Modelling and sustainable management

Comparison of Sampling Methods Used to Evaluate Forest Soil Bulk Density

volume: 39, issue: 2

The objective of this study was to compare forest soil bulk density values obtained through
conventional sampling methods such as the volumetric ring (VR: diameter 5 cm, length 10 cm)
and paraffin sealed clod (PSC), with a variation of the VR, where rectangular boxes (RB) of
four different dimensions were used. Sampling transects were established on a machine operating
trail located in a beech (Fagus orientalis Lipsky) stand in Northern Iran. At each
transect, three soil samples were collected at three different locations. Samples from different
methods were spaced by a 50 cm distance to avoid direct interactions. The soil class of our
study area was Combisols according to the WRB classification with a clay texture. Soil bulk
density differed significantly between the three sampling methods. The lowest values were
obtained with the RB (average 1.25 g cm-3), followed by the VR (average 1.40 g cm-3), and
lastly the PSC (average 1.52 g cm-3). The values obtained with four variations of the RB
method ranged from 1.22 to 1.28 g cm-3 and were not found significantly different. When soil
bulk density was calculated after the removal of the weight and volume of roots included in
the samples, the values were determined to be higher than before but with the same range of
magnitude. The lowest coefficient of variation was found for RB4 (CV=2.3%), while the highest
values were observed for VR and RB1 (CV=5.7%).

Root Tensile Force and Resistance of Several Tree and Shrub Species of Hyrcanian Forest, Iran

volume: 39, issue: 2

Shallow landslides are a frequently recurring problem in some parts of Iran, including the
Hyrcanian forest. In addition to traditional civil engineering measures, a potential solution
for this problem is the application of soil bioengineering techniques. The mechanical reinforcement
effect of plant roots is one of the major contributions of vegetation to the mitigation of
shallow landslides. Given the lack of information on the mechanical properties of common
Hyrcanian forest species, the present study assessed the root strength of 10 common species
of this forest. Eight tree species occurring in natural regeneration sites (Carpinus betulus,
Fagus orientalis, Parrotia persica and Quercus castaneifolia) and plantations (Acer velutinum,
Alnus glutinosa, Fraxinus excelsior and Picea abies) and two shrub species
(Crataegus microphylla and Mespilus germanica) were selected. Fresh roots were collected
and mechanical tests were carried out on 487 root samples. The ranges of root diameter,
tensile force, and root resistance were 0.29–5.90 mm, 3.80–487.20 N, and 2.41–224.35 MPa,
respectively. Two different algorithms, including the nonlinear least square method and logtransformation,
were used to obtain power regressions for diameter-force and diameter-resistance
relationships. The results of the two algorithms were compared statistically to choose
the optimal approach for soil bioengineering applications. The nonlinear least square method
resulted in lower Akaike information criteria and higher adjusted R2 values for all species,
which means that this model can more efficiently predict tensile force and resistance based on
root diameter. Log-transformation regressions generally underestimate tensile force and resistance.
Significant differences were found among mean root tensile force (ANCOVA;
F=37.36, p<0.001) and resistance (ANCOVA; F=34.87, p<0.001) of different species. Also,
root diameter was significant as a covariate factor in tensile force (F=1453.77, p<0. 001) and
resistance (F=274.26, p<0.001). Shrub species and trees in natural regeneration sites had
higher tensile force and resistance values, while trees from plantation stands had lower values.
The results of this study contribute to the knowledge on the root force and resistance characteristics
of several shrub and tree species of the Hyrcanian forest and can be used in evaluating
the efficiency of different species for bioengineering purposes.

Impacts of a High-Capacity Truck Transportation System on the Economy and Traffic Intensity of Pulpwood Supply in Southeast Finland

volume: 40, issue: 1

High-capacity transportation (HCT) of roundwood is a road transport concept that is currently
being demonstrated in Finland and Sweden. In Finland, HCT trucks are in most cases
unable to access roadside storages, but they are expected to bring cost savings in highway
transportation between transshipment terminals and mill yards. Evaluating the optimal solutions
is challenging due to the complexity of the transportation systems. This paper presents a
dynamic simulation model, SimPulp, which was developed to generate information about the
impacts of substituting HCT for a part of the present pulpwood transportation system. A case
study in the area of the most intensive pulpwood use in Finland was conducted. The results
indicate that HCT has potential for reducing transport costs and especially the traffic intensity
of roundwood procurement in the studied area. The economic advantages of pulpwood HCT
could be more significant in a larger area or in the use of inter-terminal backhauling.

