Whitebark Pine, an elder in peril: a literature review

Whitebark pine (Pinus albicaulis), an ecologically important tree species in high-elevation ecosystems of western North America, is declining across most of its range in North America because of the combined effects of an exotic pathogen (white pine blister rust; Cronartium ribicola) and a native insect (mountain pine beetle; Dendroctonus ponderosae), as well as climate change and its effects on the frequency and severity of wildfire. Concern over the status of whitebark pine has led to its listing under both the US and Canadian Endangered Species Acts and the adoption of coordinated, trans-boundary restoration strategies, such as the Range-Wide Restoration Strategy and the National Whitebark Pine Restoration Plan. These restoration strategies call for active restoration measures including silvicultural treatments and prescribed burning, among other treatments. Despite widespread agreement on the need to restore and conserve whitebark pine, there is little information on the efficacy of proposed restoration treatments and there is some concern that treatments aimed to concern the species, such as prescribed burning, may in fact have adverse effects. In order to improve restoration strategies for white bark pine, I conducted a literature review on the status of knowledge on the species in general, with a particular focus on restoration. Specifically, I identified all publications listed on Web of Science and grey literature available on AGRICOLA (National Agricultural Library, USDA) from 1950 to 2017 using the search terms whitebark pine and “Pinus albicaulis”. I only reviewed articles that mentioned the species in the abstract or title, or studies in which whitebark pine ecosystems were a main focus (e.g. biotic interaction studies - Nucifraga columbiana, Ursus arctos, Cronartium ribicola, etc). Although I found that the number of published articles has been increasing over the last 30 years, most studies focused on biotic interactions (27%), pathogens and mountain pine beetle outbreaks; 25%) or mortality, distribution and regeneration dynamics (16%, 19%, 12 % respectively), highlighting interest in understanding the impacts of the main threats to the species. On the other hand, experimental studies focused on the efficacy and effects of restoration practices and management had little research (less than 10% of all articles and only 402 publications. There were also few articles published on the species life history, fire ecology and successional dynamics. My findings indicate a significant gap in information required for effective conservation planning and restoration for whitebark pine. To improve management, there is a need to recognize the value and complexity of alpine ecosystems and to invest in research that aligns with conservation need and that can inform conservation plans, restoration strategies and management practices