Tree mortality following drought in the central and southern Sierra Nevada, California, US
Tree mortality following drought in the central and southern Sierra Nevada, California, US
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DOI：
10.1016/j.foreco.2018.09.006
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发表时间：
2019-01-15
影响因子：
3.7
通讯作者：
Foulk, Patra B.
中科院分区：
文献类型：
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作者：
Fettig, Christopher J.;Mortenson, Leif A.;Foulk, Patra B.
美国加利福尼亚州的大部分地区在2012-2015年间经历了一场严重的干旱，在内华达山脉中部和南部引发了一场大规模的树木死亡事件。我们基于在Eldorado、Stanislaus、Sierra和Sequoia国家森林的三个海拔带(Eldorado、Stanislaus、Sierra和Sequoia National森林上的914-1219、1219-1524和1524-1829米；在红杉上的1219-1524、1524-1829和1829-2134米)上安装的11.3米固定半径样地网络，评估了树木死亡率和对森林结构和组成的短期影响，这些地区的树木死亡最严重。2014年至2017年间，约有48.9%的树木死亡。树木死亡率从Eldorado国家森林的46.1+/-3.3%到塞拉利昂国家森林的58.7+/-3.7%不等。低海拔带的树木死亡率(60.4+/-3.0%)显著高于高海拔带(46.1+/-2.9%)。黄皮松、黄皮松、黄皮松。除法律外，林木死亡率最高(89.6%)，39.4%的样地失去了所有的黄杨。黄皮松的死亡率在海拔最低处最高，集中在较大直径的树木上，主要归因于西部松毛虫的定殖。在直径最大的三个等级中，约89%的黄松被杀，这意味着这些森林的一个重要结构成分的丧失，对受保护的野生动物物种构成了影响。樟子松的死亡率位居第二(48.1%)。兰氏松毛虫的死亡率主要集中在中等径级，主要归因于山松甲虫的定殖。白冷杉，冷杉康色(高德。&Glend.)林德尔。Ex Hildebr.和香柏Calocedus decurrens(Torr.)弗洛林的死亡率分别为26.3%和23.2%。只有一只栎树死了。林木死亡率(林木死亡数)与林木密度、坡度呈正相关。干旱的发生与树木的大部分死亡之间存在一定的时滞。树木更新(苗木和树苗)主要由华山松和栎属植物组成，这代表着以黄杨为主导的森林的组成可能发生了长期转移。约有22.2%的样地含有被认为是入侵的植物物种，包括无芒雀麦、牛蓟、蓟属植物和黄星蓟属植物L。
Much of California, U.S. experienced a severe drought in 2012-2015 inciting a large tree mortality event in the central and southern Sierra Nevada. We assessed causal agents and rates of tree mortality, and short-term impacts to forest structure and composition based on a network of 11.3-m fixed-radius plots installed within three elevation bands on the Eldorado, Stanislaus, Sierra and Sequoia National Forests (914-1219, 1219-1524 and 1524-1829 m on the Eldorado, Stanislaus, Sierra; 1219-1524, 1524-1829, and 1829-2134 m on the Sequoia), where tree mortality was most severe. About 48.9% of trees died between 2014 and 2017. Tree mortality ranged from 46.1 +/- 3.3% on the Eldorado National Forest to 58.7 +/- 3.7% on the Sierra National Forest. Significantly higher levels of tree mortality occurred in the low elevation band (60.4 +/- 3.0%) compared to the high elevation band (46.1 +/- 2.9%). Ponderosa pine, Pinus ponderosa Dougl. ex Laws., exhibited the highest levels of tree mortality (89.6%), with 39.4% of plots losing all P. ponderosa. Mortality of P. ponderosa was highest at the lowest elevations, concentrated in larger-diameter trees, and attributed primarily to colonization by western pine beetle, Dendroctonus brevicomis LeConte. About 89% of P. ponderosa in the three largest diameter classes were killed, representing loss of an important structural component of these forests with implications to wildlife species of conservation concern. Sugar pine, P. lambertiana Dougl., exhibited the second highest levels of tree mortality (48.1%). Mortality of P. lambertiana was concentrated in the mid-diameter classes and attributed primarily to colonization by mountain pine beetle, D. ponderosae Hopkins. White fir, Abies concolor (Gord. & Glend.) Lindl. ex Hildebr., and incense cedar, Calocedrus decurrens (Torr.) Florin, exhibited 26.3% and 23.2% mortality, respectively. Only one Quercus died. Tree mortality (numbers of trees killed) was positively correlated with tree density and slope. A time lag was observed between the occurrence of drought and the majority of tree mortality. Tree regeneration (seedlings and saplings) was dominated by C. decurrens and Quercus spp., representing a potential long-term shift in composition from forests that were dominated by P. ponderosa. About 22.2% of plots contained plant species considered invasive, including cheatgrass, Bromus tectorum L., ripgut brome, Bromus diandrus Roth, bull thistle, Cirsium vulgare (Savi) Ten., and yellow star-thistle, Centaura solstitalis L The implications of these and other results to recovery and management of drought-impacted forests in the central and southern Sierra Nevada are discussed.