Variation in survival and growth strategies for seedlings of broadleaved tree species in response to thinning of larch plantations: Implication for converting pure larch plantations into larch-broadleaved mixed forests

Production of raw wood material and its regulation has a great ecological and economic importance in every country. The aim of the paper is to analyze the prospective production of raw wood with respect to the expected basic tree species composition and assortment structure on an example of long-term development of selected indicators of forest condition in Slovakia. For this analysis we used data on the area, growing stock and planned decennial timber felling in the forests of Slovakia in 1980, 1996 and 2003. The production potential of forests was evaluated on the basis of the annual perspective allowable cut by 2020, from which the prospective production of assortments was derived using the models of assortment yield tables of tree species. The results show that in the forests of Slovakia there is an about half proportion of coniferous and half proportion of broadleaved tree species, very good structure of growing stock as well as its trend in the last years. Production of raw wood assortments for industrial processing for the years 2010–2020 is limited by the volume 6.3–6.4 mil. m<sup>3</sup>. About one half of this volume comes from coniferous and the other half from broadleaved tree species. For coniferous tree species the proportion of spruce and fir is 87% and for broadleaved tree species the proportion of beech and oak is 80%. For coniferous tree species sawmill assortments have a decisive, almost 70% proportion. Regarding broadleaved tree species, pulpwood assortments with 47% proportion prevail, although with 11% the highest quality assortments for the production of veneer from beech and oak are also significant.

Download Full-text

Harvester Productivity in Inclined Terrain with Extended Machine Operating Trail Intervals: A German Case Study Comparison of Standing and Bunched Trees

Sustainability ◽

10.3390/su12219168 ◽

2020 ◽

Vol 12 (21) ◽

pp. 9168

Author(s):

Ferréol Berendt ◽

Eduardo Tolosana ◽

Stephan Hoffmann ◽

Paula Alonso ◽

Janine Schweier

Keyword(s):

Tree Species ◽

Timber Harvesting ◽

Forest Stands ◽

Operational Conditions ◽

Thinning Operation ◽

Standing Trees ◽

Broadleaved Tree Species ◽

Broadleaved Tree ◽

Multiple Tree

The complexity of highly structured forests with multiple tree species, especially when coniferous and broadleaved tree species are mixed, as well as stands with extended machine operating trail spacing and inclined terrain, create challenging operational conditions for mechanized timber harvesting and extraction. Motor-manually felling trees within the midfield and bunching them at the machine operating trails, prior to the arrival of a harvester-forwarder system, is a complex operation. The aim of this study was to assess and compare tethered harvester productivities of a thinning operation, for felling and processing standing trees and for processing bunched trees, through a time study in forest stands with 40-m distances between machine operating trails. Total operational costs of the analyzed thinning operation were 69 €/m3o.b., including extraction using a multiple forwarder approach. Tree species, merchantable timber volume, and whether the trees were standing or presented as bunched logs all had a significant effect on the harvester time consumption. Moreover, harvester positioning time was significantly shorter when trees were already bunched at the machine operating trail. While the productivity of standing or bunched spruce trees did not differ significantly between the cases (approximately 18 m3o.b./productive machine hours excluding all delays (PMH0)), the productivity of standing broadleaved tree species (8.3 m3o.b./PMH0) was much lower than that of bunched trees (15.5 m3o.b./PMH0). Thus, the described timber harvesting and extraction system may be a valuable option for forest stands with high proportion of broadleaved trees.

Download Full-text