Multi-Criteria Decision Analysis (MCDA) in Forest Operations – an Introductional Review

volume: 40, issue: 1

Decision making in forestry is very complex and requires consideration of trade-offs among
economic, environmental, and social criteria. Different multi-criteria decision analysis
(MCDA) methods have been developed for structuring and exploring the decision-making
process of such problems. Although MCDA methods are often used for forest management
problems, they are rarely used for forest operation problems. This indicates that scholars and
practitioners working with forest operations are either unaware of MCDA methods, or see no
benefit in using these methods. Therefore, the prime objective of this review was to make
MCDA methods more intelligible (compared with current level of understanding) to novice
users within the field of forest operations. For that purpose, basic ideas as well as the strengths
and limitations of selected MCDA methods are presented. The second objective was to review
applications of MCDA methods in forest operations. The review showed that MCDA applications
are suitable for forest operation problems on all three planning levels – strategic, tactical,
and operational – but with least use on the operational level. This is attributed to: 1) limited
availability of temporally relevant and correct data, 2) lack of time (execution of MCDA
methods is time consuming), and 3) many operational planning problems are solved with
regards to an economic criterion, with other criteria serving more as frames. However, with
increased importance of environmental and social aspects, incorporating MCDA methods into
the decision-making process on the operational planning horizon (e.g., by developing MCDAbased
guidelines for forestry work) is essential.

Assessment of Broad-Leaved Forest Stand Management: Stock Densities, Thinning Costs and Profits over a 60-Year Rotation Period

volume: 40, issue:

There are many broad-leaved forests in Japan that were formerly managed for charcoal production, which have been abandoned for decades. Appropriate thinning can revitalize these forests if the cost balance of the management is positive. Two critical elements are the construction of spur roads to facilitate mechanized harvesting operations and management planning that considers stand properties such as the growing stock, species, and tree size distribution. We surveyed three abandoned former broad-leaved coppice stands; one coastal, one cool temperate and one warm temperate. The stock in all three stands exceeded 300 m3 ha-1, two- to three-fold the official forest registry data estimates. The dominant species in terms of tree numbers are Castanopsis sieboldii, Pieris japonica, and Quercus glauca. Medium-sized trees involve those well suited for firewood, i.e., Quercus acuta, Quercus glauca, Quercus serrata, etc. Each plot contained a few large trees that potentially have a high market value, e.g., Cinnamomum camphora, Zelkova serrata, Abies firma, etc. The average income from harvested trees was estimated to be 10200 JPY (Japanese Yen) m-3, whereas the thinning costs would be 3200 to 5400 JPY m-3, with the additional spur road construction costs. The management cost balance of a broad-leaved stand in a 60 year rotation was evaluated with both Net Present Value (NPV) (for interest rates of 1, 2, 3, and 4%) and Internal Rate of Return (IRR). This balance was compared with that of a typical plantation stand of Japanese cedar (Cryptomeria japonica) and of a fast-growing plantation stand of Chinese fir (Cunninghamia lanceolata). The estimated NPVs were largest for the fast-growing plantation stand, second largest for the typical plantation stand, and lowest for the broad-leaved stand with a NPV interest rate of 1 + %. However, the IRR of the broad-leaved stand was the highest, followed by that of the fast-growing plantation stand, while the IRR of the typical plantation stand was the lowest. This order was the same for NPVs assuming higher interest rates.

