Category:808 Planting Trees, Shrubs, and Other Plants
808.1 Construction Inspection Guidance for Sec 808
Description (Sec 808.1)
Roadside plantings consist of deciduous and evergreen trees, shrubs, vines, seedlings, and ground cover plants. Plantings are placed in roadside parks, in rest areas, for screening unsightly areas, and for enhancement of roadway locations where future development will not require their removal.
Material (Sec 808.2)
Basic types of trees and shrubs are deciduous, which shed their leaves seasonally, and evergreens. Plantings may be balled and burlapped, bare root, or seedlings. Balled and burlapped plants will generally be evergreens over two years old, shade trees of not less than one-inch caliber, medium size flowering trees, and a few other flowering shrubs. Bare root plants will be most flowering shrubs, shade trees with less than one-inch caliber, and small flowering trees. Balled plants should have a ball of firm soil in which the plant grew, be wrapped securely with burlap and tied. Broken or loose root balls are not acceptable. Bareroot plants should have a balanced, well-developed root system, free of broken or split roots. Trees and shrubs must meet specifications. All smooth bark deciduous tree trunks must be wrapped with waterproof paper according to specifications to prevent sunscald.
All plants must be certified free of insects and disease by the Missouri Department of Agriculture.
The bid item will have seven digits, with the first three numbers to indicate the plant materials. The fourth and fifth numbers will indicate type of plant and the last two numbers indicate variety.
Example: 808-01.01 808 Landscape Plant -01 Material: Major Deciduous Trees .01 Variety: Norway Maple
The inspector can use the following list of types, as indicated by the fourth and fifth numbers, as a guide to eventual height. Heights shown are approximate. There will be some overlap between types.
|Item Code||Material||Height Range, (ft)|
|808-01||Major Deciduous Trees||30+|
|808-02||Intermediate Deciduous Trees||20 - 30|
|808-03||Minor Deciduous Trees||12 - 30|
|808-05||Deciduous Shrubs||2 - 12|
|808-06||Evergreen Shrubs||0.5 - 6|
|808-07||Vines||0.5 - 2|
|808-10||Shrub Seedlings||2 –12|
Invoices And Certifications
Specifications require each shipment to be accompanied by an invoice showing size and varieties of materials included in the shipment. The invoice should be retained in the project file. It will indicate that the proper number and type of plants were delivered to the project. Each truckload or shipment of plants must have evidence of certification, to the effect that the stock is free from insects and disease. Use of either Form 800.9 or 800.10 is considered satisfactory. Construction inspection forces should inspect the shipment and physically remove the certification tag so it becomes a part of permanent records. The inspector should note date of delivery on both the invoice and certification.
If the exact species of plant shown on the plans is not available, the contractor may request approval of a substitution by submitting a letter from three competent sources to this effect noting unavailability of item specified with the proposed substitution. All reasonable requests should be carefully reviewed and sent to the district office with the resident engineer's recommendation. The substitution will normally be a similar variety of plant at no additional cost to MoDOT.
Whether stock delivered meets requirements of the specifications often depends on the inspector's judgment of appearance. Again we must remember that we are dealing with a living plant that is seldom perfect.
Construction Requirements (Sec 808.3)
The inspector shall keep a complete record of the plants delivered, the number accepted and planted or rejected. A positive procedure should be established to insure that none of the rejected materials are returned to the project. It is expected that during the progress of large projects, the inspector may request inspection of the plants as they arrive and are planted. This requires close contact with the inspector to solve any questions that may arise and to insure that no inferior plants are planted.
Specified height and spread of each plant will be noted in the contract. Each plant should be measured in accordance with directions on plans before any pruning or thinning. Measurements are to be recorded in a bound field book.
If the contract specifies number of branches, as defined by plans, branches should be counted before thinning and the findings recorded in a bound field book.
Caliber is diameter of the tree measured as noted on the plans. Hole sizes indicated for plants are minimums.
Root spread and ball size will be indicated in the contract. Ball size is measured at the widest point. Root spread is measured tip to tip as shown in plans. The ball should be wrapped in any acceptable material that will not deter future growth. Plastic burlap is an example of material that should not be permitted.
Staking or plant plans are primarily a guide to locations for plants. Precise indication of locations for plants is not generally required for highway work. Occasionally, accurate locations may be necessary and will be so indicated on the plans. It is necessary in all cases to interpret intent of plans and to meet local conditions, such as having trees in proper relation to utility lines, and maintaining required sight distances, drainage, etc. Avoid straight lines and geometrically regular patterns. Typical safety sections for roadway construction require that all plants or trees with eventual trunk diameter of 4 inches or more be set not less than 30 feet from edge of pavement. The resident engineer should feel free to adjust plan locations if he keeps in mind at all times just what the final appearance will be after the plant, tree, or shrub has reached full growth.
Bare root plants should never be allowed to dry. A temporary planting, or some method by which the contractor covers the plant root system may be necessary to keep it moist at all times until actual placement.
