Protect your seedlings after planting

Your seedlings are safely in the ground after great effort and cost. Now, what can you do to help ensure they survive to become trees?

Even healthy young trees face a number of threats, one of which is their tastiness to various animals--deer, rabbits, rodents, insects and others. There are a number of options available for protecting seedlings: physical barriers, repellents, habitat modification, hunting, etc. Your decision will be based on what animals are after your trees, the characteristics of your site, and, last but not least, cost. As with anything else, each method has advantages and limitations.

€ Fencing. Fencing works well to keep out deer and animals that don't climb or burrow (if it's high enough). However, fencing is costly and excludes everything--humans and other nontarget wildlife. Fences can be electrified for greater deterrence.

€ Vexar tubes. Perhaps the most common protective barrier used for conifer seedlings is vexar tubing, usually put in place at the time of planting. These diamond-shaped rigid mesh tubes are available in various sizes and can protect against a number of herbivores. The material biodegrades in sunlight but can be purchased with UV inhibitors that increase the life of the tube (this is unnecessary if the protection is needed for only one season. Note that biodegradation is variable and tubes may need to be removed by hand.) Tubes should be set up with two stakes to hold them upright and prevent seedling damage in strong winds. For protection from rabbits they need to be at least 2' high; 3' for deer.

€ Vexar leader tubes. These are similar to vexar tubes but protect only the seedling terminal bud. It may be necessary to support smaller terminals to prevent bending.

€ Below-ground deterrents. To protect against burrowing animals such as gophers, various types of cages can be constructed. One relatively easy design uses aluminum screen placed around large yogurt or cottage cheese containers that are open at both ends and slit at the sides. The container is buried in the soil so that the top is at the soil surface. The cage prevents stem damage while the container keeps out burrowing animals that can damage roots.

€ Netting. Plastic mesh can be easily slipped up over seedlings and may be pulled up over the elongating terminal during the growing season. While the netting is effective in preventing browsing, it can cause bent leaders. To prevent this, bamboo stakes can be used to hold the netting away from the seedling.

€ Bud caps. Paper bud caps are rectangular pieces of weatherproof paper folded lengthwise and stapled around the terminal leader and bud. These are not as effective as vexar tubes for protection. Polyester bud caps are also available.

€ Sleeves. Porous, polyester sleeves are sewn into tubes and secured by staples around the seedling. Sleeves can cause heat injury to seedlings on hot, dry sites which can be minimized by using larger diameter sleeves and lighter-weight material.

€ Tree shelters. These protective devices are used for hardwoods such as oaks; not for conifers. Tree shelters are tall plastic tubes that not only protect seedlings from animals but also create a small greenhouse effect around each individual plant. As with a greenhouse, the plastic tube creates a microclimate that traps carbon dioxide and moisture and moderates the temperature, while allowing light to pass through for photosynthesis. Tree shelters are common in England but are still relatively new to the US. The shelters appear to improve seedling survival especially on difficult sites where the soil is poor, the climate extreme, or competition strong. Concerns include biodegradability and stem abrasion due to wind.

€ Repellents. There is a great variety of repellents in use including moth balls, hot pepper sauce, human hair, bone tar, and a number of commercial formulations. Repellents can be costly with extremely variable results, therefore are not generally considered for large areas. Some repellents need to be reapplied after rainfall. Those formulations that repel by taste are most effective when applied to dormant trees since new growth that develops after treatment will be unprotected. Other repellents act by smell such as putrescent egg solids or putrefied meat scraps. Effectiveness varies for many reasons including the weather, animal hunger level, alternative food availability, and conditioning. A chili-garlic repellent that appeared to be successful in northern California was tested in the southern part of the state. There the rabbits preferentially sought out those plants with the chili-garlic.