Fulltext search in archive

This study was done to quantify the amount of soil organic matter and to evaluate physicochemical properties and vegetation cover changes along the altitudinal gradient. Nine altitudinal transects were selected from 100 m a.s.l. to 1 700 m a.s.l. Then, 160 circular plots of 1 000 m2 area with a distance of 150 m from each other were studied. Soil texture, bulk density, particle density, soil base saturation, phosphorus and potassium values did not indicate any specific variation pattern. Whereas pH decreased powerfully, the highest and the lowest value of pH was measured at 100 m a.s.l. and 1 700 m a.s.l., respectively. Soil organic carbon content increased significantly with increasing altitude (P ≤ 0.01). Density of trees decreased dramatically from 100 to 900 m a.s.l., whereas this trend was ascending from 1 100 to 1 700 m a.s.l. Density of shrub species increased with increasing altitude along the gradient and the highest value was revealed at 1 300 m a.s.l. The highest percentage of herbaceous species cover was found at a lower altitude and a decreasing trend was found along the altitudinal gradient.

Central Tire Inflation Systems (CTIS) have been introduced to forestry transportation in the last 30 years to the point the forest industry is one of the biggest users of the technology (Pletts 2006). The benefits of operating with this CTIS technology mentioned in the literature include: (i) reduced road surfacing and/or base course requirements, (ii) reduced road maintenance, (iii) reduced driver fatigue and medical complaints, (iv) lower vehicle operation costs, (v) increased vehicle mobility, (vi) extended haul seasons (Bradley 1995). This paper presents a literature review of previous international studies on the impacts of CTIS. This document can assist the forest industry and research users to gain basic information on this transportation technology.

Crop trees are the main bearers of qualitative and value production of the stands. Although the number and production of the mentioned trees are affected by various factors, crown development by means of the thinning regime can be considered as very significant. The paper aims at the comparison of crop trees in homogeneous beech (Fagus sylvatica Linnaeus) stands, which were managed by three different management or thinning regimes for a long period (ca. 50 years): (i) heavy thinning from below (C grade according to the German forest research institutes released in 1902), (ii) Štefančík's free crown thinning, (iii) without interventions (control). Selection of crop trees was carried out at the beginning of research using the best stem quality, diameter and height dimension and regular spacing). In this paper only the last assessment of crop trees aged from 83 to 105 years including 23 subplots established across the Slovakian territory was analysed. The highest number of crop trees has been reached in forests where Štefančík's free crown thinning was applied. The proportion of these trees on subplots with the mentioned type of crown thinning was 61% out of the basal area at stand age of 100 years. A much lower proportion was found on subplots managed by thinning from below (32%) and on control ones (20%). Crown parameters (crown width, crown ratio, crown projection area, crown surface area and volume) showed the most appropriate values on subplots where Štefančík's free crown thinning was used. It was: 8.36 m (crown width), 0.50 (crown ratio), 56.84 m² (crown projection area), 289.56 m² (crown surface area), and 481.75 m³ (volume). Based on the results obtained after almost 50 years of systematic investigations, the mentioned thinning method was recommended for beech forests.

The paper analyses the growth, structure, production and soil chemistry of different tree species stands 20 years after allochthonous spruce dieback. The experiment was carried out at lower altitudes (300 m a.s.l.) at rich sites of the Central Europe region. Norway spruce (Picea abies Linnaeus) and beech (Fagus sylvatica Linnaeus) stands established by artificial regeneration were compared with silver birch (Betula pendula Roth), aspen (Populus tremula Linnaeus) and birch-aspen stands, which were regenerated naturally. Spruce stands showed a decrease of site index (site index 3), compared with the previous generation (site index 2). This leads to an expected lower production at the age of 100 years, compared to mature beech stands, which showed a site index of 1. The highest production (tree overbark volume) was found out in the aspen stand - 294 m³.ha^-1. The production (tree overbark volume) of other monoculture stands was comparable and reached 201-222 m³.ha^-1. Most of the soil chemical characteristics under the compared stands (Ca and Mg content, Al content and active and potential soil reaction) were significantly better under aspen and decreased in the following trend: birch - beech - spruce.

