While growers are often encouraged to protect newly planted hazelnut trees with trunk guards, best management practices for guards have not been established for new plantings.  There are a myriad of options that growers can choose from that claim to protect trees and/or enhance growth, but data supporting such claims is lacking, and there are a number of complications that may arise such as burning from a greenhouse effect inside the guard, or exacerbation of diseases.  Trunk guard removal timing is also important because trunks may still be sensitive to sunburn and herbicides.   We tested five types of trunk guards (translucent blue, clear, peach, corrugated white trunk wraps with black interiors and cardboard), against trees with painted white trunks or those that were not painted.  Blue, peach and clear guards reached the highest temperatures during the summer, and more watersprouts were noted on trees that did not have guards, or those that had opaque guards.  Bare trees tended to have sun damaged trunks and cambium.  Black and white corrugated guards produced the best tree growth after the first season, and performed better by several metrics including reduced watersprout development and trunk damage.  This project is being funded by the Oregon Hazelnut Commission.