Mendocino’s Pygmy Forest

In Mendocino County, California, there is a fascinating ecological phenomenon called the “pygmy forest.” Here, highly stunted trees grow on patches of acidic, shallow soil that is extremely low in vital nutrients. These trees remain only five to fifteen feet tall, despite living up to three hundred years old. When transplanted onto richer soils, however, these trees grow to full height (to the dismay of gardeners who want ready-made, adorable bonsai trees).

So, we already know that the unique soil of the pygmy forest causes the trees to be stunted. But, what I want to know, is exactly how the soil is causing the stunting. Is the lack of nutrients in the soil limiting the amount of enzymes the plants can produce, and thus limiting plant growth? Does the trees’ small size help them survive in such difficult soil? I am working on figuring out how the physiology of these pygmy plants differs from the physiology of nearby non-stunted plants.

I am also examining how the pygmy plants deal with water. I think they may transport more water to their leaves, because that would speed up the rate the plants can move nutrients, as well. However, there is often a trade-off between rate of water transport and resistance to drought, so I also predict that these pygmy plants will be more vulnerable to dry conditions. Furthermore, if the pygmy plants lack the nutrients to build strong wood, they may be even more vulnerable to drought. Have these plants made any anatomical changes that mitigate that vulnerability? Several species are very common in the pygmy forest and seem well up to the task of growing in such difficult conditions, while other species barely maintain a foothold in the pygmy forest. What are these species doing differently?

A thorough understanding of the physiology of these unique pygmy plants has the potential to aid in conservation of the pygmy forest as well as help fill in our understanding of how plants can change their physiology to survive in harsh conditions.

Pygmy forest in Hans Jenny State Reserve

Pygmy forest in Hans Jenny State Reserve

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