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Friday, January 9, 2015

Thinking Historically



               
A house in the Old Headquarters/Tejon Canyon area of Tejon Ranch, 1888. Note the relative barren vegetation in the foreground. Is this because it was a livestock pen, or would the ground condition have looked like that naturally?
 

              One of the great things about working on Tejon Ranch is its incredible history. This applies to only the natural history of plants, animals, invertebrates, soils, and geology, but also the rich human history that goes back millennia. Where these two aspects of history meet is particularly intriguing.  Human activity has always made an indelible mark on the landscape across California. From indigenous burning and harvesting practices to the introduction of Mediterranean grasses by European explorers and settlers, the composition and function of natural systems have been intimately tied to human activity in this landscape since time immemorial.
                 Today, as an organization whose mission is to “protect, enhance, and restore native biodiversity and ecosystem values,Tejon Ranch Conservancy is working to gain a better understanding of what it would mean to actively return parts of this landscape to their historical condition. One of the first and most profound questions that has to be asked during such an effort is, “What is the baseline?” That is to say, what historical condition do we want the landscape to return to? Should it look like it did 50 years ago? 250 years ago? 1,000 years ago? The answer to this question is typically limited by what information is available and what landscape you are looking to restore. It would probably be a Sisyphean task to eradicate non-native grasses such as wild oats (Avena sp.) and ripgut (Bromus diandrus) from over 100,000 acres of grassland on Tejon Ranch. Even if we were able to remove all of the non-native grasses from say, the Antelope Valley portion of the ranch, there is precious little information available about what that landscape would have looked like 50/250/1,000 years ago from a vegetation perspective.   
Tejon Ranch was heavily grazed by sheep in the late 1800s. How much change might they have affected on vegetation and soil communities on the ranch even before cattle were introduced?
                 To address some of the issues surrounding restoration on a place like Tejon Ranch, the Conservancy has begun seeking out resources that might help us understand what this landscape would have looked like (and how it functioned) at different points in history. Fortunately, many travelers and naturalists have passed through these mountains over the last three centuries and documented what they saw (to varying degrees of accuracy). With the help of our volunteers, the Conservancy has been working to identify and collect primary sources that contain useful information about the vegetation, animals, and conditions of the past.
John Xantus was a Hungarian-born naturalist stationed at Ft. Tejon from 1857-1859
                We also have the benefit of being able to reference 130 years’ worth of photographs. Starting with Carleton Watkins in 1888, there is a rich history of photographers documenting the landscapes of Tejon. While these images only give us a (relatively) recent snapshot of these resources, the objectivity with which they report is hard to beat. We’re now compiling as many historic photos as we can find with the hopes of establishing long-term monitoring stations at the old photo points.
                This Tuesday, our Public Access Coordinator Scot Pipkin went out with Chuck Noble, one of our volunteer docents to seek out some of these old photo points and retake the photos in the southern San Joaquin Valley. It was surprisingly difficult to line up many of the shots properly. Haze, altered fence lines, and road changes made it even harder to line up foreground features with the background. Despite these challenges, we were able to recapture a couple of photo points. We’ll try to go out again in the spring when visibility will be better, but timing of these photos will also be an important aspect of our monitoring effort. As anyone who has spent an entire year in southern California knows, a hillside in March can look vastly different from the same hillside in August. This is just one more factor to consider when reconstructing historic landscapes. There will certainly be many more that we learn about as we continue this project!

Image showing a dry wash just north of Tunis Creek, 1966  

The same wash in 2015. Photo by Chuck Noble