1 JPY=0.0086 € on April 29, 2019.

Reengineering the Romanian Timber Supply Chain from a Process Management Perspective

volume: 41, issue: 1

Implementation of process management in the forest supply chains has a great potential for organizational and managerial improvement, at least by resource saving. Nevertheless, techniques of process management have been scarcely used to improve the forest supply chains in many parts of the world. In this study, for both Romanian state and private forests, the processes of the timber supply chain – from the harvest site to the forest-based industry plant – are mapped and analyzed. The main objectives of this work were to identify process optimization potentials and to redesign processes in order to improve the performance of the Romanian timber supply chain. Results show that particularly inter-organizational processes offer great saving potentials, mainly due to the existing multi-level hierarchy and multi-level control obligations. Therefore, introducing a web-based platform to enhance a collaborative workflow can considerably decrease the time needed for providing harvest sites or logs to customers via auctions. Further process optimization can be reached by the empowerment of lower level hierarchies facilitating the reduction of hierarchy levels of involved state organizations

Assessment of Costs in Harvesting Systems Using WoodChainManager Web-based Tool

volume: 41, issue: 1

The rationalization of working procedures during difficult market conditions is gaining increasing importance. For rational production, it is necessary to always be aware of what and how much to invest in the business process to obtain the desired products or services without economic loss. This article presents a tool for the assessment of costs in forest wood supply chains. WoodChainManager is a Web-based tool composed of three user modules intended for the assessment of material costs of individual machines or the total costs of all selected machines in a forest harvesting system. Users can test the impact of individual technologies on the total material costs of the harvesting system and thus optimize operation processes. The basic tool for describing harvesting systems is the matrix, which visualizes cutting and hauling from the standing tree in the stand to the forest products at the end user. The tool has built-in algorithms that prevent the selection of an illogical harvesting system. The selected method for calculating costs for individual machines is simple, but still reflects the state of the actually incurred costs. WoodChainManager offers cost calculations for a wide range of technologies, machines and appurtenant attachments. The authors of this paper wish to increase awareness and understanding of cost calculations and to offer the possibility to directly compare different harvesting systems

Improving Economic Management Decisions in Forestry with the SorSim Assortment Model

volume: 41, issue: 1

The sustainable supply of timber is one of the most important forest ecosystem services and a decisive factor determining the long-term profitability of forest enterprises. If timber production is to be economically viable, there must always be a way to analyse forest stands and trees felled for exploitation with regard to the wood assortments they contain. Only then can the expected timber yields, achieved by various silvicultural strategies or actions and different sorting options, be quantified with sufficient accuracy. The SorSim assortment simulator was developed for forest practitioners and forest scientists in Switzerland to realistically simulate the sorting of individual trees and entire forest stands based on defined specifications. SorSim has a simple user interface and comes in a number of different language versions (G, E, F). The software is implemented in Java, making it platform-independent. It can be downloaded for free at ( This article provides an overview of how the simulator works and demonstrates its potential applications based on a practical and a scientific example. A particular practical advantage is that the composition of the assortments of the planned harvests can be estimated according to quantity and value. When used in strategic planning and especially in research, SorSim provides a basis for analysing either long-term developments in yields from forest stands or silvicultural treatment methods. Based on an even-aged and a selection forest stand, the scientific example shows how strongly the assessment of the advantageousness of two different silvicultural strategies depends on the time when the calculation was made (using historical and current assortment revenues and timber harvesting costs). In particular, the combination of SorSim with timber harvest productivity models enables differentiated forest economic insights. Various approaches for value-based optimisation in the sorting of individual trees and for the optimal allocation of harvesting activities to defined customer demands are currently being examined as further SorSim developments.

Temporal Patterns of Vehicle Collisions with Roe Deer and Wild Boar in the Dinaric Area

volume: 41, issue:

The purpose of this study was to determine the frequency of wildlife-vehicle collisions (WVC) based on the animal species, and to deepen the knowledge of temporal patterns of vehicle collisions with roe deer and wild boar. The study analyses the data from police reports on vehicle collisions with animals on state roads, by date and time, section of road, and animal species over a 5-year period (2012–2016). These data were analysed to determine the temporal dynamics of vehicle collisions with roe deer and wild boar by month, time of day, and moon phase. On the state roads in the Dinaric area, roe deer are most commonly involved in vehicle collisions (70.1% of all collisions), followed by wild boar (11.0%). Other large species involved in collisions were fallow deer (4.8%), brown bear (1.8%), red deer (0.9%), grey wolf (0.7%), and European mouflon (0.5%), respectively. Most collisions with roe deer occurred in the period April–August, with reduced frequency during autumn and winter. For wild boar, there was no association between month and frequency of collisions. At the annual level, collisions with roe deer were significantly higher during night (37%) and twilight (41%) than during the day (22%). For wild boar, most collisions occurred during twilight (26%) and night (72%), although the difference between these two periods was not statistically significant. For roe deer, collisions had no association with lunar phase, though wild boar collisions during twilight (dawn or dusk) were more common during twilight periods on days with less moonlight. Since vehicle collisions with wildlife showed certain temporal patterns, these should be taken into consideration in developing statistical models of spatial WVC patterns, and also in planning strategies and countermeasures to mitigate WVC issues.

