Issues

Abstract

The paper presents results of a study on the radial growth of Scots pine (Pinus sylvestris L.)
in lichen-green moss pine forests of III-IV age class in natural conditions and in varied environment
influenced by air pollution in the European North of Russia. We found that the growth of
pine in young age depends more on intrapopulation interactions than on climatic factors, which
is confirmed by the data on dynamics of radial growth of overripe pines. It is observed that while
radial increment of pine has natural fluctuations, its dynamics changes significantly induced by
atmospheric pollutants. The significant negative correlation between radial growth of pine and
volume of pollutants emitted by 'Severonickel' smelter is determined.

Abstract

Black pine (Pinus nigra Arn.) provenance trials were established in North West Bulgaria in
1978 to study the hereditary potential of selected offspring of some of the most valuable populations
in Bulgaria. Given the planting interval of 2 x 2 m, 13 provenances are assessed through
three performance indicators including survival rate, quality of stems and general health status. At
the age of 36, the average survival rate of the plantation is 68 %, varying between 38 % and 92 %
for the different plots, without specific linkage to the altitude of origin. The impacts of wet snowfalls
have played a primary negative role on the status of the plantation. Competition has also been an
important factor for the survival rates as expected, with the most significant losses endured during
the early life of the plantation. The field data reveals that there are no definite evidences on the
influence of the provenance on mortality, quality and general health of the stands. Thus, the considerations
on the provenance selection in afforestation practices may not have such a significant
role and visible effect within the established plantations. A possible reason for this is that nature
conditions of the specific site, although outside the natural range of distribution of Black pine, are
relatively favourable but not within the range limits for its survival.

Abstract

In the last decades, the international energy demand has risen greatly due to the world's population
growth and the economic development of some big countries (e.g. China, India, Indonesia). The
intensive use of fossil fuels is recognized as unsustainable in the long-term period. In this framework,
renewable energies represent important sources in order to satisfy the energy demand in a sustainable
way. European Union (EU) promotes the use of renewable energy sources (RES) to reduce
greenhouse gas (GHG) emissions, to increase energy independence and to promote the renewable
industry. Renewable energy policy must take into account the technical aspects of energy production
and also the environmental, economic and social aspects, following an integrated approach.
Consequently, sustainability assessment has become a fast developing research field and impact
assessment tools - based on methods that take in consideration stakeholders' opinions and expectations
- are commonly used to support policies or projects implementation. Sustainability Impact
Assessment (SIA) is a tool that supports decision-makers in identifying potential impacts of possible
policy actions. Environmental, economic and social aspects related to renewable energies are often
analyzed with sectorial approaches. To overcome this gap, it is fundamental to develop practical
instruments useful for an integrated assessment considering environmental, technical-logistics,
financial and social parameters of renewable energy systems. Starting from these considerations,
this research investigates the indicators useful to support the SIA of a policy, a plan or a single action
related to a renewable energy system. Social and economic dimensions and related indicators are
analyzed, also including indicators which straddle between socio-economic and environmental sector.
A comprehensive in-depth literature review has been made in order to create a database of criteria
and indicators. After creating the database, authors selected 308 suitable indicators: 93 relating to the
economic dimension, 152 to the socio-political and cultural one and 63 to the social-environmental
dimension. Furthermore, indicators were aggregated into three main impact dimensions (economic,
social-political and social-environmental) and six general criteria. Finally, some recommendations are
given to contribute at developing new indicators for the assessment of effects of renewable energy
systems on sustainability.

Abstract

Contemporary technologies for afforestation of forest areas, based on the use of specialized
milling units for soil preparation, mulching, shredding of stumps and other typical forest
operations, are characterized by relatively high environmental and quality indicators, lower
cost of labor and a smaller number of used technical means. These indicators are due to the
use of specialized milling machines, which can operate in wide range of strength and type of
deformation and interaction of the cultivated object. To achieve good results and low technology
speeds, more energy and powerful tractors are needed. This article presents results of
some basic performance of forest milling aggregate PT-400, with multi-purpose forest tiller
FAE 300/S. The survey has been carried out on experimental poplar sites and slashes along
the Danube river valley in the north-west region Bulgaria. For the purpose of the study the
following parameters were determined: fuel consumption, operating speed and operational
performance of the milling unit under certain conditions: 1) crushing stumps with diameters up
to dav = 65 cm, mulching False indigo-bush (Amorfha fruticosa) with height of 2.5–3.0 m and
clearing debris; 2) milling of the soil to a depth of 0.5 m. The obtained results will be useful
for better determination and establishment of technological capacities and performance of the
studied specialized milling unit.

