Randy Briggs gave two reasons for expanding his business by adding the Cowboy Tree Yard and Garden Center to the already established Cowboy Tree service. He said he needed something that was less taxing on his back, and he saw a need for such services and products right in the middle of Roseburg. The center is a new venture into yard and landscape services and products. It opened Nov. 23 at the corner of Stephens and Chestnut streets in Roseburg. There’s an area outside for the display of products, and the back half of the former Umpqua Resale building has …