The Forestry Forum
General Forestry => Ask The Forester => Topic started by: DouginUtah on August 22, 2012, 10:11:26 PM
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(https://forestryforum.com/gallery/albums/userpics/10332/IMG_0369.jpg)
Why do you think these trees (cottonwood poplar) are not all the same height?
The tallest ones are to the west--left side of the picture.
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Maybe soil differences, hard pan, prevailing winds, or crop spraying chemicals, etc.
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Same as suggested. Usually soil and water affects the height growth the most on a site. If outside influences like farm chemicals excluded. Being that they are on the same site I would rule out wind, frost hardiness and elevation.
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They could be planted in a ditch. Or they could be planted in an angle away from the picture, which would distort the view. It seems that the brush in the foreground is denser on the east side than on the west, which would lend to those on the east side being further away.
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planted near a septic drain field, bigger ones get first draw.
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The ones near the road might get more sunlight!
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These trees were planted ten years ago on the USU Experimental farm in Providence, UT. For the first five years they were watered with sprinklers. Those involved were/are puzzled by the unequal growth but their best guess is it has been caused by the water table--the Blacksmith Fork creek is a couple hundred yards to the west.
It was very interesting to talk to the professor involved. He showed me how they were planted--a new-growth twig smaller than a straw was placed in the ground. All from the same ?? (OP367)--the same as used for the thousands of acres of poplars growing in tree farms along I-84 in Oregon--for pulp wood, cut after growing for eight years. They are irrigated by water from the Columbia River. Apparently, water availability makes a difference. :D
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It's true with aspen up here as well. On a wet site they will be diseased and weak and not amount to much. On an elevated spot in a swamp they will be much larger and live longer. Balm-of-gilead or balsam poplar will do better on wetter soils. In fact if the soil is too well drained or on the dry side the leaves drop this time of year. I see a lot of this happening this summer already.