Fagus Silvatica Research Articles

Quantification of enrichment processes in throughfall and stemflow in a mixed temperate forest

AbstractForest ecosystems depend on throughfall and stemflow fluxes for both water and nutrient input. Spatial and temporal variability of throughfall and stemflow fluxes are large and differ between tree species. The nutrient fluxes that accompany throughfall and stemflow are affected by climate, precipitation intensity, the seasonality of dry deposition, and canopy exchange processes. The interdependence of these factors makes it challenging to quantify changes in throughfall and stemflow amounts as well as their nutrient content. Here, we provide observation‐based evidence from 3.5 years of data collection with 222 rainfall events, of the seasonal variability of throughfall and stemflow magnitude and ion concentrations under a beech (Fagus silvatica) and spruce (Picea abies) tree. Interception and canopy cover were seasonally variable, average annual interception was 53% below beech, 61% below spruce and 68% below young spruce canopies. Further, we assess seasonality of ionic nutrients such as NH4 and NO3 as well as Mg, Ca and K and their dependence on both dry deposition and canopy exchange. Throughfall and stemflow were enriched compared to precipitation, with large differences between ions and different months. Antecedent precipitation was a main control on throughfall and stemflow enrichment. We developed a conceptual model of the potential drivers of throughfall and stemflow enrichment based on our observations. While NH4 and NO3 enrichment are likely dominated by dry deposition and dew and fog accumulation, Mg, Ca and K were additionally affected by canopy exchange. Observation based studies such as this one are needed to understand precipitation and nutrient partitioning across forests, which enables the prediction of how changes in climate and forest composition will affect local hydrology and nutrient inputs into forest ecosystems.

Естественное возобновление на валежной древесине в реликтовом лесу Янь Республики Сербской

The paper investigates the natural regeneration of downed deadwood in the Janj primeval forest. The old-growth forest is located in the southwestern part of the Republic of Srpska, which is dominated by dolomite geological base on which cambial soils were formed. The climate is perhumid and mountainous and the plantation belongs to the Piceo-Abieti-Fagetum community. The hectare contains 517 live trees with a total basal area of 53.0 m2/ha and a volume of 876 m3/ha. Twenty six downed deadwoods classified into three different degrees of decay were included in the study, where fir and spruce seedlings were found to be predominant and beech seedlings were rarely represented. The first degree of decay includes 7 (26.9 %), the second 8 (30.7 %), and the third 11 (42.3 %). The total volume of deadwood is 110.82 m3/ha with an average volume per tree of 4.2 m3/ha. The total number of seedlings on fallen dead trees is 836 seedlings (Abies alba – 89.59 %, Picea abies – 10.17 %, Fagus silvatica – 0.24 %). Fir seedlings are found on 25 fallen trees, spruce on 18 fallen trees, and beech on 2 fallen trees. Regarding quality, on average fir seedlings are better than spruce seedlings, but both species show a lot of senescence and very small size of current height increment. Most seedlings belong to the third quality class (fir – 46.2 %, spruce – 61.1 %), followed by second class (fir – 34.6 %, spruce – 22.2 %) and third class (fir – 19.2 %, spruce – 16.7 %). The total number of seedlings was found to have a statistically significant difference in the amount of downed deadwood depending on the degree of decay, and the number of seedlings depended on the degree of tree decay. The number of seedlings increased with increasing volume and length of rotten trees. For citation: Govedar Z., Prokhorova N., Babić V., Dukić V., Kanjevac B., Bilić S. Natural Regeneration on Deadwood in the Primeval Forest Janj. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 90–102. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-90-102

Analýza rizika iniciácie usadenej vrstvy prachu smreka vybranými iniciačnými zdrojmi

The article evaluates the minimal initiation temperature and hot surface temperature of the spruce dust layer using selected ignition sources. The influence of selected physical properties of wood dust, the size of the contact area between the ignition source and the combustible material, the ignition time, and the thermally degraded area are monitored. The article describes the behaviour of a 15 mm beech dust layer (Beech Fagus silvatica L.) under the action of three potential initiating sources: a hot surface, an electric spiral, and a smouldering cigarette. Prior to the experimental determination of the minimum ignition temperature, the dust moisture was determined and the sieve analysis was performed. The lowest minimum ignition temperature on the hot plate was 280 °C. The ignition mechanism of wood dust was comparable for all initiators investigated, differing in the ignition time and the area of the thermally degraded layer. The least effective was the initiating source of the smouldering cigarette.