Abstract

Red deer has been reintroduced in 18 lowland and mountain former habitats by releasing
animals from two neighbouring populations, supposed to be genetically identical. The mean values
of measurements of trophies obtained from newly-created and initial populations have been
compared by Student's t-test. The significant differences found did not depend on new habitats
remoteness, as well as on the mean age of animals hunted for trophy. Evidently, it seems that
ecological variables are the most important cause of red deer trophy size variability, and further
investigations are needed to study the relationship between altitude, climate, vegetation, etc. and
the most important trophy measurements.

Abstract

Having in mind the assortment and age structure, the tree composition and other specific peculiarities of Bulgarian forests, as well as the national timber market, about 70 % of the harvested timber is used for technological purposes, e.g. for production of particle boards, cellulose and for energy purposes, like firewood for residential heating. Along with the harvested logs (saw logs, pulpwood and firewood), Bulgaria has also considerable recovery of other biomass. In 2014, the share of the categories 'woods' and 'brushwood' is about 50 % of the total timber harvested volume in Bulgaria. Practically, in our country the wood waste from felling together with the brushwood is about 1.4 Mio (m³/y) of solid waste. That wood waste presents a significant energy potential but the degree of its quantitative concentration is low and often this resource is at big distances from the settlements. The most important advantages and benefits of the utilization of solid wood biofuels in the form of pellets, briquettes, charcoal and chips for energy purposes are: ecological - decrease of the carbon emissions and air pollution and economic (social in this account) - decrease of the costs of energy resources, which ensures both economic and social effect of the use of biofuels produced from wood biomass. In Bulgaria, the volume of wood energy products in 2014 is: 52,550 t pellets, 6,800 t briquettes, 11,550 t charcoal and 9,400 t wood chips, respectively. About 60 % of the number of pellet producing companies has a share of 15-20 % in the total pellet production. Such small-size firms use small-size pressing machines. The general analysis related to the sale of wood pellet and briquette shows that about 2/3 are realized for export based on preliminary signed contracts and the introduction of quality requirements. Most often the export is for Greece, Turkey and Italy. According to our assessments, the best conditions for development exist for briquettes production and wood chips designed to home market, of pellets designed to international one and of charcoal for both.

Abstract

The potential of Black locust (Robinia pseudoacacia L.) wood for production of chemical pulp
and glucose was studied. Different clones of Black locust growing in various habitats in Bulgaria
were analysed and their chemical composition and density was compared. It was established
that the differences in the content of cellulose, lignin, pentosanes and extracted substance in
the respective clones were not high and were within the range of 10 % of the corresponding
component. Hence, the effect of the chemical composition on the pulp yield was relatively
low. The differences in the planting schemes (density) of the Black locust clones had greater
influence on the productivity and efficiency of the pulping process. The authors found that Robinia
pseudoacacia L. has the highest potential in Bulgaria for glucose production. The glucose yield
after enzymatic hydrolysis of steam-exploded Black locust is approximately higher in comparison
with corresponding treatment of maize stalks, wheat straw and fast-growing poplar and willow.
The conclusion is that there are opportunities for plantation harvesting in Bulgaria of separate
Robinia pseudoacacia L. clones for chemical pulp or glucose for production bioethanol.