After spruce, the Scots pine (Pinus sylvestris Linnaeus) is the second most important commercial coniferous tree species in the Czech Republic. However, we are finding out that awareness of the variability of properties, and possibilities to affect them, are noticeably small for this type of tree species in our conditions. The goal of this study is to primarily evaluate the importance of site conditions, silvicultural measures and other factors for the density of Scots pine wood in the Doksy locality in the Czech Republic. The Doksy locality is represented by three forest stands with different silvicultural history. Samples were taken from each stand, the basal and central parts of which were subsequently processed for test samples with dimensions of 20 × 20 × 30 mm. Wood density at 12% moisture content was ascertained in the test samples. The highest density value of 0.541 g.cm^-3 was reached in a stand that is regenerated using the shelterwood method with long regeneration period, and the lowest density value of 0.488 g.cm^-3 was recorded in a stand that was regenerated using the clear-cutting method. From a forestry perspective, it can be further stated that the wood density of Scots pine is also affected by the site conditions and position of samples in the trunk.

Puccinia psidii sensu lato was detected in Australia in 2010 causing myrtle rust. A nationally cost-shared eradication program was conducted based on well-established emergency response arrangements for incursions of emergency plant pests into Australia, but it was ultimately decided that the pest was not eradicable from Australia. At this time, no formal mechanisms existed to provide a clear path for decision making and cost-sharing when transitioning from an eradication focus to long-term management of a plant pest. In 2011, the Australian Government established and funded a set of pilot transition to management programs for a number of noneradicable pests, one of which was for the myrtle rust pathogen, with the goal of using the outcomes of the pilot programs to guide the ongoing development of formal transition arrangements.

The aim of this study was to evaluate the effects of closure best management practices (BMPs) on runoff volume and soil loss on skid trails that received two densities of soil cover mats and were located on two slope gradients in an Iranian temperate mountainous forest. The treatments included combinations of three closure BMPs (water bar only, water bar + sawdust, and water bar + hardwood slash), two amounts (densities) of mats (7.5 and 15 kg.m^-2), and two levels of slope gradients (≤ 20% and > 20%). Results showed that the water bar treatment was the least effective erosion control treatment, followed by the hardwood slash and sawdust treatments. Averaged over mat densities and both slope gradients, the average runoff rates and amounts of soil loss from the skid trails with the water bar treatment were 46.7 l per plot and 6.1 g.m^-2, respectively, 16.8 l per plot, 2.8 g.m^-2, respectively, with the hardwood slash treatment and 11.7 l per plot, 1.9 g.m^-2, respectively, with the sawdust treatment. The results indicated that surface cover is a necessary element for controlling erosion losses following a skidding disturbance, particularly on steep slopes.

The study of young poplar tree characteristics like initial diameter and height as well as mineral fertilization that promotes the rapid growth of trees for biomass production was the aim of this research. In two forest nurseries of northern Greece, the growth of Populus sp. clone I-214 under five fertilization treatments per dosage was studied, i.e. (i) 120 kg (NH₄)₂SO₄.ha^-1, (ii) 200 kg (NH₄)₂SO₄.ha^-1, (iii) 150 kg (NH₄)₂SO₄.ha^-1 and 300 kg mixed fertilizer 11-15-15 (i.e. 11 kg N, 15 kg P₂O₅ and 15 kg K₂O per 100 kg of fertilizer) per ha, (iv) 150 kg (NH₄)₂SO₄.ha^-1, 200 kg mixed fertilizer 16-20-0 (i.e. 16 kg N and 20 kg P₂O₅ per 100 kg of fertilizer) per ha and 100 kg K₂SO₄.ha^-1, (v) no fertilization. Results showed that initial diameter was the variable that had the greatest effect on growth, while the fertilization with 150 kg (NH₄)₂SO₄.ha^-1 and 300 kg mixed fertilizer 11-15-15 per ha improved significantly diameter growth. Nevertheless, no specific pattern was found statistically for the best fertilization treatment concerning the height growth of young poplar trees. These findings could be taken into account for the best management practices for rapid poplar tree growth and biomass production under similar edaphoclimatic Mediterranean conditions.

