Lee E Henry, Beedlow Peter A, Waschmann Ronald S, Tingey David T, Cline Steven, Bollman Michael, Wickham Charlotte, Carlile Cailie
U.S. Environmental Protection Agency Corvallis OR USA.
Department of Statistics Oregon State University Corvallis OR USA.
Ecol Evol. 2017 Nov 18;7(24):11167-11196. doi: 10.1002/ece3.3573. eCollection 2017 Dec.
The fungal pathogen, , causing Swiss needle cast (SNC) occurs wherever Douglas-fir is found but disease damage is believed to be limited in the U.S. Pacific Northwest (PNW) to the Coast Range of Oregon and Washington (Hansen et al., , 2000, , 773; Rosso & Hansen, , 2003, , 790; Shaw, et al., , 2011, , 109). However, knowledge remains limited on the history and spatial distribution of SNC impacts in the PNW. We reconstructed the history of SNC impacts on mature Douglas-fir trees based on tree-ring width chronologies from western Oregon. Our findings show that SNC impacts on growth occur wherever Douglas-fir is found and is not limited to the coastal fog zone. The spatiotemporal patterns of growth impact from SNC disease were synchronous across the region, displayed periodicities of 12-40 years, and strongly correlated with winter and summer temperatures and summer precipitation. The primary climatic factor limiting pathogen dynamics varied spatially by location, topography, and elevation. SNC impacts were least severe in the first half of the 20th century when climatic conditions during the warm phase of the Pacific Decadal Oscillation (1924-1945) were less conducive to pathogen development. At low- to mid-elevations, SNC impacts were most severe in 1984-1986 following several decades of warmer winters and cooler, wetter summers including a high summer precipitation anomaly in 1983. At high elevations on the west slope of the Cascade Range, SNC impacts peaked several years later and were the greatest in the 1990s, a period of warmer winter temperatures. Climate change is predicted to result in warmer winters and will likely continue to increase SNC severity at higher elevations, north along the coast from northern Oregon to British Columbia, and inland where low winter temperatures currently limit growth of the pathogen. Our findings indicate that SNC may become a significant forest health problem in areas of the PNW beyond the coastal fog zone.
引起瑞士针叶枯病（SNC）的真菌病原体，只要有花旗松生长的地方就会出现，但据信在美国太平洋西北地区（PNW），病害损害仅限于俄勒冈州和华盛顿州的海岸山脉（Hansen等人，2000年，773页；Rosso和Hansen，2003年，790页；Shaw等人，2011年，109页）。然而，关于SNC在PNW地区影响的历史和空间分布的知识仍然有限。我们根据俄勒冈州西部的树木年轮宽度年表重建了SNC对成熟花旗松树木影响的历史。我们的研究结果表明，SNC对生长的影响在有花旗松生长的任何地方都会发生，并不局限于沿海雾区。SNC病害对生长影响的时空模式在整个地区是同步的，显示出12 - 40年的周期性，并且与冬季和夏季温度以及夏季降水量密切相关。限制病原体动态的主要气候因素因地点、地形和海拔的不同而在空间上有所变化。在20世纪上半叶，当太平洋年代际振荡暖期（1924 - 1945年）的气候条件不利于病原体发展时，SNC的影响最不严重。在低至中海拔地区，经过几十年温暖的冬季和凉爽、湿润的夏季，包括1983年夏季高降水量异常之后，SNC的影响在1984 - 1986年最为严重。在喀斯喀特山脉西坡的高海拔地区，SNC的影响在几年后达到峰值，并且在20世纪90年代最为严重，这是一个冬季温度较高的时期。预计气候变化将导致冬季变暖，并可能继续增加SNC在高海拔地区、从俄勒冈州北部沿海向北到不列颠哥伦比亚省以及内陆地区（目前冬季低温限制了病原体生长）的严重程度。我们的研究结果表明，SNC可能会成为PNW地区沿海雾区以外地区的一个重大森林健康问题。
