Turning the Desert Green

The planting of Yatir Forest, now the largest forest in Israel, started in 1966. It was created at the insistence of Yosef Weitz, a principal visionary of KKL-JNF to use trees to roll back the desert. His single-mindedness gained Weitz the affectionate title “the father of forests”. His vision has proved itself: The magnificent Yatir Forest has completely changed the arid landscape of the northern Negev despite opinions of many experts who declared then that the project would totally fail.
The accumulation of greenhouse gases in the atmosphere is a mater of concern for all of humanity. There is an international effort to reduce carbon dioxide emissions, but there is one process that actually works in the reverse direction (along with carbon sequestration by the oceans) – the process of photosynthesis in trees that stores carbon while releasing oxygen into the atmosphere.

The very existence of Yatir Forest, on the edge of desert regions, is a prime ecological instrument, having already halted desertification on the heights north-east of Beersheba. Now, it is an undisputed fact: The forest has significantly affected the quality of its environment.

Consequently, Yatir Forest has become the focus of recent research by Professor Dan Yakir of the Weizmann Institute of Science. This research is part of worldwide studies on mechanisms that absorb damaging hothouse gases, an international project carried out in parallel in a hundred sites around the globe, with financing from the European Union.
Prof. Yakir's study has provided surprising results. It turns out that this KKL-JNF coniferous forest on the edge of the desert, which grows in extreme climate conditions, sequesters oxygen to the same degree as European forests.
Yatir forest. Photo: Benny Mor, KKL-JNF Jerusalem
Yatir forest. Photo: Benny Mor, KKL-JNF Jerusalem
Since 2000, Yatir Forest has actually been serving as a living laboratory: It has a sophisticated monitoring station that checks natural data – precipitation, moisture, growth, the trees’ natural development mechanisms, their emission of gases, the air’s composition, and other factors. The forest’s “unnatural” desert location makes this research even more important.

One of the main parameters examined in this research is the amount of carbon dioxide the forest absorbs from the air, taking into account the fact that average annual rainfall has gradually decreased from 350 mm to only 300 mm whilst the quantity of compounds in the air is increasing. Professor Yakir’s survey is the only one in recent years that checks the forest’s overall functioning from the viewpoint of both the ecology and its independent functioning.

Partial results of the research by Professor Yakir and his team show that the forest’s trees have adapted themselves to arid environmental conditions by naturally smart use of the high level of carbon dioxide in the air. Professor Yakir explains that because of the rise in the level of carbon dioxide in the air, the trees absorb all the carbon dioxide they require without needing to fully open all the stomas (apertures) in their leaves’ membranes. Partial opening of the stomas reduces the evaporation of the water on the leaves and so a tree uses less water without any damage to its development.

Professor Yakir says that this is the solution to the mystery of the “disappearance” from the atmosphere of some seven billion tons of carbon dioxide from industrial emissions worldwide. In the course of the complex measurements carried out in Yakir Forest it was discovered that, contrary to the accepted assumptions, the desert forest of Yatir absorbs carbon dioxide just as efficiently as forests in wet areas- and in fact it does it better. Yakir’s premise is that the rising percentage of carbon dioxide in the atmosphere helps forests expand to semi-arid and desert areas, because when the air has a relatively high level of carbon dioxide, a plant is able to evaporate less water while still absorbing the carbon dioxide that it needs for the photosynthesis process.

The Yatir Forest has its own “biological clock” dictated by its environmental conditions. While similar pine forests in Turkey are in a state of full metabolic activity in the summer months, during that same hot, dry period the Yatir Forest is in suspended animation, with its trees at a very low level of physical activity. Only in winter-time does the forest return to full metabolic functioning, and that is when most of its growth, and most of its absorption of carbon gases, takes place.
Yatir Reservoir. Photo: Albetros, KKL-JNF Photo Archive
Yatir Reservoir. Photo: Albetros, KKL-JNF Photo Archive
This research and others at the Desert Research Institute of Ben-Gurion University spearhead the Green focus that has become the target of KKL-JNF activity in recent years, arousing much interest and curiosity among international bodies, including the US Forest Service which is closely monitoring their progress, plus various government ministries in countries where KKL-JNF representatives have direct work and research relationships.

Another parallel research study within Yatir Forest is the investigation of annual and multi-annual growth, where controlled grazing by flocks from local Bedouin villages is permitted within the forest; an arrangement has been in existence in the last few years to the mutual satisfaction of both KKL-JNF foresters and Bedouin owners of flocks.

