Issues


Issues: 1-5 | 6-10
Downloads: 1757

ECTOMYCORRHIZA – NATURE AND SIGNIFICANCE FOR FUNCTIONING OF FOREST ECOSYSTEMS

Teodor Nedelin

Department of Silviculture, Faculty of Forestry, University of Forestry, 10 Kliment Ohridski Blvd.,
1797 Sofia, Bulgaria. Е-mail: nedelin@ltu.bg; teodor_nedelin@hotmail.com

Abstract:

The ectomycorrhiza has a great influence on vegetation and for the forest ecosystems it is essential.
The present review aims to provide brief information about main participants – myco- and
phytobionts in such a well-organized mutualistic association, their structural elements, function
and role in the natural processes. It also emphasizes that ectomycorrhizas has no equal value
through the fungal species. Furthermore the last complement each other in their ecological niches
and as a result we can observe optimal exploration of site which is very outlined in habitats, where
there is a deficit on one or more mineral elements. Describing ectomycorrhizal mycocoenosis is
very challenging task and provide valuable information about all the community as a whole. For
this, the molecular markers are excellent tools but must be combined with morphological and
anatomical studies, because only thorough studies can bring better understanding of the driving
processes at ecosystem levels.

(Forestry Ideas, 2014, Vol. 20, No. 1) [Download]
Downloads: 759

DYNAMIC THIRD-GENERATION WHOLE-STAND MODEL FOR SCOTS PINE PLANTATIONS IN BULGARIA

Tatiana Stankova(1)* and Ulises Diéguez-Aranda(2)

1. Department of Forest Genetics, physiology and plantations, Forest Research Institute of the Bulgarian Academy of Sciences, 1756 Sofia, Bulgaria. E-mail: tatianastankova@yahoo.com
2. Department of Agroforestry Engineering, University of Santiago de Compostela,
27002 Lugo, Spain. E-mail: ulises.dieguez@usc.es

Abstract:

The main objective of this investigation was to derive a dynamic third-generation whole-stand
model, which consists of a flexible system of mathematical equations presented graphically -
Stand Density Management Diagram (SDMD) – and allows good description of the development
of the stands over time. A new SDMD for Scots pine plantations in Bulgaria was elaborated that
included two improvements as compared to the preceding SDMD. The Natural thinning curves
(NTC) sub-model was presented in a dynamic equation form and was estimated over repeated
measurements data from permanent sample plots. The Equivalent height curves (EHC) submodel
was reformulated to include a site index-specific parameter, which produced SDMDs differentiated
by site index classes. The principal sub-models of the SDMD were fitted with high level of
determination and produced unbiased and statistically significant parameter estimates. The NTC
in generalized algebraic difference equation form provided the maximum possible model flexibility
by means of stand-specific shape and asymptote of these trajectories. The slope parameter of the
self-thinning asymptotes α had value of 1.74. The new model improvements added to its precision
and assured improved predictive abilities.

(Forestry Ideas, 2014, Vol. 20, No. 1) [Download]
Downloads: 939

APPLICATION OF GEOGRAPHICAL INFORMATION SYSTEM FOR MAPPING FIRE RISK AND DESIGNING FOREST ROADS

Aidin Parsakhoo

Department of Forestry, Faculty of Forest Science, Gorgan University of Agricultural Sciences
and Natural Resources, P. Box 386, Gorgan, Iran. E-mail: Aidinparsakhoo@yahoo.com

Abstract:

Fires are one of the most important disturbances in forests and they damage them. This study
was conducted to classify fire risk for a deciduous forest and to predict the locations of forest
stands for which fire control operations are required. Normalized Difference Vegetation Index
(NDVI) and Moisture Vegetation Index (MVI) were extracted from satellite imagery of IRS LISS III
and Landsat 7 ETM+, respectively. Altitude, slope aspect and slope gradient maps were obtained
from a digital elevation model using surface analysis in ArcMap. Buffers were created from 0 to
300, 300 to 600, 600 to 900 meters and over 900 meters along the road and around the cattle
pens as zones with different levels of fire risk. All the thematic layers were then integrated using
the overlay procedure in GIS. Results from the analytical hierarchy process showed that vegetation
indices were given the largest weight. The influence of slope gradient on fire behavior was assessed
the third largest weight. Slope aspect was assigned the same weight as to slope gradient.
The distance from roads and cattle-pens was evaluated with the fourth largest weight. 25 % of the
forest area is classified as area with very high degree of vulnerability to fire. This class is generally
distributed in the entire region, while areas with very low fire risk are found in the northern parts.

