Tree Cages, Tree Shelters: a (very) quick overview of pros and cons

August 21, 2023 11:20 AM

If you’re considering establishing a new tree planting in spring 2024, late summer 2023 is the ideal time to start planning. Also – congratulations, you’ve obviously realized the potential for windbreaks and other forestry practices (e.g., riparian forest buffers) to add value to your property and/or overall agricultural enterprise! Ordering seedlings is easy – protecting them once in the ground is a different story. A well thought out plan for seedling protection is one thing I see forgotten far too often in young tree plantings. With the amount of labor and cost that go into planting tree seedlings, protecting them from deer and rabbit damage, herbicide drift, and other factors is absolutely critical.

Tree shelters (also known as tree tubes) and cages are two common means of seedling protection. Both can be highly effective if implemented correctly, with careful consideration of seedling species, site, and the specific damage you are looking to discourage. Both have pros and cons, and selection will depend on your specific situation and budget (Table 1). Your professional forester can assist in making this decision. An initial question I often ask is “what critters am I protecting these seedlings from?”. A quick assessment of existing damage and/or browse evidence on your property will help inform your strategy and material selection. Deer-browsed twigs have a torn/shredded appearance, while rabbit-browsed twigs have a clean-cut, angular appearance – as if pruners have been used.    

Tree shelters: description and tips

Shelters, again – often referred to as “tree tubes”, are lightweight, small-diameter, translucent, plastic sleeves that may range in height from 4-6’ (Photo 1). A unique action of shelters, in addition to physical protection, is the creation of a “greenhouse” condition within the tube (i.e., warmer, more humid) that encourages rapid initial height growth. Shelters are held upright using (preferably) metal rods or T-posts. Shelters should be ventilated (perforated) to encourage seedlings to “harden off” in fall and prepare for the coming winter. It’s advantageous to have a “rolled lip” top, which will protect young stems from damage (e.g., bark abrasion) during high winds. Shelters are designed to break down over time, as plastic is exposed to sunlight and temperature fluctuations. Conveniently, the breakdown often occurs at the proper time, when trees are tall enough, and bark thick enough, to withstand browse and/or other damage. Unfortunately, the abundant shards of old plastic can be quite unsightly.

Photo 1: Plastic tree shelter protecting native northern pecan seedling. Note the impressive height growth on this 3-year-old seedling, a result of the “greenhouse condition” created within the shelter. Ideally, metal support rod should extend at least 4/5 of tube height - budget and time prevented that in the above photo, and will need to be addressed in future growing seasons. Also note presence of mulch at base – critical for weed control, root insulation, and moisture retention.

Tree cages: description and tips

Cages take many forms and thus cost may vary widely. Cages offer opportunities for unique designs and material selection – often driven by budget. Cages are commonly constructed of metal mesh, and secured using (preferably) heavy-gauge rods or T-posts. Mesh size and gauge are one of the more important characteristics to consider. Heavy gauge with larger mesh size would be appropriate in areas with significant deer pressure. Conversely, smaller mesh size and lighter-weight material would suffice in areas with heavy rabbit pressure. Often, we are protecting against both, so wrapping the base of large cages with small-mesh material offers added insurance. A detailed overview of deer protection methods may be viewed at this link.

Photo 2:  Metal tree cage protecting native northern pecan seedling. Note, this seedling is the same age as the seedling in Photo 1! What this seedling lacks in initial height growth, it makes up for in superior wind firmness. This cage is too short and structurally weak for long-term protection against deer, and will need to be enhanced in a few years.

Table 1: Pros and cons of tree shelters and cages.

Tree Shelters

Pros

Cons

Easy to install

Costly

Encourage rapid height growth

Seedlings less wind firm

Some protection from herbicide drift

Less structurally sound vs. cages

Highly visible in brushy areas

Birds may become trapped in tube

“Self-removal” at appropriate time

Base of shelter may be a potential mice/voles overwintering spot

 

Tree Cages

Pros

Cons

Structurally sound

Labor intensive installation

More permanent vs. shelters

Difficult to see (watch your chainsaw!)

Promote wind firm seedlings

Weed control around cage is challenging

Less chance of mice/voles overwintering

No herbicide drift protection

You can get creative with materials

Require manual removal