Round Wood Waste and Losses – Is Rationalisation in Scaling Possible?

volume: 41, issue:

The term »loss« should be distinguished from the term »waste« commonly used by forestry practitioners to indicate the difference between gross volume (planned production based on official tariffs) and net volume (produced timber volume) of trees. Volume loss in round wood refers to the difference between the actual volume of round wood and the volume determined based on the prescribed method of measurement and calculation. As a result of prescribed scaling methods and calculations, volume losses appear due to 1) used volume equations, 2) prescribed method of measurement (i.e. measurements of length and mid-length diameter) and 3) deduction of double bark thickness. In Croatia, round wood is cross-cut and transported with bark, while logs are measured and sold without bark. In this way, the bark is an unnecessary ballast in production, but has many possible applications such as energy source, in the production of wooden boards in construction, in nurseries and horticulture, etc. The research was conducted on 225 butt-logs of sessile oak (Quercus petraea (Matt.) Liebl.) ranging in diameter classes from 27.5 cm to 67.5 cm from even-aged forests in the central part of Croatia. Deduction of double bark thickness caused a higher average loss in the volume when using Huber’s equation at 14% and when using Riecke-Newton’s equation at 13.5%. In both volume estimation methods, the loss due to double bark thickness was slightly reduced exponentially as the diameter of but-logs increased. The determined dependence of the bark thickness on diameter of butt-logs over bark indicates the need for correction of the bark deduction tables that are in operational use in Croatian forestry and are provided by trading practices, and since they are not the result of scientific research, they lead to unfair payment between sellers and buyers of round wood. Comparison analysis of the simulation of butt-logs indicated that the introduction of Riecke-Newton’s equation for estimating the volume of commercially important assortments in Croatian forestry is justified. The use of Riecke-Newton’s equation in these terms leads on average to a 6.6% higher volume of butt-logs than the use of Huber’s equation for estimating the volume of assortments.

Logging Mats and Logging Residue as Ground Protection during Forwarder Traffic along Till Hillslopes

volume: 42, issue:

Forest soils in Northern Europe are generally trafficked by forest machinery on several occasions during a forest rotation. This may create ruts (wheel tracks), which could increase sediment transport to nearby surface water, reduce recreational value, and affect tree growth. It is therefore important to reduce soil disturbance during off-road forest transportation. In this study, rut depth was measured following forwarder traffic on study plots located along four harvested till hillslopes in Northern Sweden with drier soil conditions uphill and wet conditions downhill. The treatments included driving 1) using no ground protection, 2) on logging residue (on average, 38–50 kg m–2) and 3) on logging mats measuring 5×1×0.2 m. The hillslopes contain areas with a high content of boulders, stones, and gravel as well as areas with a significant content of silt. Six passes with a laden forwarder with four bogie tracks were performed. On the plots with ground protection, the application of logging residue and the application and removal of logging mats necessitated additional passes. Rut depth was measured using two methods: 1) as the difference in elevation between the interpolated original soil surface and the surface of the rut using GNSS positioning (Global Navigation Satellite Systems), and 2) manually with a folding rule from an aluminium profile, placed across the rut, to the bottom of the rut. The two methods generally gave similar results. Driving without ground protection in the upper part of the hillslopes generated ruts with depths <0.2 m. Here, the rut depth was probably modified by the high content of boulders and stones in the upper soil and drier soil conditions. In the lower part of the hillslopes, the mean rut depth ranged from 0.21 to 0.34 m. With a few exceptions, driving on logging residue or logging mats prevented exposure of mineral soil along the entire hillslope. Soil disturbance can thus be reduced by acknowledging the onsite variability in ground conditions and considering the need for ground protection when planning forest operations.

