The city of Los Angeles has been permitting the removal of our protected native oak trees at a rate of at least 1 every week. Wide-spread development of the unimaginative kind that doesn’t take our unique landscape into account is to blame. Also to blame is an attitude that mature oaks are easily replaceable.  They’re not.

Oaks are not really a renewable resource because they grow slowly. While they may grow slow, oaks can live a really long time. The average lifespan for a healthy Coast Live Oak, for instance, is 900 years.  Because they are slow growing and have dense tissues they hold more carbon than practically any other trees, and they can hold that carbon a really long time because they can live a really long time.

The bigger they are, the more carbon they pull out of the atmosphere, the more they protect areas from flooding and anchor the soil from erosion. Our Coast Live Oaks also protect homes from wildfires because they catch flying embers.  They provide shade, which not only offsets our increasingly hot summers but can help keep folks’ utility bills down. An oak can make the land beneath it 20 degrees cooler than the surrounding terrain. Reducing the city’s heat imprint is going to be critical to quality of life with increasingly hotter summers.  In addition, LA’s growth increases air pollution, and oaks help to soak up and reduce that pollution. This isn’t rocket science — but it is science.

In other words, oaks are the best green tech money can buy.

Cutting down an oak, is really like destroying an ark. Hundreds of species of plants, mammals, birds, insects and amphibians depend on them, especially birds. Those birds — both our year-round birds and migratory birds that winter in our city — depend on the arks that are oaks.  When you cut oaks down, most of those animals don’t go elsewhere — they die when the tree is gone, they starve in the week after or they wind up adding stress to our already overburdened wildlife shelters. The more oaks that are cut down for development — the more numbers of birds drop, the more our unique urban wilderness plummets. The less unique we become.

You hear all the time that the birds are disappearing and the insects are disappearing.  Nothing is “disappearing”, we’re killing them.  We have 3 billion fewer birds now than we had 50 years ago. We have global insect decline because we kill them all the time and take away the oaks they need.  This is why earth is experiencing its sixth grand extinction event, but this is the only one that has been caused by us.  So, we have a biodiversity (aka nature) crisis.  It’s a crisis for humans because this is the biodiversity that runs ecosystems that supports us.  The good news is that there’s a solution.  We can turn this around by protecting nature and landscaping to capture carbon and support the animals that run the ecosystems that we depend on. We can turn this around by protecting and planting oaks.

How to plant a Coast Live Oak tree.

  1. Plant in late fall, winter, or early spring.
  2. Plant the youngest oak you can. It’s usually best to start with 1 gallon trees. Within 2-3 years after planting they’ll be as big as the trees that started out in 5 gallon containers. Root-bound plants should not be planted as they will never develop a healthy root structure and are not likely to live long.
  3. Dig a square hole that is twice as wide and half again as deep as the container. Square holes prevent the roots from circling after planting. If the soil is very dry, fill the hole with water and let it soak through before continuing. Rough up the sides and bottom of the hole so the roots will be able to dig in as they grow.
  4. If planting on a dry bank or slope, it’s best to create a flat area around the hole, at least twice the diameter of the hole to help the new tree retain a bit more water.
  5. Fill the hole with the native soil removed to make it. Do not amend the backfill around newly planted oaks. Put back enough loose dirt in the bottom of the hole, so that when you put the tree in the hole, the root flare is above the ground slightly.
  6. Don’t rough up the roots when you take the tree out of the container. It’s best to leave the roots as undisturbed as possible. Tamp loose dirt gently into the gap around the plant, but don’t push down on the root ball itself.
  7. Plant without staking.
  8. Plant oak away from turfgrass or any frequently irrigated plants and keep it that way!
  9. Once the oak is in the ground, generously soak it. The initial soaking is probably the only time you can’t water the oak too much. It’s important to keep the root ball moist but not soggy during the first three months after planting
  10. Coast Live Oaks prefer to have their roots shaded, so it’s a good idea to surround young trees with a thin layer of mulch.
  11. Coast Live Oaks are fairly easy to grow. Water 1x per week the first year after planting, decreasing to about 1x per month after the first year, until the tree is about 10 feet tall. After that, it’s best to avoid direct summer water entirely. In areas with less rainfall, best to plant Coast Live Oaks 30 feet away from an irrigated area. They’ll get the water they need by stretching their roots out to the wetter area, but they’ll keep the area close to their trunk nice and dry. Once they get their roots into the wetter areas, they’ll grow rapidly and stay healthy looking all year round.