Forest Stewardship Basics of soils Rob Harrison, Professor of Forest Soils College of Forest Resources University of Washington Seattle, WA

Forest Land Stewardship includes a faith in the future, and that what you do today will benefit and be enjoyed by people a long time from now. To quote Aldo Leopold… "We abuse land because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect." "A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise." If you think you're owning forest land for the money, you may want to think again. However, many people should be able to pay the cost of owning their land (taxes, etc.) and enjoy some financial benefit from the land by growing and selling trees. That may not be among your goals, and often isn't, but it is a very worthy goal for many landowners.

Tree growth expression is a factor of: 1) Tree genes 2) environment, including edaphic, or soil factors An “Edaphologist” focuses on the soil as a habitat for living things, particularly plants

Soil provides (or doesn’t): 1) physical support 2) air, CO2 to green, O2 to roots 3) water 4) temperature moderation 5) protection from toxins (buffering) 6) nutrient elements Often not included: Home for plant-beneficial organisms (mutualists)

That said…. Trees do NOT need soil to get any of those Trees can grow without soil However, if that was the case, what would the poor soil scientists do? Also important, though some of the processes of soil formation create better conditions for plant growth, many don’t, and soil development doesn’t necessarily coordinate with optimizing plant growth.

A typical elemental content life of granitic soil development

RobHarrison:whole soil structure texture

Ectomycorrhizae Endo- mycorrhizae

N Cycle of 38-y old DF (Wash State) vs. 22-y-old Eucalyptus grandis plantation, S. Brazil