Olive Tree Monitoring on Santa Cruz Island

While my regular duty station is John Muir National Historic Site, 360 miles away from Santa Cruz Island, my mentor Keith Park and I were called in to give another perspective onto the issue of the historic olive trees, producing thousands of feral seedlings. Some of the park employees that had been battling the constant feral seedlings wanted another experienced persons say so to see if it was ok or not to remove the heaviest and most problematic producers of olive seedlings.  I was really intrigued by this sort of project because I’ve done never any kind of tree inventory before and I wanted some insight on how the whole process works. My whole background in tree care never dealt with data collection and managing large amounts of trees all at once, so of course this was all so new to me and fascinating. I liked that the whole methodology of orchard management is quite different from singular trees and what I was used to. So when you considering that I really enjoy finding solutions to problems and finding how things work, this seemed like it would be a really good way to challenge my problem solving abilities, and this was definitely a challenge.

In the meantime, my mentor and I had the fantastic opportunity to travel to Channel Islands National Park, located off the coast of Los Angeles to do tree assessments on an olive orchard consisting of 500 trees. We stayed on Santa Cruz island for 5 days, giving our best opinion of the trees based off of previous conditions recorded by some of the natural resources employees over the past few years and assessments we would be making over those five days. The olive orchard itself was planted in the late 1800’s by a wealthy french rancher named Justinian Caire. His intent was to gain more profit from the trees, but they never went into production, and 20 years later, the farm was abandoned and taken on by two other families. It was only three years ago that the park cleaned up the old ranch house and is in the process of making it available for housing.

While Santa Cruz island is a wealth of history and knowledge, it has needs just like every park does for maintenance, research, and documentation. This project focused on a particular maintenance issue regarding that historic olive orchard that had been planted a few hundred years prior. At the same time, this orchard with its sheer amount of trees produced an incredible amount of seeds that were carried off by mainly birds, but also sheep and pigs when they were on the island. This consequently led to 11,000 seedlings and trees in various states being treated and removed all over the island. At the same time, there are still seedlings that are yet to be discovered and some that are popping up in the same area they were already treated in. In contrast to this unfortunate state of the orchard, again, it is historic. Planted by ranchers in the 1800’s it tells the story of their life and work and while the orchard wasn’t successful we at least know their farming practises and the kinds of things ranchers would look for in a truly successful orchard. There are some trees in the orchard that are massively grand and gorgeous. Of course, these trees are the heaviest producers of fruit and the biggest problem on the island. All of these things we had to take into consideration as Keith and I were doing our assessments and thinking of a way to best handle the situation that would be pleasing to both the natural resources side of taking out all the trees and the cultural resources side of preserving these ancient trees.

With all that in mind Keith and I set off on figuring out this problem. We started by talking to the employees working on the olives, whether it was removing the seedlings or otherwise, to get their take on the situation and better understand what we were up against. We had a general idea what we were doing, but the more specific information from the employees that were actively fighting this olive battle made the objectives a lot clearer. Once we finally got a bit settled in our living area  we walked around the orchard to get a better physical understanding of our work. This part was a real shock because I hadn’t anticipated the drastic steepness of the hills. It was so difficult, that the park gave us these devices that stretched over the soles of our shoes to help prevent slipping, though falling was inevitable. With all this in mind, we knew that we only had a few days to see every single tree and write down anything we considered noteworthy and would help come to a conclusive decision about the orchard. Therefore we came up with a really quick plan to simply record the Diameter at Breast Height(DBH), the number of trunks, a quick health assessment based off of previous , and any notable things about the trees. That may have been the fact that some roots were exposed or the sight of a bug or cavities or splits in the tree. We did these assessments with every one of the 500 trees, miraculously in only two days, and in the end concluded that the trees should be left as they are. They may be vectors of feral trees and they may look bad, but they’ve been prospering on since the 1800’s, and they are too grand and historic to remove. We wish that we could’ve come up with a better solution to the original problem of the seedling, but for right now the trees have to stay.

My mentor Keith Park


2 responses to “Olive Tree Monitoring on Santa Cruz Island

  1. Good greetings to you. How fascinating to hear of the olive trees on Santa Cruz Island. We are raising Santa Cruz Island sheep and coincidentally have olive trees here in northern California. We’d love to know more about the olive trees if you are inclined. Many thanks to you.


  2. Five hundred trees in 2 days, that’s impressive! You and Keith deserve medals! Thanks for all that you’ve done at EUON/JOMU and CHIS this summer. We’re so grateful to you.


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