TREE 2018
| Undergraduate Students | High School Students |
| Abby Klahs Iowa State University |
Michael Cupicciotti Chicago High School for Agricultural Sciences, Sophomore |
| Jayla Pettway Alabama A&M University |
Daisy Hernandez North High School, Sophomore |
| Victoria Villanueva Iowa State University |
Eva Jordan Turner Ashby High School, Junior |
| Nathan Kutok Cary Grove High School, Sophomore |
|
| Shelby Truckenbrod Marian Central Catholic High School, Senior |
|
| Ethan Untch Cary Grove High School, Sophomore |
TREE 2017
| Undergraduate Students | High School Students |
| Andrea Fondren Iowa State University |
Colin Bradley-Connolly Central High School, Junior |
| Morgan Muell Iowa State University |
Ricardo Ortega Lincoln High School, Sophomore |
| Kaitlyn Murphy Iowa State University |
Sydnee Rogers Clinton Middle School |
| Sydney Pulliam Alcorn State University |
Lilliana Romero Chicago High School for Agricultural Sciences, Freshman |
| Lexxus Thomas Clinton High School, Freshman |
|
| Shelby Truckenbrod Marian Central Catholic High School, Junior |
|
| Jessie Ulmer Robert Lindblom Math and Science Academy, Sophomore |
|
| Zaria Voss Parkway South High School, Junior |
|
| Vanessa Weigel Forest Lake High School, Junior |
TREE 2016
| Undergraduate Students | High School Students |
| Nathan Cook Iowa State University |
Kaleb Banks Morrison High School, Sophomore |
| Andrea Fondren Iowa State University |
Nathan Kutok Cary Junior High School |
| Morgan Muell Iowa State University |
Isaiah Lieberenz Lisle Junior High School |
| Jasmin Murphy Morgan Park High School, Freshman |
|
| Faith Satern Xavier High School, Junior |
|
| Rocio Sotelo Patria Latorre Ramirez High School, Junior |
|
| Ansley Watkins Living Science Home Studies, Junior |
TREE 2015
| Undergraduate Students | High School Students |
| Nathan Cook Iowa State University |
Kaleb Banks Morrison High School, Freshman |
| James Quick North Carolina A&T University |
Andrea Fondren North High School, Senior |
| Kammie Voves Iowa State University |
Katelyn Hearn Chicago High School for Agricultural Sciences, Junior |
| Nathan Kutok Cary Middle School |
|
| Torrie Lanhart Camanche High School, Junior |
|
| Kaitlyn Murphy Lincoln High School, Senior |
|
| Kathy Polich Agoura High School, Junior |
TREE 2014
| Undergraduate Students | High School Students |
| Mitch Barazowski Iowa State University |
Estefany Argueta East High School, Sophomore |
| Brooke Bodensteiner Iowa State University |
Chione Brooks Marshalltown High School, Senior |
| Shekinah Cosby Langston University |
Kat Finch Hoover High School, Junior |
| Kammie Voves Iowa State University |
Andrea Fondren North High School, Junior |
| Julie Wiemerslage Iowa State University |
Shannon Miller Bishop O'Connell High School, Junior |
| Faith Satern Xavier High School, Freshman |
TREE 2012
| Undergraduate Students | High School Students |
| Mitch Barazowski Iowa State University |
Chione Brooks Marshalltown High School, Sophomore |
| Brooke Bodensteiner Iowa State University |
Ray Duran Kelly High School, Senior |
| Jackie Fuentes University of Illinois-Chicago |
Cecilia Hinsley CCA High School, Junior |
| Jessica Maciel Iowa State University |
Andrea Moore North High School, Freshman |
| Maribel Pinon Iowa State University |
Amra Softic Hoover High School, Sophomore |
| Malik Turner Newman International Academy, Freshman |
|
| Daniel Vazquez Kelly High School, Senior |
|
| Edmund Wu Kelly High School, Senior |
TREE 2011
| Undergraduate Students | High School Students |
| Brooke Bodensteiner Iowa State University |
Cecilia Hinsley CCA High School, Sophomore |
| Abigail Jergenson Iowa State University |
Salvador Jahen Kelly High School, Senior |
| Jessica Maciel Iowa State University |
Michelle Liu Detroit Country Day High School, Junior |
| Maribel Pinon Iowa State University |
Yasmine Morales Kelly High School, Sophomore |
| Jaymie Reneker Iowa State University |
Kevin Quinteros Roosevelt High School, Junior |
| Korina Rodarte Kelly High School, Sophomore |
|
| Alma Salas East High School, Senior |
TREE 2010
| Undergraduate Students | High School Students |
| Rafael Alverio-Newton Iowa State University |
Michelle Cruz Kelly High School, Senior |
| Sara Kinsey University of California-Berkeley |
Demonta Francis Hillcrest High School, Junior |
| Nick Kiriazis Eastern Illinois University |
Cecilia Hinsley CCA High School, Freshman |
| Jessica Maciel Des Moines Area Community College |
Mia Lyons Thornridge High School, Sophomore |
| Maribel Pinon Lincoln High School, Senior |
|
| Kevin Quinteros Roosevelt High School, Sophomore |
|
| Alma Salas East High School, Junior |
|
| David Zaragoza Kelly High School, Senior |
TREE 2009
| Undergraduate Students | High School Students |
| Rafael Alverio-Newton Iowa State University |
Nicole Bradley Math and Science Academy, Junior |
| Alyssa Hoffmeister Iowa State University |
Micah Hamilton Chicago Military Academy, Freshman |
| Blanka Lederer University of California-Berkeley |
Cecilia Hinsley CCA, Eighth Grade |
| Ricky Johnson Thornton High School, Sophomore |
|
| Jessica Maciel Lincoln High School, Senior |
|
| Maribel Pinon Lincoln High School, Junior |
|
| Alma Salas East High School, Sophomore |
TREE 2008
| Undergraduate Students | High School Students |
| Kyndra Lundquist Iowa State University |
Taira Adams Lincoln High School, Junior |
| Lori Neuman-Lee Iowa State University |
Nicole Bradley Math and Science Academy, Sophomore |
| Tyler Brown Morrison High School, Senior |
|
| Marlon Harris Thornton Fractional South, Freshman |
|
| Cecilia Hinsley CCA, Eighth Grade |
|
| Max Hoy Nevada High School, Junior |
|
| Jessica Maciel Lincoln High School, Junior |
TREE 2007
| Undergraduate Students | High School Students |
| Nadya Gonzalez Iowa State University |
Carolina Aguilar East High School, Junior |
| Lori Neuman-Lee Iowa State University |
Alyssa Hoffmeister Marshalltown High School, Senior |
| Sarah Spencer Washington University in St. Louis |
Max Hoy Nevada High School, Sophomore |
| Amanda Ingoli North High School, Sophomore |
|
| Tracy Lara Lincoln High School, Sophomore |
|
| Jessica Maciel Lincoln High School, Sophomore |
|
| Aaron Williams Roosevelt High School, Sophomore |