Forest Fire Risk Zone Mapping of Eravikulam National Park in India: A Comparison Between Frequency Ratio and Analytic Hierarchy Process Methods

volume: 43, issue:

Forest fire is one of the most common natural hazards occurring in the Western Ghats region of Kerala and is one of the reasons for forest degradation. This natural disaster causes considerable damage to the biodiversity of this region during the dry fire season. The area selected for the present study, Eravikulam National Park, which is predominantly of grassland vegetation, is also prone to forest fires. This study aims to delineate the forest fire risk zones in Eravikulam National Park using remote sensing (RS) data and geographic information system (GIS) techniques. In the present study, methods such as Analytic Hierarchy Process (AHP) and Frequency Ratio (FR) were used to derive the weights, and the results were compared. We have used seven factors, i.e. land cover types, normalized difference vegetation index, normalized difference water index, slope angle, slope aspect, distance from the settlement, and distance from the road to prepare the fire risk zone map. The area of the prepared risk zone maps is divided into three zones, namely low, moderate, and high. From the study, it was found that the fire occurring in this area is due to natural as well as anthropogenic factors. The prepared forest fire risk zone maps are validated using the fire incidence data for the period from January 2003 to June 2019 collected from the records of the Forest Survey of India. The investigation revealed that 72% and 24% of the fire incidences occurred in the high risk zone of the maps prepared using the AHP and FR methods, respectively, which ascertained the superiority of the AHP method over the FR method for forest fire risk zone mapping. The receiver operating characteristic (ROC) curve analysis gives an area under the ROC curve (AUC) value of 0.767 and 0.567 for the AHP and FR methods, respectively. The risk zone maps will be useful for staff of the forest department, planners, and officials of the disaster management department to take effective preventive and mitigation measures.

Introducing a New Approach in Stand Tending Planning and Thinning Block Designation by Using Mixed Integer Goal Programming

volume: 43, issue:

Long-term management plans have been developed for nearly all of the forests in Turkey. These plans are applied at a sub-district management unit level and may contain guidance for both intermediate yield and final yield harvests. To implement an intermediate yield plan, which involves the scheduling of forest thinnings (stand tending), consideration in Turkey is given to the advantages of working in the same terrain and the same general area each year. Therefore, compartments are often clumped together to create thinning blocks, taking into consideration the thinning priority of the stands, road conditions, site index, age, and proximity of the compartments. Further, when preparing annual budgets and planning to meet the market’s needs, forest enterprises require an even flow of intermediate wood volume each year. In this paper, we introduce a new approach in stand tending planning designed to schedule an equal amount of intermediate wood volume each year and to create thinning blocks by minimizing the distance to pre-defined ramps (landings). We developed both linear and nonlinear goal programming models to minimize both the deviations from a harvest volume (annual intermediate yield allowable cut) target and the deviations from a target value determined for the distances (total and average) of the centroid of each compartment to the hypothetical forest ramps. By using the extended version of Lingo 16, we solved the problem with different weights for the deviations in volume and distance that ranged from 0.0 to 1.0, in 10% intervals, which created 11 scenarios. We carefully analyzed the results of each scenario by taking into consideration the wood volume and distance of compartments to the ramps. The best scenario using the linear model produced a deviation in volume scheduled for the entire decade of 6 m3, while the deviation in total distance between harvest areas and ramps was 59.7 km. Scenario 5, with weights of 0.6 for volume and 0.4 for distance, produced these results, where compartments were closest to one another. The best scenario using the nonlinear model also produced a deviation in volume of 0 m3 and the total average deviation in distance between harvest areas and ramps was 8.7 km. Scenario 3, with weights of 0.8 for volume and 0.2 for distance, produced these results. The approach and models described through this study may be appropriate for further integration into forest management planning processes developed for the planning of Mediterranean forests.

