scholarly journals Productivity and costs of two low-investment biomass harvesting systems applied in a situation of mixed forest of semi-natural regeneration

2018 ◽  
Vol 39 (3) ◽  
pp. 419-430
Author(s):  
Patricio Carey ◽  
Rodrigo Labbé ◽  
Guillermo Trincado ◽  
Oscar Thiers ◽  
Daniel Gárate
Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 763 ◽  
Author(s):  
Cho ◽  
Choi ◽  
Paik ◽  
Mun ◽  
Cha ◽  
...  

Interest in the production of renewable energy using forest biomass is increasing in South Korea, and improved knowledge on operations logistics to lower biomass harvesting costs is needed. This study aimed to build a low-cost forest-biomass harvesting system by analyzing the costs of two integrated (cut-to-length and whole-tree) harvesting systems for logs and logging residues. Two integrated harvesting systems were carried out in the clear-cut mixed forest on a steep slope. Compared to the cut-to-length system that separately extracts logs and logging residues in a forest, the cable whole-tree harvesting system can save $8.8/green weight ton (Gwt) because it requires no additional yarding operation cost of logging residues. Moreover, a breakeven analysis shows that the required machine utilization rates that favor whole-tree harvesting systems over cut-to-length harvesting were more than 70% for cable harvesting systems. The introduction of the whole-tree harvesting system is, therefore, required to produce forest biomass at a low cost. In the future, studies on forest-biomass processing and transportation systems will be needed to provide a biomass feedstock supply cost from stump to biomass power plant.


2012 ◽  
Vol 55 (5) ◽  
pp. 1651-1658 ◽  
Author(s):  
D. K. Brownell ◽  
J. Liu ◽  
J. W. Hilton ◽  
T. L. Richard ◽  
G. R. Cauffman ◽  
...  

2020 ◽  
Vol 66 (No. 12) ◽  
pp. 607-615
Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný

The study focused on the effects of gap size on natural regeneration of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies L.) and micro-environmental soil conditions in gaps of different sizes under temperate mixed forest in the Czech Republic. Six gaps comprising two for small (≥ 200 m<sup>2</sup>), medium (≥ 500 m<sup>2</sup>) and big (≥ 900 m<sup>2</sup>) each were selected. Ten circular 1 m<sup>2</sup> subsampling plots were established at 2 m intervals along individual North-South-East-West transects, including one at the gap centre. Regeneration was monitored in 2014 and repeatedly in 2019. Soil conditions were only measured in 2019. Gap size was found to be a significant parameter for European beech natural regeneration in 2014. Besides, the quick occupation of European beech in gaps at natural beech zone provoked its prolific regeneration compared to Norway spruce in 2014. However, in 2019 the recent threat of weather variabilities was responsible for the general abysmal growth performance of natural regeneration. Division of gap microsites into different within-gap positions based on prevailing light or shade conditions was helpful in assessing the significant variations of soil conditions within-gap positions and among gap sizes. Soil temperature and moisture significantly influenced the regeneration of European beech and Norway spruce, respectively.  


Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 735
Author(s):  
Xueying Huo ◽  
Dexiang Wang ◽  
Deye Bing ◽  
Yuanze Li ◽  
Haibin Kang ◽  
...  

