LGAP 1 PLANTING METHODS TREE SELECTION The most important factor in establishing a vigorous and healthy tree, is undoubtedly: match the tree to the site! Each tree species has certain cultural requirements: light, water requirement, preferred soil, and adequate growing space. Each tree site has environmental characteristics, which may limit your choices in plant material. temperature extremes, soil pH, light levels Most trees are planted to fulfill a particular function in the landscape. -shade for a backyard patio -fruit production -year round screening Adaptability of the tree to different growing conditions. How wide is the range in its native habitat? Pg. 1 Acclimation is a process in which a tree adapts to its environment. Usually internal and/or external changes to the plant parts will be involved. While it is possible for some trees to become acclimated to certain site conditions – i.e. adapted to less sun and perhaps a drier soil - most trees would prefer to be planted in areas that host similar growing conditions to their native area. Computer aided programs can remove a lot of the legwork! The user can specify the characteristics wanted, and the program will generate a list of species which match the specifications. A. Site Considerations A site analysis needs to be the first step. Landscape Architects will often do this analysis before the design is put together. The site analysis records the existing site conditions, bearing in mind as well, the ultimate function of the proposed site. Appropriate plants are selected based on the data from the site. The data collected, should detail: Adverse weather patterns affecting site…i.e. prevailing winds b. Water availability and drainage Knowledge of the drainage patterns and water holding capacity of the soil is critical. Trees that are planted in sites that are too wet or too dry will often fail within the first year. c. Soil pH and Soil type As trees differ in their requirements, tt is wise to perform a soil analysis to determine nutrient levels, pH and soluble salt levels. Pg. 2 Compacted soils will greatly reduce tree growth due to the insufficient oxygen in the root zone, and the inability for easy root penetration into surrounding soil. d. Light levels The light levels on the site can significantly affect a tree’s growth and survival. Microclimates are often a result of shading from the buildings Excessive shade is a problem to many tree’s, and the growth of their branches will reflect this lack of light. Expect to see long and spindly branches. Leaf drop is also a common reaction to low light levels. Excessive light can also can also cause problems if the tree cannot adapt to the increase in light and heat. Reflection from the buildings and heat from asphalt can result in scorched leaves and wilt. Some trees will adapt by producing small, thick leaves with sunken stomata. e. Enough growing space! -there needs to be enough area above ground and below ground to accommodate both the crown and the root mass of the tree, without interfering with any surrounding infrastructures. Pg. 3 -large trees offer many benefits to the site…providing shade, CO2 storage, cleaning pollution from the air, and helping to manage the watershed through their use of water. They offer erosion control and filtration of waters that will become part of the groundwater system. -some problems with large trees occur because the tree was NOT suited to the site. Know the mature branch and root spread of the species selected, to avoid planting trees too close to buildings where damage to the roof and siding may occur, or limiting visibility to pedestrian or motor traffic. Another consideration to be factored in to the planting plan, is If the chosen tree species if known to have a large and aggressive root system. Such trees need to be isolated from water lines and asphalt. f. Design criteria that deserves attention. Trees are often used to: - direct vehicle and pedestrian traffic flow. - hide unsightly building features. - act as climate controls for wind screens. - provide shade from a SW exposure. g. Aesthetics The tree can also be used as a focal point. Considerations such as colorful foliage, striking bark, unusual form, abundant or fragrant blooms deserve attention. Pg. 4 B. Tree Considerations Choosing the Species Growth Rate and Mature Size Rapidly growing trees are often tolerant of poor soil conditions and neglect. They quickly reach a size where shade and screening can be provided, however, many fast growing trees often have weak brittle wood, that fails easily in wind or snow loads. They are often prone to decay and are generally shorter lived trees that trees with a more moderate growth rate. A tree’s form can offer a solution to a growing-space problem. Often it is the developed cultivars of a tree species that are chosen for an upright, pyramidal, or weeping form. Hardiness is the plant’s ability to survive in low temperatures. Many trees that are native to warm climates, are not hardy in northern areas. Maps of hardiness zones label each geographic area for low temperature