Provided herein are compositions and methods for producing transgenic plants. In specific embodiments, transgenic plants comprise a construct comprising a polynucleotide encoding microRNA167 (miR167), or precursor thereof, operably linked to a plant pericycle-specific promote, wherein the miR167 is ectopically overexpressed in the transgenic plants, and wherein the promoter is optionally a constitutive or inducible promoter. In some embodiments, the transgenic plant has an improved agronomic or nutritional characteristic when cultivated in nitrogen-rich conditions as compared to a wild type plant cultivated in the same conditions. Also provided herein are commercial products (e.g., pulp, paper, paper products, or lumber) derived from the transgenic plants (e.g., transgenic trees) produced using the methods provided herein.