Research Highlights: Natural regeneration is important in pine–oak mixed forests (Pinus armandii Franch., Pinus tabuliformis Carr., and Quercus aliena Bl. var. acuteserrata Maxim.ex Wenz.), but allelopathy as a limiting factor has not been studied. Our research provides insights into allelopathy in pine–oak mixed forest litter. Background and Objectives: Allelopathy among tree species occupying the same ecological niche in mixed forests may adversely affect regeneration. We studied allelopathy in pine and oak forest litter to determine the effect on regeneration, whether it is offset by adding activated carbon or plant ash, and what allelopathic substances are present. Materials and Methods: We used laboratory seed culture and field seeding to determine pine and oak litter regeneration effects on P. tabuliformis and P. armandii in the Qinling Mountains, China. In the laboratory, we irrigated seeds with three different litter concentrations. A fourth treatment incorporated activated carbon. The field study established small quadrats in mixed forest to study how removing or retaining litter and spreading plant ash affected sown seeds. High performance liquid chromatography–mass spectrometry was used to compare differences in chemical substances in extracts with and without activated carbon. Results: Litter extracts significantly affected germination rates in both species. Seedling morphological and physiological indexes showed that litter extracts negatively affected growth in both species, but activated carbon alleviated this inhibitory effect on P. armandii. Forest stand and litter did not affect P. armandii seed germination. Pinus tabuliformis germination rates were significantly higher in plots with removed litter than when litter was retained or plant ash spread, and lower in oak than pine forest. Allelopathic substances detected in pine forest were trioctyl trimellitate, amyloid β-Peptide 10–20, and triisobutyl phosphate, potentially affecting P. armandii seed germination and growth. Conclusions: Appropriate removal of litter in mixed forests can improve the natural regeneration ability of P. tabuliformis.


1996 ◽  
Vol 72 (5) ◽  
pp. 519-527 ◽  
Author(s):  
David Pothier

Between 1982 and 1984, 289 sample plots were established on cutovers distributed across the mixed and the boreal forest zones of Québec. Regeneration surveys before and after clearcutting were used to determine the proportion of regeneration destroyed by four different harvesting systems. Moreover, information on the evolution of the regeneration over the medium term was gathered from surveys realized five and ten years following logging. For all stands combined, harvesting resulted in a reduction of 25 to 40% of the stocking of the regeneration. The lowest decrease in stocking was produced by a feller-forwarder that was more efficient to protect regeneration shorter than 50 cm as compared to harvesting systems using cable skidders. Differences between harvesting systems were no longer apparent after the first five-year-period following logging because establishment of new seedlings was observed in most of the sampled cutovers. The ability of balsam fir to establish under a canopy generally caused an increase of its proportion in the new stands as compared to the original stands. The proportion of hardwood species also tended to increase in comparison to the original stand in such a way that some conifer stands would evolve toward mixed stands if no change in stand composition occurred after the first ten-year period following logging. Natural regeneration of jack pine stands after harvesting seems difficult to obtain since these stands have scarce advance regeneration that is partially destroyed during logging operations. Plantation, fill plantation or seeding could be applied in these stands but harvesting methods providing protection for regeneration should be used in the other stands in order to protect advance regeneration and particularly tall individuals. Key words: clearcutting, advance regeneration, harvesting system, cable skidders, feller-forwarder


2016 ◽  
Vol 06 (04) ◽  
pp. 281-294 ◽  
Author(s):  
Emma Holmström ◽  
Per Magnus Ekö ◽  
Karin Hjelm ◽  
Matts Karlsson ◽  
Urban Nilsson

2008 ◽  
Vol 54 (No. 3) ◽  
pp. 92-101 ◽  
Author(s):  
Š. Hofmeister ◽  
M. Svoboda ◽  
J. Souček ◽  
S. Vacek

Two permanent sample plots (both 0.25 ha) were established in a mixed forest in the Orlické hory Mts. Protected Landscape Area (northeastern Bohemia) to analyze the natural regeneration of Norway spruce (<I>Picea abies</I> [L.] Karst.) and silver fir (<I>Abies alba</I> Mill.). All the seedlings (height 0.1–0.5 m), saplings (height 0.5 m, <I>d</I><sub>1.3</sub> 3 cm) and trees (<I>d</I><sub>1.3</sub> > 3 cm) were localized and measured. The analysis of the spatial pattern and statistical evaluation were carried out by means of Ripley’s <I>K</I>-function. All the growth stages of the spruce and the fir showed an aggregated (clump) pattern, whereas the regeneration of fir was positively correlated with mature spruces and the regeneration of spruce was in a positive relation with mature firs. The results indicate that for germination and stable growth in the first stages of development, the fir can find more favourable conditions under the crowns of spruce trees and the spruce under mature firs.


2009 ◽  
Author(s):  
Douglas Kent Brownell ◽  
Jude Liu ◽  
James W Hilton ◽  
Tom L Richard ◽  
Glen R Cauffman ◽  
...  

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