Analysis of the Internal Mounting Forces and Strength of Newly Designed Fastener to Joints Wood and Wood-Based Panels.

This study aimed to numerically and experimentally analyze the effects of internal mounting forces and selected materials on the stiffness and bending moment capacity of L-type corner joints connected with novelty-designed 3D printed fasteners. The experiments were carried out using medium-density fiberboard, high-density fiberboard, beech plywood, particleboard, and beech (Fagus silvatica L.) wood. The results showed that the joints made of beech wood were characterized by the largest bending moment capacity (12.34 Nm), while the worst properties were shown by particleboard (2.18 Nm). The highest stiffness was demonstrated by plywood joints (6.56 kNm/rad), and the lowest by particleboard (0.42 kNm/rad). Experimental studies have reasonably verified the results of numerical calculations. The test results confirmed that the geometry of new fasteners promotes the mounting forces under the assembly of the joints. It was shown that the higher the density of the materials, the greater the value of the mounting forces (164 N–189 N).

Influence of Citric Acid on the Bond Strength of Beech Wood.

In this study, beech wood (Fagus silvatica L.) has been chemically modified with citric acid (Acidum citricum) and sodium hypophosphate (SHP) as the catalyst and gradually thermo-condensed in the dryer. Afterwards, wetting angle, surface energy, and shear strength of glued joints of modified and unmodified wood were determined. Testing of the bond strength according to standard EN 204 and comparison between modified and unmodified samples were executed. The adhesive used for bonding samples was polyvinyl acetate (PVAC), commonly used for gluing solid wood panels. Testing material was divided into three groups (dry, wet, and wet conditioned samples), within which statistical analysis was performed, and the significance of the differences between the modified and unmodified samples was determined. Surface energy is correlated with the bond strength, indicating that modification with citric acid negatively affects the adhesive properties of beech wood. A reduction in the bond strength of modified wood glued with PVAC glue compared to unmodified wood was determined. All the results indicate that the modified samples do not meet the minimum requirements for EN 204 bonded with PVAC glue. Therefore, it will be necessary to conduct further studies using other types of adhesives to investigate whether modified wood might be suitable for gluing.

Numerical and experimental investigation on the elastic stiffness of glued dovetail joints

This study investigates the stiffness of dovetail joints by both numerical and experimental methods. Test specimens were made of Spruce (Picea abies L) and Beech (Fagus Silvatica L) wood, which were bonded with polyurethane (PUR) and polyvinyl acetate (PVAc) adhesives into dovetail joints. To determine the mechanical behavior, the joints were loaded according to grain direction under compressive and tensile load. The results of the experiment indicated that, under compression load, beech wood bonded with polyvinyl acetate (PVAc) adhesive had maximum elastic stiffness. Based on the experimental results, a numerical model using the finite element method (FEM) was developed by the Abaqus program to predict the stiffness of dovetail joints under compressive and tensile load. For numerical analysis, the assumption was made that arm deflection was caused by a displacement in the supports. The value of deflection corresponds to the limit of linear elasticity and the value of the force reduced stresses, which was determined on the basis of deflections. A cohesive zone was developed, which shows stress behavior under compressive and tensile load. A positive correlation was found between the numerical model and experimental study.

Ignition of Deposited Wood Dust Layer by Selected Sources

The main waste of wood sanding technology is wood dust. The formation of wood dust affects its behaviour. Wood dust can be in a turbulent form and behaves explosively or in a settled form where it becomes flammable. Dust particles are barely detectable by the naked eye, wood dust still presents substantial health, safety, fire and explosion risks to employees. This article deals with the evaluation of ignition temperature and surface temperature of deposited wood dust samples by selected ignition sources. The influence of selected physical properties of wood dust, the size of the contact area between the ignition source and the combustible material, the spatial arrangement during the ignition and the application time of the ignition source are analysed. The paper describes the behaviour of a 15 mm deposited layer of wood dust of spruce (Picea abies L.), beech (Fagus silvatica L.). oak (Quercus petraea Liebl.) caused by three potential ignition sources—a hot surface, an electric coil and a smouldering cigarette. Prior to the experimental determination of the ignition temperature, dust moisture content which did not significantly affect the ignition phase of the samples, as well as sieve analysis of tested samples were determined. The lowest minimum ignition temperature on the hot plate, as an important property of any fuel, because the combustion reaction of the fuel becomes self-sustaining only above this temperature, was reached by the oak dust sample (280 °C), the highest by the spruce dust sample (300 °C). The ignition process of wood dust was comparable in all samples, differing in the ignition time and the area of the thermally degraded layer. The least effective ignition source was a smouldering cigarette.

