Issues


Issues: 1-5 | 6-10
Downloads: 21

DECLINE MODELLING OF OAK TREES UNDER EFFECTS OF PHYSIOGRAPHIC FACTORS IN SEMI-ARID FORESTS OF IRAN

Mehrdad Mirzaei (1)*, Amir Eslam Bonyad (1), Reza Akhavan (2), and Ramin Naghdi (1)

1. Deparment of Forestry, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran. *E-mail: mehrdadmirzaei28@gmail.com
2. Forest Research Division, Research Institute of Forests and Rangelands, Tehran, Iran.

Abstract:

Recent dust and droughts caused stress to physiological weakness of oak trees, so that insect
outbreaks and pathogens lead to decline of oak trees in the Zagros forests. In addition to evaluate
the effects of physiographic factors (elevation, slope and aspect) on the amount and distribution
of decline, the objective of present study was to make a model of decline of Quercus brantii species
in semi-arid forests of Iran. For this purpose, 509 hectares of Zagros forests, known as Dalab
forests in Ilam province, were selected. Based on systematic-random sampling method, 100
circular plots (2000 m2) were measured in grid inventory of 200×250 m dimensions. In each plot,
physiography factors and percentage of decline were measured. ANOVA and Duncan tests were
used to compare the decline of oak trees in different physiography factors. Then, an individual
tree decline models were developed with a data set from a total of 1370 oak trees. To evaluate
the effects of physiographic factors on the decline of oak trees, a logistic regression model was
used. Omnibus test, log-likelihood, and pseudo r-square coefficients were used to evaluate the
logistic regression model. The results showed that physiography factors had significant effects
on the decline of oak trees. Also, the results showed that with increasing slope and elevation,
the decline of oak trees was increased. Lowest and highest declines belonged to east and south
aspects, respectively. Values of both statistics related to the pseudo determination coefficient are
acceptable (0.395 and 0.584), and these values indicated that the three independent variables
of this study had the power of a relatively high explanation of the variance and changes in the
dependent variable of trees decline. The results of this study can be effective in the oak decline
area conservation.

(Forestry Ideas, 2018, Vol. 24, No. 2) [Download]
Downloads: 17

WILLINGNESS TO PAY ESTIMATION FOR RIVERS BIODIVERSITY CONSERVATION, CASE STUDY OF GUILAN PROVINCE, NORTH IRAN

Tooba Abedi (1), Ladan Kazemi Rad (1), Nazi Avani (2)*, and Behnam Yusefi (3)

1. Academic Centre for Education, Culture and Research. Environmental Research Institute,
Rasht, Guilan, Iran. E-mails: t.abedi@acecr.ir, L_Kazemi@erijd.ir
2. Teaching Fellow, School of Distance Education, Universiti Sains Malaysia.
*E-mail: avani.nazi@yahoo.com
3. Graduate Student of Forestry, Faculty of Natural Resources, Guilan University, Iran.
E-mail: behnamyousefi67@gmail.com

Abstract:

This study attempts to value the biodiversity and landscape services provided by four river
spots: Khalkaei, Ghaleeroodkhan, Pasikhan and Shemroud of the North region of Iran, Guilan.
The Contingent Valuation Method were used for estimation willingness to pay (WTP) for conserving
these areas. This method tries to define the individual’s WTP of given hypothetical market. It
was estimated with a logit model for which indices were obtained based on a maximum precision
criterion. The results show that 79.45 % of people were willing to pay for the landscape and biodiversity
value of the rivers. Among the variables of the model presented, monthly expenditure
and gender had a negative impact and age, education, environmental opinion and income had a
positive impact on the WTP at 1 % level. The average monthly WTP per visitors was calculated as
21,913 Rials (0.74 $). The annual landscape and biodiversity value in terms of WTP for the landscape
and biodiversity was estimated for Khalkaei, Ghaleeroodkhan, Pasikhan and Shemroud as
2 milliard, 15 milliard, 2 milliard and 8 million Rials, respectively. One unit change in descriptive
variables (Education and Environmental opinion) showed the highest change in the probability
of a positive response to the WTP among individuals. Therefore, in order to facilitate individual’s
involvement in public decision-making policies, improvement in perceptions of environmental
awareness and educational level would seem desirable.