(Forestry Ideas, 2014, Vol. 20, No. 1) [Download]
Downloads: 756

THE EFFECTS OF FOREST SITE CONDITIONS AND STANDS’ AGE ON LITTER MICROARTHROPOD DENSITY AND COMMUNITY STRUCTURE IN ZHYTOMYR
POLISSYA, NORTHERN UKRAINE 

Nazar Kalynovskyi

Department of Forest Resources Exploitation, Zhytomyr National Agroecological University, 7,
Staryi Blvd., Zhytomyr 10008, Ukraine. E-mail: nkalynovskyi@mail.com

Abstract:

The effects of forest site conditions and age of stands on absolute density and community
structure of litter microarthropods were studied in pine forest in Zhytomyr Polissya, northern
Ukraine. Litter samples from cuts, non-closed, young, middle-aged, and mature stands in a mesofilic
pine forest (site condition A2) and mesofilic Pinetum compositum (site condition B2) were
collected, microarthropods were extracted, counted and identified to main taxa. Mean absolute
density of total microarthropods and their main taxa was higher in B2 site conditions for all ages
of stands, except the young. Within each type of forest site conditions, litter microarthropod density
fluctuated depending on the age of stands. However, the differences in absolute densities
for most microarthropod taxa were statistically significant only between stands of distant age
groups: between cuts and middle-aged or mature stands. Decreased absolute density of total
litter microarthopods, Acari, and Collembola observed in cut sites and non-closed stands may be
the result of forest floor disturbance associated with harvesting and decreased litter input. In microarthropod
community structure, relative densities of Mesostigmata and Astigmata increased,
whereas Collembola density decreased along forest age gradient. The differences were significant
in middle-aged and mature stands relative to cut sites.

(Forestry Ideas, 2014, Vol. 20, No. 1) [Download]
Downloads: 835

ANALYsIS OF THE FOREST SEED PRODUCTION BASE OF ACER PLATANOIDES L. IN BULGARIA

Vladimir Tomov, Nasko Iliev, and Ivan Iliev*

University of Forestry, 10 Kliment Ohridski blvd, 1797 Sofia, Bulgaria.
  *E-mail: ivilievltu@yahoo.com

Abstract:

The research considers all Norway maple seed sources included in the National Register of
Forestry Seed Production Base in Bulgaria. Also, all forest stands and plantations where Norway
maple shares more than 50 % of the composition were selected from the National Data Base of
Forest Territories in Bulgaria. The age, mean height and diameter at breast height (DBH) were
determined. For the plantations, where the initial planting design was known, the percentage of survival
was calculated. For estimation of growing indicators, Tables for High Beech Stands were used,
according to the accepted Equivalency List of Tables for Tree Species and Used Abbreviations.
The site index, height rates, density (DS), basal area (Gba) and volume (V) per 1 ha, mean annual
diameter increment (Zd) and mean annual height increment (Zh) were calculated. The selection category
of the stands was defined according to the height, in the tables for growth and productivity for
High-stemmed beech stands, I-st site index. For determining the selection structure of the stands,
the categorization of trees, accepted in the method for analysis of forest plantations was used. The
altitude of the forest stands, where the Norway maple predominates, varies from 100 to 1000 m
with mean value of 400 m. Both natural stands and plantations are located in habitats, categorized
as moderately-rich to rich. The moisture level of the soils is relatively good – from fresh to humid.
The terrain expositions of the stands are heterogeneous i.e. 61 % of them are located on shady
and 39 % on sunny expositions. The analysis of silvicultural and dendrometric characteristics of the
investigated objects shows that Norway maple could have predominantly participation in both forest
plantations and natural forest stands. The intensive height growth of the species was registered in
both the sub-belt of plane-hills Oak forests and the sub-belt of low-mountain forests of Sessile oak,
Common beech and Common fir. This fact shows its pliability to the habitats within the altitudes
from 150 to 900 m. The mean diameter at 1.3 m, in the 44–54 years old stands varies from 18 cm to
30 cm. In the category “absolute plus” fall the stands in SFS Berkovica, Vidin, Byala and Gurkovo.
However, the results show that the number of stands valuable from the breeding point of view with
predominant participation of Acer platanoides, is limited, especially in South Bulgaria. Meanwhile,
the presence of valuable phenotypes requires their conservation and wider use for production of
seedlings for forestry and urban planting.

(Forestry Ideas, 2014, Vol. 20, No. 1) [Download]
Issues: 1-5 | 6-10