A. Location And Spacing:
1. No planting holes, pits or excavation for street trees shall be prepared on city parking/planting strips until the planting site has been identified and approved by the urban forester. In addition to the urban forester's approval, Blue Stake Location Services must clear all planting sites of utilities in accordance with Utah state law. Trees shall be centered between the sidewalk and the curb. Only trees listed in section 1900-4 of this policy meeting applicable individual parking/planting strip dimensions shall be planted. In the event that there is no sidewalk or curb, the urban forester will designate the planting location of the tree.
2. No tree species which will attain a mature trunk diameter greater than twelve inches (12"), a base swell greater than sixteen inches (16"), or extensive surface rooting characteristics upon maturity shall be planted in a parking/planting strip less than six feet (6') in width. On parking/planting strips less than three feet (3') in width, or where there are overhead utilities the urban forester shall determine lines or where structural conflicts exist, species and location selection.
3. No street tree shall be planted within ten feet (10') of any building, structure or fence, unless otherwise specified by the urban forester.
4. No street tree shall be planted within fifteen feet (15') of a streetlight, utility pole, driveway or alley.
5. No street tree shall be planted within eight feet (8') of any water meter.
6. At street Intersections, no street tree shall be planted within forty feet (40') of the vertex (the corner point if the 2 curbs intersect in straight lines rather than having a radius) of any corner within an intersection.
7. Street trees planted in parking strip must have a minimum of sixteen (16) square feet exposed area (4' x 4' opening) at the base of the tree. The tree must be set back a minimum of two feet (2') from the curb and gutter.
8. In general, minimum spacing between trees to achieve optimum individual growth rates when canopies mature shall be: small trees twenty five feet (25'), medium trees thirty five feet (35') and larger trees should be forty five feet (45'). The urban forester may make specific spacing requirements for street tree plantings based upon individual site condition/characteristics and species or varieties characteristics and requirements.
B. Planting Techniques:
1. Public planting on city property may be done by using trees grown in containers, tree supplied in burlap and balled baskets or trees dug and moved with a tree spade. The three (3) different types of trees (containerized, balled and burlapped or tree spade) supplied by nurseries or landscape companies require three (3) different planting techniques. The different techniques are described in greater detail, further in this section. Bare root planting will not be used unless special circumstances require its use as recommended by the urban forester.
2. All planting holes shall be constructed in a circular fashion with outward tapering walls (vase shaped). Planting holes should be dug when the soil is moderately moist, not saturated. When the hole is constructed in moist conditions the walls of the hole may become "glazed". Although glazing conditions are more severe when using a soil auger or tree spade to dig the hole, glazing can be a problem with shovel constructed holes when soil moisture conditions are high. Glazing should be alleviated prior to planting the tree by reversing the shovel angle and scuffing the glazed walls of the hole with the tip of the shovel. This will allow an interface for newly developed roots to easily penetrate and adapt to the new soil conditions. Generally, holes should be dug one and one-half (11/2) times the diameter and the same depth as that of the root ball and soil mass.
3. Trees should be centered in the planting hole and set at the depth where each tree's original soil line is equal or slightly higher than the top of the planting hole's soil line. (This will compensate for the settling of the soil backfill.) The tree should be completely perpendicular to the ground when viewed from two (2) locations at right angles to one another.
C. Planting Containerized Stock:
1. Containerized planting stock should be placed in the prepared hole no deeper than the existing soil line that is in the container; not to the container top itself. Careful inspection should be made to locate the root collar of the tree. The root collar is the region of the tree where the trunk of the tree meets the roots. The root collar can usually be identified by green tissue just above the brown or white tissue of the roots when lightly scraped with a fingernail. Oftentimes, trees are planted too deep in the containers from the nursery. If the root collar is too deep in the container then plant the tree so that the root collar is just at or slightly above the existing soil line of the planting hole. If the root collar is at the right height with the soil in the container then the tree can be placed in the hole and the top soil level of the container be made equal to or slightly higher than the planting hole's soil line. The tree can be straightened and be made perpendicular to the ground by tipping the tree and packing soil under the appropriate side. A tree growing crookedly in its container can be straightened in the same manner. Always lift the tree by the container, not by the trunk. Once the planting hole has been completely prepared, the container must be removed.
2. Containers must be carefully removed from these types of trees, even if the containers are of decomposable material. Container can be removed in two (2) different ways:
a. With the tree lying on its side, carefully cut a slit down the container wall with tin snips or shears, then continue the cut across the bottom of the container. Peel back the container and place root mass into planting hole.
b. With the tree lying on its side, sharply slap container's walls with an open hand, rotate container and repeat. Gently slide root mass out of container and place in planting hole. During either procedure caution should be exercised to ensure that soil is not separated from root mass and that no damage is sustained to the tree's roots.
