New Forest Planning Model Could Help Protect Stream Water Quality

A new model for planning and timing of forest harvesting could help minimize the effects on water quality levels in nearby streams.

The model, which focuses on forest harvesting activities and the level of dissolved organic carbon (DOC) levels in stream water, is outlined an article in the November 2009 issue of AMBIO: A Journal of the Human Environment, published by the Royal Swedish Academy of Sciences.

“The strength of the model is that it is simple to use and it could be included in traditional forest planning models,” wrote Karin Ohman, Jan Seibert and Hjalmar Laudon in the article, “An Approach for Including Consideration of Stream Water Dissolved Organic Carbon in Long Term Forest Planning.”

For the study, the three researchers developed and evaluated a model that accounted for the downstream DOC concentrations produced from cumulative forest clear-cuts over time in a watershed. Their research—among the first studies of its kind—examined a watershed in northern Sweden, where forestry is a vital part of the economy.

“Our hypothesis was that by optimizing the distribution and timing of forest harvesting activities over a rotation period in a large catchment, the combined downstream effect in sensitive stream locations could be minimized,” the researchers said.

Their model allows users to specify a maximum DOC concentration increase for any location along the stream.

“As a result, habitats sensitive to increased DOC levels can be protected while forestry activity continues,” they wrote.

The model also could be used to monitor other water quality parameters.

When DOC is not considered during forest planning, the researchers said, streams could become unsuitable habitats for many species, including Brown Trout. They also said the study shows that the costs involved with DOC considerations have little effect on total harvest volumes.

The model could help analysts balance timber production with the effects of forestry on water quality and could provide an alternative to legislative restrictions regarding harvesting. It also shows promise as a long-term planning tool for forest managers.

“The results from the case study further indicate that with a more even distribution of harvests over time, the variation in DOC concentration over time will also decrease,” the researchers said.

Source: ABMIO