Patterns of biomass allocation were determined for seedlings of five provenances of Quercus castaneifolia from west to east of the Hyrcanian forest along a rainfall gradient. Experimental design was executed under controlled conditions at seven different light levels (10, 20, 30, 40, 50, 60, 70 and 100% full light). We quantified the biomass allocation patterns to leaves, stems and roots. For all provenances total mass increased with irradiance at low light levels, reaching an optimum at an intermediate level but decreasing at a high irradiance level. As results show, in drier provenances and at high light levels, the seedlings invest more biomass into root mass to facilitate water uptake and to alter their leaf size to prevent overheating. In contrast, at wetter provenances and low light levels, towards increased light interception, more biomass is allocated proportionally to leaves and the stems but, accordingly, less to roots. The leaf to root ratio (L/R) was negatively correlated with light, with high correlation at wetter provenances compared to drier ones. In contrast, the relationship between the root to shoot (R/Sh) ratio and light was positively correlated with light, but it was weak at drier provenances and became gradually stronger at wetter ones. Such relationships indicated that chestnut oak seedling growth strategies are different along a rainfall gradient to irradiance levels. Despite similar growth conditions in the greenhouse, different growth strategies may be the result of genetic adaptation to the ecological conditions, especially when precipitation regimes prevail in the native habitat.

We examined the effects of nanoparticles (NPs) of TiO₂ and ZnO at 0.5, 1, 2 or 3% concentrations for 10, 20, and 30 min in stratified seeds of Prunus mahaleb Linnaeus. Then, seedlings produced were irrigated to field capacity with NP solutions at control, 1, 5, and 10% concentration for 7 months in the greenhouse conditions. Treating seeds at 1% concentrations of TiO₂-NPs for 20 min resulted in the highest germination percentage (65%) and at concentrations of 3% for 30 min it showed the lowest germination percentage (13%). The highest total seedling height was obtained after exposure of seeds to 0.5% TiO₂-NPs for 10 min. Irrigation of seedlings with TiO₂-NPs at the concentration of 1% seems to be a suitable method how to increase their total height, survival, and total dry weight. A decrease in the relative water content and an increase in proline were observed in response to the application of high levels of NPs.

The serious oak decline was reported for the 1979-80 period and 63.0% of adult oaks died in a mixed oak forest in the Síkfőkút site, Hungary. The data were used to obtain (1) quantitative information on diversity indices of shrub layer and shrub canopy, including foliage cover percentage of the shrub layer, mean cover of shrub species before and after the oak decline and (2) structural information on shrub basal area and shrub foliage arrangement. Since 1972 we have determined diversity indices, cover percentage and basal area of shrubby vegetation on the monitoring and plus plots. A negative relation was detected between Shannon-Wiener and Evenness indices of the shrub layer and living oak tree density. A positive relation was confirmed between basal area and mean cover of dominant woody species (Acer campestre, Acer tataricum and Cornus mas). The mean cover of shrub species except of A. campestre increased non-significantly after the oak decline on the 48 m × 48 m plot. The findings of the study indicate that diversity indices of the shrub layer and mean cover of A. campestre can be used as a principal indicator of natural disturbance in the studied mature stand and the species of the shrub layer respond differently to the decreasing stand density.

To compare breaking of dormancy in relation with climatic conditions and reaction to late frost fir plants growing in sun, in shade and at magnesium deficiency were evaluated. Sprouting and chlorophyll a fluorescence of needles measured with the Plant Efficiency Analyser were evaluated from March to May 2011. As a consequence of May frost 100% of plants from sunny treatments and 70% of firs shaded with shade cloth were affected by necrosis of sprouting shoots; fir-trees shaded by the stand remained fully intact. No relationship between the index of shoot sprouting and damage was confirmed. Firs with Mg deficiency had the lowest maximum quantum yield of PSII photochemistry of the dark-adapted tissue (F_V/F_M) and performance index on absorption basis (PI_abs) in the long term. Regression models of parameters F_V/F_M and PI_abs and selected environmental parameters showed that chlorophyll fluorescence was influenced to the largest extent by minimum temperature of the day of measurement. The process of breaking of dormancy increased fir vulnerability to thermal stresses of the environment - late frosts.

