Tree planting
Now that you’ve taken all of the preparatory steps in planning a project and you’re ready to plant trees, you will need to consider all of the steps required before you get to the planting site.
Site Preparation
Many sites need some form of preparation of the land before it’s ready for trees to be planted. Deciding why, how and when to prepare the site depends on existing site conditions, type of competing vegetation, and soil type. For example, grasses and non-desirable woody plants will compete with the newly planted trees for water and nutrition. In dry seasons where trees can’t get adequate water after planting, removing grasses will give the trees a better chance to out-compete. Soils that are heavily compacted will make it more difficult for the trees to establish than soils with more porous space. Scarifying the site can improve soil porosity and reduce bulk density, making the conditions more favorable for tree growth. Approaches taken for site preparation varies across Canada and it isn’t commonly done in northern communities (Yukon, NWT and Nunavut) except for low-impact approaches like scarification or mounding due to the risk of impacts on permafrost (Yukon Government, 2015)[1]. It’s important that you research the site preparation techniques commonly used in the region you’re working in. Site preparation for tree planting comes in a variety of forms: cover cropping, mechanical site prep, chemical prep, animal grazing and prescribed burning, to name a few.
Cover cropping: widely used practice for site preparation ahead of planting trees on old agricultural fields. Seeding a low-lying herbaceous species such as Dutch white clover and/or alfalfa among a nurse crop such as barley, wheat, and/or rye grass the season ahead of tree planting can support an ideal soil microclimate, fix nitrogen and prevent other competing vegetation from establishing on the site until the planting can take place. Cover cropping is typically used when a land manager/farmer is converting active crop rotation on an agricultural field over to forest in the following season. The cover crop is added to the field after final harvest of the commercial crop in the fall, and readies the soil for the next year’s tree planting.
Mechanical land preparation: equipment is employed to reduce or remove competing vegetation, prepare the soil for tree planting or manage the debris on a site to allow tree planters to do their work safely and more efficiently. A work plan should be scheduled in advance for mechanical preparation and should be considered at the first site visit since you will need to plan for organizing the equipment, ensuring site access to bring the equipment in, roles for the operation if any, and the timing of planting and other site preparation scheduled. All mechanical site preparation will encourage growth of herbaceous competition, so it’s usually done in combination with chemical treatment. Light scarification and mowing are the least intense methods of mechanical site preparation and so could be employed for sites where chemical herbicides will not be used.
An overview of mechanical site preparation methods is given in Table 2. All these applications are usually just completed once before planting except with mowing and bush hogging which is usually done at least once before planting, then monthly for 1-2 years after planting. Keep in mind that most machines cannot be safely operated on slopes above an angle specified in the operator’s manual. Consult the safe operating procedures, paired with your site visit, to create the planting prescription, allowing you to map out which areas of the site you can and cannot carry out mechanical preparation. For detailed descriptions with photos of some various methods used in Canada, visit Replant.ca's online resource.
Table 2 Overview of mechanical site preparation options for tree planting in Canada.
Application categories: competition, soil, debris | Method of Mechanical Prep | Equipment Options | Targeted Use |
|---|---|---|---|
Competition | Brush cutting / bush hogging | Brush saw, bush hog, grass trimmer attachment, brush cutter, mower | Removes competing small diameter woody trees and shrubs Often followed by secondary site preparation treatments |
Mowing | Push or ride-on lawnmower | Reduces competing grasses and herbaceous competition on sites with low levels of debris | |
Competition + Soil | Disking / disk trenching / furrowing | Tractor with rotating disks | Removes competing grasses and herbaceous competition on sites with low levels of debris Creates porous space in the soil Creates linear planting rows which are easy to follow Done after ploughing for agricultural fields |
Scalping / scarification | Excavator, bulldozer, tractor with tiller | Creates porous space in the soil surface Exposes mineral soil suitable for seedling growth Reduces competing grasses and herbaceous competition | |
Soil | Mounding / pit and mounding / bedding | Excavator, other specialized machine | Provides a well-drained mound on wet sites to plant trees into Reduces frost damage |
Ploughing | Tractor with blade attachment | Creates porous space in the soil Makes soil surface uniform for tree planting Typically only for agricultural fields or when deep soil tilling is needed | |
Single furrowing | Tractor with plough | Creates porous space in the soil Single furrow created allows for two microsites: mound for wet conditions or in the furrow for dry sites | |
Ripping, RipPlowing | Bulldozer, RipPlow (ripper) implement/ attachment | Breaks up heavily compacted soils Commonly done in the winter with partially frozen soil | |
Subsoiling | Bulldozer or tractor with subsoil shank | Similar to ripping but breaks up soils to a greater depth | |
Debris | Windrowing / shear, rake and pile | Bulldozer, backhoe, V-cut blade if shearing | Organizes large woody debris into rows on the side to improve access for tree planting in the cleared sections |
Chopping / drum chopping / mulching | Heavy machinery / chipper | Disintegrates large woody debris into smaller pieces and left on-site to improve access for tree planting | |
Shearing | Bulldozer with V-cut blade | Removes lateral branches of debris with minimal soil disturbance on sites with low levels of debris | |
Spot tillage | Specialized equipment | Breaks up soil surface in microsites 3-4 feet wide Used on more sloped terrain |
Chemical site preparation (ie. herbicide application): usually done in combination with mechanical site preparation. Chemical herbicides fall into two broad categories: pre-emergence or post-emergence. This describes the timeframe in which its active ingredients eliminate target competing plants either before they emerge on the landscape, or after they are flushed. There are also two categories of methods of application: broadcast spray (general application over the entire site) or spot spray (targeted applications on a singular target plant). For herbicide application, work within your provincial and local regulations surrounding application and regulatory licensing requirements. Consult the Pest Management Regulatory Agency (PMRA) of Health Canada for more information for your local regulations on the use of herbicides. If there will not be any herbicides used in your site preparation, this will affect the species selection and you should plan out alternative approaches to manage competition.
