Collaborative Research: IUSC: Using the past, present, and future to investigate the effects of global change agents on tree reproduction across the boreal forest

About This Grant

Seed production by trees plays an essential role in the ecological and economic stability of future forests because seeds directly contribute to the growth of new trees. This is especially critical in boreal forests, which cover about 30% of the Earth’s area. Previous studies of the effects of environmental variability on boreal tree species have focused on tree growth and species’ range shifts, however a key gap in knowledge is understanding how tree reproduction is affected by abiotic conditions, such as temperature or precipitation. Advancing our understanding of the North American boreal forest is challenging because it is very large, the environmental conditions vary by region, and boreal tree species differ in their habitats and traits. Also, current forest models either ignore tree reproduction entirely or simplify it to assume that seed availability is constant. This project will test how abiotic factors (CO2 levels, temperature, water availability, nitrogen deposition, wildfire) interact to affect seed quantity and quality (seed mass, seed chemistry, seed germination rates). This information will be used in models to predict the future of boreal forests. This research will inform federal and state agencies about drivers of seed production and viability, increase public scientific literacy about tree dynamics and boreal forests, and add cone specimens from North American boreal forests to the Missouri Botanical Garden herbarium for future use. The project will train three graduate students and six undergraduates in conducting scientific research, as well as support a youth training program. Boreal conifer species with widespread distributions, including balsam fir, black spruce, eastern tamarack, jack pine, and white spruce, are ideal for investigating how abiotic factors affect seed production. This project will combine historical collections of cones and seeds in herbaria dating back to the 1820s, present day cone and seed collections across the distribution of boreal conifer species, and cones from trees in an ecosystem-scale experiment. The information from these field collections will be used in spatial modeling of landscapes from interior Alaska to the eastern North American boreal forests, in order to forecast the future composition of boreal forests. This research provides more than a snapshot in time or space, as it leverages specimens going back 200 years and then forecasts until the end of this century, as well as sampling vast regions of the continental distribution of the North American boreal forest and forecasts across regions totaling 18 million hectares (44 million acres). This research has important implications for understanding the future of boreal forests across North America, and for forestry and future timber production. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.