Data from: Long-term survival, growth, and reproduction responses of Engelmann spruce provenances to climate

Our data comes from an Engelmann spruce provenance study established in 1970 on the White River National Forest in the Moniger Creek area of the Eagle-Holy Cross Ranger District, Colorado, USA. A randomized, complete block design was used with 4 trees from each of 20 provenances planted in 12 replicated blocks, for a total of 960 trees planted in 1970. The 20 provenances span a large range of latitude, elevation and climate. Survival, height, diameter at breast height (DBH), and the presence or absence of cones (current year or older) on each tree were recorded. Survival was measured six times between 1974 and 2014, whereas height was measured from 1979 onward, DBH was measured from 1991 onward, and cone presence/absence was measured four times from 1985 – 2006. In the summer of 2016, we revisited the site and collected increment cores at a height of 30 cm from six to eight live trees from each provenance in eight randomly selected blocks. Some blocks sampled had no survivors from certain seed sources, resulting in the decreased number of cores for some provenances. Annual ring widths were measured on each tree core, and we calculated the correlation between ring growth and the climate at the plantation each year. We also looked at whether these correlations, and other measured tree traits, differed depending on the climate of the provenance that the tree came from.

We found that the best surviving provenances were climatically similar to the plantation with dry climates and short growing seasons, but this did not apply to overall growth. Seedlings from provenances with higher summer to spring precipitation ratios were faster to reproduce and were taller at outplanting, which was advantageous for all but the tallest seedlings. Annual growth rings of provenances responded similarly to climate, with most having both high resistance and resilience to drought. Growth was positively correlated with high temperatures year-round and wet summers. One provenance (Gila NF) was obviously maladapted to the site with outlying values for survival, growth and cone production amongst other provenances.

Here we provide all measured trait data as well as climate data for the plantation (extracted from PRISM) and the provenance locations (extracted from ClimateNA). We also include the code used to do the analyses for our accompanying paper published in Forest Ecology and Management titled, "Long-term survival, growth, and reproduction responses of Engelmann spruce provenances to climate."