Understanding of the basic determinants of cooperation among private forest owners is of crucial importance to forest owners, private forest owners' cooperatives and other key players in the forest sector. This topic concerns complementary empirical and theoretical studies from the fields of economics and social studies. A recent study shows that private forest owners differ in their attitudes towards forest management and processes of cooperation in terms of the time perspective and, correspondingly, make different decisions in various situations related to forest management. Based on the data from two surveys, this paper shows how private forest owners' views of forest management in Lithuania have developed over the last thirteen years and finds some basic socio-economic aspects that drive cooperation among private forest owners for joint forest management.

Burnout imposes consequences and costs on the organization and employees, such as frequent job and workplace replacement, frequent absenteeism and permissions, and reduced work quantity and quality. So it seems necessary to perform institutional interventions to reduce the staff burnout. The aim of the present study was to determine prevalence of burnout among forest workers in Mazandaran. This descriptive cross-sectional study was conducted on a sample of workers in the forests of Mazandaran province. Result showed that a significant proportion of workers had burnout in terms of the three dimensions of Maslach Burnout Inventory. 46.90% of respondents suffered from high emotional exhaustion, 43.36% had high depersonalization and 49.56% of respondents suffered from low personal accomplishment. In this study it was shown that people with bachelor or higher degree (compared to people with a lower education level) were in better conditions in terms of all three dimensions of burnout; they had higher personal accomplishment and higher emotional exhaustion and lower depersonalization. It was shown that burnout is highly prevalent among chainsaw operators and skidder drivers.

Taxocenosis of psocids (Psocoptera) was studied in the territory of the Drahanská vrchovina Hills in the Czech Republic. Representative research plots were selected in forest ecosystems with natural species composition and spatial structure (small-scale strictly protected areas) as well as in forest ecosystems with altered tree species composition and spatial structure. Research was conducted in three altitudinal vegetation zones (AVZ): in 2^nd communities of Fagi-querceta s. lat. (beech-oak forests), 3^rd Querci-fageta s. lat. (oak-beech forests) and 4^th Fageta abietis (beech forests with fir). Research plots are situated at altitudes ranging between 275 and 540 m a.s.l. In the 2013 growing season, totally 3,474 imagoes and 2,532 nymphs of 32 psocid species were collected. Of those, 748 imagoes of 25 psocid species were collected in Fagi-querceta. The occurrence of Caecilius burmeisteri, Caecilius flavidus and Graphopsocus cruciatus was eudominant. 2,194 imagoes of 23 psocid species were found in Querci-fageta, eudominant were there Caecilius flavidus and Caecilius burmeisteri. 532 imagoes of 18 psocid species were found in Fageta abietis, eudominant were there: Caecilius flavidus, Peripsocus subfasciatus and Caecilius burmeisteri. In respect to the species composition, 3^rd AVZ and 4^th AVZ are similar to each other while 2^nd AVZ is less similar.

This Czech-American research collaboration is investigating interspecific hybridization among various fir species produced via control pollination. Its aim is the development of newly bred material for specific needs of Christmas tree production. The specific target of the breeding is increased growth rate, development of resistance to diseases, insect pests, and limiting environmental conditions (e.g. drought). Experimentation follows a traditional hybridization program of the Czech department focusing on the genus Abies and a long-term breeding program of the American department aimed at Christmas tree production. For hybridization, mainly Mediterranean fir species are used together with American species (especially Abies fraseri) and other species (e.g. Abies koreana). Generally overcoming 5% of viable seeds in the sample can be considered a success. Only few of our hybrid combinations have complied with this condition so far. In 2008 the hybrid combination CZ1 × NC73 brought 16% of viable seeds. In 2009 the most successful hybrid combination CZ1 × FF81 brought 6% of viable seeds. These crossing experiments will initially be followed by Phytophthora cinnamomi resistance screening trials.

The effect of thinning on litterfall and decomposition of biomass was investigated in Norway spruce IUFRO thinning experiment (CZ-13), Czech Republic. The experiment was established in 1971 in an 8-year-old spruce stand on former farmland. Quantity and quality of litterfall and biomass from humus horizons were analysed in two treatments (1C - no thinning, 2T - heavy thinning at the young age). Forest floor was investigated in 2002, 2004, 2005 and 2009 and litterfall was observed in the period 2002-2009. Accumulated dry mass in forest floor after 39 years of existence of spruce stands continually decreased until the age of 46 years (from 80-100 to 30-50 Mg.ha^-1). Under thinned stand, a lower amount of dry mass was observed compared to the control. Although mean total annual litterfall was the same in both treatments (5.3 Mg.ha^-1), the observed trend indicates a possible effect of thinning on the higher rate of decomposition. With the exception of calcium (2002-2005 samples) we found the forest floor lower in nutrients and litterfall higher in nutrients in thinned plot compared to the control. Our results supported the theory that early thinning is an appropriate silvicultural strategy helping spruce to cope with growth conditions on sites naturally dominated by broadleaves.

