The prophet, prayer and peace be upon him, said: The time will not come until Muslims will fight the Jews (and kill them); until the Jews hide behind rocks and trees, which will cry: O Muslim! there is a Jew hiding behind me, come on and kill him! This will not apply to the Gharqad, which is a Jewish tree (cited by Bukhari and Muslim).
If Gharqad trees protect Jews, then maybe they are eucalyptus.
One other case where eucalyptus trees protected Israel was the famous story of Eli Cohen, Israel's spy in Syria in the 1960s:
Eli's connections enabled him to be taken to the Golan Heights - a major strategic asset for Syria from 1948-67. As we saw, the Syrians continually harassed Israel's northern settlements from 1948-67. The Golan Heights defenses were top-secret and closed only to top military staff. "Nevertheless, Kamal Amin Ta'abet (Eli Cohen) succeeded in visiting each and every position. With senior staff officers acting as guides, Eli Cohen was provided an in-depth intelligence briefing of monumental proportions." They even photographed Eli on the Golan Heights, looking over into Israel, alongside the most high-ranking Syrian officers. He remembered and passed on to Israeli Intelligence the "positioning of every Syrian gun, trench, and machine-gun nest in each Golan Heights fortification; tank traps, designed to impede any Israeli attack, were also identified and memorized for future targeting." One of the more famous aspects of his spying regarded a trip he took to the Golan Heights. As the Syrian Army officer explained to Eli the fortifications the Syrian Army had built, Eli suggested that the Syrians plant trees there to deceive the Israelis into thinking it was unfortified, as well as to provide shade and beauty for the soldiers stationed there. The Syrian officer readily agreed - and Eli immediately passed the information onto Israel. Based on the eucalyptus trees, Israel knew exactly where the Syrian fortifications were.(h/t Petra)