Volume 9, July 2007

By Naama Tessler (naamat@rmh.org.il), Lea Wittenberg, Dan Malkinson and Alon Halutzy, Dept. of Geography and Environmental Studies, University of Haifa, Haifa, Israel


Development of a GIS-based Archive

Forest fires are a common phenomenon in Israel during the summer and the transition seasons, and they are characterized by high spatio-temporal unpredictability in terms of occurrence and damage caused. Forest fires in Mediterranean ecosystems have complex effects on geomorphological and ecological processes, because of the complexity of landscape structures and of the differing responses of such systems to various types of fires regimes.

The Mediterranean ecosystem of Mt. Carmel in Israel is subjected to increasing numbers of forest fires of various extents and severities. During the last 28 years, at least 9 large wildfires occurred, each of which consumed areas of 80–530 hectares, as well as dozens of smaller fires.

As part of our research efforts a GIS-based forest fire archive of the Mt. Carmel region of Israel was developed; it currently contains data for the period 1978-2006. The methods used to collect data included: acquiring and processing the Jewish National Fund (JNF) database, including definition of polygon outlines and centroids based on JNF records; digitizing fire polygons from paper maps; and digitizing fire polygons from aerial photographs. Field survey tasks included registering points by means of GPS, and building polygons.

The GIS platform was used to analyze forest fire patterns in the region. Results indicate that half of the upper-Carmel open areas had burned at least once during the period during which the data had been collected. It seems that fires are not a random phenomenon, as they are associated with the intense human activities in the region. Characterization of historical fire regimes provides information essential for developing fire management strategies. Historical information on forest fires such as: extent, severity, intensity, and frequency, may contribute to our understanding of the ecological systems and may be useful in improving management practices.

Click here for the Hebrew texts containing graphs and tables with English titles

By (1) Anat Madmony and Josef Riov (riov@agri.huji.ac.il), Faculty of Agriculture, Food and Environmental quality Science, The Hebrew University of Jerusalem, Rehovot, Israel; (2) Ami Zehavi, David Brand and Aviv Eisenband, KKL Forest Department; (3) Moshe Yosef, Agriculture Research Organization - Volcani Center, Ministry of Agriculture, Bet Dagan, Israel


Ha-Masreq Nature Reserve Stand

The Pinus halepensis stand in the Ha-Masreq nature reserve is the southernmost stand of the seven natural populations of this species in Israel, which can be considered as a specific provenance. The stand is in danger as the trees have deteriorated during the two last decades, and no natural regeneration is observed. Natural regeneration from seeds might be problematic, because of possible genetic introgression from introduced pine provenances planted around the reserve. Conservation of this unique provenance is planned ex situ and in situ. Analysis of the annual rings of both old and young trees, in the reserve as well as in adjacent plantations, indicates that during the last decades the trees, including the young specimens, have hardly grown. Genetic examination of the trees showed only a slight variance among them. Because of the low vitality of the trees and their age, rooting of cuttings has been very low. Therefore, rehabilitation of the pine population of this stand should be done by grafting. The genetic uniqueness of this population should be further studied, by means of additional genetic markers.

Click here for the Hebrew texts containing graphs and tables with English titles

By A. Arnon (amirarnon@gmail.com), E.D. Ungar and A Pervevolotsky, Department of Agronomy and Natural Resources, Institute of Plant Sciences, Agricultural Research Organization – the Volcani Center, Bet Dagan 50250 Israel; (2) T. Svoray, Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel; (3) M. Shachak (and A. Perevolotsky), The Jacob Blaustein Institute for Desert Research, Ben Gurion University of the Negev, Sede Boqer Campus 84990, Israel


Initial Documentation and Management Implications

Our study focused on the association between woody and herbaceous vegetation in the transitional zone between Mediterranean and desert vegetation. This association manifests itself as a circlet of annual herbs around the shrub Sarcopoterium spinosum. Because the circlet may constitute a major proportion of the net primary production, especially the one that is utilized by free-ranging livestock, the phenomenon may have important implications. We characterized the dimensions and biomass production of circlets, and evaluated the proportion of the landscape which is covered by them. We also conducted four treatment manipulations to elucidate the mechanisms that create the circlet: leaving the shrub intact and allowing sheep to graze the plot, leaving the shrub intact and protecting the plot from grazing, removing the shrub canopy and allowing sheep to graze the plot, removing the shrub canopy and protecting the plot from grazing. To estimate the amount of herbaceous vegetation we developed a method that used low-altitude aerial photography, image processing, GIS software and empirical calibration. In addition, we sampled nutrient concentrations in the soil beneath the different patch types (shrub, circlet, open area), to test for correspondence between below-ground and above-ground patchiness. We also conducted behavioural observations to evaluate the allocation of sheep grazing time to the three patch types in relation to their relative cover.

Our results confirmed that circlets of annual herbs around the shrubs do exist. The average circlet width at the peak of the green season is approximately 15 cm, and the biomass in it is 25 to 40% higher than at greater distances from the shrubs. Circlets occupy more than 20% of the surface area of the landscape. Based on the results from the four treatments, we concluded that the primary mechanism for their formation was facilitation rather than mechanical protection from grazing, probably via nutrient availability and perhaps also by amelioration of microclimate conditions. Sheep allocated more grazing time to the circlet than expected by random or uniform allocation.

Our study suggests that the phenomenon of the circlet plays a crucial rule in the structure and functioning of the ecosystem of the transitional zone. Rangeland and ecosystem management practices in the region should take it into account.

By Nir Becker (nbecker@telhai.ac.il) and Yael Choresh, Department of Economics and Management, Tel-Hai College, Upper Galilee, Israel

The recreational value of Biria forest, which is a non-market good, was estimated by the Travel Cost Method (TCM). We used three different models. The first two yielded a total value of the forest; the third one presented the values of different recreational attributes in the forest.

Based on the different models, it was concluded that the total recreational value of the Biria forest is between NIS1.6 and NIS12.9 million annually, with a geometrical mean of NIS7.25 million annually.
The most significant factors that affect visitors' decisions to visit the forest were the fortress and the income level of the visitors.

By comparing the annual benefit of the fortress with its operating and maintenance costs, we found that the annual net benefit of the fortress is NIS0.57 million. With respect to income, it was found that each NIS1.00 added to the average hourly income increases the value of the forest by NIS4,000 annually.

A Cost Benefit Analysis was also performed, with respect to other features, such as road development and observation sites. Ranking those net benefits is helpful to decision makers in sharing limited budgets, not only between forests but also between amenities within a given forest, enabling them to take its various attributes into account in order to maximize social welfare.

Click here for the Hebrew texts containing graphs and tables with English titles

By Pninit Cohen (51pninit@bezeqint.net), Oded Potchter (potchter@post.tau.ac.il) and Arieh Bitan, Department of Geography and the Human Environment, Tel Aviv University, Israel

The city of Tel Aviv is characterized by a coastal Mediterranean climate, and during the summer experiences hot and humid weather that causes heat stress during most hours of the day. Previous studies have shown that green areas inside cities create a cool island, whose intensity depends on the type and quality of the vegetation. The aim of this study was to examine the climatic behavior of several designs of urban parks during the summer, and to study its influence on climatic parameters and on heat stress. Three main types of urban parks were investigated: