MAINTAINING THE RANCHO YOLO URBAN FOREST

CARE AND MAINTENANCE 

Common Suggestions for Care and Maintenance

(Note: This section was taken directly from the website of the Gardeners Supplies Co. [https://www.gardeners.com/how-to/tree-planting/8741.html]. They provide a fairly comprehensive set of instructions. Before purchasing and planting a tree, residents should consult with a qualified nursery person or arborist to determine examples of appropriate species and to see if there are special instructions/concerns).

Planting a tree

When you plant a tree, you celebrate the earth by increasing its leafy canopy. According to the U.S. Department of Agriculture, "One acre of forest absorbs six tons of carbon dioxide and puts out four tons of oxygen. This is enough to meet the annual needs of 18 people." Trees also add beauty, increase the value of your home, provide cooling shade and offer shelter for wildlife. Proper planting is critical to their survival and long-term success.

Digging the hole

Planting too deep is the top reason that trees and shrubs die. Follow these simple steps to ensure the correct planting depth for both balled-and-burlapped (B&B) and potted trees.

1.    Locate the point at which the trunk flares out to join the roots. On B&B trees, remove the twine and burlap at the base of the trunk. If necessary, gently push the soil away from the base of the trunk to find the flare.

2.    Measure the distance from the bottom of the root mass to the trunk flare. Dig the hole no deeper than this; you want the root mass to sit on undisturbed soil. When planting is complete, the trunk flare should be slightly above the existing soil grade.

3.                            Dig the hole two to three times the diameter of the root ball or container, sloping the sides gently outward to the existing soil grade.

Backing

The thinking on backfill has changed in recent years. Although it was once common to modify the backfill soil with amendments — such as compost, peat moss, aged manure and other ingredients — it is now considered best practice to leave the backfill soil unaltered or add minimal amendments. This encourages roots to spread out into the native soil, rather than staying within the confines of the planting hole.

It is commended adding mycorrhizal fungi and bone meal to the backfill. Mycorrhizal fungi form associations with plant roots and help them extract and absorb minerals and water from the soil. Trees and shrubs with mycorrhizal-enhanced root systems adapt better and are more tolerant of stressful environments. Bone meal provides essential minerals that promote sturdy root systems and stimulate plant growth.

Planting

When moving your plant into the planting hole, disturb the rootball as little as possible. Lift B&B trees and shrubs by using the rope, burlap or wire cage on the rootball. Lift potted plants by grasping the container. Don't lift plants by the trunk, stems or branches. Don't allow the root system to dry out before or during planting.

For balled-and-burlapped trees and shrubs:

1.    Place the tree in the center of the hole. If necessary, straighten or stabilize the tree by adjusting or filling beneath the root ball with the backfill mix.

2.    Cut away any twine or burlap from the base of the trunk and remove any burlap that is on the top of the rootball. Remove excess soil from the top of the rootball to expose the trunk flare, if needed.

3.    Use bolt cutters to remove as much of the wire basket as possible. Don't try to remove the entire wire basket. The plant will thrive even if there is some of the basket left in the hole. Remove all the rope and twine from the rootball, as well as any nails holding the burlap together. Pull back the burlap and cut away any loose material. It's OK to leave some burlap in the hole to decompose. However, remove all plastic or treated burlap.

For potted trees and shrubs:

1.    Tip the container on its side and slide the plant from the container. Place the plant in the hole by lifting the root mass, not the plant itself. If the plant has become pot-bound, it may be necessary to cut the container before the plant can be removed.

2.    To encourage root growth, tease the outer roots from the soil. If the roots are tightly matted, use a knife to score the root mass in several places and gently loosen the root ball. This won't harm the plant and will encourage new root growth.

Backfilling and watering the planting hole

1.    Add backfill soil to your planting hole until it comes about halfway up the root ball. Use your foot or hands to firm the soil and eliminate air pockets. Make sure the trunk is vertical and confirm that the trunk flare will sit slight above soil grade once backfilling is complete. Continue adding backfill and packing it down until you've reached the top of the root ball, taking care not to cover the trunk flare.

2.    Construct a 3–4" high ridge of soil around the outer edge of the planting hole. This berm will create a basin to hold irrigation water and concentrate it over the roots. Use a hose to fill the basin, allowing the water to soak it, repeating several times. Or, let the water run at a trickle for 15 to 30 minutes to ensure that the entire root zone is moist. The goal is to ensure even watering so the soil is drenched and any large air pockets are eliminated.

3.    Recheck that the trunk flare is completely exposed and the top of the root ball has not been covered with additional soil. Remove any plant tags or labels from the tree.

Adding mulch during planting

Apply bark mulch or pine straw to a depth of 2–3" over the entire planting hole. Mulching helps conserve water and prevent weeds. Taper the mulch toward the base of the tree, but do not allow it to touch the tree trunk.

Staking

Staking at planting time is not always necessary. Consider the stability of the rootball, trunk size and strength, direction of prevailing winds, canopy size and density when determining whether or not to stake. If in doubt, ask a nursery professional.

Fertilizing

Fertilizing newly planted trees and shrubs during their first year of growth is not recommended.

Watering a new tree

Proper moisture is critical to the survival of your young tree or shrub. The roots should never dry out completely, nor should they be waterlogged. The best way to check soil moisture? Use your finger. Dig down 2–4" just outside the root mass of the plant and water if the soil feels dry. Newly planted shrubs and trees should be checked and watered every other day for the first two weeks. After the first two weeks, limit watering to once a week if less than 1" of rain falls during the week. Thorough soakings that moisten the soil to the entire depth of the root mass are better than frequent light watering. A soaker hose can be placed in wide circles around the tree for watering newly planted trees.

Watering Once the Tree has Been Established

Trees of all ages require watering to remain healthy. It is important to know a tree’s preferred moisture conditions. Newly planted trees require regular watering to become established. At the time of planting, a basin can be constructed around the tree, slightly larger than the root ball to help direct water to the trees roots. Fill the basin with water once or twice a week, as needed, to keep the root ball moist.

More frequent watering may be required during periods of hot weather. Periodically check the soil to see that it is not too wet or too dry and that you are watering deeply enough. Poke a hole in the soil so you can feel down to a depth of about two inches. A damp soil that dries for a short period will allow adequate oxygen to permeate the soil. Be sure to water the entire root area and slightly beyond.

Overwatering, a common mistake, leads to soggy soil and poor tree health. Young, established trees require infrequent deep watering for root development and good tree growth. Drip irrigation is best to apply water slowly onto the soil, allowing the water to infiltrate into the root zone.

Mature trees may only require watering in the hotter summer months. Water should be applied under the drip line when possible. Protecting them by keeping them in great health is an effective way to protect your investment and the long-term look of your landscape. Planting under the tree, whether existing and new, optimally share similar water needs with the tree.

Drought tolerant species, as well as other vegetation in the xeriscaped area (dry), still need water (just less than other species). Likewise trees that have roots near the xeriscaped area are often at risk for dying due to lack of adequate water. It is tragic to loose the tree focal point and its important shade for a water thrifty garden.

Mulching of maintenance

Types of wood mulch

We’ve been taught that wood mulch is essential, and in a lot of ways it is. If you use it, chunky wood mulch at a depth of 3 to 4 inches is best at suppressing weeds and adding organic matter to the soil, while also allowing good water infiltration. Finely shredded wood mulch tends to create a dense, impermeable mat and even blow away, but it’s great at weed suppression. The point here is that the kind of wood mulch you use matters. And don’t use cypress, as it’s often harvested unsustainably.

Too much can be very bad for plants

What about mulch volcanoes; you know, mountains of mulch piled up 1 foot to 2 feet against a tree trunk. This practice will lead to disease and trunk rot and tree death. Trees like river birch even seem to prefer plants around their root zone, which better shade and cool the soil.

Some studies show that a circle of mulch around trees and shrubs increases their rate of establishment and growth over the years. Keep in mind, though, that a tree’s feeder roots will eventually reach out to at least twice the tree’s height — that’s one really big potential mulch circle.

Eventually you won’t even need mulch

After a few years, as your plants establish, you won’t really need any kind of trucked-in mulch. The taller and thicker plants create a shade barrier to most weeds and help conserve soil moisture. If anything, top-dress with some nice compost in the fall, since compost can be both a mulch and a natural fertilizer. Letting it soak in over winter is also a smart idea.

Pruning

During their lifetime, trees will require pruning. Pruning is an important part of an overall tree care program. Pruning should be performed for the following reasons:

·       Remove dead, damaged, and diseased branches

·       Correct or remove structural defects

·       Restore the canopy after a catastrophic limb failure (storm damage)

·       Reduce branch weight

Proper pruning builds structural stability in the tree and promotes tree health. When to prune depends to a large extent on why you prune. Light pruning and the removal of dead wood can be done anytime.

Winter: Pruning during winter dormancy is the most common practice. It results in a vigorous burst of new growth in the spring and should be used if that is the desired effect. It is usually best to wait until the coldest part of winter has passed. Some species, such as maple, walnuts and birches, may “bleed”—when the sap begins to flow. This is not harmful and will cease when the tree leafs out.

