Jack's Philosophy of Tree Care

Trees don’t need to be pruned; people need trees to be pruned for human purposes.

Most trees are adapted to forest conditions. When we put them in other situations they grow in ways foreign to their genetic makeup. This is the underlying source of most of our problems with trees. On the other hand, the ways they grow in response to novel stresses can be interesting.

The thick layer of decaying plant material on the forest floor is missing in the urban forest, depriving the trees of beneficial organisms and nutrients, and exposing it to greater temperature and moisture fluctuations.

Solution: leave mulch where possible (but not against the trunk - see volcano mulching).

Often the qualities of the soil are further changed by traffic and development. The soil can have reduced water-holding capacity and gas-exchange potential. Water from the soil is needed to keep the leaves cool, and the roots need oxygen to use the sugars made by the leaves. Solution: protect soil! Remediating soil damage is a doubtful and expensive enterprise. Still, it is possible to try: soil aeration and amending may be advisable in some cases.

Lower branches thrive rather than getting shaded-out and dying; multiple sprouts at the tops of small trees all grow rather than becoming reduced by the competition for light in the forest understory. These grow to become multiple great trunks, not well attached to each other (a condition called Co-Dominance). They may eventually break apart, causing major decay to set in, thus shortening the life of the tree.

Solution: Subordination can help young and middle-aged trees grow more like ones in the forest. Old trees with these problems well established can often be cabled or braced together to prevent breakage.