The present study examines the relationships between the indicators of tree species and structural diversity and the quality of timber production in young even-aged forest stands with the average age below 40 years. The study is based on the forest inventory data from University Forest Enterprise Kostelec nad Černými lesy, Czech Republic, performed from 2009 to 2011. The examined young stands were recorded in 256 sample plots representing 21.2% of the enterprise area. On each sample plot, we quantified 171 partial biodiversity indicators. In total, we analysed 16,416 different variants of the relationship between the diversity indicator and the quality of timber production. The analysis revealed that similarity indicators such as the range of tree heights, Canberra distance, Bray and Curtis index, and index of species evenness and heterogeneity were the most frequent basic indicators occurring in significant correlations. The results indicate a positive relationship between the proportions of assortments in quality classes I to IV and stand diversity expressed by the number of tree species and Canberra distance.

The aim of the present study was to analyse the impacts of different logging intensities after five years from logging including non-logged, low (3.4 felled stems per hectare), medium (5.2 felled stems per hectare) and high (7.1 felled stems per hectare) treatments on stem density, basal area, canopy cover, and forest biodiversity indices. The study area was located in northern Iran. Data was collected on a set of 120 circular plots with 5 m radius from both non-logged and logging areas. Stem density, basal area, and percentage of canopy cover were measured. Biodiversity study was done by measuring two diversity indices including Simpson's and Shannon-Wiener's, two richness indices including Margalef's and Menhinick's and two evenness indices including Pielou's and Hill's indices. The results indicated that the treatment with the medium logging intensity was found to cause the highest amount of positive effects on stem density, basal area, and biodiversity indices. It is concluded that harvesting intensity should be limited to a medium level (approximately 5 felled trees per hectare) during each logging operation to improve forest biodiversity indices.

High-value native timber species are being promoted in reforestation in Southeast Asia. However, slow growth during early establishment, coupled with poor soil fertility, poses challenges for promoting tree planting programs. Field trials were undertaken on agroforestry land in Thailand to examine the efficacy of reforestation treatments. The first trial examined the effect of applying microorganisms and fertiliser on directly seeded Acacia mangium Willdenow, Dalbergia cochinchinensis Pierre and Xylia xylocarpa (Roxburgh) Theobald. After 20 months, a mixed inoculum of arbuscular mycorrhizal and ectomycorrhizal fungi improved survival and basal diameter of D. cochinchinensis by 15 and 43%, respectively. The co-inoculation of arbuscular mycorrhizal fungi and N2-fixing bacteria improved survival by 17%. The second trial investigated the effects of fertiliser and a water retention polymer on directly seeded A. mangium, Afzelia xylocarpa (Kurz) Craib, D. cochinchinensis, Eucalyptus camaldulensis Dehnhardt, Sindora cochinchinensis Baillon and X. xylocarpa. Height was improved by 40% at 20 months. Our findings suggest that reforestation is viable, provided that suitable treatments are used. These principles can be applied for reforestation of nutrient-impoverished soils of continental Southeast Asia.

In this study, five biochemical traits obtained for seedlings of five different provenances of Quercus castaneifolia C.A. Meyer were used to evaluate the available light environment using instantaneous electronic readings as a standard. Experimental design was executed under controlled conditions at six different irradiance levels (10, 20, 30, 50, 60, and 70% of full light). Results show that among total chlorophyll (Chl_mass), chlorophyll a to b ratio (Chl_a:Chl_b), N, chlorophyll to N ratio (Chl:N), and peroxidase (POD) quantitative activity, the latter provides the highest realistic correlation with available irradiance. Ranking irradiance treatments on a Chl_mass basis, Chl:N ratio, and Chl_a:Chl_b ratio do not consistently distinguish different irradiance levels either within or between provenances, while the ranking produced by POD was an accurate reflection of the degree of irradiance within the shade houses, especially at 10-30%.

