It's All Relative
On Dec. 2, 2010, the sky over the Carmel Ridge in northern Israel darkened at 11:07 a.m. At this time of the year, clouds typically blanket the sky, bringing refreshing early-winter rains after the long, dry summer months. On this day, however, plumes of thick smoke covered the sky. Over the next three days, Israel would experience its largest recorded forest fire. Although not as big as those in other regions of the world, this fire was a seminal event in the densely populated country — it consumed 2,250 hectares (5,560 acres) and killed 44 people.
Strong easterly winds drove relative humidity into the single digits, leading to extensive torching and crowning.
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Large wildfires greater than 100 hectares had not been documented in the region until recent decades, primarily due to a lack of a mature forest. Exploratory expeditions in the 19th Century describe most of what is now Israel as denuded of vegetation, with the Carmel region as covered by a suppressed forest of dwarf trees. The British Rev. Henry Baker Tristram, who traveled through the region in 1857 and 1863, described the Carmel Ridge as barren and exposed, dominated at the lower elevations by Prickly Burnets (spiny, cushion-like shrubs) and at the higher elevations by "trees of no great size." This sparse maquis — the Mediterranean basin equivalent of North American chaparral — has similar structural properties but is made up of short tree species such as Quercus (oak) and Pistacia (shrubs and trees in the pistachio family). British expeditions that mapped the region under the auspices of the British Exploration Fund during the late 19th Century also identified a patchy landscape of scattered maquis and isolated stands of Aleppo pine (the only pine species native to Israel).
During the 1920s, the British mandatory government conducted the region's first large-scale afforestation efforts in an attempt to establish a protected park. These efforts continued more intensively following the proclamation of the state of Israel in 1948. By the 1950s, 3,000 of the approximately 16,000 hec-tares of open areas in the Carmel region were planted with various pine species.
Alongside these reforestation efforts, two other processes led to the expansion of densely vegetated maquis. First, timber harvest, which was carried out particularly for tinder provision, was strictly banned in the region. Second, grazing gradually diminished as it became less feasible, and in attempts to protect the natural areas, goat grazing was actually outlawed in open areas. Together, these processes led to a rapid growth of forest and maquis occupying most of the open areas of the Carmel Ridge. In 1996 the Carmel Biosphere Reserve was established over most of the region in an attempt to preserve its natural, undeveloped state.
The Spanish plant ecologist Juli G. Pausas suggests that the abandonment of agriculture around the Mediterranean basin has inadvertently led to many areas becoming densely forested, with a corresponding increase in the number of fires and areas burned. This process has occurred at the Carmel Biosphere Reserve with the maturation of the maquis and forested areas. In addition, the growth of the human population in Israel, coupled with the increased quality of life and decreased availability of open spaces and natural areas, exerts higher pressure on outdoor recreation sites.
Until the late 1970s, only four large fires had been documented in the region, but since 1983 there have been 10. Calculating the time intervals between large wildfires in the Carmel region since the earliest archival records from the 1940s yields a mean return period of approximately one large fire every six years up to the end of the 1970s, and one nearly every three years since 1983. These results clearly highlight the changes in fire frequencies and regime.
Similar to other places around the world, fires do not occur randomly within the region. A 1992 study suggested that more than 99% of the fires in Israel are from non-natural causes, and practically none has been reported to be the result of summer thunderstorms. Wildfire causes include recreationists' negligence, arson and acts of terrorism. There is a strong correlation between fire location and human activity, with fires concentrated in the northern part of the area. An analysis of 167 points of fire ignition indicates that most of them occurred in close proximity to roads and recreation areas.
This pattern may be attributed to the structure and distribution of vegetation communities. Of the approximately 15,700 hectares of the Carmel Ridge, close to 2,400 are covered by pine stands of various species — approximately 15% of the area. Of the 167 fires for which the location was known, 20 occurred in pine stands, amounting to 12%. The analysis of the total area of different vegetation types consumed by fires tells a different story, however. From 1983 to 2009, large fires consumed a little over 1,700 hectares. A random distribution of fires would suggest that 15% of burned vegetation would be pine stands, but in reality they amounted to more than 45% of the burned area. Therefore, the fire patterns observed at the Carmel Ridge depend not only on human activity and forest maturation, but also on the structure of the vegetation community.
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