until the 1930s and 1940s
...that until the 1930s and 1940s people in the United States and Canada obtained their Christmas trees mostly from native forests?
...that <b id="mwCnk"><a class="mw-redirect" href="./History_of_Christmas_tree_cultivation" id="mwCno" rel="mw:WikiLink" title="History of Christmas tree cultivation">until the 1930s and 1940s</a></b> people in the <a href="./United_States" id="mwCns" rel="mw:WikiLink" title="United States">United States</a> and <a href="./Canada" id="mwCnw" rel="mw:WikiLink" title="Canada">Canada</a> obtained their <a href="./Christmas_tree" id="mwCn0" rel="mw:WikiLink" title="Christmas tree">Christmas trees</a> mostly from native <a href="./Forest" id="mwCn4" rel="mw:WikiLink" title="Forest">forests</a>?