extremes. Plant reference books list either the coldest zone in which the tree will thrive, (ie. zone 2), or a range of zones where the tree will be vigorous (zones 5–8) However, a tree that is considered hardy in a given zone, may still decline or die due to low temperatures, if their roots are above ground in containers, or are unprotected. Pg. 5 Insect and disease resistance is often developed in cultivars if they are prone to specific pests. Some species are simply not suited to severely cold temperatures, and some are stressed by high temperatures or drought conditions. These stresses lower the vigor of the tree and leave it open to attack. It is wise to avoid trees that require constant pest management. Maintenance requirements Often a tree’s root system is ignored. Some trees have a strong tendency to form surface roots that can cause problems for mowers. Other trees have far-reaching root systems that can damage water and sewer lines. Heavy water users may require supplemental irrigation, or the drainage may need to be improved at the site to accommodate the roots. Some species require regular pruning. Desirable characteristics may cause one to favor one species above another… exfoliating bark bird attractant outstanding flower display brilliant fall leaf color vibrant winter wood color unusual summer foliage in color or shape or in some instances, a plant may fall out of favor if one of its features becomes a maintenance nightmare… excessive leaf drop messy fruit shedding of branchlets Pg. 6 Selecting the Tree at the Nursery -Start with a healthy plant! Look for good twig extension (branching and new growth). Trees with good branch spacing and trunk taper are more desirable than those that have been headed back. -Foliage should be evenly distributed in the upper 2/3 of the tree, and not concentrated at the top. Avoid trees with many upright branches. -Except for small growing, multi-stemmed ornamentals, select trees with a single trunk and leader with spreading branches. -Check the plant for mechanical damage. Don’t purchase a tree that has an injury to the trunk or branches. -Look for an abundance of healthy green shoots – new roots will only grow if there has been an adequate storage of carbohydrates. -Check for the presence of insects or disease. -Examine the root ball of the tree. The condition of the roots will greatly affect the chances of transplant success. i) Ball and burlap trees should have a solid root ball that has been kept moist and protected from drying. ii) Avoid containerized trees with blackened or brown roots. These indicate a health problem. The roots should be abundant and white. III) Avoid trees with circling roots. Pg. 7 C. Planting the Tree 1st – match the tree to the site! 2nd – select a healthy and vigorous tree 3rd – check the root ball. Nursery trees are available in three different forms. Bare Root…(BR) are usually small and easy to transplant are usually light in weight as there is no soil in the root ball MOISTURE is vital to keep this root system alive and functioning Are ideally planted when dormant – (before the buds break and the roots grow) must be stored COLD (32-40 deg. F.) and have moist packing around the roots if they cannot be planted immediately upon digging usually only deciduous trees are handled BR Planting a Bare Root Tree: -should be planted on mounds within the holes at THE TRUNK FLARE. Avoid deep planting as it causes trunk rots and root suffocation. -keep moist by limiting exposure to drying air. -BR trees are usually staked, as they have a limited root mass. Pg. 8 Containerized Trees have their roots in soil not all containerized trees are container grown! Some are BR trees, potted up in containers and sold. all containers must be removed before planting, unless the container is biodegradable, as in a peat pot. often the roots will have grown to follow the form of the pot…growing in a circular pattern. This entrainment pattern must be broken or girdling roots may form. The root mass of a container grown plant is often sliced vertically 2 – 3 times around the mass to encourage lateral root formation – branching roots. Girdling roots can choke off the vascular system of the plant, and cause decline and death of limbs or even the entire tree. Girdling roots should be removed. If properly maintained, container grown trees can be planted at any time of the year. MOST IMPORTANT FACTOR is keeping the soil moisture levels up, especially during establishment, (MINIMUM one year). Ball and Burlap Trees These trees are dug with the root balls intact and wrapped in burlap. Natural fiber burlap is biodegradable, and can be left to surround the roots after the tree is planted, however it is recommended that the burlap be folded back when planting to avoid the ‘wicking’ effect and to allow easy water infiltration. when transplanting B & B trees with a large root mass, the burlap is often held in place with twine. All non-biodegradable twine should be removed. Any ropes or twine tied around the trunk needs to be removed to avoid girdling the trunk. Pg. 9 Some larger B & B trees