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Amateur Naturalist: Growth Of Ponderosa Trees

on September 29, 2017 - 3:44pm
A mature ponderosa stops growing upward but its horizontal branches continue to grow, becoming twisted and thicker. Photo by Robert Dryja 
Amateur Naturalist: The Growth of Ponderosa Trees
By Robert Dryja
The Aquatic Center was constructed 30 years ago. The construction involved landscaping that extended about one hundred feet out from the building. 
There may have been only one large ponderosa tree that was not cut down as part of the clearing of land behind the Aquatic Center. It now is a mature tree. It has a flat top since it has stopped growing upwards. Its horizontal branches are large since they still are growing. This tree may have been spared because it was growing at the outer perimeter at one end of the construction.
The cutting down of trees and the turning over of soil in the construction area would have disrupted the fungi and earthworms living there. The roots of trees provide nourishment for fungi and earthworms. Unless living close to a tree, there would not have been little nourishment available for the few remaining fungi and earthworms. It would have taken years thereafter for fungi and earthworms to grow and burrow outward from the mature tree into the disturbed soil.
Trees in turn receive nourishment from fungi and earthworms. The first trees to benefit would have been the ones germinating closest to the roots of the mature tree.
These would have been the first to receive nutrients from the fungi or additional moisture coming through worm tunnels. Today medium to large ponderosa trees are growing adjacent to the mature tree. 
The fungi would have grown along side the Aquatic Center after growing for years through the soil, helped along with the composting work of earthworms. Tree seeds that germinated close to the Aquatic Center now could benefit from the improved soil. Young trees would have the advantage of being in an open sunny area, away from the shade of larger trees that could block their growth. The large number of small trees now growing close the Aquatic Center is the result. Sun loving shrubbery also is benefiting from the direct sunlight, fungi and earthworms.
These young trees and shrubs will be competing with one another for direct sunlight as they continue to grow. The taller ones will start to create shade over the shorter ones, limiting their growth. Various plant predators will afflict the trees from year to year. The number of small trees surviving to become medium or large will become much less in coming years. The area with the medium and large trees gives a hint of what the area with small trees could look like in future years.
Fungi and earthworms grow more sucessfully in association with the roots of a mature ponderosa tree. Newer trees then begin to grow successfully in nearby disturbed soil when fungi and earthworms move outward over the years from the mature tree.
A mature ponderosa tree with a flat top is in distance while younger trees with conical tops grow close to it. Very young ponderosa trees grow away from the taller trees and adjacent to Aquatic Center wall. Photo by Robert Dryja
Young trees are growing closer to the Aquatic Center, helped along with movement of fungi and earthworms. Photo from Google Earth