The front fields of a property in South Langley, BC have established western red cedars with the tops of the western red cedars turning brown during the summer months. The browning became more pronounced and started to slowly move down the trees as time passed. Recently, I noticed the trees are now dead at the top, without any needles and brown throughout.
The browning and subsequent death of the tops of Western Red Cedars (Thuja plicata) in South Langley, BC, as observed by Connie Olsen, could be indicative of a phenomenon known as "top dieback." This condition can be caused by a variety of factors, including drought stress, root diseases, and insect pests. The Western Red Cedar is particularly susceptible to drought stress, and given the changing climate patterns and the increase in the frequency and severity of droughts in British Columbia, this could be a contributing factor (Wang, T., Hamann, A., Spittlehouse, D. L., & Murdock, T. Q. (2012). ClimateWNA—High-Resolution Spatial Climate Data for Western North America. Journal of Applied Meteorology and Climatology, 51(1), 16–29. https://doi.org/10.1175/JAMC-D-11-043.1).
Additionally, the presence of pests such as the balsam woolly adelgid (Adelges piceae) or root diseases like Phytophthora could also be responsible for the observed symptoms. It is important to conduct a thorough examination of the affected trees, including soil analysis and inspection for signs of pests or disease, to determine the exact cause of the dieback. Management strategies will vary depending on the identified cause but may include improving soil moisture through mulching or irrigation, pest management, or the removal of severely affected trees to prevent the spread of disease or pests to healthy trees.
Further investigation by a local arborist or a forest pathologist would be beneficial to diagnose the issue accurately and recommend appropriate remedial actions. The health of Western Red Cedars is crucial, as they are a significant component of the Pacific Northwest's forest ecology, providing habitat for wildlife and playing a role in the cultural practices of indigenous peoples (Daniels, L. D., Maertens, T. B., Stan, A. B., McCloskey, S. P. J., Cochrane, J. D., & Gray, R. W. (2007). Western Redcedar Dieback in the Southern Range of British Columbia. Western Journal of Applied Forestry, 22(4), 222–227. https://doi.org/10.1093/wjaf/22.4.222).