Precautions necessary in handling balled plants are similar to those required for bare root plants with the additional requirement that wrapping of the root system must remain intact. Manufactured balls are those in which burlap is filled with peat moss and plant roots placed in the peat moss. These may be detected by uniform shape and lightweight. The balled root system, to be acceptable, must be filled with the soil in which the plant grew. After balled plants are set, all twine around the trunk should be cut. This should be done after the plant has been set in the hole and partially backfilled. Wire baskets used on large balled trees may be partially removed after planting.
Maximum size of holes should be kept reasonable. Too much vegetation is destroyed when the size of hole is appreciably increased. Actual size of ball on the plant being placed determines necessary hole-size.
Removal of sod by stripping with a sod cutter may be necessary for preparation of plant beds. Vegetation is typically removed and disposed of outside the limits of right of way, or as directed by the engineer. Existing vegetation must not be worked into the plant bed. Plans will indicate size and locations of plant beds. The outermost row of plants should be set approximately two feet from the edge of the plant bed. Should plans not indicate a minimum or maximum spacing between plants in the plant bed, the inspector should understand that the required number of plants would be placed over the entire limits of the plant bed using approximately even spacing between plants and a scattered pattern, i.e., not in rows. In some instances, plans will indicate that plants are to be placed in a definite location. If so, care should be exercised to assure that the plants will serve the intended purpose. Both balled and bare root plants should be set slightly high to allow for settlement.
Trees, vine and shrub pits are backfilled to the proper planting depth and firmed by trampling or with tamping tools. This operation is necessary to remove air pockets around the roots and should not be overlooked. Deep planting is a common fault of inexperienced planters and is one cause for many transplants dying. In heavy soils or poorly drained areas, it is often advisable to provide a mound instead of a depression around the plants.
Care should be taken to spread the roots of plants while backfilling and to firm the soil around the roots. Inspector should reject any plants that have been damaged by careless handling. This would show up as trees that are loose in the ball, broken or crushed balls, or any other damage that would decrease the chance of making a satisfactory plant.
It is good practice to water the plant when the backfill is ¾ complete and as often thereafter as necessary. Cultivating an area outside the pit, providing a cup or depression, fertilizing, mulching, staking and wrapping trees promote the plant’s survival. When staking bare root trees, it is desirable to place the stake prior to planting the tree. This will prevent the stake from damaging the roots.
Plant pruning encourages root growth. As a rule, thinning of approximately 20% of branches will be necessary to balance loss of the root system. Pruning of deciduous shrubs consists first of removing all dead wood and broken branches, and then of removing or heading 1/3 to 1/2 of the remaining branches. This may be accomplished either by a heading cut, as indicated by plans, of 1/2 to 1/3 of all branches, or by cutting off 1/2 to 1/3 of the branches remaining after removal of dead and broken branches. Evergreens are pruned only to the extent of removing dead or damaged portions of branches, unless otherwise directed by the engineer. Vines are pruned to retain a 6-inch length above ground surface. All cut surfaces over 1 inch diameter on trees must be painted with a commercial tree paint or tar. Directions for use will normally be on the container.
Plans and specifications note the type of bracing required for trees and for some evergreens. The inspector should see that steel bands for trees and rubber hose for evergreens are not loose enough to slip and not tight enough to damage the tree.
Care and Replacement (Sec 808.4)
At the time of plant inspection as specified in the specification, the inspector should designate all questionable plants as well as dead plants for replacement. It is possible that some questionable plants may recover by the time of the replacement period. If so, the particular plant should be removed from the replacement list and so documented in the inspector's diary.
Final Plant Inspection (808.4.2)
The contractor is relieved of all further responsibility for plants accepted at the time of the final plant inspection, and the Maintenance Division shall be so informed. A procedure must be developed so there is no question concerning those plants that have been accepted. Items that are in a dying condition shall be replaced with good quality plants. In case it is so late in the season that transplanting is not advisable, the items rejected shall be replaced during the following planting season. A list of items to be replaced and a description of the remaining work to be done to put the project in an acceptable condition shall be completed furnished to the contractor. The resident engineer will make the final inspection and determine acceptance of a project. When all replacement plants are in place, the total project is to be accepted from the contractor and MoDOT will assume maintenance. Time of this acceptance should be noted in the inspector's or resident engineer's diary.
Method of Payment (Sec 808.5)
The contract provides for withholding 25% of the contract price for plants until final acceptance. This would be shown as a partial payment on the estimate. Do not make this deduction by reducing number of plants shown as being in place.
Many plants have a size specification. This should be checked and the record should show that it was done. A convenient time to check for proper size and number is when a shipment arrives. It is not necessary to record each measurement. However, notes should show the number of plants of each variety that were checked and found to comply with size requirements. If plants are rejected, notes should be specific as to reason, and should include measurements if the rejected plant is deficient in size.