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Coarse woody debris variability due to human accessibility to forest
Full text linkOriginally published in Forests (MDPI):
Behjou FK, Lo Monaco A*, Tavankar F, Venanzi R, Nikooy M, Picchio R (2018) Coarse woody debris variability as result of human accessibility to forest. Forests 9(9): article number 509 (open access)
Corresponding author: Angela Lo Monaco, [email protected]
DOI: 10.3390/f9090509
The article can be dowloaded at: https://www.mdpi.com/1999-4907/9/9/509
Abstract: Coarse woody debris (CWD) plays an important role in supporting biodiversity and
assisting ecological processes. Sometimes local people intervene modifying the expected distribution
of CWD components, harvested as fuel wood. The effect of the human accessibility (HA) on the
volume and characteristics of CWD (snag, downed log and stump) was investigated in the natural
uneven-age mixed hardwood stands of the Hyrcanian forests of Iran to quantify the impact on CWD.
The HA was classified into three classes (easy, medium and difficult) on the basis of slope class,
slope direction to the nearest road and road type. As expected, a negative relationship between
the degree of accessibility was found with respect to the main qualitative and quantitative indices
referring to CWD. The results showed that the volume of CWD decreased with an increase in
human accessibility class (HAC), thus the mean volume of CWD in the difficult, medium and easy
accessibility classes were 14.87 m3 ha1, 8.84 m3 ha1 and 4.03 m3 ha1, respectively. The decrease in
CWD volume was more associated with the decreasing volume of small diameter of low decayed
downed logs. The ratio of snag volume to standing volume, the ratio of downed log volume to the
volume of trees and the ratio of CWD volume to standing volume increased with a decrease in HAC,
while the ratio of downed log volume to snag volume decreased with a decrease in HAC. No selective
behaviour on the botanical species of CWD was recorded. For ecological forest management, the effect
of HAC on CWD should be considered. A constant supply of snags and downed logs must be
preserved to assure a high level of biodiversity. To balance social needs and biodiversity requirements,
an increased level of CWD retention might be needed in areas with easy accessibility. The obtained
results may be useful when ecological and socio-economical needs have to be taken into consideration
in future policy-making decisions.
Keywords: snag; downed log; stump; forest road; uneven-agemixed hardwood stands; Hyrcanian forest
Post-harvest evaluation of soil physical properties and natural regeneration growth in steep-slope terrains
Full text linkProtection of forest soils during harvesting operations is necessary to reduce damage and accelerate recovery time. The current study aims to evaluate soil physical properties, natural regeneration, and its recovery process in treatments including slope gradient, traffic intensity and skid trail after long periods of time, after ceasing the timber harvesting operations. The most recent skidding operations within each 5 years recovery period were studied for a chronosequence of 20 years. Soil samples were taken in abandoned skid trails and data were recorded on naturally regenerated species and density. The results revealed that most soil disturbances occurred on the slopes > 20%, as well as the highest levels of traffic intensity. Bulk density and penetration resistance were still higher than the control area, with a significant difference between them, while total porosity was partially recovered. Twenty years after the skidding operation, soil bulk density and penetration resistance were 13.2% and 23.7% higher than the control area, while total porosity was 9.78% lower the than value of the control area. Seedlings of 50-150 cm and > 150 cm in height on skid trails had significantly lower density than those in the control. The number of seedlings per m2 was less than the control area in all skid trails and for all height classes. The proportion of seedlings present in low traffic intensity was higher than in medium and high traffic intensities. The findings confirmed that full recovery rates are lengthy, and more time than 20 years is required to fully recover, especially with regards to penetration resistance
Short-term recovery of residual tree damage during successive thinning operations
Full text linkIn this study, damage to residual trees during thinning performed by motor-manual felling and whole tree skidding was studied in a loblolly pine (Pinus taeda L.) plantation. Forest intervention was carried out in 2016 and tree wounds were studied and examined over a period of three years. The results indicated that 8% of the residual trees suffered damage, of which 52% was caused by felling operations and 48% by extraction operations. Among the damaged trees, 13% had damage to the root system, 53% to the bole, and 34% to the crown area. The average wound size at the time of occurrence was 71.3 cm2. This was found to be reduced to 54.4 cm2 after a three year period. Wound intensity decreased with higher wound height and increased size. Three years after wound occurrence, only 6.6% were closed, 90.6% were still open, and 2.8% were decayed. The diameter growth in damaged trees was 1.7% lower than in undamaged trees (p > 0.05). Damage to the root system of residual trees reduced diameter growth by 3% (p < 0.05). Intensive wounds (damaged wood) caused a reduction of 22.7% in diameter growth (p < 0.01). In addition, the diameter growth in trees with decayed wounds was 27.4% lower than unwounded trees (p < 0.01). Pre-harvest planning, directional tree felling, marking of the extraction path before logging operations, employment of skilled logging workers, and post-harvest assessment of damaged residual trees are essential implementations in timber plantations
Ground-Based Extraction on Salvage Logging in Two High Forests: A Productivity and Cost Analysis
Full text linkSoil recovery assessment after timber harvesting based on the sustainable forest operation (SFO) perspective in iranian temperate forests
Full text linkMinimizing the impact of timber harvesting on forest stands and soils is one of the main goals of sustainable forest operation (SFO). Thus, it is necessary to make an accurate assessment of forest operations on soil that is based on the SFO perspective. The present study was conducted according to SFO principles to investigate the time required for the natural recovery of soil after disturbance by skidding operations in some Iranian forests. The physical, chemical, and biological properties of soil found in abandoned skid trails from different time periods were compared with undisturbed forest soils. The soil bulk density, the penetration resistance, and the microporosity of a 25-year-old skid trail were 8.4-27.4% and 50.4% greater, and the total porosity, macroporosity, and soil moisture were 1.9-17.1% and 4.6% lower than the undisturbed area. In a 25-year-old skid trail, the values of pH, Electrical conductivity (EC), C, N, available P, K, Ca, and Mg, earthworm density, and biomass were lower than in the undisturbed area, and the C/N ratio value was higher than in the undisturbed area. High traffic intensity and slope classes of 20-30% in a three-year-old skid trail had the greatest impact on soil properties. In order to have sustainable timber production, SFO should be developed and soil recovery time should be reduced through post-harvest management operation
Indices and indicators for sustainable managing and impact assessment inside italian and iranian beech forests
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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