Greenhouse treatments before planting enhance ponderosa pine reforestation success
Presentation Type
Oral Presentation - Campus Access Only
Category
STEM (science, technology, engineering, mathematics)
Abstract/Artist Statement
Global environmental change has increasingly negative direct and indirect effects on forests. Indirectly, hotter and drier conditions make fires more frequent and more severe. Large patches of stand-replacing fire can result in forest loss by killing resilient adult trees and thus limiting seed sources at the site. Even if seeds are available, hotter and drier conditions also directly limit seedling establishment post-fire, especially if there was significant adult tree mortality and thus less canopy shade. Combined, the direct and indirect effects of global environmental change threaten western USA forests, and reforestation is common practice to mitigate ecosystem change.
While standard operating procedures for reforestation are informed by decades of research and are necessities for coordinating planting, recent plant ecophysiological research suggests a revision may increase seedling drought tolerance, survival, and post-fire restoration success. Two key steps in the reforestation pipeline, freezer and cooler storage of the seedlings, likely reduce plant carbohydrate storage. This is concerning because reduced carbohydrate storage decreases seedling drought tolerance in several woody species. Generally, carbohydrate-depleted plants die more frequently and faster under droughts. In summer 2021, I investigated whether manipulations to increase seedling carbohydrate storage prior to planting improve conifer seedling drought tolerance, survival, and post-fire restoration success. I grew ponderosa pine seedlings in a greenhouse for three weeks in full light (“light seedlings”) or 3% light (“shade seedlings”) to elevate or further decrease, respectively, carbohydrate storage before planting. A control group of seedlings were subjected to standard reforestation procedures (“control seedlings”; no greenhouse treatment). I planted seedlings in early May and monitored them throughout the following summer and fall.
Overall, my preliminary results suggest that greenhouse light treatments, intended to increase carbohydrate storage before planting, improved conifer seedling water relations and overall health relative to shade or control treatments. Specifically, I found that the greenhouse light treatment resulted in less needle dieback, more root biomass, less drought stress, and improved survival when compared to shade and control treatments in the field. These results suggest that changes to reforestation procedures will improve reforestation outcomes in a hotter, drier world of the future. Producing more resilient, drought- and heat-tolerant conifer seedlings is critical for cost-efficiently restoring western USA forests post-fire.
Mentor Name
Anna Sala
Greenhouse treatments before planting enhance ponderosa pine reforestation success
UC 326
Global environmental change has increasingly negative direct and indirect effects on forests. Indirectly, hotter and drier conditions make fires more frequent and more severe. Large patches of stand-replacing fire can result in forest loss by killing resilient adult trees and thus limiting seed sources at the site. Even if seeds are available, hotter and drier conditions also directly limit seedling establishment post-fire, especially if there was significant adult tree mortality and thus less canopy shade. Combined, the direct and indirect effects of global environmental change threaten western USA forests, and reforestation is common practice to mitigate ecosystem change.
While standard operating procedures for reforestation are informed by decades of research and are necessities for coordinating planting, recent plant ecophysiological research suggests a revision may increase seedling drought tolerance, survival, and post-fire restoration success. Two key steps in the reforestation pipeline, freezer and cooler storage of the seedlings, likely reduce plant carbohydrate storage. This is concerning because reduced carbohydrate storage decreases seedling drought tolerance in several woody species. Generally, carbohydrate-depleted plants die more frequently and faster under droughts. In summer 2021, I investigated whether manipulations to increase seedling carbohydrate storage prior to planting improve conifer seedling drought tolerance, survival, and post-fire restoration success. I grew ponderosa pine seedlings in a greenhouse for three weeks in full light (“light seedlings”) or 3% light (“shade seedlings”) to elevate or further decrease, respectively, carbohydrate storage before planting. A control group of seedlings were subjected to standard reforestation procedures (“control seedlings”; no greenhouse treatment). I planted seedlings in early May and monitored them throughout the following summer and fall.
Overall, my preliminary results suggest that greenhouse light treatments, intended to increase carbohydrate storage before planting, improved conifer seedling water relations and overall health relative to shade or control treatments. Specifically, I found that the greenhouse light treatment resulted in less needle dieback, more root biomass, less drought stress, and improved survival when compared to shade and control treatments in the field. These results suggest that changes to reforestation procedures will improve reforestation outcomes in a hotter, drier world of the future. Producing more resilient, drought- and heat-tolerant conifer seedlings is critical for cost-efficiently restoring western USA forests post-fire.