Our Overstory

CSUN’s first campus tree inventory was created in 1989 by Robert Gohstand. In 2009, it was recreated and expanded by then Institute for Sustainability director Helen Cox. Since then, it has been updated by students in CSUN Geography courses, who use the opportunity to expand their skills in GIS while also contributing to a valuable campus resource. Additionally, two graduate students have classified over 200 different campus species based on their status as common, threatened, endangered, or invasive species. Most recently, the inventory was updated by California Climate Action Corps. fellow Jesse Woltal, who spent two years inventorying trees and improving the Sustainable Food Garden. CSUN’s tree inventory includes over 2,000 trees, and is used by CSUN’s Grounds Department to track tree health, maintenance, tree-related hazards, and more.

Trees perform a variety of different functions that make them valuable in both the built and natural environment. From our five-acre orange grove to our high-performance buildings, learn how CSUN’s trees serve and enhance our campus.

Shade and cooling Trees provide shade not only for outdoor spaces, but for buildings as well. Deciduous trees drop their leaves in the winter, allowing them to provide shade during hotter summer months, and still allow sunlight to reach buildings during the winter. Trees also help cool down spaces through the evaporation of their moisture, in a process known as evapotranspiration. 

Erosion prevention Trees prevent erosion by stabilizing soils with their roots. This helps reduce the pollution of storm water by soil, reduces maintenance costs after rain events, and reduces the risk of landslides and mudslides.

Water absorption and filtration Trees help soils absorb more water, and absorb water themselves, which reduces flooding and runoff during rain events. Trees also filter this water before it’s released back into the atmosphere through evapotranspiration.

Coastline Protection Coastal tree species such as Mangroves play a critical role in protecting coastal land, habitats, and infrastructure. They not only stabilize ground, but also absorb much of the impact of waves before they can cause major damage to structures or erosion of the coastline. Coastal tree species also help filter pollutants from the water, and provide habitats for a variety of marine life.

Carbon sequestration Trees remove carbon dioxide (CO2) from the atmosphere through respiration, storing the carbon within their tissues and releasing the oxygen. Atmospheric CO2 levels have risen rapidly during the last century due to human activities. Preventing the drastic rise of atmospheric carbon dioxide is vital to reducing the impacts of climate change, and many countries around the globe have launched large-scale reforestation efforts for this reason.

Animal and insect habitat Trees, both living and dead, provide valuable habitats and food sources to a huge variety of birds, insects, mammals, amphibians, reptiles, and even other plants. More than half the earth’s animal species rely on trees in some form or another.

Air purification Trees can filter harmful particulate pollution out of the air by trapping it on their leaves. Trees also release chemicals to protect themselves from insects. When inhaled by humans, these chemicals lead to increased counts of white blood cells, boosting one’s immune system.

Occupant well-being Research has found that spending time around trees and looking at trees reduces stress, lowers blood pressure, and improves one’s mood. Spending time around trees can also help reduce fatigue and improve focus by resting certain parts of the brain.

Food Trees provide countless varieties of fruits and nuts that people consume on a regular basis. Volunteers in CSUN’s orange grove harvest over 30,000 pounds of fresh fruit each year that is donated to local organizations. In November of 2020, CSUN started a new orchard containing fig, plum, peach, apple, citrus, and pomegranate trees.

Explore some highlights of CSUN’s trees

These four, roughly half-mile loops will take you on a tour of some of CSUN's most fascinating and unique tree species. While they can be explored virtually, observing each tree in person will of course provide a more complete experience. Click on each tree to learn more about the species.