Dwarf mistletoe’s quaint name belies its severity. The native parasitic plant commonly infects western hemlock trees in western Oregon and Washington via projectile seeds that land on branches and bore through the tree’s bark, where the plant induces tissue swelling and deformities. The result: a diminished ability to transport water and other physiological effects, which reduce tree growth and increase mortality, especially among heavily-infected trees.
A new research project at the Andrews Forest aims to shed light on how changes in temperature and precipitation affect patterns of biodiversity. The Forests of Oregon Elevation Gradient (FOREG) is a network of large sample plots, established in 2019, within the HJ Andrews Experimental Forest. Field studies and experiments will test the importance of species interactions to changes in density dependence and biodiversity across environmental gradients.The FOREG project was designed to dovetail and connect with the long-running Reference Stand study at the Andrews Forest.
Western hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) is a small, parasitic plant that infects the leaves and branches of its host plant, the western hemlock (Tsuga heterophylla) tree. Within a forest, like the HJ Andrews Experimental Forest, areas of mistletoe infection are patchy. Some areas of the forest have trees that are not infected, while other areas have trees that are heavily infected. Hemlock trees infected with dwarf mistletoe grow dense, multi-branched growths, called witches’ brooms.
Stephen Calkins ascends into the canopy of a western hemlock tree
The Spring 2019 issue of the Andrews Forest Newsletter, is now available as an online version or as a downloadable PDF.
The Andrews Forest Newsletter is a semi-annual publication of the Andrews Forest Program. View past issues at https://andrewsforest.oregonstate.edu/publications/newsletter
We are hiring up to three students to conduct research on forest dynamics in the Cascade Mountains of Oregon. Employees will traverse very steep slopes to evaluate the conditions and causes of tree mortality in young and old-growth forests impacted by a major snowstorm in 2019. Successful candidates must be capable and comfortable with hiking and navigating off-trail for long distances on steep, unstable slopes. We seek current students who are interested in ecological research, enjoy working outdoors as part of a team, and can live cooperatively with others. This work is part of the Pacific Northwest Permanent Sample Plot Program, one of the longest-running research projects of its kind in the world. For more information: http://pnwpsp.forestry.oregonstate.edu. Apply by May 17, 2019. See full position announcement (pdf).
Congratulations to Oregon Season Tracker (OST), winner of the 2018 PhenoChampion Award of the National Phenology Network. Started by Oregon State University Extension and HJ Andrews Experimental Forest LTER in 2014, OST links natural resource managers, educators, researchers, and community members in the shared goal of understanding how plants respond and adapt to regional variations in climate. You can read about how OST is training the next generation of climate scientists in this article from Clearing Magazine. As the PhenoChampion Award winners, OST received a customizable trail sign to tell visitors about their efforts. Find out more or learn how to get involved at http://oregonseasontracker.forestry.oregonstate.edu/