Those small palm trees are Areca trees, that produce a nut commonly called Betel nut.
The Areca nut is wrapped with Betel leaf and chewed for its exhilarating lift. Betel chewing has been claimed to produce a sense of well-being, euphoria, heightened alertness, sweating, salivation, a hot sensation in the body and increased capacity to work.
Just like alcohol, tobacco, coffee and sakau, Areca nut and Betel leaf are culturally-approved psychoactive drugs.
The Areca nut, by association, is sometimes inaccurately called the "Betel nut" or "Betel Quids".
See the Areca nut Wikipedia article.
See the Betel leaves Wikipedia article.