Occupy Portland | Roots & Soil vs. Rope Damage (landscaping, move)

[mdvaden]

This post is not political, but factual, about Occupy Portland, and effects on trees.

Yesterday, someone from a local radio station called me to ask about potential damage to park trees from ropes, where Occupy Portland was at.

BTW - the station is 1 ... oh ... something. If you catch comments on the air, post them. I will be outdoors the next day or two.

Anyway, if the bark is thick, there is no "rope burn" so to speak. But if there are young trees with thin bark, two zones can be destroyed. There are two thin layers beneath the bark. Closest to the wood, is the cell dividing layer Cambium, which makes new wood behind it as the layer moves outward, and makes new Phloem ahead or outside of it. The Phloem is the other thin layer, right at the inner bark. That's the downward freeway in the trees for food from leaves to reach the roots.

But the worst matter by far for these trees, the public's trees, is soil compaction. When soil gets even moderate foot traffic, it can compact. Heavy foot traffic is worse. The soil particles compress closer together, and a more impervious layer of soil occurs on the surface. This hinders the exchange of gases between the soil and air above the ground.

Tree roots are backwards of leaves, because leaves use carbon dioxide and release oxygen. But roots need, and use oxygen, then release carbon dioxide. And when soil is compacted, the carbon dioxide gets trapped in the root zone, increasing toxicity. It's similar to putting a bag over one's head and trapping CO2, or running an automobile in a garage with the door shut (C. monoxide). Although with trees, the decline occurs slower, and the culprit may go undetected due to the time interval.

Soil compaction can be hard to correct, if even possible.

It's worse on wet soils, because the water lubricates particles, making the compression easier. Often, in wet weather, less people walk outside on wet lawn, landscaping, etc.. And in summer, if ground dries and firms a little, the problem may decrease in warm weather.

So the worst case - a #10 on a scale of 1 to 10 for severity - is when many people trample wet soil in the winter time. When the ground is wet, and lawn, if any, can't recover with growth.

Wherever Occupy Portland people are walking on ground or lawn around trees, soil compaction damage should be occurring. Anywhere they, or their tents are on hard concrete or paver blocks, there should not be a problem. It looks like they are presently in some areas where there is bare earth being walked on continuously.

Similar to this ... one reason Golf Courses move the holes and flags daily, is to reduce wear and tear to the greens. If you ever play at the end of a day, note how weathered the turf becomes around the pin. And that's usually just from one single day, and people walking carefully on thick sand-based specialty soil on top.

For those interested further, Google about soil care, compaction, even drainage. Because compacted soil causes more rain water runoff.