Spring and Summer: If your purpose for pruning is to enhance of flowering of trees that bloom in spring, prune when their spring flowers fade. Trees and shrubs that flower in mid- to late summer should be pruned in winter or early spring. Summer pruning is done to direct the growth by slowing the branches you don’t want; or to slow “dwarf” the development of a tree or branch, pruning should be done soon after seasonal growth is complete. The reason for the slowing effect is that you reduce the total leaf surface, thereby reducing the amount of food manufactured and sent to the roots. Another reason to prune in the summer is for corrective purposes. Defective limbs can be seen more easily, or limbs that hang down too far under the weight of the leaves. Surprisingly, fall is not the time to prune. Decayed fungi spread their spores profusely in the fall and healing of wounds seems to be slower in the fall.

Consider having a qualified tree service to perform the tree pruning. It makes such an important difference to the health of the tree. A Certified Arborist, Tree Worker or Board Certified Arborist, licensed and insured for the protection of the tree owner, should be on site to supervise the work and to protect the health of your tree. Likewise, a professional can best identify and remedy insect problems and plant diseases. Davis Forestry Resources page has information about proper tree pruning and more. 

SUGGESTED TREES TO PLANT

Information below offers our resident a wide range of trees that they might consider for their gardens. One was created by Yolo County Master Gardeners and can be found at http://ceyolo.ucanr.edu. The second is a list from the City of Woodland (2019). These trees do not require too much watering and are fairly disease resistant. As water continues to be a limited resource in California, cities, landscapers, arborists, designers and urban forest managers are turning to drought tolerant choices. As noted above, all newly planted trees require regular watering until they are established. It is important to note that even if a drought tolerant species is planted, it will need some water, off and on, in the dry summer. If your tree's leaves are starting to droop, or wilt, give it a drink fast.  Planting in summer requires more monitoring.  Fall and Spring plantings are best, if possible.

Be Careful: These suggestions are not good for all spaces and locations. Please consult with appropriate experts before selecting a tree.

City of Woodland Recommended Trees (2019)

The format for each tree is as follows - Common Name: Scientific Name. Tree Type. Height.  Spread. Growth Rate. Water requirement. Uses and Comments

Crabapple, Flowering: Malus floribunda. Deciduous. H 15'-20, S15'-20'. Slow to moderate growth. Water use moderate. Colorful leaves, flowers and fruits. Very resistant to disease and makes a great ornamental tree in small spaces or under power lines.

Crape Myrtle: Lagerstroemia indica/hybrids. Deciduous. H 20'-30', S 15'-25'. Moderate growth.  Water use low. Year-round interest—showy flowers, fall color and decorative bark only plant disease resistant varieties to keep care low-maintenance.

Hawthorn, Washington: Crataegus phaenopyrum. Deciduous. H 18'-25', S 15'-25'.  Moderate growth. Water use moderate. Springtime flowers and small, bright red berries that hold on into winter Very decorative. Thorny branches. Fireblight resistant.

Redbud, Western:  Cercis occidentalis. Deciduous. H 20'-25', S 20'-25'. Moderate growth.  Water use moderate. Heart shaped leaves and magenta Towers in early spring.  Pollinators enjoy this tree, drought tolerant once established, California native.

StrawberryTree:  Arbutus 'Marina'. Evergreen. H 25-30', S 20-25'. Slow to moderate growth.  Water use low. Evergreen tree with clusters of small cream color flowers, good for bees, hummingbirds. Forms1”red strawberry like fruit. Attractive red bark.

Ash, Fan Tex 'Rio Grande':  Fraxinus velutina. Deciduous. H 30'-50', S 30'-40'.  Rapid growth. Water use moderate. Thrives in hot, dry climates with windburn resistant leaves. Good replacement for Modesto Ash.

Buckeye, California:  Aesculus californica. Deciduous. H 30', S 30'-45'.  Moderate growth. Water use low. California native. Conserves water in summer by going dormant. Large, fragrant flowers.

Linden: Tilia cordata. Deciduous H 30'-50', S 15'-30'. Slow to moderate growth. Water use moderate. Fragrant, light yellow flowers bloom in July. Pyramidal shape in maturity.

Maple, Trident : Acer buergeranum. Deciduous. H 20'-30', S 20'-25'. Moderate. Growth. Water use moderate. Does well in many different soil types. A nice, dense shade tree for smaller spaces.

Olive, Fruitless, 'Wilsonii': Olea europaea. Evergreen. H 25-30', S 25-30'. Slow to moderate growth. Water use low. Good in hot dry climates, silver grey foliage, fruitless, attractive bark with age.

Pistache, Chinese: Pistacia chinensis. Deciduous. H 30'-50', S 30'-50'. Slow to moderate growth. Water use low. Striking fall color. Tolerant of drought and heat.

Cedar, Deodar: Cedrus deodara. Evergreen. H 80', S 40'. Rapid growth. Water use moderate. Performs best in unconfined areas so plant only in areas with plenty of space. Texture is softer and lighter than other cedars.

