Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling
Bark beetles and their associated fungi kill trees readily, but we often ignore which organism is the leading cause of tree mortality. While phloem feeding beetles inhibit photosynthate transport, their associated fungi block the tracheids disrupting transpiration. Within the family Pinaceae, knowle...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-12-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/12/12/1722 |
| _version_ | 1797504584827011072 |
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| author | Javier E. Mercado Robert T. Walker Scott Franklin Shannon L. Kay Susana Karen Gomez Robert M. Hubbard |
| author_facet | Javier E. Mercado Robert T. Walker Scott Franklin Shannon L. Kay Susana Karen Gomez Robert M. Hubbard |
| author_sort | Javier E. Mercado |
| collection | DOAJ |
| description | Bark beetles and their associated fungi kill trees readily, but we often ignore which organism is the leading cause of tree mortality. While phloem feeding beetles inhibit photosynthate transport, their associated fungi block the tracheids disrupting transpiration. Within the family Pinaceae, knowledge of tree physiological decline following bark beetle and associated fungi colonization is limited to the genus <i>Pinus</i>. Here we investigate the physiological response of <i>Pseudotsuga</i> (<i>P</i>. <i>menziesii</i>) to bark beetles or its fungi. We hypothesized that fungi block water transport in Douglas-fir causing faster mortality than by bark beetle activity alone. We successfully lured Douglas-fir beetle to attack a subset of trees in our experimental area using pheromones and compared Beetle-Killed trees with mechanically Girdled, and Control trees. During spring snowmelt, nine months after treatments were applied, Control, Girdled, and five trees that Survived beetle attack had higher transpiration rates and less negative pre-dawn water potential than five Beetle-Killed trees. Declines in transpiration and leaf water potential in our Beetle-Killed trees occurred much earlier than those in studies of beetle-attacked lodgepole pines, suggesting stronger defensive traits in Douglas-fir. Our data suggest that, as in pines, bark beetle-associated fungi are the leading cause of mortality in Douglas-fir beetle-attacked trees. |
| first_indexed | 2024-03-10T04:06:38Z |
| format | Article |
| id | doaj.art-c6c53e84574742509c7db6585969092f |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T04:06:38Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-c6c53e84574742509c7db6585969092f2023-11-23T08:21:29ZengMDPI AGForests1999-49072021-12-011212172210.3390/f12121722Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical GirdlingJavier E. Mercado0Robert T. Walker1Scott Franklin2Shannon L. Kay3Susana Karen Gomez4Robert M. Hubbard5USDA/FS Rocky Mountain Research Station, Fort Collins, CO 80526, USABoulder Valley and Longmont Conservation Districts, Longmont, CO 80501, USASchool of Biological Sciences, University of Northern, Greeley, CO 80639, USAUSDA/FS Rocky Mountain Research Station, Fort Collins, CO 80526, USASchool of Biological Sciences, University of Northern, Greeley, CO 80639, USAUSDA/FS Rocky Mountain Research Station, Fort Collins, CO 80526, USABark beetles and their associated fungi kill trees readily, but we often ignore which organism is the leading cause of tree mortality. While phloem feeding beetles inhibit photosynthate transport, their associated fungi block the tracheids disrupting transpiration. Within the family Pinaceae, knowledge of tree physiological decline following bark beetle and associated fungi colonization is limited to the genus <i>Pinus</i>. Here we investigate the physiological response of <i>Pseudotsuga</i> (<i>P</i>. <i>menziesii</i>) to bark beetles or its fungi. We hypothesized that fungi block water transport in Douglas-fir causing faster mortality than by bark beetle activity alone. We successfully lured Douglas-fir beetle to attack a subset of trees in our experimental area using pheromones and compared Beetle-Killed trees with mechanically Girdled, and Control trees. During spring snowmelt, nine months after treatments were applied, Control, Girdled, and five trees that Survived beetle attack had higher transpiration rates and less negative pre-dawn water potential than five Beetle-Killed trees. Declines in transpiration and leaf water potential in our Beetle-Killed trees occurred much earlier than those in studies of beetle-attacked lodgepole pines, suggesting stronger defensive traits in Douglas-fir. Our data suggest that, as in pines, bark beetle-associated fungi are the leading cause of mortality in Douglas-fir beetle-attacked trees.https://www.mdpi.com/1999-4907/12/12/1722transpiration declinetree physiological responsephytopathogenic fungiirruptive bark beetlestree defense |
| spellingShingle | Javier E. Mercado Robert T. Walker Scott Franklin Shannon L. Kay Susana Karen Gomez Robert M. Hubbard Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling Forests transpiration decline tree physiological response phytopathogenic fungi irruptive bark beetles tree defense |
| title | Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling |
| title_full | Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling |
| title_fullStr | Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling |
| title_full_unstemmed | Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling |
| title_short | Changes in Transpiration and Leaf Water Potential in Douglas-Fir Trees following Douglas-Fir Beetle Attack and Mechanical Girdling |
| title_sort | changes in transpiration and leaf water potential in douglas fir trees following douglas fir beetle attack and mechanical girdling |
| topic | transpiration decline tree physiological response phytopathogenic fungi irruptive bark beetles tree defense |
| url | https://www.mdpi.com/1999-4907/12/12/1722 |
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