26 research outputs found
Survey of Directional Felling and Analysis of Effective Factors on Felling Error (Case Study; Iranian Caspian forests)
Economic and environmental logging is important for sustainable wood production in the Caspian
forests, north of Iran. Predetermination of the skid trail network and directional felling is a usual
recommended method to reduce logging impact. The aim of this study was evaluation of directional
felling and finding factors effective on felling error. Totally 135 trees were selected randomly for
directional felling in mountainous forest in Nav watershed in the Caspian forest. Felling error was
calculated for each observation in relation to lay deviation of ground slope, tree length, tree lean, the
extent of rot on stump, and tree volume using multiple regression models. Tree volume, interaction of tree
volume and terrain slope, and extent of rot in the stump were the most influencing factors on felling error.
Results suggest that felling workers should be enough trained for proper use of tools and equipments.
The most common tools and devices for manual felling are wedge and hydraulic jack which should be
provided in advance
Residual trees injury assessment after selective cutting in broadleaf forest in Shafaroud
In the Shafaroud forest, logging operation is generally performed by using selective cutting methods. Chainsaw and cable skidder are two main forest machines for harvesting of this forest. However, forest harvesting operations result in serious residual stand damage during felling, winching and skidding operations in this forest. Residual stand damage resulting from selective cutting was assessed on Avardim district in the Shafaroud forest in the north of Iran. Logging operation was performed by chainsaw and cable skidder. To gain benefit of directional felling, Landing and skid trail was planned prior to felling. Study area was cruised using 14 random sampling plots centered on transect lines uniformly distributed throughout the harvested area. Study results indicate majority of the injuries that occurred belong to the skidding and winching stage and the bole portion of tree (> 1m). Beech trees were injured more than trees of other species, and the mean area of injury was 290.3 cm2. Investigation on felling error showed that 40% of felled trees were at an angle of about 45-70 degrees with skidding direction, therefore felling crew could not lead the felled trees toward the skid trails. Increase felling error made the remaining trees more susceptible to injuries. This research indicated that preliminary planning of skid trail prior to felling is not a sufficient measure to minimize residual stand damage but proper training of crew is essential to insure a good performance of the operation. Felling crew should be not only trained and experienced workers but also aware of the value of residual crop trees, and the importance of minimizing stand damage if uneven-aged stand management practices are to be successful
Coarse woody debris variability due to human accessibility to forest
Originally 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
Long-term effects of single-tree selection cutting management on coarse woody debris in natural mixed beech stands in the Caspian forest (Iran)
Effect of logging wounds on diameter growth of beech (Fagus orientalis Lipsky) trees following selection cutting in Caspian forests of Iran
Background Logging damage to residual trees during selection cutting may lead to serious economic losses in terms of both timber quality and diameter growth reduction. In this study, we investigated the effect of logging operations on residual tree damage and the consequence of injuries on diameter growth in an uneven-aged mixed forest dominated by beech (Fagus orientalis Lipsky)
The Effect of Selection Cutting on Frequency and Characteristics of Thick Trees (Normal, Rotten, Dead Trees) in Asalem-Nav Forest
Rotten and dead trees are the main component of forest ecosystems and play an important role in maintaining forest biodiversity. In this research frequency and characteristics of large diameter trees (normal, rotten, and dead trees) with diameter at breast height greater than 60 cm were studied in two compartments (selective logged and protected) in Asalem-Nav forest. Random systematic sampling method with grid of 100 × 100 m and plot area of 0.2 ha was used for data collection. The results showed frequency and volume of large diameter trees of all three groups in the logged parcel were lower than protected parcel (P < 0.01). The height of rotten trees and dead trees in the protected compartment were greater than logged compartment (P < 0.01). Thick trees of all three groups in the protected compartment were compounded from more species than logged compartment as well. Cavities created by forest birds on the bole of rotten trees and dead trees have more frequency in the protected compartment than the logged compartment. This research indicated that protection of rotten trees, dead trees and remaining thicker trees from different species have special importance for protection of natural structure and biodiversity of forest stands
Healing rate of logging wounds on broadleaf trees in Hyrcanian forest with some technological implications
