Effectiveness of winter temperatures for satisfying chilling requirements for reproductive budburst of red alder (Alnus rubra)
- Published
- Accepted
- Subject Areas
- Climate Change Biology, Forestry
- Keywords
- Climate change, flowering, phenology
- Licence
- This is an open access article, free of all copyright, made available under the Creative Commons Public Domain Dedication. This work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
- Cite this article
- 2018. Effectiveness of winter temperatures for satisfying chilling requirements for reproductive budburst of red alder (Alnus rubra) PeerJ Preprints 6:e26489v1 https://doi.org/10.7287/peerj.preprints.26489v1
Abstract
Background. Experiencing an adequate amount of cold temperatures over winter is necessary for many temperate tree species to break dormancy and flower in spring. Thus, changes in winter and spring temperatures associated with climate change may influence when trees break dormancy and flower in the future. There have been several experimental studies that have quantified the effectiveness of cold temperatures for chilling requirements for vegetative budburst of temperate trees, however, there are few experimental studies addressing the chilling requirements for reproductive budburst of trees, as it is difficult to place reproductively mature trees in temperature-controlled environments.
Methods. To identify how changing temperatures associated with climate change may impact reproductive phenology, we completed a temperature-controlled growth chamber experiment using cuttings of reproductive branches of red alder (Alnus rubra), one of the most widespread hardwood tree species of the Pacific Northwest, USA. The purpose of this study was to examine how colder (4 °C) and warmer (9 °C) winter temperature regimes influenced the timing of reproductive budburst of red alder cuttings in spring.
Results. We found that cuttings flowered earlier after pretreatment with a 4 °C winter temperature regime than after a 9 °C winter temperature regime. We used our experimental data to estimate a “possibility-line” showing the accumulated chilling and forcing temperatures necessary prior to reproductive budburst of red alder.
Discussion. This study provides a preliminary indication that warmer winters with climate change may not be as effective for satisfying chilling temperature requirements of Northwest hardwood tree species.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Chilling and forcing functions from Prevéy et al (2018)
These functions were used to calculate the chilling and forcing units accumulated from 11/2/2017 through reproductive budburst for red alder cuttings, and trees at Webster Nursery..
Code used for analyses in manuscript. All code was run in the statistical program R (R Core Development Team 2017)
Raw data of dates of reproductive budburst for cuttings in all experimental treatments and trees at Webster Nursery
Raw data for hourly temperatures for all experimental treatments and Webster Nursery
Temperature data were collected with Hobo pendant temperature dataloggers (Onset Corporation, Contoocook, NH). One datalogger was placed alongside cuttings in each treatment, under a conical shade structure, and one datalogger was hung in a red alder tree under a conical shade structure at Webster nursery.