The health of forests plays a huge role in shaping water quality and quantity and each land owner has an opportunity to help prevent erosion and increase water yield through enlightened forest management. Healthy forests protect soil properties, increasing infiltration, and reducing overland flow and erosion. The size and age of the forest can affect the amount of base-flow in a stream.
Old growth forests act like a sponge as the energy of falling rain is intercepted by vegetation and infiltrates into the ground. Studies by Humboldt State University researchers have found that 40 to 60 years after clear cutting, forests are over-stocked, trees are too closely spaced, and they have very high rates of evapotranspiration that can deplete summer base flows. Trees within these forests can become stressed during drought and succumb to disease outbreaks that make the forest more vulnerable to catastrophic, stand-replacing fire. Harvesting smaller diameter trees to reduce stand density can improve forest health forest and reduce water use.
Thinning forests around your home and garden has multiple benefits, including fire safety, increased groundwater and surface water supply, decreased sources of mold and fungus, and a shorter time for trees to grow to a merchantable size.
When forest stands are over-stocked, growth slows as each competes for water with adjacent trees. Release of larger trees left after thinning promotes faster growth, improving wildlife habitat and shortening the time for trees to reach merchantable size. The increased light and air flow in the thinned forest also increases native herbaceous plant species diversity, also a plus for wildlife. When managing forests on your property, make sure not to disturb the riparian buffer near streams.
Farmers living and gardening in or near forests should routinely harvest smaller diameter trees to promote forest health. After thinning, the your forest requires less ground water volume than in an over-stocked stand. This reduces the fuel load, lessening fire risk and provides woody material for that can be used as mulch when chipped or as a source of biochar. Opening the air flow through nearby forests reduces pest and mold populations too. See Slide show about forest health.
Fire is an essential element in shaping the mosaic of landscape vegetation and it can be very beneficial for forest health. For example, the Wilderness Lodge Fire in 2014 burned more than 12,000 acres in the upper South Fork Eel and actually improved forest health. ERRP hosted a meeting with BLM and CALFIRE in October 2015 where effects were discussed by experts.
Re-cap of Public Meeting: Resources Available for Controlling Erosion & Improving Forest Health
The California Department of Forestry and Fire Protection (CalFire) mandates that vegetation within 100 feet from every home and out building be protected by fuels removal annually. Within 30 feet CalFire requires removal of all dead material, dry leaves, and making sure tree limbs are trimmed to a height of 15 feet. On land that doesn’t slop, tree limbs must be at least 10 feet apart, but that distance varies with slope See more information from CalFire (www.readyforwildfire.org/thelaw/)