Abstract

The regeneration of montane Norway spruce (Picea abies (L.) Karst.) forests is among the most challenging silvicultural issues due to the extreme climatic conditions at high altitudes, particularly after large-scale natural disturbances. The aim of the study was to compare the development of the natural and artificial regeneration in the period 2006-2014 in a cleared windthrow area of 14 ha, which resulted from a wind-disturbance in 2001. The study area was situated in Ofeliite site, Vitosha Mountain, West Bulgaria. The forest regeneration was studied in 16 permanent sample plots of size 10 m x 10 m (100 m²). We found that the intensity of natural regeneration decreased significantly five years after the windthrow. Dominant species was Picea abies, which regenerated most frequently on decaying deadwood. The artificial regeneration had 5 times lower numbers than the natural one. This could be due to the low planting density and the higher mortality rate of planted spruce seedlings in comparison to the naturally established ones. The risk of mortality was highest among saplings lower than 0.5 m. The main reasons for the observed mortality were the withering and suppression by other plant species such as Rubus ideaus L. and Calamagrostis arundinacea (L.) Roth. Our results suggest that the natural regeneration was more important than the artificial planting for the restoration of the wind-disturbed spruce forest in Ofeliite site. In this respect, sustaining abundant seedling bank as well as sufficient quantities of decayed deadwood as regeneration substrate and microhabitat in the managed spruce forests can help adequate natural regeneration after large-scale disturbances.

Abstract

In the area of Jablanica Region (Public Enterprise Srbijasume, Forest Estate Leskovac), after
a thirty-year period of latency, significant increase of gypsy moth population level occurred three
times (1996-1997, 2002-2005 and 2011-2014). In the culmination phases, attacked areas were:
22,425 ha (1996), 38,856 ha (2004) and 18,272 ha (2013). The retrogradation phases occurred
in the autumn of 1998, 2005 and 2014, so it was the result of effective aerial control in the larval
instar with microbiological (Foray 48B) and biotechnical (Dimilin SC-48) insecticides as well as
of the increased activity of natural enemies. The analysis of gypsy moth egg masses was made
on a yearly basis. The average number of eggs ranged from 297.7 (1997; 320 investigated egg
masses) to 507.2 (2013; 580 investigated egg masses). The percentage of vital eggs ranged from
89.5 in 2013 to 97.2 in 2012. Average parasitism of eggs ranged from 2.5 % in 2012 to 25.4 % in
2004. Every year only two species of egg parasites Anastatus japonicus Ashmead and Oencyrtus
kuwanae (Howard) were present. Every year the ratio of them was relatively equal with the clear
dominance of O. kuwanae. In the spring of 2012, 2013 and 2014, the increased mortality rate of
larvae was reported and analysed. During the field research clear symptoms of disease caused
by Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV) and typical symptoms of
the fungal diseases caused by Entomophaga maimaiga Humber, Shimazu and R. S. Soper were
found on dead gypsy moth caterpillars. By microscopic analysis of dead caterpillars, the presence
of LdMNPV occlusion bodies, conidiospores and azigospores of E. maimaiga was confirmed.

Abstract

A study of the Ðœaritsa barbel in the Stryama River, a tributary of the Maritsa River was carried out. The material was collected in autumn from 2006 to 2011 by electrofishing. A total of 537 specimens of Ðœaritsa barbel were caught. The population was represented by six age groups. The rate composition was simple. In the catch of the barbels in the Stryama River dominated third age groups. The dominating size group in the sample of barbel in the Stryama River was between 61-70 mm long. The relationship between the average values of L (standard length) and S (scale radius) was described by the equation: L = 13.7486+2.8974.S; correlation r = 0.9694. The barbel in the Stryama River reaches a smaller length than the barbel in the rivers Arda and Doirani. The relation between fish weight (W) and length in the population was represented by the equation: W = 0.00002. L^2.896; r = 0.9996. The Maritsa barbel in the Stryama River had a lower condition factor than the barbel in the rivers Arda and Maritsa.

Abstract

A study of the Ðœaritsa chub in the Stryama River, a left tributary of the Maritsa River was carried out. The research was conducted in autumn in the period 2006-2011. A total of 458 specimens of Maritsa chub were caught by electrofishing. The size-age composition was simple. The population was represented by five age groups. The chub's population in the Stryama River was dominated by young and middle size groups. The relationship between the average values of L (standard length) and S (scale radius) was described by the equation: L = 17228+2.1934.S; correlation r = 0.9979. The length growth of the chub in the Stryama River is relatively fast. The relation between the fish weight (W) and length of the population was represented by the equation: W = 0.000009.L3.1154; r = 0.9996. The condition factor of the chub in the Stryama River is one of the lowest in comparison with the other water courses in the Aegean catchment area.