come in wire baskets to maintain the integrity of the ball during handling and planting. Though it is impractical to remove the entire basket, it is best to cut away as much of the wire as possible during planting. This eliminates interference with rakes or lawn mowers if the tree is a shallow-planted tree, and allows the tree roots to grow and spread freely in the upper soil profile, where the water and warmth are most abundant. D. The Planting Hole Make as wide as possible!...but the minimum should be 18 – 24” wider in diameter than the root ball. If the soil is compacted, the hole should be 3 – 5 times the width of the root ball. Some references recommend the hold be wider at the top with sloping walls to encourage some shallow and lateral root formation. The hole should never be deeper than the root ball. In clay soils, the planting hole can act like a dish, holding the water. Oxygen levels are very low at the bottom of these holes, and thereby not conducive to good root growth. Planting a tree too deeply can stress the tree and drown or suffocate the roots. Do not add soft fill to the bottom of the hole. As the root ball settles, it will be planted too deeply. In dense clay soils, the tree should be planted slightly shallow, with 3 – 5 inches of the ball higher than in its original grade. The exposed ball should be covered with an inch of soil and 2 – 3 inches of mulch. Pg. 10 E. Drainage Drainage is critical. Roots must have adequate oxygen. Poor drainage is characteristic of heavy clay soils and accounts for many transplant losses. Large trees may need weeping tiles installed to facilitate drainage, while shallow planting may suffice with smaller trees, as they can develop roots in the more well-aerated upper soil layers. Gravel at the bottom of the hole does NOT aid in drainage. F. Backfill Sometimes the natural soil is so poor that topsoil may be the only alternative. It is best to backfill the hole with the same soil type that was removed from it. If backfill must be amended, increase the diameter of the hole so that several years of new root growth can occur in the backfilled area. Work soil around the roots so that air pockets are removed. Firm the soil enough to hold the tree vertically, but do not pack. Water thoroughly while you are backfilling. Pg. 11 G. Interface Problems What is interface? It is a drastic change of one soil type to another or from one zone to another.. i.e soil + airspace. Wire baskets and burlap are considered interface. Why would burlap be an interface? Burlap will cause airspaces to form between the material if it does not break down. Roots may not be strong enough to cross over or break out of the burlap. Interface can be alleviated by: Dig a hole which will accommodate the soil type and tree. Amend with the best and closest soil type possible. Add organic matter. Rototill the area around the tree. Remove the burlap and all twines. Remove as much of the wire basket as possible, or at least, remove the wire down to the 12” level. H. Mechanical Tree Spades A tree spade is a mechanical device used to transplant trees. Several large blades make diagonal cuts into the existing root mass and form a root ball. Trees that are mechanical tree dug (MTD) trees will most often have their rootball transported in burlap in a wire mesh basket. Any damaged roots from entanglement between the blades should be removed after the tree is removed from the hole. Pg. 12 Tree spades are often used to dig the receiving hole prior to the dig. These will not be exact holes as angles can be changed during the process, so some modification of the tree hole will usually have to be undertaken so the tree is planted with a straight trunk and at the correct depth. 3 Principle Reasons why industry uses the mechanical tree spade for moving a tree. Reduction of Labor – There is often acute labor shortage in our industry, both skilled and unskilled. Using a machine allows the industry to address the shortage of workers. Available Time - In Alberta, we have a relatively short ‘windows of opportunity’ in which to move trees with a high degree of success. There is often only a couple of weeks from the harvest date to the budding process. Mechanization is really the only solution to the problem of getting the work done in a timely manner. Large Tree Transplants – allows for the movement of very large trees from a nursery to the landscape site. Tree spades are available in various sizes. No attempt should be made to transplant trees larger than the size limitation of the spade. Although larger trees can be removed from the hole, transplant survival is not likely because the size of the ball must be proportional to the tree size. The large percentage of tree failure occurs because the size of the tree spade was too small for the size of the tree. Pg. 13 I. Staking and Guying It is recommended to use three supports when staking and guying to prevent bark damage and breakage of the trunk in high winds, however, staking methods using only one stake or two stakes are also used. Reasons for staking and guying of trees: Stability