Posts Tagged: Safeeq Khan
To effectively reduce these adverse effects of harvest, foresters first need to know the precise causes of sediment increases. Historically, researchers investigating the effects of timber harvest on the land have considered two primary drivers: hydrologic changes following timber harvest or fuel reduction that drive sediment transport, and increased sediment supply from ground disturbances and/or mass movements that result from those harvest or fuel reduction activities.
While these causes are tightly linked, little is understood about the relative role each plays in transporting sediment from the watersheds. In other words, which is dominant in increasing sediment delivery and transport: increased streamflow due to greater water availability that can sweep up and transport sediment, or a greater supply of sediment entering the waterway in the first place?
A new analytical approach developed by Safeeq Khan, UC Cooperative Extension specialist in water and watershed sciences at UC Merced, and collaborators now provides valuable insights into this issue, and ways to target effective mitigation strategies.
Published in the Journal of Hydrology last fall, the team's study analyzed long-term (1952-2017) streamflow and sediment data from two adjacent paired watersheds in the H. J. Andrews Experimental Forest in the western Cascades Range of Oregon. One of the watersheds was harvested and replanted in the 1960s, while the second was not disturbed and used as a control.
“The data is from Oregon, but highly relevant for our work in the Sierra Nevada,” said Khan, lead author of the study. “We have tried to quantify the effect of hydrologic changes and increased sediment supply from logging activities on total sediment yield.”
To isolate the relative contributions of streamflow changes and increased sediment supply on sediment transport, Khan and colleagues developed a statistical reconstruction technique to account for the hydrologic changes following harvest.
“This approach allows us to analyze and estimate background sediment production in the treated watershed during the post-treatment period as if the harvest had not occurred, which is remarkable,” said Khan.
The new approach demonstrated that sharp increases in sediment following harvests can be confidently attributed to ground disturbances associated with timber harvest or thinning operations to reduce fuel. Changes in sediment supply overwhelmingly dominate streamflow in terms of contributions to increased sediment in the watershed. Streamflow increases alone led to modest increases in sediment, less than 10%, with the watershed transporting about twice as much total sediment than it would have had the area been left unharvested. This effect diminishes more or less exponentially over time, especially with respect to suspended sediment, as bare areas revegetate, which reduces hillslope sediment supply, and as streamflow returns to pre-treatment levels.
“Once we know the background sediment production, we can easily attribute how much of the increase is due to what mechanisms” said Gordon Grant, a hydrologist with the U.S. Forest Service Pacific Northwest Research Station and co-author on the study.
“Determining that increased sediment in watersheds after harvests is primarily driven by ground disturbance is crucial in targeting mitigation efforts,” explained Khan. “Now, we know that strategies that limit ground disruption – like suspending logs while transporting instead of dragging them, avoiding heavy machinery when and where possible, and mastication and mulching – are likely to be highly effective in reducing sediment yields.”
These changes are most pronounced in the first few years following harvest, but the treated watershed did not return to pre-harvest levels of sediment for two decades, underscoring the long-term effects of harvest on a forest's hydrologic and geomorphic systems.
While clearcutting is no longer practiced on U.S. federal land, it is still the primary timber harvest method used across the globe. Additionally, many other types of forest disturbances such as wildfires, mass tree die-offs, and salvage logging create hydrogeomorphic conditions not too different from clearcutting.
"Our findings provide insights that can help land managers and foresters better target land management and restoration in the future,” said Khan. “We're hopeful that these results will lead to strategies that minimize the long-term impacts and legacies of intense land-use disturbances.”
The full study, titled “Disentangling effects of forest harvest on long-term hydrologic and sediment dynamics, western Cascades, Oregon" is available online in the Journal of Hydrology at https://www.sciencedirect.com/science/article/pii/S0022169419309941?via%3Dihub.
Expanding its expertise in water, soil, pest management, forestry and small farms, five new academics and a county director have joined the ranks of UC Cooperative Extension.
