DOI: 10.5061/dryad.qjq2bvqh7
title: Response of northern populations of black spruce and jack pine to southward seed transfers: Implications for climate change

description: A variety of responses to climate change have been reported for northern
 tree populations, primarily from tree-ring and satellite-based studies.
 Here we employ provenance data to examine growth and survival responses of
 northern populations (defined here as those occurring north of 52oN) of
 black spruce (Picea mariana) and Jack pine (Pinus banksiana) to southward
 seed transfers – a space for time substitution that affords insights into
 potential climate change responses by these important northern tree
 species. Based on previous work, we anticipated relatively flat response
 curves that peak at much warmer temperatures than those found at seed
 source origin. These expectations were generally met for growth-related
 responses, with peak growth associated with seed transfers to environments
 2.2oC and 3.6oC warmer than seed source origin for black spruce and jack
 pine, respectively. These findings imply that northern tree populations
 harbor a significant amount of resilience to climate warming. However,
 survival responses told a different story, with both species exhibiting
 reduced survival rates when moved to warmer and drier
 environments.  Together with the growth-based results, these
 findings suggest that the warmer and drier conditions expected across much
 of northern Canada under climate change may reduce survival, but surviving
 trees may grow at a faster rate up until a certain magnitude of climate
 warming has been reached. We note that all relationships had high levels
 of unexplained variation, underlining the many factors that may influence
 provenance study outcomes and the challenges in predicting tree responses
 to climate change. Despite certain limitations, we feel that the
 provenance data employed here provide valuable insights into potential
 climate change outcomes for northern tree populations.
description: Black spruce provenance data were obtained from measurements on a
 portion of the Canadian Forest Service’s (CFS) long-term black spruce
 provenance trial, which originally incorporated 202 seed sources across 34
 test sites in Canada and the United States.  Measurements of height and
 diameter of all surviving trees at each test site were made in 2003, at 33
 years of age from seed. These data were obtained through a collaborative
 research agreement with William H. Parker at Lakehead University, Thunder
 Bay, Ontario. In total, 192 seed sources at 18 test sites in Canada and
 one test site in Minnesota were included in the measurement.
 Jack pine provenance data were obtained from measurements on a
 portion of the CFS 255 series rangewide provenance trial, which consisted
 of 99 seed sources planted in various combinations at test sites across
 eastern Canada, the United States, and Europe. During the summer of 2005,
 at 39 years of age from seed, all 16 remaining viable test sites in Canada
 and the United States were remeasured. We obtained these data through a
 collaborative research agreement with William H. Parker at Lakehead
 University, Thunder Bay, Ontario.
description: This dataset contains measurements of the average height and
 survival of black spruce and jack pine provenances (or seed sources)
 planted at a variety of test sites in eastern North America. Also included
 are estimates of climate at the test site and at provenance origin.
  Following is a brief explanation of the variables found in the
 dataset:<br><br>Species - Name of the tree species associated
 with the data<br>Test_Name - Test site identifier<br>Test_Long
 - Longitude of the provenance (decimal degrees)<br>Test_Lat -
 Latitude of the provenance (decimal degrees)<br>Test_Elev -
 Elevation of the provenance (m)<br>Prov_Name - Provenance or seed
 source identifier<br>Prov_Long - Longitude of the provenance
 (decimal degrees)<br>Prov_Lat - Latitude of the provenance  (decimal
 degrees)<br>Prov_Elev - Elevation of the provenance
 (m)<br>Height - Average height of provenance at test
 site(m)<br>Survival - Average survival of provenance at test site
 (%)<br>AMEANT_T - Average annual mean temperature at test site for
 period spanning year of plantation establishment through year of height
 measurement(C)<br>ANNP_T - Average annual precipitation at test site
 for period spanning year of plantation establishment through year of
 height measurement(mm)<br>CMIANN_T - Average annual climate moisture
 index at test site for period spanningyear of plantation establishment
 through year of height measurement (cm)<br>GSLENGTH_T - Average
 growing season length at test site for period spanning year of plantation
 establishment through year of height measurement (days)<br>AMEANT_P
 - Mean annual temperature at provenance over the 1961-1990 period
 (C) <br>ANNP_P- Average annualprecipitation at provenance location
 for 1961-1990 period (mm)<br>CMIANN_P- Average annual climate
 moisture index at provenance location for 1961-1990 period
 (cm)<br>GSLENGTH_P- Average growing season length at provenance
 location for 1961-1990 period (days)
 Notes:<br>Details on the climate moisture index can be
 obtained from Hogg et al. (1997).<br>Details on all other  climate
 variables can be obtained from McKenney et al. (2011).<br>Details on
 the provenance remeasurement can be obtained from Thomson et al. (2009)
 and Thomson and Parker (2008).
 Acknowledgements:<br>The data provided here was collected
 and compiled by Dr. William H. Parker and students at Lakehead University.
 He kindly shared the data with us and agreed to having it published
 online. References:<br>Hogg, E. H. Temporal
 scaling of moisture and the forest-grassland boundary in western Canada.
 Agricultural and Forest Meteorology, 84, 115-122
 (1997).<br>McKenney, D.W., et al. Customized spatial climate models
 for North America. Bulletin of the American Meteorological Society, 92,
 1611-1622 (2011).<br>Thomson, A.M., Riddell, C.L., & Parker,
 W.H. Boreal forest provenance tests used to predict optimal growth and
 response to climate change: 2. Black spruce. Canadian Journal of Forest
 Research, 39, 143-153 (2009).<br>Thomson, A. M., & Parker,
 W. H. (2008). Boreal forest provenance tests used to predict optimal
 growth and response to climate change. 1. Jack pine. Canadian Journal of
 Forest Research, 38(1), 157-170.