Impact of Irregular Tooth Pitch of Circular Saw Blades on Power for Wood Cross-Cutting

The article deals with the influence of irregular tooth pitch on energy consumption of cross-cutting wood. In this article, the effect was assessed of feeding velocity and parameters of saw blade on the cutting power Pc of spruce (Picea Abies), pine (Pinus Sylvestris) and beech (Fagus Silvatica) wood during sawing with a guided circular saw. For the research, two types of circular saw blades were used, one of them having irregular tooth pitch. The circular saw blades had sintered carbide inserts with a diameter of D = 350 mm and the same number of teeth. The feed velocities were vf = 4, 8,12 m∙min-1 and revolutions n = 3000 min-1. The results showed that the circular saw blades with irregular tooth pitch have higher energy consumption than the circular saw blades with regular tooth pitch. The highest cutting power Pc was shown in the case of beech. It was also shown that energy consumption is increasing linearly with increasing feed velocity.

Фотосинтетичні індикатори стану забруднення атмосферного повітря Покутсько-Буковинських Карпат

Досліджено взаємозв'язок стану атмосферного повітря та показників фотосинтетичного апарату представників дендрофлори Покутсько-Буковинських Карпат бука звичайного (Fagus silvatica L.) та тополі пірамідальної (Topulus pyramidalis Moenoh.), що вегетують в умовах різного антропогенного навантаження. Зразки листків відбирали із чотирьох екотопів, що відрізняються рівнем функціонального призначення та забруднення атмосферного повітря. Вивчено вміст хлорофілів та їх співвідношення, а також інтенсивність процесів світлової фази фотосинтезу. Встановлено, що зменшення відносного вмісту хлорофілу "b" в умовах забруднення атмосферного повітря тісно корелює із швидкістю переносу електронів по електрон-транспортному ланцюгу (реакція Хілла). У порівняно чистих, за показниками атмосферного повітря, територіях (заповідній зоні та зоні стаціонарної рекреації національного природного парку) існує тісна позитивна кореляція між вмістом легких негативних аероіонів, нагромадженням зелених пігментів та активністю фотофізичних процесів. Побудовано кореляційну матрицю взаємозалежності показників активності фотосинтетичного апарату рослин та стану атмосферного повітря досліджених територій. Обґрунтовано доцільність використання фотосинтетичних показників дендрофлори заповідної зони об'єктів природоохоронних територій як індикаторів стану екологічної безпеки атмосферного повітря. Результати досліджень опрацьовано статистично.

Analysis of logging forest residues as an energy source

Forest residue extraction levels in Greece are currently very low, but logging residues have the potential to be an important component of the wood energy supply chain. Forests are a major supplier of renewable energy. Exploring the possibilities of utilizing the biomass of logging residues for energy requires analysis and knowledge of its properties. In this research work the properties (ash, volatiles, fixed carbon, carbon, hydrogen, oxygen, nitrogen and calorific value) of the various constituents of the biomass of fir (Abies borisii - regis), pine (Pinus nigra), oak (Quercus frainetto) and beech (Fagus silvatica) logging residues were determined. Bark and ash content increased with decreasing diameter of branches. Ash content was higher in bark than in wood of branches in all species. Ash and nitrogen content was several times higher in bark and in foliage or needles than in wood of branches. Oak branches and twigs of all species had ash and nitrogen content higher than that required by the EN ISO 17225-2 standard for domestic pellets and they should not be used for energy, at least for pellets production. Volatile mater, fixed carbon, carbon and hydrogen content were in the range given by other researchers. Heating value is higher in softwood (fir and pine) than in hardwood (oak and beech) and ranged from 18.72 MJ/kg to 21.00 MJ/kg. In addition, Duncan's multiple range test was used to compare the means between the various constituents in all species.

