Volumes 5-6, December 2004

For a full text of this issue in Hebrew click here. Graphs and tables include English titles.

By Zvi Avni, Forest Department, KKL, Eshtaol, Israel Zvikaa@kkl.org.il

In 1960 the Israeli Government’s Afforestation Division was shut down. The areas it had managed, some of its manpower and most of its equipment and assets were transferred to KKL-JNF’s Afforestation Department. The merger was a preliminary step in advent of the agreement (Covenant) to be signed a year later between the Government and KKL-JNF. The process of closing down the Government’s forestry operations took a year and a half, and highlighted a number of crises that resulted in widespread public and media involvement.

The decision to end the Government’s afforestation role and to separate forestry research from forest work stemmed chiefly from personal and organizational power struggles. Factors contributing to the decision included: the sorry state of the Government’s forests due mainly to lack of resources as well as irregularities, the partial functioning and absences of the Division director, Dr. Amihud Goor, and the possibility of raising funds for forestry via KKL-JNF.

While the merger did solve financial and administrative problems that had impeded the Division’s functioning, it also established a number of facts that have remained problematic for forest management in Israel. Since most of these facts were largely ignored, they have continued to plague forest management to this day. The problems are legal, professional, land-related and organizational. They include: making afforestation subordinate to a body in charge of developing open spaces, giving preference to field and development workers over professional staff, separating forestry research from afforestation, an archaic forest management law, neglecting the management of forest reserves, the problematic appointment of a KKL-JNF staffer to oversee the Forestry Ordinance, and the absence of state control over afforestation even though it is a body that manages state lands.

By A. Lavi (lavital@agri.huji.ac.il), J. Kigel and I. Noy-meir, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environmental Quality Science, The Hebrew University of Jerusalem, Rehovot, Israel; A. Perevolotsky, Department of Natural Resources, A.R.O. The Volcani Center, Bet-Dagan, Israel.

Pinus halepensis, a Mediterranean species that has been introduced throughout the world, is considered to be one of the most invasive pine species, threatening native biodiversity in various habitats. In Israel, natural stands of P. halepensis occur in restricted areas and, since 1920, it has been planted in extensive afforestation projects throughout the country. In recent years, spontaneous pine establishment was observed in natural vegetation adjacent to pine plantations. The objective of this research was to examine spatial and temporal patterns of invasion by Pinus halepensis in Israel.

The research was carried out in two nature reserves: "Gvaot-Gad" (GG) (dry Mediterranean climate) and “Ya’ar-Hasolelim“ (YH) (Mediterranean climate), that are adjacent to pine plantations. The density of invading pine plants was measured in relation to the distance from the plantation edge. Plants were categorized by age, height, basal stem circumference and developmental stage. The age at which half of the invading plants began to produce cones was 12 years at YH and 9 years at GG.

Plant density declined sharply with distance from adult trees, and showed a good fit to a power law function. Most invading plants were found within 20 meters from the plantation edge, but a few individuals reached distances up to 100 m and became new invasion foci. Higher densities of pine plants were found on the western side of the plantation in both sites. Analysis of plant age distribution indicates that the invasion process started when the plantations were 20-25 years old.

Invasion of P. halepensis from plantations into natural vegetation, as observed at the two study sites, was also recorded in other sites in a wide range of habitats in Israel. The process is expected to accelerate as invading trees reach reproductive age.

By Nili Liphschitz (nilili@post.tau.ac.il), Institute of Archaeology, the Botanical Laboratories, Tel Aviv University; Gideon Biger (biger@post.tau.ac.il), Department of Geography, Tel Aviv University, Israel

The distribution of Pinus brutia today extends mainly over the eastern Mediterranean region. Dendroarchaeological research, based on identification of archaeological wood remains, and dendrohistorical research of historical buildings in Israel, show that Pinus brutia was not part of the country’s native arboreal landscape, and may have been of relatively minor importance in the eastern Mediterranean region as a whole. Pinus brutia was introduced into plantations in Eretz Israel from the 1930’s onwards, and today replaces Pinus halepensis in the country’s planted forests.

By Haim Zaban, Noa Feller, Liron Amdur – Zenovar Consultants, Givatayim, Israel zenovar@zenovar.com; Yoram Avnimelech, Ofira Ayalon – Neaman Institute, the Technion, Haifa, Israel

Agriculture takes a relatively marginal place in Israel’s economy today. The future of agriculture demands public involvement.

An important consideration to sustain agriculture is its external contribution, beyond its function in the production of food and fibers: aesthetical contributions by generating open green spaces; social contributions, values of the contact between people and the land; and, ecological contributions – increased water infiltration, absorption of CO2, an outlet for organic waste and recycled water, soil preservation and protection.

On the other hand, agriculture has negative influences on the environment: soil and water pollution as a result of excessive fertilization, disinfestations, and increase of soil erosion.

There is a need to create a mechanism to encourage the positive values of agriculture, and reduce its negative impacts. Governmental bodies, together with “green” organizations, which until now have dealt mainly with natural areas, will be asked in the future to contribute to the protection of agricultural areas.

