For thousands of years, people have successfully and continually occupied the landscape of Arenal, Costa Rica despite the relatively frequent environmental catastrophes, especially volcanic eruptions of Arenal Volcano. By analyzing the experiences of the ancient Arenal populations when faced with environmental disasters, archaeology can assist in preparing and coping for similar threats we face on a worldwide scale today. Paleoethnobotanical data collected from domestic structures in the Arenal region demonstrate the plant-human interactions that occurred in this volcanically active landscape in northwestern Costa Rica. These data provides a diachronic perspective, with a view of the plant resources used by residents in the Tronadora phase house structure at G-995 La Chiripa (1616-1108 BCE) as well as the Late Arenal phase village at G164 Sitio Bolívar (430-540 CE). The macrobotanical data (seeds, fruits, geophytes, and wood charcoal) reveal a subsistence strategy that was dominated by a diverse assemblage of forest-based products as well as root crops supplemented by minimal agricultural foods such as maize, beans, and squash. Notable fruit trees in both of the assemblages include avocado (Persea), cacao (Theobroma), cashew (Anacardium occidentale), cherry or plum (Prunus), coyol (Acrocomia aculeata), guanabana or cherimoya (Annona), guava (Psidium), jocote (Spondias mombin), nance (Byrsonima), ramón (Brosimum), sapodilla (Manilkara), pejibaye (Bactris), and mamey (Pouteria). A diet which primarily relied on agroforestry practices and root-crop agriculture may have aided these ancient inhabitants in navigating their ever-changing landscape. This is because low-lying vegetation, especially agricultural fields would not have survived depositions of volcanic ash and tephra, whereas underground root crops and stands of forests with fruit trees would have remained available, providing a bank of food either within their local surroundings or neighboring regions. Such a subsistence regime provided these ancient peoples with the ability to maintain their daily routines with a sense of resilience to their environmental setting that often experiences extreme conditions.