Differences in humic acids structure of various soil types studied by DRIFT spectroscopy

The method of diffuse reflectance infrared spectroscopy (DRIFT) proved to be useful for studying the soil organic matter structure. The aim of this study was to compare DRIFT spectra of humic acids (HAs) separated from various soils and to identify their specific nature. Samples of agricultural soils (Dystric Cambisol, Haplic Chernozem, Greyic Phaeozem, and Haplic Luvisol) were collected from humic (A) horizons. Soil samples of reclaimed dumpsites (Haplic Technosol (molic) and (calcic)) were taken from the upper part of the soil profile. Samples of forest soils were collected from surface organic (H) horizons of Cambisols in spruce (Picea abies L. Karst.) and beech (Fagus silvatica L.) forests. The selected soil types differ in pH, carbon content, texture, and humus quality. An extraction of HAs was performed using a mixture of 0.5 M NaOH and 0.1 M Na<sub>4</sub>P<sub>2</sub>O<sub>7</sub>. The separated HAs were freeze-dried and analyzed using a DRIFT spectrometer (Thermo Nicolet Nexus) without KBr dilution. There were found differences in relative aromaticity among the agricultural soils HAs. The most aromatic character was observed in HAs from Chernozems and the least in Cambisols. Preservation of the natural structure of Chernozem HAs during the reclamation process was documented on the HAs spectra from Haplic Technosols (molic). By using the DRIFT spectra of HAs of forest H horizons, it is possible to identify the fragments of decomposed material (gymnosperms or angiosperms). HAs isolated from these horizons represent a certain interstage between lignin and the matured soil humic acids.

Analysis of variations in and correlations between selected physical parameters of common beech (Fagus silvatica L.) nuts

The basic dimensions and the mass of common beech nuts and seeds from five nut batches, harvested from tree stands in northern Poland, were determined. Environmental conditions had a greater influence on seed plumpness than the age of tree stands. The results of measurements were analyzed statistically by analysis of variance, correlation analysis and linear regression analysis. Despite differences in their plumpness, nuts were characterized by nearly identical cross-sections which resembled an equilateral triangle. The thickness of nuts and seeds was highly correlated with their mass, and this information can facilitate seed husking and separation into mass categories. Before and after husking, seeds should be separated with the use of a mesh screen with longitudinal openings. Medium-sized (most numerous) seeds were separated into the following plumpness categories using a screen separator with ≠6 mm and ≠7 mm openings: 84% of moderately plump seeds, 3% of seeds with reduced plumpness, and 13% of plump seeds.

Moisture content during and after high- and normal-temperature drying processes of wood

ABSTRACTThe aim of the article is to present the results of moisture content of wood during and after the high-temperature steam and air–steam mixture drying processes and after an open air-drying process. The knowledge of moisture content changes of wood in the process of its drying is one of the important parameters to economy drying process and to keep the quality of dried wood. Wood samples, namely, spruce (Picea abies K.) and beech (Fagus silvatica L.) from the northern part of Poland, were subject to steam, air–steam mixture and, air-drying, respectively, with a temperatures about 105, 80, and 25°C. The samples of thickness 70 mm and length about 1,050 of spruce, and about 1,500 mm of beech were used. They were machined by the modern narrow kerf frame sawing machine. Temperature of the cross section of dried wood was measured by thermocouples, wood moisture content was determined during process using moisture sensors. Measurements of moisture content for steam-dried and air-dried samples, as reference, allowed to reveal the effect of drying process on moisture content of wood. It has been recognized that steam wood drying causes almost constant amount of moisture in treated material in comparison to air-drying one.

