Reference for Sanhedrin 225:10
אבירם ושגוב מאי עבוד (מאי קאמר) ה"ק באבירם בכורו היה לו ללמוד לאותו רשע בשגוב צעירו ממשמע שנאמר באבירם בכורו איני יודע ששגוב צעירו מה ת"ל שגוב צעירו מלמד שהיה מקבר והולך מאבירם עד שגוב
IT MAY NOT BE REBUILT, BUT MAY BE CONVERTED INTO GARDENS AND ORCHARDS. Our Rabbis taught: If it contained trees already cut down [before the city was condemned], they are forbidden; but if still growing [in the soil], they are permitted.<span class="x" onmousemove="('comment',' Thou shalt gather … and thou shalt burn excludes that which cannot immediately be gathered into the public square, but must first be cut down. ');"><sup>17</sup></span> But the trees of a different city, whether cut down or growing in the soil, are forbidden. What is alluded to by 'a different city'? — R. Hisda said: Jericho; for it is written, And the city shall be accursed […] to the Lord.<span class="x" onmousemove="('comment',' Josh. VI, 17; hence there everything was forbidden. ');"><sup>18</sup></span>