TREES, PLEASE: The Million-Pollard Question

Rows of willow trees two years after pollarding. Photo credit: Wikimedia Commons user Charles01.

By Tim Clancy.

What has a dense head and was once used for animal fodder or for sustainably harvesting wood? A pollarded tree, or course!

On a recent visit to the Central Valley, I noticed trees in a residential neighborhood were being maintained as pollards. This is a recognized pruning technique that maintains trees to a desired height. At first and from a distance, it looks like topping, which is the undesirable tree "maintenance" technique. However, closer examination reveals a tree that responds to the pruning cuts in a way that allows the tree to continue to grow properly.

Pollarding was used as a woodland management process in Europe many hundreds of years ago. Trees were pruned above the height that freely grazing animals could reach. The trees produced a sustainable crop that was harvested and used for a variety of purposes. Some trees were pruned annually while others were pruned less frequently depending on the desired size of the wood to be harvested.

Some trees were used to create "pollard hay" to be consumed by livestock. Others were grown to be used as fence poles or in the building of boats. Still others were used to make baskets or fuel. It was quite an ingenious method to keep trees alive and continually produce a usable product.

Pollarded trees at Big Tree Nursery.

Pollarding today is typically used as an ornamental enhancement. There aren't many pollarded trees in San Diego, but I did see some at Big Trees Nursery on Pomerado Road. They are easily seen from the road and, in my opinion, are quite striking. As you can see in the image at left, the pollard heads are well developed and distinct; trees that are topped do not develop this type of growth at the topping location. (As an interesting side note, these trees were part of a project for arboriculture students at Cuyamaca College. Once the trees reached their current size, Big Trees bought them and will now find good homes for them.)

San Francisco has many pollarded trees both on public and private property. If you do a Google search using ("San Francisco, City Hall, pollard"), you should be directed to some great pictures of the fabulous collection they have there.

Pollarding is labor intensive and requires someone with a good understanding of tree pruning. Not all trees are good candidates to pollard. Certain species produce abundant epicormic growth following pruning and are ideal candidates. These include crape myrtles (Google search "crape myrtle, pollard" for some great pictures), willows, sycamores, and mulberry trees.

One interesting side effect of pollarding is an extended tree life. In fact, pollarded trees hundreds of years old exist and are maintained to this day in many locations in Europe.

Pollarded trees can and should be part of our urban forests in San Diego. They provide an interesting tree form and have high ornamental value. Pollarding can also be used as a teaching tool to inform the general public about how trees respond to pruning.