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1.
Effects of boom-corridor thinning on harvester productivity and residual stand structure
Dan Bergström, Raul Fernandez-Lacruz, Teresa de la Fuente, Christian Höök, Nike Krajnc, Jukka Malinen, Yrjö Nuutinen, Matevž Triplat, Tomas Nordfjell, 2022, original scientific article

Abstract: Biomass derived from small-diameter, dense, thinning stands is largely underutilized within the European Union, mainly because of in-effective harvesting methods and cutting technology, leading to high supply costs. Therefore, the efficacy of boom-corridor thinning (BCT) and selective thinning (ST) on harvester felling and bunching productivity was compared for the first thinning of whole tree biomass in small-diameter, dense stands. BCT working method is when trees are cut with linear movements of the harvester’s boom reach, along narrow corridors, instead of cutting each tree selectively (ST). Trials were performed in six forest stands, one in Sweden, two in Finland, and three in Slovenia, using the same harvester and operator. A time-and-motion study was carried out in 64 pre-marked study units (32 replications per method), across a variety of stand conditions. The biomass removal for both treatments averaged 40.2 dry t ha -1 and BCT productivity averaged 5.4 dry t PMh -1. For BCT, harvester work time consumption (sec tree -1) and productivity (dry t PMh -1) were on average 27% lower and 16% higher, respectively, compared with ST. The effectiveness of the accumulating felling head technology used could potentially be increased by implementing a feed-roller system when handling excessive tree lengths. Developing dedicated harvesting technology for BCT could further boost productivity, facilitating cost-effective and sustainable utilization of low-value small-diameter tree biomass and replacing fossil resources.
Keywords: bioenergy, accumulating felling head, multi-tree handling, silviculture, bioeconomy, forestry
Published in DiRROS: 20.04.2022; Views: 526; Downloads: 367
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2.
Microsites influence the light response of young douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
Matjaž Čater, 2021, original scientific article

Abstract: Two comparable sites with uneven-aged mixed forest stands with more than 20% Douglas-fir in the growing stock at an altitude of 650 m a.s.l. were selected. The physiological response of young trees to different light intensities was measured during the main growing season in three consecutive years, and four different light categories, which were determined from hemispherical photographs. The four light intensity categories were defined according to Indirect Site Factor (ISF%): in the open (A-ISF > 35%), at the outer forest edge (B-25% < ISF < 35%), at the inner forest edge (C-15% < ISF < 25%), and under complete canopy under mature forest stand (D-ISF < 15%). Climate data were obtained from the Royal Netherlands Meteorological Institute %Climate Explorer% website. For the intensive micrometeorological observations, four monitoring sites were established along the elevation gradient at each site during summer and late fall to record relative humidity (RH%) and temperature (°C) with a 30 min recording interval sequence. Measured assimilation responses (A) and light use efficiency (%) at one site followed the expected pattern, while humidity combined with microsite conditions proved significant in explaining the specific response of young Douglas-fir to the different light intensity at the other site. For higher survival and optimal future development of Douglas-fir in the changing environment, microsites with higher capacity for storage moisture and favorable microclimate should generally be preferred to exposed and dry sites.
Keywords: Douglas-fir, light response, photosynthesis, light use efficiency, silviculture
Published in DiRROS: 28.05.2021; Views: 944; Downloads: 689
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3.
Harvesting intensity and tree species affect soil respiration in uneven-aged Dinaric forest stands
Matjaž Čater, Eva Dařenová, Primož Simončič, 2021, original scientific article

Abstract: Forest management, especially thinning and harvesting measures, has a significant impact on the forest carbon balance especially in the forests with long-term continuous cover history. We measured soil CO2 efflux (Rs) in three forest complexes of mixed, uneven-aged Dinaric forests with predominating silver fir (Abies alba Mill.), beech (Fagus sylvatica L.), and Norway spruce (Picea abies Karst.). Rs was measured after removal of mature forest stands with 50% and 100% intensity of living stock and compared with Rs on the control plots without any applied silvicultural measures. Rs was measured monthly in three consecutive 2012, 2013 and 2014 growing periods. Soil CO2 efflux increased after harvest of both intensities in all studied forest stands. The biggest increase was measured in beech stands and amounted up to 47 and 69% for 50% and 100% harvest intensities, respectively. The effect of harvest on Rs in spruce and fir stands was similar - up to 26% for 50% harvest intensity and 48% for 100% harvest intensity. Despite the biggest increase after harvest, Rs in beech stands returned the fastest to the level of the uncut forest and this levelling period (LP) took 14-17 months with a little delay of the stands with 100% harvest intensity. The LP for all fir stands, for spruce stands with 50% harvest intensity and for one spruce stand with 100% harvest intensity, was 26-29 months. At two spruce stands with 100% harvest intensity we did not record Rs levelling during our three-year study. This study involved forest stands of three predominating tree species growing under the same conditions, which allowed us to determine the species-specific sensitivity of soil CO2 efflux to the different harvesting intensities.
Keywords: harvesting intensity, soil CO2 efflux, silviculture, carbon release, silver fir forests, Beech forestrs, Norway spruce forests
Published in DiRROS: 08.10.2020; Views: 1285; Downloads: 543
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4.
The interplay between forest management practices, genetic monitoring, and other long-term monitoring systems
Darius Kavaliauskas, Barbara Fussi, Marjana Westergren, Filipos Aravanopoulos, Domen Finžgar, Roland Baier, Paraskevi Alizoti, Gregor Božič, Evangelia V. Avramidou, Monika Konnert, Hojka Kraigher, 2018, review article