A system of supports for the external values of agriculture is common in various countries the world over. In order to adopt such strategy in Israel, there is a need to measure the economic value of the external influences of agriculture.

Our research found that the external annual environmental contributions of agriculture are 260 million $US, the average external value of one hectare being $73. The external value of agriculture amounts to 8.4% of its direct production. It may be assumed that around 20% of the agricultural land of Israel will realize its external value within the next few years, in the total sum of 52 million $US per year.

The research presents a wide range of organizational tools, which may be used in the realization of payment to farmers. Realization of such tools may be the key to strengthening sustainable agriculture in Israel.

By Zion Madar - Forest Department, KKL, Kiryat Haim, Israel, Zionm@KKL.org.il; Naftali Gedalyahu - Natural Reserves and National Parks Authority, Jerusalem, Israel; Zvi Mendel, Department of Entomology, Volcani Center, Bet Dagan, Israel.

In spring 2001 an outbreak of local gypsy moth (Lymantria dispar var. disparina Mull.) occurred in central and northern Israel; severe damage was observed in Quercus calliprinos stands on Mt. Carmel (over 1000 ha). The outbreak was also noticed in several sites between Hilla (Upper Galilee) and Yakir (Samaria). The preferred tree species by the gypsy moth were: Q. calliprinos, Arbutus andrachne and Crataegus aronia. less preferred species were Q. ithaburensis, Pistacia lentiscus and P. palaestina.

The following tree species grown on the infested sites were not colonized: Laurus nobilis, Phillyrea media and Ceratonia siliqua. We studied the life cycle of the gypsy moth on Mt. Carmel. the pest is univoltinous. the eggs were laid between May and the end of July, mostly under stones, and hatched in the next spring (March). Larvae development lasted from March to early May. Flight period occurred from May and late June. Male moth capture using sex pheromone traps suggested that the population occurs in non-damaged areas as well. In a preliminary control trial, the fifth instar larvae of the local gypsy moth displayed high susceptibility to Bacillus thuringiensis formulations (Bactospine, Delphine) as well as to insect growth regulator (Dimillin).

By Ofrit Shavit, Institute of Evolution, Haifa University, Mount Carmel, Haifa, Israel, ofrit@betalfa.org.il; Avi Shmida, Department of Evolution, Systematic and Ecology. The Hebrew University, Jerusalem; Gidi Ne’eman, Department of Biology, Haifa University - Oranim, Tivon, Israel

Delonix regia, which originates from Madagascar, can be found in dry savanna areas throughout the tropics. It is grown in gardens mainly for its bountiful and abundant red flowers, which are large and produce plenty of nectar. The young flowers have a large and yellow banner, while in mature flowers the banner is red and folded. Delonix is bird pollinated in Africa, but in Israel it is not visited by the local honey eater Nectarinia osea.

This study reviews the adaptation of the flowers for bird pollination; compares between young and mature flowers, and examines whether the bees prefer the young virgin and rewarding flowers over mature unrewarding flowers.

We found that several floral traits are in accordance with the bird pollination syndrome: The flower is red, seen well by birds but not by bees; it flowers during day time and produces plenty of nectar; the nectar tunnel is long, but wide enough to guide birds’ beaks; the floral basal parts are thick protecting the ovules from beaks’ damage; the anthers are long and the pollen sticky.

The major pollinator of Delonix in Israel is the carpenter bee Xylocopa pubescens, which can distinguish between young rewarding flowers and old unrewarding ones. The bees prefer to visit the young pre-color change flowers and skip the old post-color change ones. This enables the tree to retain its old flowers, which contribute to the overall attraction of pollinators to the tree, without reducing the probability of pollination of the young virgin flowers.

By Nativ Dudai (nativdud@volcani.agri.gov.il), Eli Putievsky and David Chaimovich, Aromatic - Medicinal and Spice Crops, ARO, Newe Ya’ar Research Center, Ramat Yishay, Israel; Meni Ben-Hur, Institute of Soil, Water and Environmental Sciences, ARO, Volcani Center, Bet-Dagan, Israel

Vetiver grass (Vetiveria zizanioides) is used as an effective and inexpensive method for erosion control in tropical and sub-tropical regions. However, in spite of the advantages of this grass, it is not common in arid and semi-arid regions, such as Israel. The objective of this study was to determine the optimum growing conditions for Vetiver grass in Israel. The effects of time of planting, irrigation and foliage treatments, and of growing in different substrates and under controlled conditions on Vetiver growth, were studied.

We found that Vetiver grows quite well under Israel’s climatic conditions; after establishment, Vetiver plants survived the dry summer without irrigation. Likewise, Vetiver could be grown in various soils under irrigation or rainfed conditions. The optimum planting season for Vetiver grass under irrigation is spring or the beginning of summer. After cutting or burning of Vetiver foliage, plant height increased sharply in the beginning of spring, and then increased gradually to its maximum value. Maximum plant height after various foliage treatments under irrigation were, in general, similar to those in the control (untreated plants), and significantly lower than the control under rainfed conditions. Increasing of daytime temperature to 290C and the night temperature to 210C led to the greatest increase of Vetiver grass growth.