Abstract

Finding ways to assess the productivity of exotic species under the new climatic conditions is
an important part of the successful introduction of silvicultural practices. The purpose of this research
is assessment of intra-population polymorphism in Douglas fir stands in terms of seasonal
development, color of female strobili and anthers, and bark texture (structure). Concerning the
seasonal development and phenology, the following phenotypes were distinguished: very early,
early, middle, late and very late; according to the color of female strobili - green, greenish-brown
and purple; according to the color of anthers - yellow, orange, purple and brown; and according
to bark texture (structure) - deep fissured cork (coarse bark), middle fissured cork (transitional)
and shallow fissured cork (plane bark) phenotype. Each of the plants was characterized by a
highly individual phenotypic spectrum. The most informative and accessible for practical use were
phenotypes on of bark structure: coarse bark phenotype - bark cork, light, in the form of massive
plates of thickness greater than 5 cm with cavities, divided by deep fissures. At the age of 70-75
years the bark in the butt-log part gradually peels off and falls to a height of 2-3 m. A new bark is
formed actively instead of the fallen one. Transitional phenotype - bark is relatively dense, thickness
up to 4-5 cm, shaked, moderately deep fissures. There is a detachment of the bark at the
root collar to a height of 0.7-1.0 m. Plane bark phenotype - bark is dense, thin, thickness up to
2-3 cm, small plates, cloven by shallow fissures, not exfoliate. Morphological polymorphism of
Douglas fir under bark texture (structure), clearly expressed in the form of introduction populations,
notably characterized by growth index. Trees of deep fissured cork (coarse bark) phenotype
are considered as the most productive. At the age of 71, their average height is 30.8 m, average
diameter - 42.7 cm. Trees of middle fissured cork (transitional) demonstrated lower height by 8 %
and diameter by 20 %. Both phenotypes had a small degree of tapering and a well-developed
crown. Trees of shallow fissured cork (plane bark) phenotype ranked below in height by 25 % and
by 42 % in diameter and are characterized by higher values of variation coefficients. They form a
canopy in the second planting as a regrowth. Thus, deep fissured cork (coarse bark) and middle
fissured cork (transitional) phenotypes are the most promising for planting.

Abstract

The present study is based on the differential concentrations of nutrients and heavy metals
observed in Pinus brutia Ten. needles resulting from the influence of various factors, such as
traffic and topographical conditions in four sites in urban and periurban areas of Thessaloniki,
Greece. The results showed that there were significant differences in nutrient and heavy metal
concentrations in the needles collected in the four sites. In particular, the samples from the periurban
forest exhibited significantly higher concentrations of Mg and Ca than the samples collected
in the sites near the centre of the city. The significantly higher concentrations of K observed in the
samples collected from two sites in the city, are possibly attributed to the fertilization of the parks.
The high concentrations of Na found in the samples collected in sites of the periurban forest, are
due to topographical conditions and aerial deposition. However, the highest level of Mn and Zn
observed in the samples collected in the site of the periurban forest located far away from the
busy ring road, is mainly attributed to soil type. High levels of Cu, Pb, Ni and Cr concentrations
were found in the needles collected from the sites close to the busy traffic roads of Thessaloniki.
No significant differences in the levels of Fe and Cd among the samples of the four sites were
found. However, the concentrations of elements measured in P. brutia needles collected in the
urban and periurban areas of Thessaloniki are below the normal level and as a result they do not
constitute an alarming pollution agent in the city.

