The brittle mechanical material behavior of fiber composites, such as e.g. wood, under tension is often numerically simulated by Continuum Damage Models relying upon different orthotropic stress-based damage initiation criteria. The main drawback associated with elastic-damaging finite element models derives from the inherent mesh dependency and the spurious loss of energy for decreasing mesh size. To overcome mesh dependency, an implicit gradient-enhanced, strain-driven, damage model for isotropic quasi-brittle materials was previously proposed in [1], where the material model was enhanced by introducing higher-order deformation gradients in the damage evolution function. This provides a localization limiter within a non-vanishing region whose width depends on the characteristic length associated with the laplacian term. Since most failure criteria for fiber composites are based on stress, the equivalent strain concept for damage initiation is replaced in this contribution by stress-based damage initiation criteria to be able to consistently simulate orthotropic materials and fiber composites. Employing a transient gradient damage function [2], micro-cracks are localized in a damage band whose ever-decreasing width captures the expected evolution of the fracture process zone into a macro-crack. The method was implemented in a FORTRANroutine (UMAT) in Abaqus using the heat analogy for solving the differential equation of the non-local field. A systematic validation is carried out by comparing numerical results to experimental tests on globally oriented fiber composites with different fiber directions. In conclusion, the model targets the application of the developed method on orthotropic fiber composites such as wood.