California's worsening drought has led the residents of this great state to continually seek new ways to save water. What can we do aside from reducing usage, installing water wise irrigation, and landscaping with drought tolerant species?
Healthy forests are critical to maintaining an abundant water supply, especially in times of drought. The forest headwaters are responsible for many aspects of conserving a healthy water supply. They maintain shade around watercourses to mediate temperatures and prevent evaporation. They slow the rate at which rain and snowfall reach watercourses, ensuring prolonged water supply into the later parts of fall when it's most critical.
Along with this, trees require water to survive and thrive; different species have varying levels of water requirements and thresholds for survival. Through the implementation of a scientific, data driven forest management plan, developed by a registered professional forester, these critical headwaters can be protected and enhanced. Through selective timber harvest and invasive species removal, California's water supply can be effectively managed for the long term.
The picture below shows a stand which burned at a very high intensity due to the overstocked and unhealthy conditions which were allowed to persist for many years. The result is increased sedimentation, poor water regulation throughout the year, and an overall devastating hit to California's water supply.
By removing individual trees which exhibit low vigor and/or insect/disease infestations from the stand, the competition for water and nutrients is greatly reduced. This has two major effects. The overall usage of water is reduced, allowing more water to reach the watercourses and eventually the river. The remaining trees are healthier and more fire resilient due to the increased distance between tree crowns and the reduced continuity of fuels. The resulting forest is less likely have a crown fire occur and thus more likely to survive when a fire does initiate. The picture below is an example of a stand immediately following a selective timber harvest plan, focused on removing unhealthy individuals.
The resulting forest has few ladder fuels and a reduced level of inter-competition among residual trees, with a lowered overall water consumption. The remaining forest has a high enough canopy cover to limit erosion while slowing percolation.
A good rule of thumb for all you forest land owners concerned about California's drought: If the tree crowns are touching, it's probably time to thin out your stand. To be sure, reach out to a professional forestry consultant near you to schedule a forest evaluation.