Determining the timing of willow shrub dieback using epicormic shoots
Kaczynski KM and Cooper DJ. 2014. Determining the timing of willow shrub dieback using epicormic shoots. Wetlands Ecology and Management
Riparian willows are declining throughout the Rocky Mountains, USA. Dendrochronological methods can be used to age dieback and disturbance dates in trees, however, these methods are not suitable for multi-stemmed shrub species. We present a new method for aging willow dieback using epicormic shoots and compare our findings with an aerial photo analysis of our riparian valley study site in Rocky Mountain National Park. Epicormic shoots initiate when stem wounding affects the apical meristem. We determined the date of stem death by comparing the age of the dead stem above a wound with the age of the live stem below a wound. Epicormic shoots initiated below wounds an average of 2 years prior to stem death, suggesting that it takes stems 2 years to die after being wounded. Aerial photo analysis demonstrated a sharp decline in willow canopy cover across the valley and we show a coinciding increase in epicormic shoots during the period of willow canopy decline. This was followed by a decrease in the number of epicormic shoots formed per year as the number of tall stems able to produce epicormic shoots has decreased. Age analysis of epicormic shoots is a promising new method for examining local scale willow dieback and decline.
- Type
- Journal Article
- Authors
- Kaczynski, Kristen; Cooper, David
- Units
- ROMN , ROMO
- Keywords
- Epicormic shoot, Salix spp., Stem aging, stem growth, Willow