Grazing by animals or livestock: used as a method of site preparation for tree planting, but this method is far less common than the others listed. Livestock such as goats, pigs, and cows can be used to browse the ground cover, keeping competing plants and undesirable species at bay until the site is ready for tree planting. Animal grazing is also used in agroforestry projects where trees are integrated into the overall agricultural system.
Cultural burning: practiced for thousands of years by Indigenous communities in what we now call Canada and, since then, prescribed burning has been carried out as a land management tool. Burning the duff layer of a site removes unwanted competition, eliminates debris/slash, and activates beneficial nutrient cycling processes in the soil, making the site more ready for tree establishment. This method of site preparation, on its own or in combination with another approach, has been shown to be an effective approach, but outside of Indigenous communities, it should be carried out according to your provincial regulations, by prescribed burn professionals with the appropriate permits in place. Broadcast burning in the western parts of Canada were common in the mid- to late 1900s following logging to prepare the site for tree planting but is not practiced as often now due to increased fire risk and a desire to retain organic debris on-site.
Tree planting practitioners have developed their own standard practices based on first-hand experience for what works, and a combination of any of these methods can be used together to accomplish great results for even the most complex projects.
Planting the Trees
Decide on how you will be planting your trees - whether hand plant or machine plant. Machines like tractors with a planter attachment are typically used where the land is relatively uniform, able to be mechanically site-prepared beforehand, and not too sloped, rocky or wet. Hand planting takes place on sites with intense sloping, rockiness, wet conditions or in areas where machines cannot access.
Delivery and storage of tree stock: Always plan for the delivery and storage of your tree stock for the day(s) you plan to be on site planting trees. Ideally the nursery stock should arrive at the site the morning of the planting or the evening prior and stored in a cool area until you’re ready to plant. Place trees in the shade and use Silva tarps or similar thermal covers to keep the tree stock cool before and during planting activities if you don’t have a refrigerated space on-site to store them.
Moisture for tree stock: If you’re planting with bareroot stock, ask your nursery beforehand if they will deliver the stock with moist paper or wood chips inside the bags. If not delivered with any mechanism for keeping the stock moist, keep a bucket of water nearby to hold the trees until planting. If planting with container stock or plugs, plan to give them a final watering just before planting if possible.
Root pruning: If planting bareroot stock, check the length of the trailing roots and prune to a length of 25 cm or so from the root flare to the ends before planting begins. The nursery may have already done this for you, so be sure to check in with them to confirm as it’s not good for the trees to do it twice. Root pruning eliminates the excessive trailing of roots, making planting easier and avoids root circling and deformation once in the planting hole.
Spacing and planting configuration: Plant the trees according to the spacing and configuration you developed in your site plan prescription.
Auditing: Supervise the planting crews and make sure to include a quality audit to record any issues observed with the tree stock or planting operation that can be corrected in the future.
Accessories: After the trees are planted, add any tree planting accessories such as rodent guards, tree shelters, staking, mulch or organic mats if applicable.
Clean-up: Ensure you leave the site better than you found it, cleaning up any waste left behind and minimize the impacts on natural ecosystems surrounding the tree planting site.
Literature Cited
Yukon Government, 2015. Yukon Forestry Handbook ISBN: 978-1-55362-725-8. Yukon Government, Energy, Mines and Resources, Forest Management branch
