METHODS

Provenance trials of genotypes and measurements

This study was carried out across Alberta's white spruce breeding regions, which represent company holdings that carry out commercial forestry (Figure 6). Each of these forestry companies is required to test their seed sources in provenance trials prior to using them in breeding or reforestation program. In provenance trials, seeds are collected from various locations and planted together in one or multiple sites. The sources that perform best can be deemed best adapted to the climatic and site conditions of the planting sites. These best sources will then be preferred for reforestation in locations that have a similar site and climatic conditions as the test environment (Government of Alberta, n. d).

Data were obtained from the oldest White spruce provenance trial series which includes nine breeding regions in Alberta planted between 1980 and 1984. Seeds were collected from 29 provenances across 10 regions in Alberta namely regions D, D1, E1, E2, G1, G2, H, Northern Montane (NM), Southern Montane, and Cypress Hills (CH). The collected seeds were planted in 9 multi-sites namely Hay River(rHsB), Zeidler Mill(rD1sC), Sexsmith (rG1sD), Swartz creek (rNMsE), Chinchaga (rG2sG), Calling Lake (rE1sH), Virginia Hills(rDsI), Hanging Stone(rE1sJ) and ATISC (rE2sP) located in regions H, D1, G1, NM (Northern montane (M, E2, D, E1 and E2 respectively. The sites were within latitude 53.4°N to longitude-111.4°W and latitude 59.1°N to -118.7°W (Table 1). The growth performance of the trees was monitored and recorded at the planting sites. The latest available heights for all the regions were assessed at age 32 except at age 15 in regions D and E2. Climate data of the study area was also obtained as a reference to the climatic characteristics of the regions.

Table 1: Summary of multi-sites including B, C, D, E, G, H, I, J, and P, year of establishment, site names, site notes which are areas closest to the sites, coordinates, Digital elevation Model derived at 250m, the seed zones ( the area within with plant materials can be transferred with the least risk of maladaptation in the new location. Natural subregion name (NSRNAME) and their corresponding white spruce breeding regions. These provenance trial sites are the oldest in Alberta initiated between 1980 and 1984.

Figure 6: White spruce breeding regions of Alberta showing provenances and planting sites . In regions that overlap (I, D and NM), the overlap boundaries are defined by the region outline of the same color. Test sites located within each region are presented as red triangles. The blue points are provenances from which the white spruce seeds were sourced. The digital elevation model shows the topographic features of the terrain such as elevation, slope and aspect.

Reference

Government of Alberta (non-dated), Retrieved 04/06/2022 from https://www.alberta.ca/tree-improvement-and-adaptation.aspx

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