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The first thing to look at when choosing a tree is the trunk. A good tree will have a single straight trunk with no sign of wounding, disease, or decay. Even though there are a few trees that should be multi-stemmed, most trees should only have one dominant leader.
| To the right is an older tree with a double leader. The arrow is pointing to the crack caused by the weak attachment. One can see the included bark, and upon closer inspection some decay. It is best to avoid stock with branch attachments like this. |
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This is another tree with a double leader. This can be corrected with pruning, but should be avoided if possible. |
| This is a tree that once had a double leader. When a leader is pruned out, the remaining leader will take over. The first couple of years the cut may be slightly noticeable, but as the tree matures the trunk will straighten, and it will appear as if it had always had one leader. |
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Some trees naturally have more than one leader. This Amur Corktree is an example. Homeowners should become familiar with the growth habits and characteristics of the different species of trees they are considering for their yard. This helps when making the final selection and verifying that the form and foliage is correct for the species. |
| Trees that are purchased should have a straight trunk. Trees that have received insufficient lighting during storing will tend to grow towards the light. The directional growth is not necessarily bad, but that means that the tree did not receive sufficient care. This could also mean there are other problems with the tree that you cannot see, or is not showing symptoms right now. It is better to avoid such stock. |
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This tree has a strongly deformed trunk. This deformity could of been caused by several things, including inappropriate storage and inadequate light. |
| A wound is an beginning point for problems like disease and decay. A tree with any type of wound should not be accepted. To the left is a tree with a canker on the main trunk. Cankers form on trees due to fungal infections. A tree like this should not be accepted. |
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This is an example of a tree with mechanical damage. Mechanical damage can happen during transport or when placed in it's final resting spot. In a yard setting, mechanical damage frequently occurs the trunk is accidentally hit with a lawnmower. Mechanical damage wounds are another entry point for decay and can disrupt the vascular system of the plant. |
| This is an example of a frost canker. Thin barked species, like maples, are very susceptible to frost cankers. They occur when the sun warms the trunk then the temperature drops suddenly. This causes the outer layer of bark to split. Frost cankers might be prevented by wrapping young thin barked species. See Stem and Tree Protection for more information on wrapping trees. |
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Here is a tree with an older frost
canker. Trees can recover from frost cankers, but the exposed wood no longer carries nutrients to and from the leaves. |
| To the left is a trunk with some fungal bodies on it. While a fungal problem may be treatable, you do not want to purchase the tree as well as whatever disease it is harboring. It is best to avoid such specimens. |
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Note the knobby appearance of the trunk in front. It is suffering from edema (watery swelling). The trunk behind is not. Both of these trees are the same species- be sure to know what the bark characteristics are so you don't buy an unhealthy tree. |
| This trunk looks healthy but upon closer inspection it can be seen that the plastic tags used to identify this tree are girdling it. The tree is starting to grow around the tags, but it is already too late for this tree. Below is a picture of what is left the canopy- center tree, and to the lower right is a picture of the size of the leaf- full grown. Compare this trees with the trees around it which are the same species (bur oak). |
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This tree has poor branching habits. You can see how there are numerous branches very close together which has resulted in crossing and rubbing branches. The tree should be thinned out. |
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This tree has a good branching habit. Note the wide spacing between the branches and the angle of attachment. |
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One should also inspect the length of annual growth on the limbs. The amount of typical annual growth will vary from species to species. In general, if the nodes, representing annual shoot growth, are extremely close together, it is an indication that the plant has experienced some sort of stress. It could be due to inadequate watering or stem girdling roots. |
| This tree has excessive suckering. Suckering is a tree's response to stress. Adventitious buds, which are inactive buds below the bark surface, are triggered when a tree has experienced drought, water deficiency, or some other adverse condition for a prolonged period of time. Suckers (or water sprouts) tend to grow very fast, and are seen as a tree's last efforts to stay alive. Trees that appear to have excessive suckering should be avoided. They are a sign the tree has experienced some unidentifiable stress, and other problems may be hidden. |
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Here is another example of water sprouts at the base of the tree. Another similar condition is root suckering, with the same implications. |
| This is an example of a spruce tree with a double leader. Trees with double leaders have weak attachments and are more prone to failure of some kind, i.e. a storm. Double leaders can not be accepted, or they can be properly pruned out when young. |
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