(Forestry Ideas, 2018, Vol. 24, No. 2) [Download]
Downloads: 18

RELATION OF SLOPE AND VEGETATION COVER WITH THE PROBABILITY OF LANDSLIDE OCCURRENCE NEAR FOREST ROADS

Alireza Ghomi Motazeh (1)*, Roghaye Baniasadi (2), and Rosanna Gahler (3)

1. University of Guilan, Department of Natural Resource, Iran. *E-mail: Alireza.Ghomi@yahoo.com
2. University of Birjand, Department of Agriculture, Iran. E-mail: Roghaye.Baniasadi@yahoo.com
3. University of Freiburg, Faculty of Natural Resources, Germany.
E-mail: Rosanna.Gahler@gmx.de

Abstract:

Many natural disturbances accrue in Iran because of its geographical condition. Mostly the recovery
of this damage is impossible or requires a lot of time and cost. The general purpose of this
research is to find out the relationship between slope of the terrain and the vegetation cover from
one side and the mass movement of land from the other and to finally illustrate applicable data in
the field of forest road construction. In this research, 39 cluster samples at a distance of 700 m
along the 28 km of road were taken by systematic random method. In each cluster, the first sample
was taken 50 m upward from the road; the second sample was taken 50 m downward from
the road and the third sample was taken 10 m off the road. The number of landslides in each area
and its relationship with road construction was analyzed in dependence of the terrain slope and
the percentage of vegetation cover. Results showed that a road construction could be an effective
factor for increasing mass movements. Moreover, excavated slope causes an increase of mass
movement, too. Results of the research also indicated that there was an inverse relationship
between an increased percentage of vegetation cover and the frequency of landslide occurrence.

(Forestry Ideas, 2018, Vol. 24, No. 2) [Download]
Downloads: 26

GAS-EXCHANGE RESPONSE OF NORWAY MAPLE (ACER PLATANOIDES L.) AND SILVER LIME (TILIA TOMENTOSA MOENCH) SAPLINGS TO FOREST THINNING

Svetoslav Anev* and Nikolina Tzvetkova

Department of Dendrology, Faculty of Forestry, University of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, Bulgaria. *E-mail: svetoslav.anev@ltu.bg

Abstract:

A species-specific initial response of gas-exchange and water use efficiency of Norway maple
and Silver lime saplings were observed after a forest thinning. The photosynthetic rate increased
significantly both in Norway maple and Silver lime leaves. The transpiration rate of Norway maple
increased more intensively, in comparison to Silver lime. Norway maple saplings suffer both from
intensive light and moisture deficit, while Silver lime saplings were more resistant to the patch
opening. Stable water use efficiency in Silver lime leaves in response to the thinning may result
from the better ability of this species to keep available water, which could be considered as the
greater resistance to patch opening. These results may serve as a basis for improvement of forestry
approaches in mixed deciduous forests with the presence of Norway maple and Silver lime.

(Forestry Ideas, 2018, Vol. 24, No. 2) [Download]
Downloads: 23

ROCK PARTRIDGE (ALECTORIS GRAECA) RECOVERY PROGRAM: FIRST EVIDENCES ON SURVIVAL AND DISPERSION RATE OF SEMI-NATURAL REARED BIRDS IN ′VRACHANSKI BALKAN′ NATURE PARK

Christo Mihajlov, Gradimir Gruychev*, Stoyan Stoyanov, and Evlogi Angelov

Wildlife Management Department, University of Forestry, Sofia 1797, 10 Kliment Ochridski
Blvd., Bulgaria. *E-mail: gradi.val@gmail.com

Abstract:

Rock Partridge (Alectoris graeca Meisner, 1804) is endemic to Europe, occurring only in the
Alps, the Apennines, Sicily and the Balkans. It is suspected to be declining moderately rapidly,
particularly in the Balkans which hold a substantial proportion of the species population and
range, based on a balanced assessment of the available evidence. Survival rates of 50 released
rock partridges in typical habitats in ‘Vrachanski Balkan’ Nature Park were studied during the reintroduction
program. Almost all released birds were monitored for 110 days. Twenty of them were
marked with radio transmitters, which allowed the survival rate to be determined, dispersion and
habitat preferences. Birds mortality reached 70 % at the end of survey period and only 6 (30 %) of
them survived and bred in the next spring. Most birds (65 %) died in the first month after release
due to predation. The main predators were mammals (92 % of mortality) while the avian raptors
caused an insignificant part of mortality (8 % of mortality). In cold winter days with temperatures
lower than -25 °C only one dead bird was found. The survival rates of Rock Partridges did not
depend on sex (χ2 = 0.05, p = 0.82, df = 1) and age (χ2 = 0.1, p = 0.9, df = 1). The birds’ dispersion
varied from 35 m to 1.3 km. However only single birds moved more than 1 km away from the
release point.

(Forestry Ideas, 2018, Vol. 24, No. 2) [Download]
Issues: 1-5 | 6-10