3. If roots have grown in a spiral fashion inside the container, the tree may be "root bound". To encourage straight roots to form, make four (4) vertical incisions down the sides of the root ball one-fourth inch (1/4") in depth ninety degrees (90°) to each other, and a crisscross incision on the bottom. Note: Once roots are removed from container, time is essential. Roots must not be exposed to direct sunlight or air for any amount of time. Immediately plant the tree to minimize exposure time.
4. Place enough topsoil in the planting hole to fill one-third (1/3) of the hole. Lightly tamp soil around the lower portion of the root mass using hands or feet, then add one-third (1/3) more topsoil and repeat tamping. Add water to hole; let water completely drain, then fill hole completely full with topsoil to surrounding soil level. Put a soil dike around perimeter of planting hole if the tree is located in an area that is not under an irrigation system and water thoroughly. If the planting site is in extremely rocky soil or soil that is high in clay, soil additives can be added to the soil that is returned to the planting hole. Additives should be high in organic matter and material designed to keep soil loose and aerated. Most compounds designed to do this are marketed, as a soil amendment not a soil additive. Such compounds include sphagnum moss, wood products, perlite or vermiculite in their compositions. Introducing these compounds into existing soil should be done at a one to four (1:4) or one to three (1:3) ratio of additive to soil. In other words, for every shovel of introduced soil additives you should combine two (2) to three (3) shovels of existing soil.
D. Planting Balled And Burlapped Stock:
1. Set the tree in the planting hole on a layer of tamped soil at the bottom of the hole and at the same depth or slightly higher than it was at the nursery. The tree can be straightened by tipping it and packing soil under the appropriate side. Always lift balled and burlapped plants from beneath the soil ball, never by the trunk.
2. Follow planting procedure as used in containerized stock with the following exceptions:
a. Once planting hole has been prepared, carefully place tree (burlap and all) at the side of the planting hole. Cut the lower portion of the wire basket completely off the bottom of the root ball. Place the root ball into the planting hole and align the tree vertically to the surrounding ground level and center it in planting hole. Fill the hole with enough soil to "set" the ball to keep it from moving while you complete the tree planting. Now that the tree is secure, cut the remaining portion of the cross braces in the wire basket in a vertical manner and remove wire basket. If the root ball is solid and does not start to break, finish the planting by cutting all of the burlap that is accessible and removing it from the planting hole.
b. If the root ball is dry or very sandy and starts to break apart during the removal of the burlap, then maintain the burlap around the ball. Cut the burlap completely around the bottom of the ball and leave in place. Fill the planting hole one-third (1/3) full and lightly compact the soil. Next gently pull the burlap up to the new soil level. Fill the planting hole one-third (1/3) more with soil and lightly compact. Gently pull burlap to that level. Complete filling the hole and compact lightly, removing the burlap completely. The ball is still intact and almost all of the burlap has been removed. Water immediately.
c. Make sure all twine, wire, and any other debris are separated from the tree. With burlap and balled trees, compaction at the time of planting is critical. If the compaction is too great, the tree will be stressed while trying to adapt to the new location. If the compact is too little, the tree will tip over from simply being watered, let alone by wind.
E. Planting Tree Spade Stock: Planting trees with a tree spade is one of the most expensive methods of planting. The average homeowner will probably never choose to use this method because of the cost. However, it is one of the few ways that large trees can be planted in a new landscape. A tree spade is a machine that digs a soil plug from a location where a tree is desired. The machine is then used in another location to dig another plug with a tree in it and then takes that tree plug to the first location and plants it in the original soil plug site. If a tree spade is to be the method used, then the following guidelines will be followed:
1. As stated earlier, mechanical tree spades and augers create the most severe cases of glazing. Roughing the sides of the planting hole with a shovel can alleviate glazing. However, when using a tree spade, one should be careful while roughening the sides of the hole with a shovel, so that deep depressions can be avoided. Deep depressions or holes in the spaded hole walls will be hard to fill with soil and will cause "air pockets" which could seriously stress the tree, if not kill it.
2. First, a soil plug is dug with the tree spade and the planting hole is created. Alleviate the glazing effect on the sidewalls by scuffing with a shovel.
3. Place the tree plug in the hole the same way that the initial soil plug was taken out.
4. Backfill with topsoil between the sides of the hole and the tree plug.
5. Water thoroughly to settle backfill and eliminate air pockets, allowing standing water to be absorbed prior to adding more soil.
6. Add enough soil to fill the space between the side of the hole and the tree plug level with the adjacent grade and tamp it. Water again to settle backfill. Repeat backfilling and watering until no additional soil will go into the hole between the tree plug and adjacent ground.
7. Water as defined in subsection F1 of this section.
F. Maintenance After Planting:
1. Watering: Newly planted trees and other woody plants require water once every other day. After two (2) weeks, watering can be reduced to every three (3) to six (6) days during the growing season, for the first year after they have been planted. Watering is mainly dependent upon seasonal temperatures: the warmer the temperatures the more water is needed. Mature trees should also be watered prior to and during severely dry periods. To properly water an established tree, let a garden hose run slowly for several hours at and around the drip line of the tree. Watering too frequently can harm a tree, so guard against overwatering. Check several inches below the soil surface for moisture. Water only when the soil feels dry or just slightly damp. As a general rule, keep trees moist but not wet. The difference between the two is when you put the soil in your hand and squeeze it and water trickles out, that is wet. If you squeeze it and the water just discolors your hand that is moist. If the tree is getting too much water from a sprinkler system, the soil dike installed at the time of planting must be removed.
2. Root Stimulants: There are several organic and inorganic root promoting hormones available on the market today. Use of root stimulant aids the plant's natural abilities to develop root biomass, and they are very effective in reducing prolonged stress due to root pruning effects on new transplants. Most of these chemicals have a vitamin B-1 compound in them. Vitamin B-1 also aids in reducing stress in new transplants. The best compounds contain vitamin B-1, chelated micronutrients (zinc, manganese, etc.) and two (2) root promoting growth hormones.
3. Mulching: A three (3) to four inch (4") layer of mulch, spread to form a three foot (3') diameter circle around the trunk, should be applied after planting. Keep the mulching material from direct contact with the tree trunk. Mulching prevents weed growth, slows moisture loss, stabilizes soil temperature, prevents soil heaving from frost, and provides a barrier between the trunk and your lawn mower/weed trimmer. Wood and bark chips are good mulching materials.
4. Fertilizing:
a. Newly planted trees and other woody plants usually do not need to be fertilized during their first growing season. If fertilizing is done during planting, only a slow release fertilizer should be used, and placed deep into the planting hole and backfilled with soil to minimize fertilizer absorption by weeds and turf. Three (3) to four (4) years after planting, young trees and other plants can benefit from fertilizers applied in the spring as soon as the frost has left the ground, or in late fall after the current growing season has ended. Use a complete slow release fertilizer, such as 16-10-8 or 10-8-6, containing nitrogen, phosphate, and potash. Trees and other plants showing loss of vigor, indicated by light green or off color foliage, smaller than normal leaves, dead twigs and slower than normal growth may need to be fertilized.
b. The fertilization of street trees shall be the responsibility of the abutting property owner. Recommendations on the type and the application method to be used to fertilize street trees shall be given by the urban forester or a licensed commercial applicator that is hired by the property owner to do such work.
5. Staking:
a. The staking of newly planted trees shall depend on tree strength and conformation, expected wind conditions, the amount of vehicular or foot traffic, the type of landscape planting and the level of follow up maintenance. Most newly planted trees will do better without staking. Young trees standing alone with their tops free to move will develop stronger trunks and root systems than those that are staked.
b. Should staking be necessary, such as when a tree is loose in the root ball or ground, and then it is important that proper methods be used to prevent injury or death. Do not tie young trees so tightly that they do not move; movement is necessary for proper development of structural support roots. Remove stakes and support off the tree after one year or after establishment of the tree has taken place. Use a soft material to go around the trees to cushion the tree from the support. If a garden hose is used put the garden hose around the tree and tie the wire support to the hose. Do not put the wire through the hose; this will still girdle the tree. Stake individual trees so three (3) stakes guide them; place each stake one-third (1/3) of the circumference of the area around the tree. Put the stake firmly in the ground, while assuring that it is not penetrating or damaging the root ball.
6. Pruning:
a. Pruning transplanted trees immediately before or after planting should be avoided. The only pruning that should be carried out upon planting is: 1) broken branches as a result of transporting or planting operation; 2) dead or diseased branches; 3) stubs and basal sprouts.
b. Pruning to correct branching orders, and for shape and aesthetics should be delayed for one to two (2) years after planting.
c. All pruning shall be done with proper and sharp pruning tools in accordance with all pruning standards. All plant labels secured around the trunk or branches of plants shall be removed after planting is complete.
7. Wrapping: The wrapping of tree trunks of newly planted trees is needed only when dealing with thin and smooth barked species. These trees can be wrapped with a protective covering of burlap or asphalt lined crepe paper to protect against sunscald injury. Thin barked species, such as young maples, lindens, honeylocusts and crabapples should be wrapped for at least one year. Begin the wrapping at the base of the trunk and continue upward in a spiral pattern to the first major lateral branches. Overlap each turn one-half (1/2) the width of the tree wrap material and fasten the free end of the wrap with itself or electrical tape. Wrapping should be done early in the fall and removed each year in the spring. (Eff. 3-14-2007)