Template-Type: ReDIF-Article 1.0 Author-Name: Jussi Manner Author-Workplace-Name: Skogforsk, Uppsala, Sweden Author-Name: Simon Berg Author-Workplace-Name: Division of Forest and Forest Resources, Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway Author-Name: Martin Englund Author-Workplace-Name: Skogforsk, Uppsala, Sweden Author-Name: Back Tomas Ersson Author-Workplace-Name: School of Forest Management, Swedish University of Agricultural Sciences (SLU), Skinnskatteberg, Sweden Author-Name: Anders Mörk Author-Workplace-Name: Skogforsk, Uppsala, Sweden Title: Innovative productivity improvements in forest operations: a comparative study of the Assortment Grapple using a machine simulator Abstract: Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders' loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple's accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple's usability will be improved by adding an own rocker switch on the forwarder's controls to command the extra claws. Keywords: crane, cut-to-length method, forwarder, loader, operator, thinning Journal: Journal of Forest Science Pages: 443-451 Volume: 66 Issue: 11 Year: 2020 DOI: 10.17221/104/2020-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/104/2020-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202011-0001.txt Handle: RePEc:caa:jnljfs:v:66:y:2020:i:11:id:104-2020-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Fahad Rasheed Author-Workplace-Name: Department of Forestry and Range Management, University of Agriculture, Faisalabad, Pakistan Author-Name: Rasool Bakhsh Author-Workplace-Name: Department of Forestry and Range Management, University of Agriculture, Faisalabad, Pakistan Author-Name: Ihsan Qadir Author-Workplace-Name: Department of Forestry and Range Management, Bahaudin Zikaria University, Multan, Pakistan Title: Trade-off between shoot and root dry weight along with a steady CO2 assimilation rate ensures the survival of Eucalyptus camaldulensis under salt stress Abstract: Salt stress is a major challenge for reforestation in arid to semi-arid regions. Therefore the effect of salt stress was tested in 4-months-old saplings of Eucalyptus camaldulensis under controlled conditions. Individuals were subjected to three levels of salt stress (2, 8, 16 d.Sm-1) and several traits describing growth and dry weight production/allocation, as well as physiological attributes were measured. The results showed that salt stress had no impact on plant height or stem diameter. Number of leaves, number of branches, and leaf chlorophyll content decreased significantly under high salt stress treatment. Leaf dry weight decreased significantly, but root dry weight increased significantly from 6.22 to 8.24 g under high salt stress treatment. Total plant dry weight remained similar while the root/shoot ratio increased significantly under high salt stress treatment. The net CO2 assimilation rate remained stable at ~ 10.1 mmol.m-2.s-1 and stomatal conductance decreased significantly to 79 mmol.m-2.s-1 under high salt stress. Consequently, water use efficiency increased significantly to 3.25 mmol.mol-1 under high salt stress. Therefore we may conclude that the young Eucalyptus camaldulensis saplings can tolerate moderate salt stress by increasing dry weight allocation towards the root system and sustaining the CO2 assimilation rate. Keywords: tolerance, salinity, dry weight production and allocation, stomatal conductance, water use efficiency Journal: Journal of Forest Science Pages: 452-460 Volume: 66 Issue: 11 Year: 2020 DOI: 10.17221/44/2020-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/44/2020-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202011-0002.txt Handle: RePEc:caa:jnljfs:v:66:y:2020:i:11:id:44-2020-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Ondřej Špulák Author-Name: Dušan Kacálek Author-Workplace-Name: Forestry and Game Management Research Institute, Opočno Research Station, Opočno, Czech Republic Title: How different approaches to logging residues handling affected retention of nutrients at poor-soil Scots pine site after clear-cutting? A case study Abstract: Biomass nutrient loss and retention were studied at nutrient-poor forest site dominated by Scots pine where two methods of logging residues handling after clear-cutting were compared. The experiment was conducted on nutrient-poor pine-oak forest site on deep sandy-gravel unconsolidated sediments at the altitude of 255 m. There were three treatments established such as (i) control - no harvesting, (ii) whole-tree harvesting with ca. 10% of the slash retained unintentionally on site as processing residues and (iii) stem-only harvesting when small-diameter wood and slash were left on site. The third treatment was found to retain much larger amounts of nutrients in logging residues representing 16% of total above-ground dry mass which accounted for 58% of N, 32% of P, 56% of K, 22% of Ca and 28% of Mg left on site. Keywords: biomass removal, nutrients, Scots pine, Norway spruce, allometry, whole-tree and stem-only harvesting Journal: Journal of Forest Science Pages: 461-470 Volume: 66 Issue: 11 Year: 2020 DOI: 10.17221/143/2020-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/143/2020-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202011-0003.txt Handle: RePEc:caa:jnljfs:v:66:y:2020:i:11:id:143-2020-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Jan Kikal Author-Name: Zdeněk Adamec Author-Workplace-Name: Department of Forest Management and Applied Geoinformatics, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic Title: Evaluation of silver birch diameter increment model based on data of the Czech National Forest Inventory Abstract: In the Czech Republic, the silver birch (Betula pendula Roth.) is considered as a pioneer and a soil preparing tree species. It occurs mainly on clearcutting areas after disturbances. The aim of this study was to fit breast height diameter increment model for birch with respect to tree age, share of birch trees and forest site type (ecological series - ES and forest vegetation zones - FVZ). We used data of both cycles of National Forest Inventory of the Czech Republic. We evaluated production potential of this species. We tested Korf and Michailoff increment models in variant of nonlinear least squares model (NLS) and nonlinear mixed effects model (NLME). Michailoff models performed better. We found seven statistically significant and practically applicable models. The greatest influence on increment of diameter at breast height have forest vegetation zone and ecological series whereas the influence of the share of birch in forest stand is smaller. The highest absolute values of diameter increment were on gleyed or enriched with water sites in the fourth forest vegetation zone. Keywords: growth conditions, Korf function, Michailoff function, share of birch trees, stand production Journal: Journal of Forest Science Pages: 471-481 Volume: 66 Issue: 11 Year: 2020 DOI: 10.17221/161/2020-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/161/2020-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202011-0004.txt Handle: RePEc:caa:jnljfs:v:66:y:2020:i:11:id:161-2020-JFS