The Importance of Trees

By Lynn Fitz-Hugh | TCAT Community Engagement Director

Most of us think of trees as sort of friendly ornamental objects. Unfortunately, we are not taught in school about all the very important things trees do for us:

  • Storm water management by sucking up water and preventing flooding
  • Air pollution reduction and removal
  • Drawdown of greenhouse gases from the atmosphere
  • Storage of climate change causing carbon in both the tree and earth below the tree
  • Protection from depression when people see trees outside their windows (as documented in studies)
  • Reduction of asthma and other health problems
  • Habitat for birds and insects that is critical and irreplaceable
  • Shade which significantly reduces energy use and cost for cooling in the summer
  • Insulation against the cold in the winter, reducing the amount of energy used for heating in the winter

This is what trees do for us. What are we doing for them? The TCAT Trees Action Group is calling for the protection of trees because of the difference they make to climate change and our over all well being.

When work began on the Thurston Climate Mitigation Plan, trees did not appear in the plan because it focused on reducing emissions of GHG’s. But early on tree planting (afforestation) was added. Later on as it became increasingly difficult to identify enough ways to reduce carbon to achieve the science based targets of the plan, the carbon sequestering benefits of trees took on more importance in the plan and tree protection was added.

A critical thing for all of us to understand about trees is that in terms of the benefits they bring not all trees are the same. Older trees are many times more efficient at drawing down carbon dioxide and already have big carbon stores. [NOTE: In this article, I’m using “carbon” as shorthand for “carbon dioxide, an important greenhouse gas (GHG).] About half of the carbon they store is lost the minute they are cut, (-and all of it is lost when they burn in forest fires-). Thus while it is common for builders to cut down trees on a lot and replace some or even the same number with saplings, this is still a huge carbon loss when it happens. It will take 30 years for the new trees to reach their full efficiency. Also deciduous trees are better at carbon draw down than confers, but confers are better at storm water management (This is a reason why the rainy Pacific North West has more native confers)

Therefore to have an effective tree strategy in the Thurston Climate Mitigation Plan (TCMP) we must both plant new trees that will increase the drawdown over time in our county, and protect the trees we already have because county wide our trees are holding 14 years worth of our annual emissions! Existing trees are also every year reducing our emissions by drawing down carbon.

There is an interesting tension in our plan, and in life, between trees and development. The TCMP calls for more urban density because when people live closer to critical services they drive less, and use resources more efficiently. This will require some development in our urban core which typically means the cutting down of trees. TCAT’s Tree Action Group knows we can both have urban density and trees. It means prohibiting the cutting of trees for arbitrary reasons and incentivizing builders to keep as many trees as they can on a property. Another strategy is to keep generous setbacks from property lines and the beginning of buildings so there is space for trees. A slightly smaller building is actually a more affordable building. Who wants a city where you cannot see a tree when you look out a window?

The TCMP does call for both planting and tree protection. However, the tree protection item could be more clearly defined. It talks about setting tree canopy goals but does not mention setting tree cutting limits which will be necessary for effective protection of trees. Please keep this in mind when you write your public comments on the TCMP.