I will start off this post by saying how happy I am to be working for the BLM and the Chicago Botanic Garden. However, when I first applied to this internship, it was with the hope that I would be offered a position with the U.S. Forest Service. I studied forestry in school, and it is a passion of mine. Being from the Northeast, I am used to being surrounded by hardwood forests filled with trees of several different species. I was a little disappointed when I first came to Susanville and discovered that the field office was pretty barren of trees, except for the occasional grove of Western Junipers. Nonetheless, I have made the most of my opportunity here and have come to appreciate the High Desert ecosystem and the plants that reside here. But still, it would be nice to see some trees…
The East Grove of the Pine Dunes
Enter the Pine Dunes Research Natural Area. I first saw the pine dunes in July, when I drove past them on the way to another project. “Wow, those pine trees seem out of place,” I stated. A co-worker explained that the pines are growing on sand dunes that are the result of an old lake bed in the area. After the lake dried up, the sand from the bottom blew across the valley and piled up at the base of some hills. The resulting dunes are a perfect, yet unusual, site for ponderosa pines to grow. The nearest pine tree is 15 miles north of the site, and is at an elevation 1000 feet higher. The nearest pine forest is 20 miles to the north, in the south Warner Mountains. It is not fully understood how the pine groves came to be, but it is estimated that they are at least 300 years old.
The pine dunes was designated as a Research Natural Area in 1987 by the BLM. The area on BLM land was fenced off from livestock and motor vehicle use, and signs were posted to inform visitors of the uniqueness of the site. Some of the pines are growing on private land, right outside the BLM fence. The hope was that the site would be monitored every year, and that each tree would be monitored every five years. After digging through documents dating back to the 1970’s, I could not find any evidence that the site had been monitored in the past 20 years. Monitoring the site is important because the trees have not been reproducing in the past 40 years, and it is important to understand why.
I, along with the other CLM intern at the Eagle Lake Field Office, Natalie, were tasked with monitoring the site. I was excited to finally do some work involving forestry. Our job the past two weeks has been to measure the DBH (diameter at breast height) using DBH tape, and height, using a clinometer, of every tree in the grove. There are about 90 trees at the site, so this is no small task. We also fill out a data sheet for each tree that involves measuring an ovulate (female), and staminate (male) cone from each tree, measuring the length of the seed and of the needles, and indicating the health of the tree based on its bark and evidence of insect infestation.
Monitoring one of the pines
We have currently monitored 61 of the trees at the site. So far the thickest tree has a DBH of 148 cm, and the tallest tree is almost 32 meters tall. These are impressive numbers, but the largest ponderosa pines in the U.S. can grow to a DBH of 263 cm, and height of 70.7 meters! Most of the trees seem to be healthy and producing plenty of seeds. However, we have not found any evidence of seedlings at the site, indicating that the trees are still not reproducing. This may be a natural occurrence, as the site is sort of an anomaly and was not meant to last long. It could also be that rodents or insects are getting to the seeds before they have the chance to germinate. We did discover some ponderosa pine cone beetles in some of the cones. Deer, rabbits, squirrels and chipmunks may be eating the seeds and seedlings as well. My theory is that since the site is restricted from fire, too much duff and debris has built up under the trees and the seeds are not able to reach the soil to germinate.
Whatever the cause for the lack of reproduction, I hope that the trees are able to overcome it. The pine dunes is such a great spot in the Eagle Lake Field Office, and a very rare and unique site for ponderosa pines in general. Even if the trees are unable to reproduce, the trees there now may be able to survive for another 300 years, as ponderosa pines have been known to grow that old. No matter how long they survive, I am grateful that they are there now, and that I have been given the opportunity to monitor them. After spending all summer in the desert, it has been a relief to be working in the shade of a forest.
My favorite tree in the grove, this tree was once hit by lightning, and was once home to a nest of golden eagles. (These events occurred at separate times, thankfully).
Eagle Lake Field Office