Effectiveness of Water Diversion Structure to Mitigate Runoff, Sediment Yield, Nitrate and Phosphate Concentrations in Skid Trail of Mountainous Forest Ecosystem

volume: 43, issue:

It is well-known that soil and water conservation actions (e.g., installing water diversion structures) are necessary to restore skid trails after logging operations. However, there are some points that have yet to be determined concerning the efficacy of rehabilitation on sediment yield and nutrient export to the aquatic environment. The objectives of this study were to determine the optimal distance among the water diversion structures (WDSs) to suppress runoff, sediment yield, and measure nitrogen and phosphorus concentrations on the skid trails of a mountainous ecosystem. The study was conducted on a total of 18 bounded runoff plots, each with a width of 4 m and a length of 120 m, divided into six treatment compartments done in triplicate. Beech logs were placed at a distance of 5, 10, 20, 30, and 40 meters. An untreated area (U) was set up during the recording period from 18 September 2015 to 17 September 2016. In all the WDS treatments and untreated trails (U), the observed peaks of runoff, sediment yield, as well as nitrate and phosphate concentrations was found to be significantly correlated with the amount of rainfall events. Results show that there was a decrease in surface runoff and runoff coefficient, sediment yield, and nitrate and phosphate concentrations by installing of WDS at different distances. The runoff and runoff coefficients (2.67 mm and 0.101, respectively) were at the lowest level in the WDS20 (WDS at a distance of 20 m). The sediment yield was significantly higher on the U, 13.52 g m-2 followed by WDS40, whereas the lowest values were detected at the WDS10. Significantly higher values of nitrate were found in the U (3.63 mg l-1), while the lowest amounts of nitrate were determined at WDS5 followed by the WDS20 treatment. The highest values of phosphate were found on the U treatment (0.278 mg l-1) followed by the WDS40 treatment, whereas the lowest phosphate values were measured in the WDS20 treated area. Therefore, it can be deduced that the recommended water diversion structure should be placed at a distance of 20 m to mitigate runoff, sediment yield, nitrate and phosphate exports on the skid trails.

Growth and Development Dynamics of Young Holm Oak (Quercus Ilex L.) Stands after Shelterwood Cutting in Open Forest Road Conditions

volume: 43, issue:

The Mediterranean forest region has been exposed to anthropogenic impacts for centuries, and the constant biotic and abiotic factors, together with increasing climate change, have hindered the proper management of forest ecosystems. This study presents the results of multiyear, systematic, specific and practical monitoring of the conversion of holm oak coppices using the principles of the shelterwood system. It also presents the growth and development dynamics of the stand on a permanent experimental plot from 1997 to 2017. The research was performed in the Eumediterranean vegetation zone of coniferous forest (Forest Management, Buzet branch, Pula Forestry Office, Magran Cuf management unit, compartment 83a). The plot has all the properties of a holm oak and manna ash forests (Orno-Quercetum ilicis H-ić/1956/1958). The basic elements of stand structure were monitored: diameter at breast height (DBH), tree height, horizontal crown projection, crown ground shading (light) and the appearance and abundance of all woody vegetation, with special emphasis on the growth and development of young generations of holm oak from seed. The paper also describes the threats limiting growth, development and survival of holm oak from seed (strong shooting tendencies of coppiced holm oak and bay laurel trees, excessive presence of shrubs). Forest management requires effective, timely and repeated tending to thin stands (already under the canopy), while also protecting young trees from wild game. The statistical method of interpolation determined the trends of stand development; trend equation with coefficient of determination (R2) is very high. This indicates the growth and development of the stand in the direction of renewal of holm oak stands. Shelterwood cutting, with regular and timely tending of young generations of trees through a seven-year regeneration period, resulted in a high quality young high forest of holm oak, the first of its kind in the broader Mediterranean area. The indigenous stands of holm oak, as the fundamental climatogenic coniferous species of the Mediterranean species, have multiple roles such as protection from erosion, resilience to biotic and abiotic factors and forest fires, tourism and landscape functions, and other general forest functions, and therefore deserve intensive and ongoing research. Holm oak stands also play a part in conserving genetic and biological diversity, the potential and persistence of forest ecosystems, improving stand structure, stability and resilience of forest ecosystems to climate change, and in the long-term increase the commercial value of forest stands in the Croatian Mediterranean.

