A new study in Morocco's Essaouira region shows that heavy goat browsing severely weakens argan trees, reducing their photosynthesis, leaf growth, and overall health. Researchers highlight the Agdal system, a traditional form of controlled grazing, as the best balance to protect forests while sustaining pastoral livelihoods. Like postcards show, goats in Morocco famously climb argan trees to nibble on their leaves, young shoots, and even fruit. This feeding practice, known as browsing, is central to the life of argan forests. But when it happens too often, it threatens the survival of this tree, endemic to the semi-desert Sous valley of Morocco. A new scientific study has shed light on how different browsing intensities affect the health of argan trees, with a focus on the Boutazart forest in the Essaouira region. Researchers point out that pastoralism has long been a pillar of these ecosystems, providing vital forage for livestock and resources for rural communities. Yet overbrowsing has become a serious threat. To understand the effects, scientists from Cadi Ayyad University in Marrakech and partner institutions tested three scenarios: no browsing, moderate browsing (the Agdal system), and heavy browsing. Their findings, published August 29 on Science Direct, show that heavily browsed trees perform poorly, with lower photosynthetic efficiency, reduced pigments, smaller leaf areas, and higher stress markers. By contrast, trees protected from browsing maintained optimal physiological functions. The Agdal system proves effective The study highlights the Agdal system, a centuries-old form of controlled grazing in Morocco, as a practical solution. Under this system, grazing is restricted during critical growth periods, giving trees time to recover. «Overall, even if the non-browsed trees performed best, the moderate-browsing system (Agdal) may be the most suitable of the three browsing systems», the authors note. It meets goats' feed needs while ensuring the sustainability of the argan forest ecosystem. Soil quality also improved under managed browsing, with more moisture, organic matter, and nitrogen compared to heavily grazed areas. The study suggests that embracing traditional systems like Agdal could help secure the future of this iconic Moroccan tree. The argan tree, recognized as a UNESCO Biosphere Reserve, supports the livelihoods of more than 1.3 million people, especially through argan oil production led by women's cooperatives. But forest density has dropped sharply in recent decades due to overexploitation, with losses estimated at 610 hectares per year by 2009.
