(If you missed them, here’s Part 1 and Part 2. Now for the final installment…)
Coweeta and other LTERs have all kinds of equipment which continuously monitor and record temperature, precipitation, stream flow, water chemistry, and so forth, and thus have compiled valuable long-term records.
At Coweeta, these records date back to 1934, and two climate trends are evident from the data that’s been collected since then. First, there’s been an upward trend in temperature since around 1980 (before that, there was no discernible trend). Second, with respect to rainfall, the wettest years have been getting wetter, and the driest years have been getting drier. They collect data on rainfall chemistry too; and interestingly, they started seeing a sharp drop in sulfate concentrations around 1990 – coincident with the passage of the Clean Air Act which was enacted in response to sulfur dioxide deposition (a.k.a. acid rain).
The biggest takeaway I left Coweeta with was an appreciation for the value and power of long-term observation. Forests grow slowly, and so we need to be really patient if we want to understand how they work. This is one of the reasons why the network of LTER sites across the country is so valuable.
This leads to some further musings. One, as a family forest landowner, you probably don’t have access to fancy monitoring equipment, or a Ph.D. scientist (or two or three) for hire. However, you do have a place that you observe on a fairly regular basis and you and your family may have a long-term connection to that place. Your observations, and more importantly your recording of your observations, have power. You can monitor changes on your property for your own purposes – wildlife sightings, stream changes – whatever fits your interests. For example, if you attend the upcoming June 23rd tour at Hyla Woods, you’ll learn how the host family has been monitoring birds in different forest types on their property for years.
Additionally, there are opportunities to contribute your locally collected data to larger networks to help scientists understand long-term and large-scale patterns of change. Some examples include the National Phenology Network, the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS), and the Oregon Invasive Species Hotline.
The final thought – partly because nature is full of long-term processes, our scientific understanding evolves over time, and sometimes what seems like a pattern or a clear result in the short term turns out to be different in the long term. I suppose that’s why forest management practices are based on the “best available science” of the time, but as time passes we might revisit and revise what is considered a best management practice. If those scientists who planted the pine watershed at Coweeta had stopped their experiment after ten years, they would have come to false conclusions about different tree species’ water use. And if climate scientists looked at trends over just a decade or two, they would certainly also miss the big picture.
