I’m sure you've seen it. A homeowner wants more sun and has their redwoods limbed way up so there is just a tuft of branches and foliage at the top. Living in the forest myself, I can understand the desire for more sun. Why is this bad for your trees? What is a better way to ensure the health of the tree and still have space to walk or park under them or open up a view?
Raising the height of the lowest branches, or limbing up, is often done to create clearance in an area where people will walk or park. Seven feet is your target height. Over-pruning removes many of the energy-producing needles and leaves taking away most of the trees’ ability to photosynthesize. Evergreens don't have food reserves like deciduous trees. They may even die completely in 8 to10 years or topple in a heavy wind because they have become so top heavy and have lost their windbreak effectiveness.
Removing the lower limbs, or limbing up, of redwood, cedar, pine or other conifers is needed to remove dead and dying branches. This improves circulation and makes them more fire-resistant. It's done naturally in the woods when limbs die and fall off. If you must remove live lower branches, do it over a longer period of time to reduce stress on the tree. The amount trimmed off should not exceed 25 percent of the total foliage. 10 to 15 percent is better but not always attainable.
Windowing of a tree should follow the same guidelines. To open up a view and preserve the health and beauty of your trees, here are some ways to make views and trees work together.
According to Plant Amnesty, windowing or cutting selected branches, works best when the subject is a large, close-in tree blocking your view. By carefully choosing what to cut, you can open a window in that tree to give you a fully framed view of whatever lies beyond. Like most pruning, there's a certain amount of art involved in this. Never top a mature tree. It's arboreal butchery.
If you're trying to decide whether or not to limb up evergreen trees in your yard, do your homework first. Oregon State University Extension Services recommends pruning when the tree is not actively growing. This is late winter to very early spring, well before any new growth will take off in the new season. For our area, January and February is best. Redwoods go into a short period of dormancy at that time, making it the best time for pruning. This gives them a chance to heal the cuts you make with their first burst of new growth in the spring.
Another scenario that wreaks havoc with the land is to clear cut large sections of forest.
When you do this, the trees left behind on the fringes are not prepared to deal with high winds. They grew up being protected by the trees around them and their trunks are not as strong. Trees channel the wind over the top and buffer it before it hits the ground. By clearing the land completely, the wind barrels through the open area and hits the next thing in its way, which may be your house, deck or landscaping. It's better to remove selected trees completely.
Put away the saw and enjoy the beauty of your mature evergreens. Prune lightly. Preserve your trees natural shape. A properly pruned tree will look as natural as possible.
- Jan Nelson, a landscape designer and California certified nursery professional, will answer questions about gardening in the Santa Cruz Mountains. E-mail her at firstname.lastname@example.org, or visit www.jannelsonlandscapedesign.com to view past columns and pictures.