This graph shows two measures of lumber prices: 1) Framing Lumber from Random Lengths through May 31, 2019 (via NAHB), and 2) CME framing futures.
Right now Random Lengths prices are down 35% from a year ago, and CME futures are down 33% year-over-year.
There is a seasonal pattern for lumber prices, and usually prices will increase in the Spring, and peak around May, and then bottom around October or November - although there is quite a bit of seasonal variability.
The trade war is a factor with reports that lumber exports to China have declined by 40% since last September.