 60-637 Poznań POLAND
Martyna Rosińska
; Poznań University of Life Sciences Faculty of Forestry Department of Forest Utilisation ul. Wojska Polskiego 71A 60-625 Poznań POLAND
Sažetak
In economic terms, the main limiting factors in harvester application in thinning operations are the stand age and thinning intensity with respect to tree size. Furthermore, harvested mean tree size depends on initial stand density but also on the number of trees cut per hectare. The objective of the research was to estimate the impact of:
Þ stand age (class),
Þ increasing stand density in each age class (AC),
Þ increasing number of trees for harvesting in each AC,
Þ thinning intensity,
on harvester productivity. 17, 19 and 20 sample plots were established within 3rd (AC3) 4th (AC4) and 5th (AC5) age classes, respectively. In each AC, sample plots were selected that had an increasing number of trees per hectare: 563÷1603, 323÷868 and 476÷836 trees ha–1, in AC3, AC4 and AC5, respectively. Also, in each AC, an increasing number of trees per hectare for harvesting was selected: 130÷853, 80÷315 and 108÷282, in AC3, AC4 and AC5, respectively, with the relevant increasing thinning intensity: 35÷84, 21÷77 and 34÷88 m3 ha–1. In each AC, the stands were divided according to different thinning intensity (THI): a<30, 30≤b≤60 and c>60 m3 ha–1, respectively. A Komatsu 931.1 harvester was used for the thinning operation in each stand. The lowest mean productivity was observed in AC3 (18.57 m3 h–1), which was statistically different to AC4 and AC5 (22.24 and 22.60 m3 h–1, respectively). Within each AC, productivity lowered as the number of trees per hectare increased in the initial stand. The productivity decreased in AC3 and AC5 with the increasing number of trees for harvesting, which was not the case in AC4. In relation to the THIs, the lowest mean productivity was obtained in THIa (16.19 m3 h–1), which was statistically different to THIb and THIc (21.44 and 21.98 m3 h–1, respectively). An increasing THI only influenced productivity positively in AC4 and AC5. It can be concluded that the productivity of the Komatsu 931.1 harvester increased along with:
Þ older AC,
Þ decreasing number of trees in the initial stand in each AC,
Þ lowering number of trees for harvesting in AC3 and AC5,
Þ increasing THI in only AC4 and AC5.
Finally, in the present model, the larger the mean DBH of the trees for harvesting, the greater the productivity. However, the mean DBH has to be considered in conjunction with the number of trees for harvesting (which depends on AC and THI, as variables in the model) when productivity is analysed.
Ključne riječi
thinning operation; productivity curves; Scots pine (Pinus sylvestris L.)
Hrčak ID:
153468
URI
Datum izdavanja:
1.2.2016.
Posjeta: 1.872 *