1) The deer population continues to grow virtually unchecked, putting more and higher browse pressure on tree seedlings.
2) Tree tubes are increasingly being used by sportsmen to improve wildlife habitat which means
- They really care about the success of each individual tree, and the speed with which it will begin producing mast
- They are planting tree species that are especially attractive to deer like fruit and nut trees
- They are planting in places with high concentrations of (hopefully!) very large deer
The reason is simple: In the majority of cases 4ft tubes provide all of the deer browse protection needed for success. Wilson Forestry Supply's web site puts it in perspective well:
- 4ft Tubex Combitube Plus Tree Tubes provide enough protection to grow trees past the deer browse line about 75% of the time. Deer can browse trees emerging from 4ft tree tubes. In most cases the tree will have enough stored energy to send a rapid growth shoot past the deer browse line. However, in some areas deer will repeatedly browse trees as they emerge from 4ft tree tubes, not allowing them to grow taller. In these cases the protection of the 4ft tube can be supplemented either with deer repellent or a 2ft Tubextender kit (sold separately).
- 5ft Tubex Combitube Plus Tree Tubes provide enough protection from deer approximately 90% of the time. In areas with extremely high deer densities, the deer can browse trees as they emerge from 5ft tree tubes. Cases of deer browsing trees emerging from 5ft tree tubes are most common with fruit trees such as apples, crabapples, pear, etc.
- 6ft Tubex Combitube Plus Tree Tubes provide enough protection from deer 99.87% of the time (OK, we made that up, but 6ft tubes are as close to complete deer protection as you can get).
1) Use 4ft Tree Tubes to optimize the number of seedlings you can plant and protect within your budget. Then, if the trees get browsed heavily upon emergence from the tubes, supplement the browse protection with either a deer repellent or a 2ft Tree Tube Extender. This is a way to spread out the cost over a span of a few years.
2) Use 5ft Tree Tubes and protect a smaller number of seedlings within your budget, but know with (almost) certainty that you will not have to supplement that level of deer browse protection.
Actually, there's a third way - one which probably makes the most sense of all: Strategic deployment of 5ft or 6ft tubes. If you are planting a field of trees, the deer do not browse them equally. They hit certain species (fruit trees in particular, such as crab apples) harder than others. They browse more heavily along creeks and alongside woods and cover. A very effective strategy is to use 5ft or 6ft tree tubes on trees that are the most "at risk" based on species or location, and 4ft tubes on the rest.
This argues heavily in favor of choosing a tree tube supplier that offers a range of sizes and lets you order any quantity of mixed sizes, so that you can customize your planting to your exact needs, budget and goals.