Roots need time to establish Trees are vulnerable to high winds, and blow down results in root damage as the tree leaves the hold. However, stakes only provide stability, not necessarily complete support. Avoid attaching the stake too tightly or too securely…movement in the wind ensures good trunk taper and is an indicator of trunk strength. Swaying in the wind also promotes a stronger root system. Twines and ties should be removed after a year on most sites, or tree can be strangled! Staking and guying of trees is not always needed. If the tree is located in an unprotected area however, and high winds are prevalent, staking will be necessary. Bare root stock has an undeveloped root system and will need staking and guying to remain upright. Pg. 14 J. Pruning Do not prune out terminal buds. Do corrective pruning of broken branches and broken roots only. We do not prune to ‘balance’ the root:shoot ratio …the tree will select which branches it will shed due to the loss of some of its root mass. Removal of deadwood can be performed the following year. With fresh transplants, prune out only the dead, diseased, and damaged wood …The 3D’s Factors to Consider When Planting the Tree Factors affecting the decision as to when is the best time to transplant. Method of Digging Bare Root - are dug in the spring, so are then planted in the spring. Ball and Burlap – even though they are often dug in the spring, they can be held over if necessary Soil Temperature and Moisture Level Low temperatures ~ Best root growth and water absorption is seen in cool soil temperatures ~ Root growth continues at temperatures near freezing in deciduous plants Evergreens are less active at lower temperatures. Pg. 15 High temperatures Evergreens don’t produce roots in the heat of the summer. Optimum root growth occurs at a soil depth of 6 – 12” if the soil temperature is between 15–21 degrees C. Soil Moisture Moisture MUST be present in adequate amounts. If supplemental water is not available for root growth during the critical establishment period, then choose the season when the moisture levels are high for transplanting. A critical requirement to evergreen transplant survival is water at the time of planting. Existing Climatic Conditions Windy Sites If the transplant site is exposed and open to the wind, it is recommended that planting be delayed until spring if possible. If fall planting is a requirement, do it early enough for some root establishment before the ground starts to freeze Evergreens should be protected from the wind during the transplanting process. Pg. 16 Plant Specifics Growth Stage of the Plant Move plants in the dormant stage Start of the dormant period is initiated by the maturation of the terminal buds In general, evergreens can be moved earlier in the fall and later in the spring than deciduous species Plant Hardiness If the transplant species is only borderline hardy, it is recommended to spring plant. If planted in the fall, there is not sufficient time left in the growing season for some root establishment and new growth. Often this transplant may not have enough time to harden off adequately. Inherent Nature of the Species Often plant species that don’t transplant well in the fall, have thick and fleshy root systems or a sparse root mass characterized in long and thin roots. Examples of species considered difficult to move: Birch, Hawthorn, Pine, Oak Examples of species considered easy to move: Ash, Elm, Maple, Poplar, Willow Pg. 17 The Pro’s and Con’s of Seasonal Planting In the Fall (from when the leaves begin to change color up until ground freeze up.) Advantages:- favorable soil temperatures in general soil has adequate moisture still early enough in the season for root establishment, and the start of new root growth Only Disadvantage- if a dry fall is followed by a cold, dry winter, there can be significant root damage from the lack of moisture In the Summer (not the optimum time, unless it is a rainy day, or the air temperatures are cooler) Advantages: - as it is the busy season in our industry, this is often when projects are timed for installation Disadvantages: - often low water supplied in relation to the amount lost in transpiration due to the high air temperatures soil temperatures are high Pg. 18 c. In the Spring (normally the best time to transplant trees. Poplars, Birch and Willow have shallow root systems that need to establish in order to survive the winter.) Advantages: - ample water available long root establishment period cool soil temperatures allows some root growth before the top growth starts Disadvantages:- none, spring planting conditions are ideal In the Winter(not recommended) Advantages: - generally considered to be the ‘slack season’, with a lower demand on equipment a personnel…this is good for the employer, but not the tree! Preferences of the Trees Deciduous prefer: Early spring before bud break OR late fall after leaf drop and before the soil freezes Pg. 19 Evergreens prefer: The best success will be found from August to early September Prefer earlier in the fall or later in the