Selection and installation - An arborist is the best technician to assure that the right tree is planted in the right place, and installed properly. The major reasons newly planted trees perform poorly and die are:
Dug trees (ball and burlap) loose 80-95% of their roots when they are dug! So take it easy on them, and your pocketbook, and plant a small one. Installing a larger tree may be visually gratifying in the short term, but lower survival rates, and poor growth rates often follow. The smaller tree may even outgrow the larger one in a few years. Look into container grown trees, as these come with all of their roots - just make sure the girdling roots are addressed, and the roots are spread during installation.
- Installing too deeply. Planting too deeply encourages the formation of small roots from the trunk, which often grow in a spiral, choking the trunk later on as the trunk grows in diameter. It also puts the trunk in a dark, damp fungal environment that can cause poor vascular performance (moisture and nutrient flow). The fungi prevalent there can even eat through the bark, killing the tree.
- Mulching too deeply. This is for many of the same reasons as #1.
- Over watering in our heavy clay, poorly draining soil (TN) can set up anaerobic conditions detrimental to most tree roots. This soil also glazes when dug with a spade, so break up the outer surface of the hole!
Look up when you plant! Conflicts with overhead wires, buildings, and other trees could mean a less desirable outcome, and increased maintenance for your new tree.
Fertilize minimally at installation. Nitrogen fertilizer encourages shoot growth for a plant that already has a greatly challenged root/shoot ratio.
Introduce mycorrhizae into the backfill. Mycorrhizae are symbiotic with tree roots, and their "reach" can increase root absorption by many times.
Pest and disease detection and treatment - These problems usually seek out weakened trees as hosts, and constitute a very complex area of arboriculture. The best approach is to keep trees healthy through regular maintenance.