Double Bark Thickness Estimation Models of Common European Broadleaved Species for Harvester Timber Volume Estimation in Czechia

volume: 44, issue:

The share of the annual volume of harvester-produced timber in Czech forest bioeconomy has increased in the last decades. To estimate under-bark timber volume, harvester systems allow choosing between two different bark deduction models – diameter band (DBM) and linear model. However, linear models were not calibrated for the conditions of Czech forestry. Therefore, the objective of this research was to develop, for local conditions in Czechia, linear functions for estimating the double bark thickness of two groups of broadleaved species (beech and oak) and to test their viability based on real harvest data. To create the linear functions, official Czech cubing tables were used. Data from real harvests were gathered from fifteen harvesters. A sample containing 4995 logs belonging to the beech group was analyzed using descriptive statistics and the Paired Wilcoxon tests. The mean double bark thickness for beech group was 15.1 mm (polynomial and linear model). For oak group, it was 15.48 mm (polynomial) or 15.49 mm (linear). The results of real harvests for beech group revealed that the mean double bark thickness estimated by the polynomial function was 7.08 mm. The linear function estimates were closer to the value estimated by the polynomial (6.84 mm) than DBM estimates (6.68 mm). Therefore, we can state that the newly developed linear models can be used in fully mechanized harvesting instead of manual bark deduction methods in Czechia.

Forest Residue Management Impact on Rodent (Rodentia: Murinae, Arvicolinae) Damage in Pedunculate Oak (Quercus robur L.) Forests in Croatia

volume: 44, issue:

Small rodents (Rodentia, subfam. Murinae: real mice, Arvicoline voles) greatly affect natural regeneration, stability and dynamics of forest communities worldwide. Every 3–4 years rodent damage in Croatian state forests is the most severe in forest regeneration stands, especially in pedunculate oak (Quercus robur L.) and narrow-leaved ash (Fraxinus angustifolia Vahl.) forests, where rodents can seriously impede natural regeneration by damaging seeds, stems and roots of saplings. These negative interactions are an even bigger challenge nowdays as pedunculate oak and narrow-leaved ash have become more vunerable in the last decades and are known as the most sensitive species of lowland forests in Croatia due to microclimatic and macroclimatic changes and the unfavourable interaction of a whole series of anthropogenic, abiotic and biotic factors. In the last 40 years, in Croatian state forests, rodent management consisted of monitoring and mainly rodenticide use. Trying to implement IPM (Integrated Pest Management) postulates into practice over the years, different prevention methods against small rodents were tested, but not many came to use. The aim of this research was to look into different logging residue management approaches and their effect on the rodent damage in two pedunculate oak forest regeneration stands in central Posavina in Croatia. Rodent damage on stem and root of tree saplings was recorded by visual inspection on three plots (5x5 m) with scattered logging residue, and one plot (5x5 m) with no residue at one micro-depression site (95 m a.s.l.), and on one micro-elevation (99 m a.s.l.) site. Plots with scattered logging residue represented a type of forest residue management in which logging debris (branches) is cut to smaller lengths and distributed evenly at the forest regeneration stand. Plot with no logging debris represented a residue management method in which wood mass is completely removed from the regeneration stand after felling. We counted, determined and inspected tree saplings found at chosen plots for rodent damage (on stem and roots) and also determined the average weight and moisture content of logging residue (branches around 5–7 cm in diameter) found at the site. In spring 2017, 3380 tree saplings (2978; 81% pedunculate oak, 7; 0.2% narrow-leaved ash and 395; 11.7% other deciduous species) were inspected for rodent damage. At micro-depression site, on a plot with no logging residue, only 13.4% of the saplings were damaged, while the average share of damaged saplings on three plots with scattered residue was more than six times higher; 87.8%. The average mass of the logging residue weighed at site with scattered residue was 10.14 kg kg/m2 and moisture content was 19.2%. At micro-elevation site, 25.4% of the saplings were damaged on a plot with no logging residue, while the average share of damaged saplings on three plots with scattered residue was two times higher; 51.4%. The average mass of the logging residue weighed at SRP 1–3 was 5.1 kg/m2. We also determined moderately strong positive correlation (R=0.69133) between the mass of logging residue and rodent damage and strong negative correlation (R=–0.89598) between wood moisture content of the logging residue and rodent damage. In years ahead, with unpredictable climate effects and potentially very variable small rodent dynamics, removing the logging residue after the felling could represent a residue management that contributes to a more effective and ecologically based rodent management. It could also become a usable preventive method within IPM and help prevent sever rodent damage, even during the outbreaks in pedunculate oak regeneration stands.