The Nour Forest Park located in the north of Iran is the most important Hyrcanian lowland forest which plays a significant role in the local/national carbon cycle. Since the forest is protectively managed, the distribution of C pools in the forest may give proper information for climate change negotiations. We investigated variations in above- and belowground C pools between three natural stand types that occur in the forest - Alnus glutinosa-Parrotia persica (AI), Acer velutinum-Parrotia persica (MI), and Ulmus glabra-Carpinus betulus (EH). The carbon stocks of trees, herbs and litter were measured in each stand based on a completely randomized design using nested plots. Soil organic carbon (SOC) stock was measured at two depths (0-20 and 20-40 cm). The mean organic carbon concentration of 20.61 ± 0.012% and of 31.13 ± 0.024% was directly measured for herbs and litter, respectively. The results of the paired t-test showed that there was no significant difference in SOC between the first depth (0-20 cm) and the second depth (20-40 cm) in AI stand though SOC was significantly different between the two depths in MI and EH stands. The carbon stock of above- and belowground biomass was not significantly different between the three stands, and carbon stock of litter was higher than that of herbs in each stand. Also, there were significant differences in the different carbon pools in each stand type; however, the different stand types did not differ in the proportion of carbon stored in different pools and in total carbon (i.e. C summed across all pools; P > 0.05). The findings in the different forest types showed that there was no high carbon stock variability suggesting that the horizontal and vertical distribution of carbon stocks in the forest could be in a balance, implying that the protective management could be a determining factor for the carbon balance in the forest. Regarding this issue, it is necessary to verify the variation of carbon stocks in non-protective and active forest management.

Mid-rotation responses to fertilization of Pinus radiata D. Don plantations after the first or second thinning have been observed in research experiments in many regions where the species is grown. The practice is not however common in commercial plantations. This is probably because the effects of soil-site conditions on the magnitude and duration of tree and stand growth responses are not well understood. The effects of nitrogen (150 and 300 kg N.ha-1) and phosphorus (0, 20 and 40 kg P.ha-1) including common base fertilization of boron (8 kg B.ha-1) and potassium (65 kg K.ha-1) were evaluated in three mid-rotation P. radiata plantations after thinning. The plantations were located on sites with contrasting nutrient and water availability, sandy, granitic and red-clay sites, in south-central Chile. The magnitude and duration of growth response was site specific. After 8 years, the growth response to the highest dose of fertilization relative to the control was 57 m3.ha-1 (16%) at the granitic and 24 m3.ha-1 (14%) at the sandy site. No response to either nitrogen or phosphorus fertilizer was observed at the red-clay site. Nitrogen and phosphorus were limiting at both granitic and sandy sites, and high fertilization doses considering 300 kg N.ha-1 plus 40 kg P.ha-1 would ameliorate nutrient resource limitations and yield a cost-effective increment in stand volume.

To understand the function of peroxidase (POD) in relation to a light gradient, changes in POD activity were studied in five different provenances of chestnut oak seedlings. An experiment was conducted in controlled conditions and six different irradiances (10, 20, 30, 50, 60, and 70% of full light) were considered. According to the results, POD activity was strongly related to irradiance and showed a decreasing response to light, with the largest changes at low light (10 to 30%) and a levelling-off at high light (50-70%). Five provenances were also significantly distinguished at 10-30% of full light. The gel analysis showed that there were several different bands between irradiances from 10 to 70% regardless of provenances. One isoenzyme with the highest electrophoretic mobility was significantly increased in response to reduced light and slightly decreased at high irradiance. Other isoenzymes were significantly increased at high irradiance, suggesting that these isoenzymes are most likely involved in response to light stress and leaf adaptation to high irradiance.

