Redwood Reader

164. Deforestation doesn't trigger floods-U.N. report By Alister Doyle, Environment Correspondent Wed Oct 12, 8:02 PM ET
Reading this Reuters article on Yahoo gave the feeling of the fox guarding the henhouse. Some of these issues are discussed regularly here, and the raison d’etre in the first place.
"There is no scientific evidence linking large-scale flooding to deforestation," the U.N.'s Food and Agriculture Organization (FAO) and the Indonesia-based Center for International Forestry Research (CIFOR) said in a report Thursday. We can see the science is not up to date, for there is no mention of soil water storage or aggregation or those functions in relation to glomalin. that the cumulative impacts of tree removal, especially ancient trees, has significantly impaired the soils ability to store and hold some of that water. We also point out one of the precipitation interfaces job is merely to slow the waters path. Arguments about storm water storage in abundant rainfall areas center on urban runoff. I am sure there will always be floods but this one factor is overlooked everywhere- native vegetation will absorb most of a normal rainfall. Peak events sculpt landscapes. Minor events act like peak events when conditions permit, such as land clearing or new roads altering swale drainages.
Recent reports about percentages of trees in a given area digging for groundwater while neighboring trees of the same species were content with surface water is also an interesting concept. As in any biological community, it makes sense that different individuals have differing strategies for acquisition of necessary components for survival of the species. We already know some species root to bedrock or groundwater, however deep that may be. In many areas these species pin the landscape to the ground. Several of these trees per acre can be the difference between a stable hillside and a disaster waiting to happen.
The authors seem to want us to believe that things are going exactly as they always have. But I disagree. While the picture of a sponge may be true, the modern sponge has been sliced repeatedly by roads and diverted drainages. It is not a huge single piece of biologically connected landscape, it is thousands of bits and pieces, the areas between channeling water into cutting torrents, giving a usual amount of water far less opportunity to be absorbed and greater opportunity to wreak havoc downslope. There is also no scientific literature about the effects of glomalin on landslide activity or in relation to flooding or about glomalin decay and landslides. That is the purpose of this blog- to get the new science recognized for the useful perspective it gives us.
Heavy rain will cause runoff in many cases. The report fails to mention a difference between surface runoff, which cuts, and water running through the biological zone at an accelerated pace. Heavy canopy and duff still operate on the precipitation although it doesn’t get absorbed into the soil.
The authors also lump trees together but we know it takes decades to centuries to rebuild fungi populations and glomalin deposits. Young trees are barely reaching production will not have excess productivity to trade growth for soil conditioning, that would happen once the tree has reached adulthood and become a leading community contributor to the subsoil infrastructure of the ecosystem. Tree roots of little trees won’t do much but slide on down with the mud. Little trees snap off in high wind, or are easily uprooted.
We would like to know how the authors think streams run all year in areas with extended dry seasons if water is not stored or held or delayed in the biological zone. We also point out far more damage is done by development than loggers. Loggers despoil new areas but they can come back. Development finishes them as functional landscapes. Farmers are in the middle- most ag practices diminish the water storage capacity of a landscape by replacing deeper rooted natives with shallow rooted crops, slowly shrinking the glomalin conditioned zone to a narrower band nearer the surface.
It seems there should be tables that show what types of vegetation do what under differing precipitation events. We find these reports regularly thrown out there that seem like poor questions in the first place, and loudly publish doom and gloom debunking any theory that points out modern economic practices are causing socio-environmental problems.
In the end, we have to agree that practices are certainly making bigger messes with smaller storms, especially in the flood plains and populated areas. I do not agree there is evidence of massive landsliding in the geologic record and that it is not a manmade phenomenon.