Forest stewardship education academic coordinator
UC Cooperative Extension Central Sierra - Amador, Calaveras, Tuolumne and El Dorado counties
In November 2019, Kim Ingram was named the academic coordinator for forest stewardship education in UC Cooperative Extension's Central Sierra office, which includes Amador, Calaveras, Tuolumne and El Dorado counties.
Previously, Ingram was an academic human resources business partner in UC ANR's Human Resources, leading academic recruitments, analyzing data and managing the academic merit and promotion process. Ingram also served as a community education specialist for the UC Sierra Nevada Adaptive Management Project and Sierra Nevada Watershed Ecosystem Enhancement Project. In that role, she planned, managed and implemented collaborations between UC, agencies, local communities and stakeholders, developed training curriculum and facilitated meetings, workshops and events related to forestry and fire issues in the Sierra Nevada. She is an instructor of record for the UC California Naturalist Program and published a “Natural History of the Sierra Nevada” for use in California Naturalist Program trainings.
Ingram earned a master's degree in education, adult education and training from Colorado State University. She also holds a bachelor's degree in political science with a minor in environmental ethics from Humboldt State University.
Ingram can be reached at firstname.lastname@example.org.
UC Cooperative Extension water and watershed sciences specialist
Based at UC Merced
Safeeq Khan joined UC ANR in October 2019 as a UC Cooperative Extension assistant water and watershed sciences specialist. His research focuses on understanding the interaction between climate and ecosystems to inform land and water management. He uses data-driven numerical models as a research tool to aid in the understanding of watershed systems. As a CE specialist, Khan will develop and carry out collaborative, multifaceted research and extension related to mountain hydrology and their linkage with downstream water uses statewide, with special attention to the Sierra Nevada-Central Valley watersheds.
Prior to joining UC ANR, Khan was a professional researcher and adjunct professor in the department of Civil and Environmental Engineering at UC Merced for five years. Khan brings more than 10 years of research, education and extension experience. He has published more than 35 peer-reviewed journal papers and book chapters, successfully secured several externally funded projects, and presented his work to a diverse range of audiences through digital and print media, workshops and conferences.
Khan has worked very closely with state and federal agencies, local landowners and nonprofit organizations, both in California and elsewhere. He has led several projects related to watershed management, from investigating the impact of non-native tree species and groundwater overdraft on streamflow in Hawaii to mapping hydrological vulnerabilities to climate change in the Pacific Northwest. More recently, his research has been focused on evaluating climate change and watershed restoration impacts on water and forest health and developing stakeholder-driven adaptive decision support tools. He serves as an associate editor for the journal Hydrological Processes. Khan is also a co-director of UC Merced's first Innovations at the Nexus of Food, Energy and Water Systems (INFEWS) grant that addresses connected wildland-storage-cropland subsystems in California.
Khan earned a Ph.D. in natural resources and environmental management from University of Hawaii at Manoa. He also holds a master's degree in agricultural systems and management from Indian Institute of Technology in Kharagpur, India, and a bachelor's degree in agricultural engineering from CSA University of Agriculture and Technology Kanpur, India. In addition to English, he is fluent in Hindi and Urdu.
Khan is based at UC Merced and can be reached at (209) 386-3623 and email@example.com. Follow him on Twitter @safeeqkhan.
Area integrated pest management advisor
UC Cooperative Extension in Sonoma, Napa, Mendocino and Lake counties
Cindy Kron joined UC Cooperative Extension as area-wide IPM advisor for Sonoma, Napa, Mendocino and Lake counties in September 2019.
Before joining UCCE, Kron studied the three-cornered alfalfa hopper as a research entomologist for USDA in their Crop Disease, Pests and Genetics research unit. She tested cover crop species as feeding and reproductive hosts of the three-cornered alfalfa hopper in addition to testing commercially available biocontrol agents against the different life stages of the treehopper. She collaborated with a UC Davis colleague to create a degree day model that predicts the ideal timing to implement cultural control measures with the greatest impact on treehopper populations.
