I received a letter from someone who is writing a history of her retirement community. Trees growing on the grounds are an aspect of her research.

She wrote: “It would add much to the history to have a short article by you telling  why it is important for people to live with trees. I would appreciate your insight.”

I’ll take the opportunity to fulfill the request, while sharing it with you.

On the personal side, some of my early childhood memories involve trees. One of the first is of falling out of a tree. I didn’t know it at the time but it was a sycamore. Fortunately for me, the extent of my injuries was a bitten lip and a few scratches. And it seems I recall my older sister, who was about 8 years old at the time, tending to my injuries, wearing her Nurse Nancy uniform. 

My next tree memory is of falling out of a peach tree. Actually, a friend and I accidentally broke it, when we climbed up into it, running away from a scary dog. Had I recognized the weakly attached codominant trunks with included bark as a structural defect that commonly leads to limb failures, I might have chosen another tree. But what can you expect from a 5-year-old?

Other early tree memories —  not the falling out kind — include the giant sequoias of Sequoia National Park and Calaveras County, the forests around Yosemite, our old willow tree in the late 1950s here in Napa, sunlight filtering through the redwood canopy on the Northern California coast, and the fragrance of bay leaves while playing on the banks of Redwood Creek after it rained. 

Beyond personal memories, trees carry meaning in culture, social traditions, psychology and religion for people across the world and deep into the past. 

 For more prosaic and business-like purposes, trees have value in a number of ways. “The Guide for Plant Appraisal,” which arborists often use to help determine the value of trees, gives four categories for the functional uses of trees: architectural, engineering, esthetic and climate control. To these I will add two more: biological and socio-economic.  Each category contains a number of beneficial functions.   

Architectural:  Trees can define space, screen an undesired view, create privacy, and frame a desirable view.

Engineering:  Trees can reduce noise, act as air conditioners, reduce glare and undesired light reflections, direct foot traffic, and control erosion.

Esthetic: Trees can foster a calm feeling, create pleasant sounds, produce pleasant scents, decorate a space and enhance or unify large urban spaces. Trees may also serve as a philosophical model for living with people and nature (“As the twig is bent …”)

Climate Control:  Trees can cool the microclimate of a garden, the mesoclimate of a park, neighborhood or city and the macroclimate of a region. They can modify wind patterns by lifting, blocking, filtering and guiding it. Trees can provide frost protection for tender plants under their canopies, absorb and sequester CO2, produce oxygen, reduce smog and dust, reduce soil surface evaporation, protect shade-loving plants and create or capture rainfall.

Biological:  Trees can improve soil, shelter and feed essential soil organisms, and provide habitat and food for wildlife. Trees and plants are beginning to be used for “phytoremediation” to absorb pollutants.

Socio-economic: Trees can add real value to property, and provide recreational opportunities such as hunting, fishing, hiking and tourism. Trees produce products such as food crops, medicine, flowers, building materials and soil conditioners. Trees provide jobs for farmers, builders, foresters, park rangers, loggers, scientists, teachers, gardeners and tree care companies.

Trees provide educational opportunities for students. They provide media and subject matter for artists and photographers. They also may have sentimental, historical and civic value.

On top of all of that, green plants and trees existed before people. Large animals, people included, cannot exist without green plants. In a large sense, people need trees more than trees need people.

Bill Pramuk is a registered consulting arborist. Please send questions to bpramuk@pacbell.net.