Challenges and Opportunities for Maintaining Ponderosa Pine Forests in the Southwestern United States

Deforestation caused by wildfire and bark beetle attacks in southwestern ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson.) forests has increased over the past century due to climate warming. Continued warming is expected to increase deforestation. Ponderosa pine regeneration after deforestation often is inadequate in the region. Opportunities exist for active management to mitigate deforestation. First, planting can promote reforestation, but survival of planted seedlings is generally poor and highly variable among sites. The region needs more research about improving early seedling performance. Secondly, improving aridity adaptation of planted seedlings by seed source selection may improve outplanting performance. New common garden studies of seedling aridity adaptation of Arizona and New Mexico provenances suggest genetic variation in aridity adaptation among populations. Early results show genetic variation in survival under extreme drought conditions. Greenhouse experiments are investigating genetic variation in mechanisms of aridity tolerance. Promotion of forest recovery using these emerging approaches will be critical for sustaining forests in the increasingly arid Southwestern United States. This paper was presented at the Joint Annual Meeting of the Western Forest and Conservation Nursery Association and the Intermountain Container Seedling Growers Association (Coeur d’Alene, ID, October 25–26, 2018).

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Author(s): Thomas Kolb, Aalap Dixit, Owen Burney

Publication: Tree Planters' Notes - Volume 62, Numbers 1, 2 (2019)

Event: Joint Annual Meeting of the Western Forest and Conservation Nursery Association and the Intermountain Container Seedling Growers Association
2018 - Coeur d’Alene, ID

Volume: 62

Numbers: 1, 2