By Jacqueline Levy, Bouverie Preserve

Sonoma County is home to many indigenous tree species including the red barked pacific madrone, towering redwoods, striking buckeyes, and the fragrant bay. All important to the ecosystem, yet arguably none more so than the oaks.

As an environmental educator I invite elementary students to look closely at the oaks before them and describe the tree from trunk to canopy. We compare the waxy prickly leaves of the coast live oak to the softer, lobed ones of valley oak. Then I ask the children, “who needs this tree to live?”  Common answers include birds, bugs, squirrels, and us. The next question is a challenge, “what could we find on or near the tree that would be proof that, birds, bugs, squirrels and people need these trees?”

What would your response be? How closely do we look at the trees in our parks, yards, and along the sidewalks? If you look closely, you will see the evidence the children find. They spot bird nests and feathers. They find tiny holes left by beetles and caterpillars on the leaves. They notice the leaf discoloration caused by aphids, white fly, and fungi. There is silk spun by spiders and caterpillars. Holes in the truck made by industrious acorn woodpeckers and on branches by sap suckers. The bark is often covered by moss and a large variety of lichen with ants marching through.

In the fall there is more to find, both leaves and stems are dotted with galls. Galls formed when Cynipidae wasps lay their eggs in leaves or stems. The tree responds by forming a gall around the egg that later hatches a larva that lives in and feeds on the tree. Stem galls can be as large as a fist. Leaf galls come in a myriad of shapes and colors: yellow disks, pink stars, striped cones, prickly red balls, each one a different species. These galls do not seem to harm the tree.

The children discover that the acorns are not just the delight of squirrels--many animals depend on them for sustenance. A hole poked through the side of an emptied acorn is evidence of Scrub Jays, Acorn Woodpeckers and other birds feasting on them. Squirrels and other rodents leave teeth markings and acorn weevils tiny holes. Deer, racoons, skunks, and foxes all include acorns in their diet, but usually only leave scat for evidence.

And what about people? We depend on native trees for shade, to sequester carbon, to hold on to the soil, and support pollinators. Trees are part of nature’s playground for children to climb. People of all ages can enjoy their beauty in every season, be they evergreen or deciduous.

When you plant a tree in your yard, I encourage you to plant a native tree, they not only support our wild neighbors, but are also more adapted to withstand wildfires.

A tree is not just a tree, it is a habitat and a gift.