Elm, Accolade: Ulmus x 'Accolade'. Deciduous. H 50-60, S 30-40'. Rapid growth. Water use low.  No Dutch elm disease and leaf beetle resistant; drought-tolerant, prefers well-drained soil; three-inch yellow fall leaves; upright arching branches.

Elm, Frontier: Ulmus x 'Frontier'. Deciduous. H 40', S 30'. Moderate growth. Water use moderate. No Dutch elm disease and leaf beetle resistant; drought-tolerant, prefers well-drained soil; three-inch yellow fall leaves; upright arching branches.

Elm, Prospector: Ulmus wilsoniana 'Prospector'. Deciduous. H 50'. S 25'. Moderate growth. Water use moderate.  No Dutch elm disease and lea is beetle resistant; some boron leaf margin burn; best in well-drained soil; four-inch leaves red in spring, yellow in fall; lower branches arching.

Gingko 'autmn gold': Gingko biloba. Deciduous. H 60', S 45'. Slow growth. Water use moderate. Beautiful golden fall color. Does well in many soil types and prefers good drainage.

Hackberry, European: Celtis australis. Deciduous. H 40'-80', S 40'-50'. Moderate growth. Water use moderate. Pest resistant and disease free. Attractive to birds when dark purple fruits are ripe.

Hornbeam, European: Carpinus betulus. Deciduous. H 40'-80, S 40'-80'. Slow to moderate growth. Water use moderate. Long life and good habits with attractive fall color.

Oak, Coast Live: Quercus agrifolia. Evergreen. H 20-50', S 20-30'.  Moderate growth. Water use low. California native and drought tolerant. Varies widely in growth habit.

Oak, Cork: Quercus suber. Evergreen. H 40', S 40'. Moderate growth. Water use low. Cork bark with dark green foliage. Very drought-tolerant and sensitive to over-watering.

Oak, red:  Quercus rubra. Deciduous. H 40'-70', S 40'-60'. Rapid growth. Water use moderate.  Adapts well to many environments. Nice fall color. 

Oak, Valley: Quercus lobata. Deciduous. H 70'+, S 70'+. Moderate growth. Water use low.  California's "signature tree." Tolerates high heat and drought conditions and makes a great shade tree for large, open space.

Pine, Canary Island: Pinus canariensis. Evergreen H 50'-80', S 20'-35'. Rapid growth. Water use moderate. Grows as a slender, graceful pyramid with attractive bark

Zelkova, Sawleaf: Zelkova serrata. Deciduous. H 50'-90', S 50'-90'. Rapid growth. Water use moderate. Great shade tree for lawns and streets with wide-spreading branches and dense foliage. Interesting fall color.

PARK RULES AND RESPONSIBILITIES

The following comes directly from that part of the State’s 2018 California Mobile Home Residency Law dealing specifically with trees (contained in Section 798.37.5):

(a) With respect to trees on rental spaces in a mobilehome park, park management shall be solely responsible for the trimming, pruning, or removal of any tree, and the costs thereof, upon written notice by a homeowner or a determination by park management that the tree poses a specific hazard or health and safety violation. In the case of a dispute over that assertion, the park management or a homeowner may request an inspection by the Department of Housing and Community Development or a local agency responsible for the enforcement of the Mobilehome Parks Act (Part 2.1 (commencing with Section 18200) of Division 13 of the Health and Safety Code) in order to determine whether a violation of the act exists.

(b)            With respect to trees in the common areas of a mobilehome park, park management shall be solely responsible for the trimming, pruning, or removal of any tree, and the costs thereof.

(c) Note: this paragraph is not applicable to trees.

(d)            No homeowner may plant a tree within the mobilehome park without first obtaining written permission from the management.

(e)This section shall not apply to alter the terms of any rental agreement in effect prior to January 1, 2001, between the park management and the homeowner regarding the responsibility for the maintenance of the trees and driveways within the mobile home park, except that upon any renewal or extension, the rental agreement shall be subject to this section. This section is not intended to abrogate the content of any existing rental agreement or other written agreements regarding trees or driveways that are in effect prior to January 1, 2001.

(f)   This section shall only apply to rental agreements entered into, renewed, or extended on or after January 1, 2001.

Homeowners are also required to comply with the Rancho Yolo park rules. If a resident wants to plant a tree or a shrub, he/she must request it in writing for the manager's review. If approved the resident will receive written permission, or a refusal if the tree is considered inappropriate. A written request, submitted to the manager is also required for the removal of a tree.

NOTE: This section is not intended to support administrative actions or in any way does it constitute legal or actionable advice. As with any public law there can be nuanced interpretations.