Morphology, growth and architecture response of beech (Fagus orientalis Lipsky) and maple tree (Acer velutinum Boiss.) seedlings to soil compaction stress caused by mechanized logging operations
The Caspian forests of Iran were monitored and evaluated for forest natural regeneration after logging activities for more than a decade. This large area has a substantial ecological, environmental and socio-economic importance. Ground based skidding is the most common logging method in these forests and soil compaction is the most critical consequence of this method. One of the current main topics and important emerging issue in forest research of the last decade are discussed in this study. Soil compaction has major influences on growth and/or mortality rates of forest seedlings. This study has lasted for over ten years so as to have a clear overview related to forest natural regeneration after logging activities. We monitored and evaluated physical soil properties (bulk density, penetration resistance and total porosity) and their effects on maple and beech seedlings on 10-year-old skid trails in the Iranian Caspian forests. Results obtained from evaluating the impact of skid trails within the aforementioned three soil physical parameters were significant; bulk density increased by 12.6% on log skidded routes (between two skidder tires on skid trail) and 36.1% on tire tracks, compared to non-skid trails (1.19 g/cm3), penetration resistance increased by 68% on log skidded routes and 220% on tire tracks, compared to non-skid trails (0.25 MPa), total porosity decreased by 12.8% on log skidded routes and 30.9% on tire tracks, compared to non-skid trails (54%). Among the morphological parameters, lateral root length (LRL) and root penetration depth (RPD) showed the highest decrease at soil compaction compared to the control (decrease in LRL: 60% in maple and 44% in beech; decrease in RPD: 56% in both maple and beech); the main response of growth parameters to soil compaction was found in roots (decrease in dry mass of 36% both in maple and beech); architectural parameters were also influenced by soil compaction, and the response of both seedling species was more evident in the ratio of main root to stem length (RRS) (reduction in RRS 42% in maple, 33% in beech); the ratio of RPD to main root length (RPL) also showed a great reduction (reduction in RPL 20% in maple 33% in beech). Physical soil properties, changes in other environmental properties of skid trails, created differences in beech and maple seedling growth between the skid trails and non-skid trails. This was closely related to the physiological characteristics of the two species studied. Beech seedlings reacted well to a moderate uncovering but they needed little disturbed soil, even if there was a very mixed bedding. Maple seedlings reacted better than beech seedlings to the uncovering and soil disturbance. The effects of the skid trail on morphology, growth and architecture of maple seedlings in the Hyrcanian beech forests showed that the maple, as a seedling, is a suitable species for maintaining the physical properties of skid trails after logging operations in the beech stands in the Caspian forests of Iran
Wound healing rate in oriental beech trees following logging damage
Beech is the most important commercial species in the Caspian forests of Iran. Selective cutting and harvesting methods may adversely impact the quality of the residual trees, as the injuries make the trees prone to future disease, insect infestations or timber defects. Although attempts to better understand how wounds affect the residual trees have been made in many different contexts, there are still few investigations on uneven-aged forests. In this study the key objectives were to determine and model the healing rate for different wound parameters (width, length, and area of wound); to analyse the relationship between wound healing rate (WHR), tree diameter growth and tree height growth; to analyse the WHR in relation to wound position on the stem; and to analyse the relationship between WHR, width and area of wound in DBH classes and social classes, with the aim of enabling the prognosis of logging wounds. Wounded beech trees were examined immediately after selective logging and after a 5-year period. The WHR was 31.2 ±7.7 cm2 year-1. The wound width healing rate (18.4 ±3.4 mm·year-1) was significantly higher than the wound length healing rate (4.5 ±1.6 mm·year-1). Only 12% of wounds were completely closed after a 5-year period, and 15 years are necessary for the complete closure of 80% of total wounds. The ratio of wound area to stem area at wound height (RWS) showed a more pronounced effect on diameter than on height. Regression analysis showed that WHR was correlated negatively with wound area and width and positively with tree diameter growth, but no significant relationship was found between height growth and WHR parameters. The WHR was significantly higher at an upper position than at a lower one, and statistical tests showed that the tree vertical layering classes had a significant effect on WHR. Finally, it was shown that WHRs in upper-storey trees are significantly higher than in the middle and lower storeys