A spectrally selective grow tube or tree shelter that improves the establishment of woody plant forms by reduction and/or elimination of certain biotic and abiotic stress factors. The grow tube may provide an enhanced micro climate that is humid and rich in CO2 and promotes photosynthesis by selectively propagating photosynthetically active radiation. In addition to providing a physical barrier to wind and herbivores, certain embodiments of the grow tube can also provide protection from chemical sprays while permitting ventilation of the grow tube. Various embodiments of the spectrally selective grow tube may comprise separate interior and exterior members for enhancement of the interior and exterior surface functions and that may be co-extruded. The interior member may be dyed or pigmented to selectively transmit wavelengths of the visible spectrum known to promote photosynthesis, such as red light and/or blue light. The exterior member may include a semi-reflective coating such as TiO2 or ZnS that reflects at least a portion of the visible light spectrum while enabling transmission of infrared wavelengths therethrough for radiative cooling.