Use of provenance tests to predict response to climate change: loblolly pine and Norway spruce.

Provenance tests are often used to determine genetic responses of seed sources to transfer to different climates. This study was undertaken to determine whether provenance tests can be used to predict tree response to rapid climate changes in situ. Data from provenance tests of loblolly pines (Pinus taeda L.), Norway spruce (Picea abies L. Karst) and other southern pines (subsect. AUSTRALES Loud.) were interpreted using regression models to relate growth to temperature variables. Results of different plantings were combined by expressing growth as a percent deviation from the "local" source, and expressing temperature at the source as a deviation from that of the planting site. The results of the loblolly pine and Norway spruce models predicted a loss of about 5 to 10% in height growth below that expected for a genetically adapted seed source, if the average yearly temperature increases by 4 degrees C.