Weak local adaptation to climate in seedlings of a deciduous conifer suggests limited benefits and risks of assisted gene flow

Assisted migration provides a potential solution to mitigate the increasing risks of forest maladaptation under climate change. Western larch (Larix occidentalis Nutt.) is a deciduous conifer species undergoing assisted migration beyond its natural range in British Columbia into areas that have become suitable based on climatic niche modelling. We established a seedling common garden experiment in raised beds in a warm location outside the natural range for three growing seasons, with 52 natural populations from across the species range and 28 selectively-bred families from British Columbia. Intraspecific genetic variation in growth, phenology and cold hardiness was analyzed to test for signals of local adaptation and the effects of selective breeding to better understand the implications for assisted migration and breeding for future climates. We found weak differentiation among populations in all traits, with the proportion of additive genetic variance (QST) values ranging from 0.10 t..., , , # Weak local adaptation to climate in seedlings of a deciduous conifer suggests limited benefits and risks of assisted gene flow

[https://doi.org/10.5061/dryad.h9w0vt4sb](https://doi.org/10.5061/dryad.h9w0vt4sb)

## Description of the data and file structure

This dataset contains original phenotypic trait data for individual seedlings from a common garden experiment of western larch. The data includes height growth, bud flush and bud set dates, and cold injury values collected during the 2021 growing season. Please see the manuscript by Roskilly & Aitken 2024 for details on how trait data was collected. Geographic coordinates and source climates for natural populations can be found in Table S1. 

### Files and variables

#### File: Roskilly\_\_\_Aitken\_2024\_EVA\_trait\_data.zip

**Description:** 

* seedlot = identification number used for each seedlot representing a natural population or full-sib family
* id = identification number for each individual seedling
* block = each bl...