This ReadMe file describes data files used in the Tree Genetics and Genomes publication: "Recombinant DNA modification of gibberellin metabolism alters growth rate and biomass allocation in Populus". The authors are Haiwei Lu, Venkatesh Viswanath, Cathleen Ma, Elizabeth Etherington, Palitha Dharmawardhana, Olga Shevchenko, David W. Pearce, Stewart B. Rood, Victor Busov and Steven H. Strauss. The paper was accepted on October 28th 2015. For any further queries, please contact Haiwei.lu@oregonstate.edu or steve.strauss@oregonstate.edu The following files are included: 1) "Lu_poplar GA_1 Promoter_GUS assay.xlsx" This file includes nine spreadsheets. The first spreadsheet is GUS assay raw data from trees that were transformed with pGA20:GUS, pGA2:GUS, pEXP:GUS, and pCES:GUS. Other spreadsheets show the calculations we done with the raw data. 2) "Lu_poplar GA_2 GH_volume index.xlsx" This file includes 12 spreadsheets. The first ten spreadsheets include height and diameter data from trees that were tested in six greenhouse trials. The last two spreadsheets summarize means and SEs we calculated for each construct and each trial. 3) "Lu_poplar GA_3 GH_biomass.xlsx" This file includes nine spreadsheets. The first seven spreadsheets include biomass data from trees that were tested in greenhouse four greenhouse trials (GH2, GH3, GH4 and GH5). The last two spreadsheets summarize means and SEs we calculated for each construct and each trial. 4) "Lu_poplar GA_4 GH_sequential harvest.xlsx" This file includes four spreadsheets which recorded height, diameter and biomass data from pRGL:GA20s, pGA2:GA20s, pBARTs and wildtype controls measured from May to June 2010 for the 6th greenhouse trial (started in August 2009). 5) "Lu_poplar GA_5 GH_GA concentration.xlsx" This file includes nine spreadsheets. The first one shows GA concentrations measured in pPHORs, pGA20s, and wild type controls. Other spreadsheets show the calculations we done with the raw data. 6) "Lu_poplar GA_6 Field_volume index.xlsx" This file includes 11 spreadsheets. The first ten spreadsheets include height and/or diameter data from trees that were tested in four field trials. Please note that data measured on controls is separated from that measured on rDNA modified trees apart from “2ATS” and “2HVS”, where we had small numbers of controls. The last spreadsheet summarizes means and SEs we calculated for each construct and each trial.