Species of honeydew producing insects useful to apicu1ture in Greece

Μέχρι σήμeρα έχουν αναφeρθeί στην Eλλάδα 38 eίδη μeλιτογόνων eντόμων. Τα τeλeυταία χρόνια, άλλα δέκα eίδη eντόμων των οποίων τις μeλιτώδeις eκκρίσeις βόσκουν και eκμeταλλeύονται οι μέλισσeς βρέθηκαν στη χώρα μας. Τα eίδη αυτά, που ανήκουν στα Hemiptera-Homoptera eίναι τα: οι αφίδeς Acyrthosiphon caraganae (Cholodkovsky) σe ποντίκια (Coluteci arborescens L.), Corylobiuiii avellanae (Schrank) σe φουντουκιά (Corylus avellana L.), Hyalopterus amygdali (Blanchard) σe αμυγδαλιά (Prunus diilcis (Miller) D. A. Webb), Cinara juniperi (De Geer) σe κέδρο (Juniperus spp.), Cinara tujufiliiui (del Guercio) σe τούγια (Thuja spp.), Phillaphis fagi (L.) σe οξυά (Fagus silvatica L.), Pterocallis maculata (Von Heyden) σe κλήθρα (Alnus glutinosa Garth.) και Tuberculoides eggleri Bornes (Quercus spp.). Από αυτές οι τρeις πρώτeς ανήκουν στην οικογένeια Aphididae, δύο στην οικογένeια Lachnidae και οι τρeις τeλeυταίeς στην οικογένeια Drepanosiphidae. Τα κοκκοeιδή Aclerda berlesei Buffa της οικογένeιας Aclerdidae σe καλάμι (Arundo donax L.), και Physokermes piceae Schrank της οικογένeιας Coccidae σe έλατο (Abies cephalonica Loud.). Από τα δέκα αυτά μeλιτογόνα έντομα δύο, τα C. tujujilina και Ph. piceae, αναφέρονται για πρώτη φορά στην πανίδα της χώρας, η δe αφίδα Cinara juniperi και το κοκκοeιδές Aclerda berlesei παρουσιάζουν το μeγαλύτeρο μeλισσοκομικό eνδιαφέρον.

Comparing canopy leaf temperature of three Central European tree species based on simultaneous confidence bands for penalized splines

Temperature is an important physical factor that is known to strongly affect biodiversity as well as ecosystems and their functioning. However, research in this area is still relatively limited; this may also be attributed to the multitude of influencing factors and the complexity of the statistics involved. This study analyzes the differences between the surface temperature of three Central European broadleaf tree species. A better understanding of these differences may help to elucidate the role of microclimate in biodiversity. We consider a time series of high-resolution thermal images taken from a meteorological observation tower and calculate mean canopy leaf temperatures for beech, ash and maple (Fagus silvatica, Fraxinus excelsior and Acer pseudoplatanus). In a first step, comparable image areas are extracted from the thermal image sections of the crown of each tree species avoiding shadow areas, branches, etc. We used an automatic segmentation technique, the Otsu thresholding. Extracted canopy leaf temperature values were then processed and the resulting temperature profiles estimated by O’Sullivan penalized splines. For comparing the differences in canopy leaf temperature over time, we propose the construction of simultaneous confidence bands. The analyses show that there are significant—though small—differences in canopy surface temperature between the three tree species.

Metal Pollution of Forest Phytomass from Uranium Industry in Czech Republic and Its Ecological Management Perspectives

The paper is focused on the issue of metals migration within the forest environment affected by deep mining of metals and the possibility how to immobilize them using an environment-friendly method. First, the paper presents the information about metal content in the tree leaves in alluvial recipients polluted by metals from uranium deep mining at Dolní Rožínka, the Czech Republic. X-ray fluorescence analysis of dried leaves results showed the increased content of Cu, Fe, Mn, Ni, Rb, Sr, Zn and U; it corresponds to the most seriously polluted areas in the world comparing with the scientific literature. However, statistically, we did not succeed to demonstrate in none of areas of interest the element heterogeneity between the upper, middle and lower streams segments. Element habitat homogeneity can be caused by current stand species composition where Picea abies L. dominates and this fact results in the negative impact on the soil pH since it is a primary factor of metals immobilization in the ecosystem and their transformation into toxic variations. Within the area of interest, there is demonstrated positive effect of reconstruction of forest stands, which are close to the dominating deciduous trees, especially Fagus silvatica L. This management change in the selected interested forest stands can result in Ca supply of up to 39 kg.ha-1 from strictly natural sources, which might be a perspective alternative to liming.