The desert boundary is itself a subject of research aimed at conserving land and water. KKL-JNF is partner in several researches on trapping flood waters and surface runoff water by constructing low embankments in planted areas, to catch whatever little water there is, to prevent soil erosion and the silting up of river channels. Such research has a strong impact on decision making about the development of new farming areas, especially in the Negev.

KKL-JNF’s research together with infrastructure on different methods to combat global climate changes, have already gained scientific recognition worldwide. The restoration of rivers, primarily the Beersheba Riverbed project will bring about major changes in the quality of life of the Negev's capital and are high in KKL-JNF’s order of priorities, with help of JNF America and Canada. Cleaning up the Beersheba Riverbed channel and removing most of its polluting elements will result in an ecological turnabout. Already floodwaters in the channel no longer pollute it as they did in the past, and their re-usage for agriculture in the western Negev – mainly the Besor Region – is a simple matter. Far less pollution from the restored riverbeds now penetrates the underground pools and the quality of those pools is being maintained at reasonable standards. It is not by chance that Efi Stenzler, World Chairman of KKL-JNF, said that KKL-JNF has moved from being an organization dealing mainly with afforestation to becoming the most important ecological body in Israel.

One of the major driving forces behind this trend in KKL-JNF is Dr. Alon Tal, a member of KKL-JNF’s directorate and head of its Sustainable Development committee. Tal, whose career includes fervent activism in environmental preservation organizations, is an eager proponent of KKL-JNF’s cooperation with academic research institutions. He says, “Yatir Forest would never have been planted where it is, if a scientist had been the one to make the decision to do so,” Professor Dan Yakir often says about the green expanse that is the topic of his important research. The results of that research, though still only partial, already show that Yosef Weitz’s vision is reaching fruition, even bringing unanticipated strength in the war on global warning. In scientific terms, Israel’s contribution to this international battle cannot be overrated: KKL-JNF’s work both enhances Israel and helps the international community.

Ecological and Social Values of a Forest

The trees at Yatir Forest reach an average height of 10 meters, the density is approximately 30 trees per dunam (quarter acre), while the precipitation consists of an average of only 285 mm. of rainfall per year.

The forest’s productivity in terms of carbon sequestration: About 230 kg. of carbon per quarter acre per year (i.e. about 7.7 kg. of carbon per tree per year). Over a period of 70–100 years (which is the estimated life extent of deciduous trees), each tree stores around 500–800 kg. of carbon. In comparison, pine forests in Europe sequester 200 kg. of carbon per quarter acre each year. The average sequestration of most pine forests in the world is 250 kg. of carbon per quarter acre per year.
Yatir Forest. Photo: Albetros, KKL-JNF Photo Archive

How does the Yatir Forest function so well and sequester carbon in its hot, dry conditions?

  • The trees use less energy for respiration than is needed for photosynthesis.
  • Its biological activity (carbon sequestration) starts early in the spring, enabling a long activity season, similar to European forests.
  • These factors lead to higher efficiency in the carbon utilization process.

Also worth noting is that side by side with the Yatir Forest’s surprising efficiency in carbon sequestration, its dark foliage causes it to become somewhat hotter than its paler edge-of-the desert environment. Although this warming process works in the opposite direction, it does not negate the high degree of carbon sequestration.

Alongside a forest’s important and unique value in terms of carbon sequestration, it has other important values. The following is what one tree accomplishes:

  • Filters and purifies about 100,000 cubic meters of air every year.
  • Absorbs approximately 20 kg. of dust per year.
  • “Swallows” 80 kg. of compounds containing polluting particles in a year produces around 700 kg. of oxygen annually.
  • Increases rainwater penetration into the soil and prevents erosion from taking place.
  • Helps lower the temperature in its surroundings in the summer by up to 4 degrees.
  • Reduces noise pollution in its vicinity.
  • May serve as a home for dozens for birds.
  • May reduce the effect of earthquakes.
  • Raises the value of nearby properties.
  • Adds beauty to the environment.

Economics-based research studies have shown that in Israel’s high-density, urban environment, the forest’s recreation value, when calculated in a cautious manner that only takes into account the price that country’s residents have to pay to get to the forest, covers the cost of establishing and tending the forest over the years. Obviously, this profit does not appear in any official cash flow record, but it is expressed in the forest’s social value when it is enjoyed for leisure purposes by all who visit it.