Kron has conducted research on a variety of insects including a two-year vineyard study on the population dynamics of Virginia creeper leafhopper, western grape leafhopper and variegated leafhopper. For her dissertation, she investigated the biology and behavior of the three-cornered alfalfa hopper and their relationship with vineyards. She also studied the effects of temperature on the developmental rate of the invasive European grapevine moth and reared brown marmorated stink bugs for USDA fumigation studies.
“My experiences have motivated me to help growers, stakeholders and the industry solve agricultural pest management problems through applied research by identifying IPM strategies and tactics that are economically feasible and implementable while having the lowest environmental impact,” Kron said.
Kron earned her bachelor's degree in viticulture and enology, with a minor in agricultural pest management, and her doctorate in entomology at UC Davis.
She is based in Santa Rosa and can be reached at firstname.lastname@example.org.
UC Cooperative Extension specialist in soil-plant-water relations
Based at UC Davis
Mallika Nocco joined UC ANR in September 2019 as a UC Cooperative Extension specialist in soil-plant-water relations, based at UC Davis. She earned her bachelor's degree in cultural studies/comparative literature and philosophy from the University of Minnesota-Twin Cities. After five years in the corporate world, Nocco decided to pursue her interest in soil, plants, and the conundrum of sustainable agriculture. She completed a master's degree in soil science and a Ph.D. at the University of Wisconsin-Madison in the Nelson Institute's Environment and Resources Program.
Nocco is based at UC Davis and can be reached at email@example.com. Follow her on Twitter @mallika_nocco.
Director of UC Cooperative Extension in Fresno, Madera, Kings and Tulare counties
Karmjot Randhawa joined UC ANR in September 2019 as the UC Cooperative Extension director for Fresno, Madera, Kings and Tulare counties.
In this newly created position, Randhawa is responsible for the coordination and overall operations of Cooperative Extension programs these Central Valley counties. Unlike traditional county director positions, Randhawa doesn't have academic research responsibilities, so she can focus on overseeing the educational and applied research programs and providing direction and leadership to the academic and support staff within the county extension programs.
Prior to joining ANR, the Central Valley native was the research translation operations manager at George Mason University's Center for Climate Change Communication.
“I look forward to increasing the visibility of UCCE by communicating the positive impacts realized by the people who live in the San Joaquin Valley and benefit from the research activities and contributions of these units,” Randhawa said.
Randhawa received her bachelor's and master's degrees in research psychology at California State University, Fresno, and received her MBA from Johns Hopkins University. She is currently completing the Climate Change and Health Certification Program at Yale University.
Randhawa is based in Fresno and can be reached at (559) 241-7514 and firstname.lastname@example.org.
UC Cooperative Extension assistant specialist for small farms in Santa Clara County
Qi Zhou joined UC ANR in September 2019 as a UCCE assistant specialist for small farms in Santa Clara County. She will work closely with project directors at UCCE Santa Clara to lead research and extension work related to food safety practices on small farms, beginning farmer education and Asian vegetable production.
Prior to joining UC ANR, Zhou conducted research on peach fruit production at Clemson University. At Huazhong Agricultural University, Zhou designed and conducted an experiment that identified the differences between flood-tolerant and flood-susceptible poplar seedlings. Zhou has published several scientific manuscripts and abstracts and given extension presentations.
Zhou earned a Ph.D. in plant and environmental sciences with a minor in statistics from Clemson University, South Carolina, a master's degree in horticulture and forestry from Huazhong Agricultural University, China, and a bachelor's degree in horticulture from Hunan Agricultural University, China. In addition to English, Zhou is fluent in Mandarin.
Zhou is based in San Jose and can be reached at (408) 282-3109 and email@example.com.