Growth and Timber Quality of European Larch Planted in Areas Reclaimed After Coal Mining in Central Poland

volume: 44, issue:

Understanding the impact of reclamation measures on the quality of timber produced in post-mining areas is crucial for the proper establishment of future forest cultures on such sites. We studied European larch trees (Larix decidua Mill.) grown since 1981 on the external dump of a brown coal mine in Bełchatów (Central Poland). In particular, the effects of stand admixture and the intensity of mineral fertilization, applied in the initial phase of tree growth, on the increments and quality of larch wood were evaluated. Total tree height and stem diameter of 4-meter sections were measured. Qualitative timber classification took into account the share of wood defects, which excluded the timber from a higher quality-dimensional class. Larch trees grown in a monoculture had a better quality of wood compared to larch grown mixed with other species. Fertilization, applied in the initial afforestation period, had only a limited effect on the growth of larch trees. Curvature and knots determined timber quality most significantly. While knots had a decisive importance in larch growing in the monoculture stands, curvature determined wood quality in the admixed larch stands.

Relationship Between Some Structural Elements of Macedonian Pine (Pinus peuce Gris.) in Different Elevations in National Park Pelister in North Macedonia

volume: 44, issue:

The influence of elevation on the forest development and also on more structural elements is evident. The aim of this paper is to research the impact of elevation on the relationship between diameter at breast height (DBH), tree height (H), crown length (L) and stem volume (V). In the area of the Pelister National Park in North Macedonia, 22 experimental plots (EPs) were established in the even-age Pinus peuce Gris. stands with an average age of 90 years. The EPs were of a circular form and covered an area of 500 m2 each; 6 of them were established at 1150 meter above sea level (m asl), 7 at 1350 m asl and 9 at 1550 m asl. DBH, tree height, and crown length of 481 trees were measured in all EPs. The DBHH model was prepared in accordance with Prodan, as well as nonlinear (polynomial) regression for the relation between DBH and L and nonlinear (power) regression for the relation between DBH and V. The stem volume was calculated with a formula by Parishko for Pinus peuce Gris. The quadratic mean of DBH, average Loray height, average crown ratio, and the density of the stands were also calculated. The relationship between DBH and H, L, and V was examined with Pearson correlation and root mean square deviation (RMSE). The differences between averages of H, L, and V from the EPs were tested with analysis of variance (ANOVA) with an elevation class (1150, 1350 and 1550 m asl) as single factor. The density of stands was 490, 429 and 409 trees per ha on 1150 m, 1350 m and 1550 m asl, respectively. The average DBH was 39.8 cm, 46.5 cm and 45.5 cm, and Loray height was 23.9 m, 24.1 m and 22.6 m at 1150 m, 1350 m and 1550 m asl, respectively. Crown ratio (CR) pointed out different results on the different elevations, with the average value of 40.5%, 43.7%, and 39.3% at 1150 m, 1350 m, and 1550 m asl, respectively. Differences between average structural elements at different elevations can be confirmed with ANOVA with a significance of p<0.05 and F of 3.4 for H, the significance of p<0.05 and F 3.2 for L data and p<0.05 and F of 9.7 for the value of V. In that way, the regression model for H is higher at a lower elevation, the tree has a longer crown length at lower elevation and also has a bigger volume at lower elevation. From the results, it can be concluded that the elevation has an influence on the relationship between DBH on the one hand and H, L and V as structural elements on the other hand. It can be said that at higher elevation trees have a smaller average height, DBH, and volume and have longer crown length than trees at lower elevation.


Web of Science Impact factor (2022): 3.200
Five-years impact factor: 3.000

Quartile: Q1 - Forestry

Subject area

Agricultural and Biological Sciences