Most people are attracted to trees, especially in our valley's long, hot summers! We may recognize that trees add beauty to our landscapes and cause us to feel better. Current research about urban trees and human health discovered that trees indeed "improve psychological and physiological functioning, boost ability to focus, improve stress recovery, and increase active living" (as researcher K.L. Wolf et al. discovered.)
Trees help clean the air, reduce smog, remove carbon dioxide from the air and release oxygen into the atmosphere. Trees collect dust, control soil erosion, serve as windbreaks, and provide wildlife habitat. Properly placed trees can reduce energy consumption by providing summer shade and winter warmth. Trees absorb solar radiation, turn it into transpired water vapor that can cool surrounding buildings. Cityscapes are enhanced with trees by offsetting the increase of pavement and concrete.
The significant importance of trees naturally resulted in encouraging us to plant more trees. However, trees are a definite investment of time and money. Emphasis is now on growingtrees well in the landscape, instead of hasty planting. This requires some research and planning. We can minimize maintenance and future problems by picking the best tree for the right area.
Knowledge of a tree's features: shape, sun and water requirements, leaf/flower/fruit litter, evergreen or deciduous (drops all of its leaves in one season) should be considered. Determine the purpose of the tree.
Most importantly, the mature size of the tree must be wisely considered. Measure the height and width of the site. Are there solar panels, utility lines, fences, buildings, walkways or roads "in the way" of your future tree? If so, pick a different site or a different tree! Nursery labels for some trees state the tree's adult size at fifteen years of age. However, many tree species will continue to grow beyond this age.
After the choice is made, select a healthy tree free of disease and defect. A younger, smaller tree will cost less, will be easier to plant, will take less time to recover from the transplanting process, and will grow faster than if you plant a large version of that tree species. Be sure the roots are firmly attached to the tree's root ball. Pick a tree with small branches growing up and down most of the trunk instead of a tree with a big, full, rounded top and a leafless trunk. These small temporary branches will shade your young tree's trunk, provide food for it, and may be removed later.
Keep the tree planting operation simple. Wash off some of the soil to examine the roots. Prune any root circling the trunk or a severely kinked root. Dig the planting hole the same depth as the tree's root ball depth and slightly wider. Place tree in the hole on firm soil to avoid settling. Back fill with original soil — no amendments or fertilizers are needed. Remove the nursery stake, then stake with two stakes outside the root ball only if necessary. Water the tree thoroughly in a basin built around the tree with soil the same diameter of the root ball. Add organic mulch to reduce water evaporation, making sure to keep the mulch away from the trunk. Trees benefit greatly from their own leaves being allowed to stay where they fall under the tree as natural mulch. This litterfall recycles tree nutrients and keeps soil from compacting.
The Water Use Classification of Landscape Species (WUCOLS IV) provides evaluations of the irrigation needs of over 3,500 plants, including trees, used in California Landscapes at https://ucanr.edu/sites/WUCOLS/. The WUCOLS project was initiated and funded by the Water Use Efficiency Office of the California Department of Water Resources (DWR). Work was directed by the University of California Cooperative Extension.
A tree list to aid your tree selection is available on our Master Gardener website (https://ucanr.edu/sites/UC_Master_Gardeners/Local_Gardening_Articles_-_Info/Landscape_Trees/).
Western redbud, crape myrtle, 'Saratoga' bay laurel, and Chinese pistache are some favorite trees on this list. In addition, a list with explanations noting "Problematic trees—Proceed with Caution" is also obtainable on our website. Some of the trees on this list are: mimosa, white birch, mulberry, and coastal redwood. Three trees are marked DO NOT PLANT: tree of heaven, saltcedar, and Chinese tallow.
Trees certainly enhance our lives. Planting the right tree in the right place in the right way can be a wise and appreciated investment for ourselves and our community.
Are you interested in becoming a Master Gardener? The UC Master Gardener program of Tulare/Kings Counties is recruiting! Our next class runs from January 19 through June 8, 2022. Applications will be available online in August and must be turned in by October 27. We will be holding a mandatory orientation at 3 p.m. on Wed., Oct. 13. to share what the training course and the volunteer commitment entail. Please call our office (684-3343) with any questions…we look forward to talking with all interested gardeners! Check us out at: