While routine tree planting and other maintenance activities are handled by the City Arborist and crew, the City appropriates approximately $50,000 annually for additional contractual pruning of larger, high value trees. In addition, the services of a private landscape maintenance company are utilized for general horticultural services, including routine tree care.

We place a high premium on our trees and their proper care, and respond to tree related requests for services by its residents for trees maintained by the City. For concerns involving tree root problems, sidewalk and curb buckling, street light blockage, low or invasive branches over streets or sidewalks or into resident's backyards, fallen or hanging branches, or removal of dead trees, the number to call is: 588-3300. If the call is emergency in nature, contact the Public Safety Dispatcher at 584-2600.

Chapter 9.64 of the Rohnert Park Municipal Code defines a street tree, and requires that a permit be obtained from the City prior to altering such a tree within the City of Rohnert Park. Permits can be obtained at Rohnert Park City Hall.

Park and Street Trees

The community of Rohnert Park received its first charter in the early 1960's. Due to this relatively recent founding, there are few trees in the city over 35 years of age. Rohnert Park is appropriately named from a botanical standpoint, as it has been developed along the lines of a neighborhood concept or design. As a new section of the city was developed, it did so around a centrally located park with its associated play equipment, sports playing fields and courts, and often a swimming pool and recreation center. Today, there are nearly 200 total acres of such parklands spreading throughout the city. Trees, and the many amenities that they provide, have always been featured parts of each one of these parks. For a more detailed description of the tree species that predominate in the city, please check the Appropriate Tree Selection section of this site.

Currently there are 1,200 street trees that have been inventoried. Redwoods, sycamores, Bradford pears, shademaster and sunburst locusts, and liquid ambers are the predominant species to be featured along the major streets of the city.

Appropriate Tree Selection

The choice of "appropriate" tree species for a given geographic area is always an ongoing experiment. Constraints placed on tree growth by climate, soil conditions, and natural irrigation patterns profoundly influence what does well. As a general rule, these conditions are very favorable for a wide palette of potential tree species that can be used to great success. The city Arborist is currently working with the Planning and Engineering Departments to develop a list of those species that are considered "most" appropriate for use within the City, with particular emphasis on size considerations for a proposed planting site.

When trying to make an intelligent decision as to which tree to plant, it is always a good idea to talk to others in your area that have actual experience with the potential candidates that you are considering. Why, because this is how the great ongoing experiment works. Certain widely used tree species are not without problems, particularly as they become mature. Size appropriateness is the critical issue, and this should include the size of the rooting environment that will be necessary to support the tree at maturity. The long-term effects of the tree's spreading root system on adjacent hardscape and underground utilities must also be taken into consideration. What are its sensitivities to damaging insect and disease agents? See Miscellaneous Tree Tips for further information.

Miscellaneous Tree Tips

In this section, we hope to provide useful information on all aspects of tree care from the time of planting, through early tree care and establishment, to periodic care, such as pruning and size reduction. We will provide useful tips on how to properly prune a tree so as to maintain its aesthetic beauty and contribution to property value, recognizing that inappropriate pruning is common.

When we plant a tree, we should accept the fact that it will require some periodic pruning to direct its proper development over time. Again, choosing the proper tree species for the location is about half of the battle, and can save us a lot of effort and heartache in the long run. Think of planting a tree as you would the adoption of a puppy, as it is long term commitment, and we all want a good end product.

When planting a tree, there are several important considerations

• Many newly planted trees fail simply because we planted them too deeply in the soil. While we encourage the digging of a large planting pit that is at least twice the diameter of the root ball, the pit need not be deeper than the height of the root ball. The root crown, or the area where the roots originate on the lower trunk, should end up being 2 to 3 inches above the grade of the planting area at completion. The reason for this is because trees that have their lower trunks sunken into moist soil are far more likely to become infected by root rotting fungi called water molds. This is especially true for young fruit trees. So, leaving your newly planted tree on a slight mound without the old watering basin is actually the current thinking. Instead of the watering basin, spread a 3-4 inch layer of mulch material over the entire planting pit area, keeping it clear of the root crown, and this will greatly aid in the maintenance of moisture around the newly establishing roots.
• To help with the quick establishment of a newly planted tree separate roots that are invariably tangled within a circular nursery container. There can be many feet of roots circling within the nursery container, and this can work toward the success of the transplanted tree or toward its ultimate demise. Our job, to untangle, spread, and direct at least a few of these roots into the entire area of the planting pit before back filling the pit with finely crumbled soil. The effect of this effort is the more complete exploitation of the moisture and mineral element resources of the planting pit by the newly expanding roots as we encourage them to eventually escape the pit into the native soil mass.
• You may have noticed that we have avoided the term planting hole and have instead made reference to the term planting pit. This is because current thinking favors any technique that will encourage a tree's roots to break away from the circular configuration of the nursery container. Thus, the concept of a squared-off configuration that would present the tree's roots with a sharp corner that would have the effect of trapping the root and further encouraging its escape from the pit. Some experts have further suggested that perforating the sides of the planting pit with a device like a spadefork (a wide tined pitch fork) would further increase the chances of root trapping and improved establishment.

One interesting observation based on the necessity of digging up the root systems of trees that had been planted approximately a year earlier and where little attention had been given toward separating the tangled rootball reveal: 1) that few if any roots escaped from the tangled central portion of the rootball. 2) Those roots that did manage to escape from the rootball all came from either the uppermost or lowermost portion of the rootball. Presumably, those roots in the center of the rootball either continued to circle and represent a problem to the tree, or simply fail and did not contribute to the tree's establishment in a positive way. When the bottom line for our landscapes is the positive performance and contribution to property value that a well-established tree can make, then the attention to such details takes on more importance.

Tree Pruning

We have previously indicated that periodic pruning of a high value landscape tree should be considered a reality, unless we have been so fortunate in our selection of the perfect tree for the location that pruning never becomes necessary. Occasionally this happens, as with that perfect little Japanese maple planted 20 years ago by the front entryway that filled the spot to a tee. Again, plant the right tree in the right place.

A word about "pollarding" as a pruning method. Pollarding is an acceptable size maintenance technique in formal arboriculture. As a matter of fact, it is an ancient pruning technique that was refined in the formal and very manicured royal gardens of Europe for centuries. The objective was to grow a durable tree to a fixed size and then maintain that tree or an entire row or circle of such trees at that same size forever. This was accomplished by pollarding or heading the scaffolding branches of the tree into a skeletal structure that would support a foliage crown of current year's growth each season. This skeletal structure normally resembled a three dimensional candelabrum. At the end of each growing season all of the new growth whips would be removed, and, in time, "fists" of callus and new bud tissue would develop at the branch ends; such a skeleton would stand naked throughout the winter until spring. The sycamores at the base of the Campanile on the U.C. Berkeley campus are a modern day example of appropriately pollarded trees.

Unfortunately, the concept of pollarding has been inappropriately extended to nearly any tree that has become too large for the space allocated to it, and these trees are mercilessly headed back into large wood in the name of size reduction. This is not appropriate pruning and is certainly not good arboriculture. Here are just a few of the negative consequences of heading done in this manner: 1) Loss in aesthetic beauty associated with loss of the tree's natural shape. 2) Loss in structural integrity leading to increased liability due to potential for limb failure. 3) An increase in pruning expense associated with the necessity for reducing the number of profuse regrowth sprouts that result from heading cuts, and from the need for safety pruning when larger sucker regrowth develop mass and begin to fail. Couple this with the need to repeat the heading process at frequent intervals just to accomplish the original intent, which was size reduction. There have been many that have abandoned this treadmill and simply cut the too large tree down and replanted with an appropriately sized tree for the area, a more sensible approach in the first place.

So, if heading is inappropriate pruning to accomplish size reduction, what is an alternative appropriate method? Simply stated, it is timely, it is periodic, it is as light as possible, and it is begun on the tree when it is young. Again, if you have questions for the City Arborist, please call 707-588-3300.