spring…except in a high wind site, in which a spring plant is best. K. Handling & Storage 1. Handling Bare Root Stock (BR) While moving bare root deciduous trees is good in cooler climates as the roots have a chance to develop and bud break is delayed, there are considerations that must be thought of for a successful transplant. Generally smaller caliper trees. Harvest when dormant. Ship when dormant. Roots must be kept moist after digging and during transport. The truck bed should have a moisture holding medium laid down. The trees can be laid horizontally, with the roots and tips staggered. Each ‘layer’ must be covered with wet mulch. Light or delicate trees can stand upright in corners, or laid down as the top layer. The load must be tarped to minimize dessication from the sun and wind. Pg. 20 2. Handling Ball and Burlap Stock (B & B) Generally large caliper stock that was dug when dormant. Ensure rootball is completely covered with the burlap. Pick up by the rootball to ensure the ball doesn’t disintegrate. DO NOT pick the tree up by the trunk or branches! Wind burn can by caused by high truck speed, an untarped load, and poor shingling. Shingling is a method of stacking the rootballs. It helps to prevent damage during transport. Trees are arranged in an overlapping fashion. Conifers should have their lower branches tied upwards to avoid damage during transport and transplant, and to maximize the number of trees that can be loaded. Conifers have a full canopy all of the time, and can NEVER be allowed to dry out. 3. Storing Bare Root Deciduous Stock Stock needing short term storage should be heeled in, shaded, and in an area where stock can be misted as needed. Stock must be dormant before placement in long term storage. Conditions for storing deciduous BR stock are: Storage area must have high humidity. Air temperatures must be low….below 2 deg.C to -1 deg.C. Deciduous are stored in darkness. Air circulation is critical to reduce mold development. If spring dug, the demand for water will be great. Water immediately. If roots are wrapped moist, deciduous can be stored all summer. Pg. 21 4. Storing Large Caliper Trees Generally larger caliper trees which are stored and held for projects. Usually dug when dormant, the rootball is surrounded with burlap, and the tree returned to the hole and stored until buds swell and expand … water, water, water! Mostly dug in the early spring up until ONSET. Transplant shock can be reduced by digging in cool, cloudy conditions. 5. Storing Coniferous Stock Ideally, conifers should be dug before they expand their buds to the candle stage. Conifers can be dug and moved again after the top growth is done for that season, and a new terminal bud has formed, (usually by the beginning of July), as long as ample water is provided at all times. Conifers will lose their needles if stored in darkness. Conifers should have their bottom branches tied up as they are moved to a long term storage hole. The burlap surrounding the root ball is often shrink wrapped to reduce dessication. The branches must be untied and released in the spring. Pg. 22 L. The Paperwork Receiving Plants The Bill of Lading is a form for receiving shipment from the truck or transport company detailing the weight of the shipment. The receiver must give a signature for acceptance. The Packing Slip is of critical importance. It will list what was ordered, what was backordered, any substitutions, and any supplier information. The plant material should be inspected as to correct numbers, species, and condition of the trees BEFORE signing acceptance of the order. The Invoice is the final bill which is paid after the receiving company has taken the order as delivered, and is in agreement with the particulars. Pg. 23 M. Associations PAC – Provincial Advisory Committee Acts as the Landscape Gardener industry representative body. Represents the Landscape Gardener trade in curriculum content. Works in conjunction with the Apprenticeship Board to further and upgrade the trade standards and certifications. Landscape Alberta – (formerly LANTA) Promotes the correct practices in the production and installation of trees and landscapes. Lobbies on behalf of the landscape and nursery trades. ISA – International Society of Arborists Promotes correct procedures for tree removals, pruning practices, tree installations. Safety in the workplace training is of top priority. Provides training opportunities to obtain certification as an arborist, a utility arborist or a consulting arborist. CNLA - Canadian Nursery and Landscape Association The CNLA provides training and qualifications to industry members through the Landscape Industry Certified designation. The CNLA provides training and qualifications to industry members through the Landscape Industry Certified designation. The CNLA advocates on behalf of the landscape and horticulture industry maintaining a presence in Ottawa on federal issues that affect the green industry factors. Lobbies in Ottawa on behalf of the landscape and nursery trades. LGAP 1 Planting Methods Darlene Morton, November 2011 Pg.24