Afforestation is a Complex Issue, but it Does Help Moderate the Climate Crisis

Monday, December 27, 2021 7:02 PM

Two KKL-JNF experts respond to an SPNI professional's claim that Israeli afforestation will actually exacerbate rising temperatures, and discuss other benefits of afforestation: shade, recreation and flood restriction.

Yatir Forest. The radiator phenomenon is expected to lead to regional cooling and an increase in precipitation amounts. Credit: Albatross, KKL-JNF Photo Archive

A translation of the original guest blog by Dr. Gilad Ostrovsky and Dr. Doron Markel, published on the Ore’ach Pore’ach section of Haaretz (Hebrew).

In an opinion published on this [Haaretz guest section] blog, Alon Rothschild, biodiversity policy coordinator at the Society for the Protection of Nature in Israel, attacked KKL-JNF’s tree-planting policy and claimed that afforestation, contrary to widespread belief, makes no real contribution towards mitigating the climate crisis. The scientific argument over the apparently contradictory effects of afforestation on the climate are indeed worthy of debate, but instead of presenting the complexities of the issue, Rothschild has chosen to continue his all-out war on afforestation in a simplistic and superficial manner.   
Rothschild’s main contention is that fixation of carbon dioxide achieved by tree-planting is largely offset by the significant change in the albedo (the quantity of reflected solar radiation, which varies according to how dark or pale the ground is). This is indeed an issue of which we need to be aware, but it does not exist in isolation.
Where climate is concerned, research has shown that decades must elapse before equilibrium between a change in the albedo and the absorption of carbon is attained (this decreases as we move from southern to northern forests). As this time lapse is equal to the age of most planted forests in Israel, most of them have already attained equilibrium, or even surpassed it. Research by Professor Dan Yakir of the Weizmann Institute also demonstrates a “radiator effect” that cools the area of the forest, above its canopy, too. In his estimation, in forests in southern semi-arid regions, like Yatir Forest, this phenomenon can be expected to cause cooling of the area and increased precipitation. This is actually a fascinating example of the complexity of the issue: even in an area where the albedo effect hypothetically causes warming, the forest continues to regulate (cool) the “local temperature” in a highly significant fashion.  
In addition, we need to remember that Israel is a minor player in the world’s carbon game, and as such its influence on moderating the global climate is minimal. Nonetheless, while we have no particular influence on climate, we are most certainly influenced by it, and so local effects and the services provided by the forest’s system should be of major interest. And indeed, on the local climate plane, forests provide real benefits, especially by the cooling effect they create. And, apart from this, can we ignore the vital need to create shade for purposes of recreation, activity and leisure pursuits? Are we not duty-bound to prepare ourselves to accommodate an ever-increasing population in our open areas, especially during the long Israeli summer and particularly in an era of climate change? Woodland thinning, which sometimes attracts adverse comment, is vital for managing the forest: it shapes it, strengthens it and improves its resistance to climate change and insufficient water.
In response to the claim that there is not enough space for afforestation: as the afforestation project in the Land of Israel has focused from the outset on areas unsuitable for farming, it has largely been confined to rocky slopes and outlying areas. Now, of all times, in a country that has become very crowded, we should focus our attention on afforestation as a means of rehabilitating degraded areas to create additional spaces on the outskirts of cities; and on assisting farming areas with plant protection services and the simultaneous prevention of erosion. In the context of climate change, the forest serves today as an area of rainwater penetration, and thus acts as a flood regulator for the coastal cities.
These benefits – shade, cooling, recreation and flood modulation – are just some of the ecological services the forests provide to the public, and which Rothschild astonishingly ignores. Apart from their ecological contribution, forests also offer a range of social, cultural and environmental benefits and form part of Israel’s ecological corridor system. Forests in Israel have become diverse, and now range widely from open conifer forests, through natural woodland and scrubland to mixed forests. According to forest management theory, the objective is to create a varied, structurally complex landscape based upon natural processes and judicious intervention. This applies also to renewal, rehabilitation and initial planting.
When we set out to plant a new forest – or to restore an existing one, for example, after fire – we pay close attention to the ecological situation countrywide, regionally and locally (rare species and species in danger of extinction), so that the forest will blend into its natural surroundings and become an attractive venue for visitors.  Are all these objectives nullified because of the warming effect of the albedo, which, as explained above, has already been offset by carbon absorption in most of Israel’s forests?   
Ecologists worldwide long ago understood that environmental costs and benefits need to be viewed multi-dimensionally, and terms such as “life-cycle analysis,” “sustainability,” and, of course, “sustainable forests” came into being as a result. It would be a great mistake now to set this major progress aside – in Israel, of all places. It is a pity that some people in the Society for the Protection of Nature insist upon turning a professional discussion into an irrelevant saga of mudslinging in which historical perspective is ignored and politics that damage both important debate and vital cooperation are gratuitously invoked.
Gilad Ostrovsky is KKL-JNF’s chief forester and director of the KKL-JNF forestry department. Doron Markel is KKL-JNF’s chief scientist.