Abstract

The present study has been carried out to reveal the structure according to height of relatively even-aged - mature and middle-aged Scots pine dendrocoenoses in Rila and the Rhodopes Mountains and Sakar Mountain. A total of 111 sample plots have been established, 68 of these being in mature, natural Scots pine forests and 43 in young and middle-aged ones. Study has been aimed at analysing the structure according to height of natural Scots pine dendrocoenoses with a view to model their volume and their assortment structure. The height curves for both age groups of stands have been investigated. Yurdan Douhovnikov's method of natural indicators (MNIs) has been applied. Three groups of curves have been found out according to their levels of declivity, namely: slightly inclined curves, characteristic of the stands of zero natural indicator (ZNI) SHo > 1.1, semi-steep curves with 0.86 ≤ SHo ≤ 1.09, and steep curves with SHo ≤ 0.85. The distribution according to types of declivity has been investigated in two scenarios - separately and as a whole. This investigation has resulted in finding distributions of close values in both scenarios for the particular age groups, especially the general distribution. That gives reasons for investigating the stands as a whole in terms of their height structure through the method of natural indicators regardless of age. It was found that the average relative curves of the heights (or average curves of normal numbers) surveyed dendrocoenoses of Scots pine and United average curve of the relative heights of Turin are too close on his course. Since an average curve of Turin has been established for all species, this proximity proves the possibility of establishing common average diluted curves of the heights of Scots pine along with other tree species.

Abstract

Acid-base properties in cinnamonic forest soils (Chromic Luvisols) and forest litter under
different fire-affected stands of tree species have been studied. The samples were taken
immediately after fire, 1 month, 3 months and 1 year after it from affected and from unaffected
(control) areas. The depth at which soil sampling was performed was from 0 cm to 5 cm and
from 5 cm to 20 cm. Soil and litter acidity (pH) was measured potentiometrically in an aqueous
extract. The most pronounced changes in pH values in comparison with the control variants was
established in soil samples, taken from influenced by a surface fire broadleaf stand of Quercus
pubescens Willd. The pH changes in the samples from forest litter were more pronounced than
the changes registered in soil samples. A trend of a soil acidity increase was established till one
year after fire influence for Austrian pine plantations and oak stands.

Abstract

The study took place in the period 2008-2012 in Pismenovo arboretum, situated in the peripheral sub-region of Strandzha Mountain (South-Eastern Bulgaria). Nitrogen and macroelement contents were examined in the leaves of 21-25-year-old specimen belonging to the following species: Pinus nigra Arn. ssp. austriaca Hoss, Pinus nigra Arn. ssp. laricio Poiret, Cedrus deodara Loud., C. atlantica Manetti, C. libani A. Rich., Cupressus sempervirens L., Quercus petraea (Matt.) Liebl. (3 provenances), Q. robur L. (4 provenances), Q. pubescens Willd., Q. rubra L., Q. suber L., Q. harwissiana Stev., Q. frainetto Ten., Fagus sylvatica L., F. orientalis Lipsky and Tilia tomentosa Moench. Nitrogen content in the leaves of most deciduous species was the highest in May, maintaining comparatively high values in June and gradually lowering in the next months until the end of growing period. P₂O₅ content had its maximum value in the summer months, keeping relatively high values until the end of the growing period. K concentration in the leaves of most species was highest in August. Ca and Mg content gradually increased from the beginning to end of the growing period. N, P and K content in the coniferous species was significantly lower as compared to the one in the leaves of the deciduous species, which makes the latter ones more tolerant to soil fertility. Of conifers, the lowest concentration of these substances was recorded in the needles of the Atlas cedar. In deciduous species the highest content was measured in Tilia tomentosa and Quercus hartwissiana and the lowest one - in the leaves of the Cork oak. There were also differences among the provenances within a species. In Cedar needles, Ca and Mg concentration is 2 times higher, compared to that one in the needles of Black pine and Pinus nigra Arn. spp. laricio. It is obviously a characteristic biological particularity. The differences should be considered when modelling nutrient circulation in forest stands and when evaluating the longterm sustainability of forest management.

Abstract

The rainfall amount and its chemical composition were studied in the period 2009–2013 in the Pismenovo arboretum, situated close to Black Sea coast (Tsarevo State Forest Service). The objective of the proposed work comprises conducting of prolonged studies on N, P₂O_5, K₂O, Ca and Mg content and the highlighting of the particularities in the seasonal dynamics of the above mentioned elements in the leaves of some tree species. The purpose of this work comprises a conducting of longer comparative research on the dynamics of the chemical composition of atmospheric precipitations under the canopy of different forest-tree plantations. The results showed that Black pine (Pinus nigra Arn.) crowns capture 29.2 % of the total rainfall amount at open field. The same percentage in Atlas cedar (Cedrus atlantica Manetti) was 34.4 %, in Common oak (Quercus robur L.) - 6.5 %, in Black locust (Robinia pseudoacacia L.) - 23.3 % and the throughfall in the 75-year-old coppice oak forest was 15.8 %. A difference in the chemical composition of throughfall has been determined, depending on age and species (coniferous or deciduous). The pH value of the throughfall and that of rain water at open field had acid to slightly acid reaction, and the acidity increased during the winter. The lowest values of pH were measured in the water passed through Black pine crowns, and the highest ones - in the water passed through the crown of Black locust. Most nitrate ions were registered in the throughfall fluxes of Black pine. Most ammonium ions were detected in the throughfall fluxes of the 75-year old coppice oak forest, and chloride ions - in the throughfall of Atlas cedar. The content of calcium and magnesium in the throughfall also increases in comparison to that one measured in open field fluxes. The highest content of these two elements was recorded in the throughfall of Black locust.

Abstract

Biodiversity of ecosystems is determined to a considerable extent by the diversity of herbaceous species. The aim of this study was to examine and compare diversity of herbaceous species in the forest, ecotone, and pasture located in upland areas in Shirud, Mazandaran Province, Iran. In each area, eight 100 m² circular sampling plots were established along a transect using random-systematic method, and coverage of herbaceous species was recorded in each plot. There were significant differences in diversity, evenness and richness among the forest, ecotone and pasture areas. The results of ANOVA and Duncan's tests indicated that the forest and pasture sites had higher diversity compared to ecotone. Jaccard and Sorensen's similarity coefficients also confirmed the better growing conditions for herbaceous species in the forest and pasture sites in comparison to the ecotone. This paper presents evidence that species diversity is closely linked to grazing intensity.

Abstract

This study investigates the effect of canopy gaps created by single-tree selection cutting on regeneration density and diversity in Oriental beech (Fagus orientalis Lipsky) forests of Northern Iran. Five gaps within each of three different size classes (small (100-200 m²), medium (200-300 m²), and large (300-400 m²)), together with 15 control areas located in the undisturbed forest surrounding each gap were randomly selected. Abundance of tree regeneration was measured in 4-m² quadrates established within each gap and control area. The percent cover of herbaceous species and litter depth was also quantified. Shannon diversity, Smith-Wilson evenness and Margalef richness indices were then computed for each quadrate. Results indicated that percent cover of herbaceous species increased significantly with increasing gap size while the opposite was observed for litter depth. Species richness and Shannon diversity index values were higher in gaps than in control areas, but significant differences were only detected between medium size gaps and control areas. With the exception of large gaps, regeneration density was higher in gaps than in control areas. These results indicate that natural tree regeneration in beech forests of Northern Iran tends to be maximized at intermediate levels of canopy gap size, which also correspond to intermediate levels of litter depth and percent cover of herbaceous species.

Abstract

One strategy for mitigating the effects of climate change on forests in an uncertain future is
the allocation of risk across a portfolio of different tree species. Since the beginning of 2009, a
project of the Bavarian State Institute of Forestry (LWF) has sought to identify warm- and droughttolerant
exotic tree species suited to conditions expected in Bavaria under climate change. As an
outcome of this process, six potential non-native tree species were selected for the establishment
of species trials in Germany (Bavaria and Thuringia), Austria and southern Switzerland. Parallel
to the creation of young trial plantations, one species - Pinus peuce - was analyzed in detail in
67- to 105-year-old planted stands in Bavaria to obtain complementary information. This effort
sought to quantify growth and performance of this species and compare these results with those
of other tree species already grown successfully in Central European forests, e.g. Norway spruce,
Scots pine, Еastern white pine, and Douglas fir. Measurements in four small planted stands in
the Grafrath Experimental Forest showed mean DBHs from 26.8 to 43.8 cm and average heights
from 24.1 to 28.4 m, with single tree volumes ranging from 0.7 to 1.8 m³. Due to drought conditions,
particularly during a period of increased temperatures, the radial growth rate of P. peuce
was considerably reduced in 1976 and 2003 and beyond, after which the species recovered only
moderately. As a consequence of decreasing precipitation and more frequent late spring frosts, P.
peuce exhibited strong negative reactions in annual ring growth. In general, these trees reacted
positively to increasing mean annual temperature. Despite high volume production, the results
revealed several uncertainties about the suitability of P. peuce for southern Bavaria under conditions
of climate change. Based on the assumption of further decreases in precipitation in the near
future, P. peuce can be expected to suffer increasingly from drought stress and to demonstrate
decreased annual increment. Nevertheless, the species seems to be appropriate for afforestation
in montane areas because of its proven resistance to wind throw and snow break.

