Low-severity fire increases tree defense against bark beetle attacksAuthor(s): Sharon Hood; Anna Sala; Emily K. Heyerdahl; Marion Boutin
Source: Ecology. 96(7): 1846-1855.
Publication Series: Scientific Journal (JRNL)
Station: Rocky Mountain Research Station
View PDF (238.0 KB)
Induced defense is a common plant strategy in response to herbivory. Although abiotic damage, such as physical wounding, pruning, and heating, can induce plant defense, the effect of such damage by large-scale abiotic disturbances on induced defenses has not been explored and could have important consequences for plant survival facing future biotic disturbances. Historically, low-severity wildfire was a widespread, frequent abiotic disturbance in many temperate coniferous forests. Native Dendroctonus and Ips bark beetles are also a common biotic disturbance agent in these forest types and can influence tree mortality patterns after wildfire. Therefore, species living in these disturbance-prone environments with strategies to survive both frequent fire and bark beetle attack should be favored. One such example is Pinus ponderosa forests of western North America. These forests are susceptible to bark beetle attack and frequent, low-severity fire was common prior to European settlement. However, since the late 1800s, frequent, low-severity fires have greatly decreased in these forests. We hypothesized that non-lethal, low-severity, wildfire induces resin duct defense in P. ponderosa and that lack of low-severity fire relaxes resin duct defense in forests dependent on frequent, low-severity fire. We first compared axial resin duct traits between trees that either survived or died from bark beetle attacks. Next, we studied axial ducts using tree cores with crossdated chronologies in several natural P. ponderosa stands before and after an individual wildfire and, also, before and after an abrupt change in fire frequency in the 20th century. We show that trees killed by bark beetles invested less in resin ducts relative to trees that survived attack, suggesting that resin duct-related traits provide resistance against bark beetles. We then show low-severity fire induces resin duct production, and finally, that resin duct production declines when fire ceases. Our results demonstrate that low-severity fire can trigger a long-lasting induced defense that may increase tree survival from subsequent herbivory.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
Hood, Sharon; Sala, Anna; Heyerdahl, Emily K.; Boutin, Marion. 2015. Low-severity fire increases tree defense against bark beetle attacks. Ecology. 96(7): 1846-1855.
Keywordsbark beetles, dendrochronology, Dendroctonus ponderosae, disturbance, herbivory, Pinus ponderosa, plant defense, resin duct production, tree rings, wildfire
- Ponderosa pine resin defenses and growth: Metrics matter
- Fortifying the forest: Thinning and burning increase resistance to a bark beetle outbreak and promote forest resilience
- Fire-injured ponderosa pine provide a pulsed resource for bark beetles
XML: View XML