Prices for Canada’s commodity exports posted a solid gain for a second consecutive month says TD Economics.

The TD Commodity Price Index, expressed in U.S. dollars, reached a four-month high in June, rising by 3.6% during the month after a 3.5% increase in May.

Despite the healthy advance in the headline index, the overall gain masked a very mixed performance by the 18 individual components. Nine commodities posted higher prices, while six experienced lower prices, with the remaining three unchanged.

“Prices for lumber and crude oil showed the most notable increases last month, while cattle and silver recorded the most marked declines,” said Craig Alexander, associate vice president and senior economist at TD Bank Financial Group.

“Generally speaking, the higher commodity prices reflected tighter supplies, rather than a significant improvement in demand,” he added.

The TDCI expressed in Canadian dollars also rose last month, but the continued appreciation of the domestic currency limited the gain to a more modest 1.2%. This was the first increase in commodity prices in Canadian dollar terms since February.