Coefficient of wood bendability as a function of selected factors

Shaping materials by bending is a frequently used technology. The measure of a material bendability can be taken as the smallest achievable curve radius for the bent material. As bendability depends also on material thickness, this property is most frequently expressed as the ratio of the material thickness and the smallest curve radius achieved. Bending is also an important part of many wood processing technologies. The theoretical expression of wood bendability is, however, rather inadequately studied. The present work focuses on various definitions of the wood bendability coefficient as well as the influence of various factors on its value. In the experimental part of the work, coefficients of wood bendability were defined for beech (Fagus silvatica L.) and aspen (Populus tremula L.) We took the following factors into consideration: wood species (WS) (Fagus silvatica L. and Populus tremula L.), material thickness (MT) (4, 6, 10, and 18mm), degree of densification (DOD) (10% and 20% of the original thickness), and the number of stressing cycles (NC) (0 versus 10,000). The study brings a new quantitative expression of a bendability coefficient.

A novel device to measure gaseous permeability over a wide range of pressures: characterisation of slip flow for Norway spruce, European beech, and wood-based materials

AbstractA novel device was conceived and built to measure the apparent gaseous permeability of porous media over a large range of permeability values (10−10–10−18m2) and mean pressures (from 1 bar down to ca. 40 mbar). An extensive series of experimental data are presented and analysed for various porous media: (1) Norway spruce (Picea abies) and European beech (Fagus silvatica) in the three anatomical directions, and, for comparison, (2) three simpler porous media, i.e. an autoclaved aerated concrete (AAC, light concrete) and two wood-based panels. For all porous media, the intrinsic permeability, the gas slippage factor, and the effective pore size were determined from the variations of the apparent permeability as a function of mean pressure. These results are in good agreement with those of previous studies for spruce and bring new insights for beech and wood-based materials, in general. For all products, the effective pore sizes identified with the new instrument are closely linked to the medium morphology. In particular, it was found that in spite of the huge anisotropic ratios between wood’s longitudinal and tangential directions, the identified pore size is similar and corresponds to anatomical features: openings in margo for spruce and scalariform perforation plates for beech. Besides, the pore size identified for beech in the radial direction suggests that radial permeability is most probably controlled by the openings in ray cells (either pits or intercellular voids).

Modeling size-density trajectories for even-aged beech (Fagus silvatica L.) stands in France

We studied the size-density trajectories of pure even-aged unthinned beech stands in the ranges of 625–40,000 trees per hectare initial densities and of 12–33 years of age. A new piecewise polynomial function family was fitted to the trajectories, giving way to various applications. Initial number of stems per hectare (N 0) and mean girth at breast height at the onset of mortality (Cg 0) were parameters of the trajectory model, in addition to the parameters of the maximum size-density line. The two former parameters were tied by a linear relationship, which allowed the prediction of trajectories not considered in this study. Furthermore, the generic trajectory equation fitted the trajectories of thinned stands not used in the estimation of the parameters. This paper models the size-density trajectories of pure even-aged beech stands, including the early development stage, which is not as well documented as are the later stages. The work reported in this paper concerns the development of a novel approach to size-density trajectories, considered as a mortality model to provide references to managers of beech forests. A 33-year-old beech spacing trial beginning at 12 years of age provided the opportunity to study the size-density trajectories of unthinned stands of this species. The beech data helped us to develop a new piecewise function to model these trajectories. The model we chose was a polynomial segment smoothly joining two linear functions. The fits of this model allowed us to estimate the parameters of the size-density trajectories of all stands, which were the quadratic mean girths at mortality onset and at maximum density. A linear relationship between these characteristics allowed us to reduce the number of parameters needed to fit the trajectories and made it possible to predict a stand trajectory from any initial density not observed in the experimental stands. A single-parameter function family could be used to fit the size-density trajectories of beech stands. The predicted trajectories have various applications in beech silviculture and growth simulators.

The Effect of Thickness of Medium Density Fiberboard Produced of Hardwood Tree Species on their Selected Physical and Mechanical Properties

In Bulgaria, there is sufficient raw material as well as established technologies for fiberboard production of hardwood tree species. In general, MDF production from such raw-material is characterized by a number of technological difficulties mainly related to low compression ratio and smaller slenderness of fiber elements. The presented scientific experiments cover characteristic features and the effect of different thicknesses on the production of MDF from hardwood tree species – beech (Fagus silvatica L) and Turkey oak (Quercus cerris L). The experimental matrix and regime factors of hot-pressing are in correlation with thicknesses of boards. The regression models describing the effect of thicknesses on main properties of medium-density fiberboard are deduced and analyzed from the output data and the proper conclusions are made.