This article was aimed at assessment of selected factors of the work environment, which influenced the operators of harvesters and forwarders. The selection of the work environment factors was based on a thorough literature survey. From the survey exposure to whole-body vibrations, noise (equivalent and peak), microclimatic conditions and mental load were selected for detailed observations. The measurements were conducted according to international standards and assessed according to European or national legislation. Subjective assessment of the effects of the work environment was conducted through a structured interview. The exposure to whole-body vibrations was 0.5 m.s-2. The equivalent noise exposure was 78 dB, peak noise exposure was 130 dB. The average temperature inside the machine cabs was 17.9°C and average airflow velocity was 0.06 m.s-2. Mental load was high according to the Meister questionnaire, three operators considered the load inadequate, two considered it adequate. Subjective assessment showed that operators considered other factors to be light or no load

The area of forest destruction as well as the annual growth loss due to road construction before constructing a road was predicted. To do this, road cross sections of 88 points along the 10 km proposed road were predicted using Multilayer Perceptron Neural Network with two input parameters of hillside slope and rock share within MATLAB software. Then according to the predicted width, the area of road earthwork as well as the area of roadside with a 10 m width was calculated in ArcGIS software. Finally, by overlaying the inventory network layer on the road map and by knowing the annual growth (m³) for each plot the growth loss of the area of road earthwork was calculated and one-third of the annual growth increment was considered to calculate the growth loss of the roadside. According to the results, for the construction of a 10 km long road in the region, 12.98 ha of forest area is destructed due to road construction, of which 5.36 ha is destructed resulting from earthwork operations and 7.61 ha occurs in the roadside and its growth is influenced by road construction. With the construction of the road, in total, 32.606 m³ of growth will be lost annually, of which 22.221 m³ is due to road earthwork that is completely removed from the forest annual growth cycle and 10.384 m³ of the growth loss belongs to the roadside which is decreased resulting from road construction.

The condition and snow damage to stands dominated by birch were studied in the area of interest in Northern Moravia. Based on basal area, the share of birch ranged from 68 to 88%. The stands came to existence on fertile sites through natural regeneration and exhibited growth at a level of the best site classes for the Czech Republic. The most severe snow damage to the stands was recorded at the upper stand height of 8-15 m. The extent of damage in the analyzed stands amounted to 67-95% of all trees. The unambiguously predominant type of damage was bending while breakages were recorded only in up to 4% of trees. Slenderness ratios of intact trees differed according to the age (height) of stands. The highest values of about 180 were observed in the youngest, ca 5-years-old and about 5 m high stand. Slenderness ratio values of intact trees in a 17-m high stand ranged about 100. The analyzed stands did not show any differences in the slenderness ratio values between intact and damaged trees. Lower values of the ratio for solitary trees (ca 130) in a 5-years-old stand were accompanied by markedly longer crowns (80% of stem) as compared with trees growing in the stand (60% of stem). Differences in the root system architecture were revealed between intact and damaged trees within a stand of about 9 m in height.

The paper deals with the occurrence, development, natural enemies and harmfulness of a heteroecious aphid Eriosoma (= Schizoneura) ulmi (L.) which showed outbreaks in elm Ulmus glabra Huds. in Moravia in 2002. At main localities under study in Bílovice nad Svitavou and Brno-Jundrov, the aphid damaged about 63% leaves. Larvae of fundatrices hatched from mid-April and their development from hatching to maturity took about 14 days. Mature fundatrices occurred in May and reproduced for a period of 14 days. Their average physiological fecundity amounted to 311 larvae and ecological fecundity 291 larvae. Migrantes alatae occurred in galls from 18 May to 15 June and their physiological fecundity was about 22 larvae. Leaves were damaged even by 3 galls of an average length of 41 and width 11 mm. Sucking affected on average 11 cm², i.e. 27% (in case of the occurrence of 2 or 3 even 100%) leaf area. Natural enemies killed 90% aphids. A bug Anthocoris confusus Reut. killing aphids in 80% galls was the most effective control agent. Its eggs occurred from 25 April to 25 May and nymphs from 3 May to 25 June. Larvae of Syrphidae [mainly Syrphus ribesii (L.)] killed the aphids in 4 and birds in 6% galls. E. ulmi should be considered to be an important occasional pest of orchards and forests.

Northern red oak (Quercus rubra Linnaeus) is a promising species which could help to mitigate the sanitary problems. Northern red oak is also a commercial species and offers many environmental services. Northern red oak prefers rather dry acidic sites commonly found in Bohemia. The literature confirms that the species is quite fertile but acorn production is highly variable. Northern red oak seedlings develop a long tap root during their first year, which enhances their survival and performance. Different silvicultural systems are proposed and pros and cons are discussed in this review including their influences on forest floor and soil.