Abstract

In this study, we investigated line transect sampling methods with k-fixed trees (k = 2, 3, 4 and 5) to estimate quantitative variables in Zagros open forests in the west of Iran. Accurate measuring and commercial benefits are two aspects of sampling methods that are important for forest managers. The results of full callipering inventory indicated that density above 12.5 cm DBH, basal area and canopy were 68.04 trees.ha^-1, 15.16 m².ha^-1 and 35.71 % ha^-1 respectively. Based on ANOVA test, mean of measured variables in the line transect sampling methods with k = 2, 3, 4 and 5 were statistical different (P = 0.00). The results of study showed that the mean of density, basal area and canopy variables using transect sampling with k = 5 trees were closest to actual means derived from full callipering inventory. Our findings showed that line transect sampling method with k = 5 fixed trees had reliable results and was statistically reliable, efficient and practical method to estimate of the quantitative characteristics in Zagros open forest area.

Abstract

One of the main consequence of intensive forest exploitation, overgrazing and recurring
wildfires over the centuries is the decay of forest cover and soil erosion. In many areas of
the Italian Apennines, Black pine (Pinus nigra Arn.) plantations were established after the
Second World War to improve forest soil quality in marginal and eroded soils. The main aim of
these reforestations was to re-establish the pine as a first cover, pioneer species. This was a
preparatory step to the reintroduction of broadleaf trees originally living in the same areas, such
as oaks and beech trees, and thus to the reestablishment of mixed forests (renaturalisation).
Currently in Tuscany, the key functions of these stands are the protection against soil erosion
and the hydrological regulation of catchments. In order to guarantee the multifunctional role of
these stands, it is necessary to realize silvicultural treatments finalized to the renaturalisation.
The present research, carried out in a mountainous area in Tuscany, aims to evaluate the
effects of different thinning (selective and traditional) on floristic and mycological diversity. Six
experimental plots were established, and different intensity of thinning were applied. Results
highlight that the intensity of thinning is directly related to the stability of the stands and also
increases the overall biodiversity. In particular, positive effects were evidenced on marketable
mushrooms production and on floristic diversity.

Abstract

In Eastern Stara planina Mountain, during a 3-year period with some intermittences due to repair
works, the following technological schemes have been studied and implemented during practical
work: 1) felling of trees using a chain saw, haulage of whole trees by a skidder, felling, delimbing,
bucking, cut-to-length (CTL) of full trees by a harvester and assortments transportation by a forwarder;
2) felling and a primary processing of trees by chain saws, haulage of assortments by a skidder
and transportation by a forwarder, and 3) felling and primary processing of trees by a harvester and
forwarder of assortments. The application of the respective technological scheme depends on the
available forest-exploitation conditions. The following machines have been used for the purpose:
TK 40 Bolgar and Universal-651 skidders, John Deere 1270D harvester and John Deere 1110D
forwarder. The machines John Deere 1270D and John Deere 1110D have been bought second
hand (as used machines). The studies have been conducted in Black pine plantations (Pinus nigra
Arn.) and Scots pine ones (Pinus silvestris L.), growing on terrains of a hilly and up to a mountain
character. The conditions are as it could be expected after fires, windfalls, snowbreaks, and calamities
but appropriate for works which are to be performed by the studied machines. The forestry targets
include a clearance of the above mentioned areas, i.e. the clear cuttings. Productivities from 26 up
to 68 m3/day have been achieved being its lower limit related to a technology where a chain saw is
used while the upper one is related to a completely mechanized technology.As for the harvester and
the forwarder, their productivities differ one from another, taking into consideration that the size of the
trees exerts greater influence on the work performed by the harvester. Multi-operational machines
operators‘ professionalism and experience are significantly important for the implementation of the
works and both professionalism and experience are gained by knowledge obtained in the course of
a specialized training.