Abstract: The conservation and sustainable use of forests and forest genetic resources (FGR) is a challenging task for scientists and foresters. Forest management practices can affect diversity on various levels: genetic, species, and ecosystem. Understanding past natural disturbance dynamics and their level of dependence on human disturbances and management practices is essential for the conservation and management of FGR, especially in the light of climate change. In this review, forest management practices and their impact on genetic composition are reviewed, synthesized, and interpreted in the light of existing national and international forest monitoring schemes and concepts from various European projects. There is a clear need and mandate for forest genetic monitoring (FGM), while the requirements thereof lack complementarity with existing forest monitoring. Due to certain obstacles (e.g., the lack of unified FGM implementation procedures across the countries, high implementation costs, large number of indicators and verifiers for FGM proposed in the past), merging FGM with existing forest monitoring is complicated. Nevertheless, FGM is of paramount importance for forestry and the natural environment in the future, regardless of the presence or existence of other monitoring systems, as it provides information no other monitoring system can yield. FGM can provide information related to adaptive and neutral genetic diversity changes over time, on a species and/or on a population basis and can serve as an early warning system for the detection of potentially harmful changes of forest adaptability. In addition, FGM offers knowledge on the adaptive potential of forests under the changing environment, which is important for the long-term conservation of FGR
Keywords: forest monitoring, forest genetic monitoring, forest genetic diversity, silviculture
Published in DiRROS: 20.02.2020; Views: 1994; Downloads: 1262
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5.
Beech and silver fir's response along the Balkan's latitudinal gradient
Matjaž Čater, Tom Levanič, 2019, original scientific article

Abstract: At the 1000km geographical distance in Dinaric montane forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.), the tree response from the north-western sites towards southern, warmer and dryer sites was performed during three consecutive growing seasons (2011, 2012 and 2013). On eleven permanent plots, positioned in uneven-aged beech and fir forests above 800m along the geographical gradient, the physiological and morphological response to light intensity were measured in predefined light categories based on the analysis of hemispherical photos. Radial growth was analysed on all plots and compared to precipitation, temperature and two drought indexes. Analysis showed a decrease in the cumulative precipitation and no change in temperature between plots. Beech was most efficient in the open area light conditions, while fir proved most efficient under shelter. Physiological response for beech increased towards SE and reached its maximal values in the middle of transect, while fir%s response decreased from the NW towards SE. Tendency to plagiotropic growth decreased from NW to SE in both species. Growth response to climatic parameters is weak, stronger in fir than in beech and decreasing towards SE.
Keywords: beech, uneven aged forests, silviculture, latitudinal gradient, response, silver fir
Published in DiRROS: 13.11.2019; Views: 2033; Downloads: 1351
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6.
Light response of Fagus sylvatica L. and Abies alba Mill. in different categories of forest edge - vertical abundance in two silvicultural systems
Matjaž Čater, Andrej Kobler, 2017, original scientific article

Abstract: In managed Dinaric montane fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) forests, the light response of young beech and fir in gap microsites was studied during three consecutive growing periods (2009, 2010, and 2011) under controlled environmental conditions in stands of single-tree and irregular shelterwood silvicultural system. According to maximal quantum yield, the different response between species in microsite light categories was evidenced for silver fir on microsites with predominating diffuse light and for beech on microsites with predominating direct light, respectively. Abundance and change of share in microsite light categories was compared over different elevation belts on comparable sites between two silvicultural systems. The share of forest edge area was bigger in the irregular shelterwood system. Change in width of forest edge (20, 30 and 40 m) did not affect the proportion and share of the microsite in both regions of different silvicultural system. Separation of microsite areas between both silvicultural systems, evident in lower elevation belts was not evident in the most conflict and highest elevation zone, while the absolute values of all categories above 700 m in both systems were almost identical, indicating the same, small-scale irregular shelterwood system, known also as the freestyle silvicultural approach.
Keywords: Fagus sylvatica, Abies alba, Dinaric silver fir and beech forests, Dinaric forests, forest edge, silviculture, selective system, irregular shelterwood system
Published in DiRROS: 12.07.2017; Views: 2922; Downloads: 1192
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