How many times a day do you cross a river? Maybe twice and you definitely realized it. How many times a day do you cross a stream? If I were to tell you that you crossed at least three streams twice today to get to the school and back home would you believe me? Small streams are sometimes not very obvious, but they are numerous! To most people the statement, “what you do upstream will have an affect downstream” seems obvious. Another obvious statement can be made about small streams, “collectively they have large impacts on downstream rivers”. Yet there are no mandatory buffers around them! Current forest harvesting regulations do not require trees to be retained around streams <3 m in width. Trees provide shade, bank stability, and inputs of coarse woody debris (CWD) that create important fish habitat once they have died and fallen into or across the streams. It is important that these buffers exist to maintain properly functioning streams.
Dr. John Rex presented his research findings of the impacts harvesting has on small streams on stream shade, temperature and CWD inputs with and without 10 m buffers. The results: there was a change in everything – imagine that. Two years post-harvest the shade recovered to pre-harvest conditions, however there was a 5˚C increase in stream temperature because the solar radiation is being absorbed from shrubs closer to the stream. There was an increase in CWD post-harvest, but this then decreases after a harvest rotation. The reason for this research is that he would like to see a minimum prescription of 10 stems/100 m. This would maintain 50-70% background shade to keep stream temperatures cool and maintain short- and long- term supply of CWD.
Dr. Rex presented his research in a humorous and enjoyable manner without diminishing the importance of his work. He emphasized the importance of going beyond the research and collaborating with industry, stakeholders, First Nations, and government.
I understand the importance of buffering streams, small streams are EVERYWHERE, and because of there quantity, from the forestry perspective, I am curious how that would shift the industry. If all streams on a block were buffered, how much would remain unbuffered? Would that force the traditional method of clearcutting into partial cutting?
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